Knowledge Boost:<br /> Ethanol Explained

Hi Speedhunters, I’m Andre Simon and since this is my first “Knowledge Boost” article I thought I’d introduce myself. For the last 13 years I’ve owned a performance tuning shop in New Zealand called STM (not to be confused with US-based STM Tuned). While I’ve tuned just about everything from a 1,200hp jet sprint boat to private planes, my passion is import drag racing and over the years STM built or tuned cars that have set five world records on the drag strip.

Andre Simon STM Docile Evo Bryn

My own Mitsubishi Lancer Evo III known as DOCILE held the outright Mitsubishi 4WD record for several years with an 8.23 @ 180mph and we also built and tuned an Evo IX known as DS9 that held the late-model Evo 4WD record until last year with an 8.34 @ 169mph. Over the time I owned STM I got frustrated with our industry due to the lack of knowledge and understanding held by a lot of engine tuners out there, and for the last couple of years I’ve been running High Performance Academy with my business partner. Our aim is to improve the level of knowledge, results and professionalism in the industry and we do this by providing online training courses for EFI tuning.


Speedhunters has invited me aboard as a technical writer, which means I’ll be putting together an informative, tech-focused story once a month that will hopefully fill in some knowledge gaps and create some interesting discussions as we go. So with the introduction out of the way, let’s talk about ethanol. You’ve heard of E85 right? A pump fuel that can offer huge power increases from your engine for a fraction of the cost of commercial race fuels? Before you pull up to the pump and fill up, read on to find out if this is the new wonder fuel for you…


What is E85?

Unless you’ve been hiding under a rock, you’ll probably know that E85 is a fuel containing 85 per cent ethanol and 15 per cent gasoline. E85 continues to increase in popularity on the merits of sustainability and reduced emissions when compared to pump gasoline. That’s great for the environment, but if you’re interested in performance the real value of E85 is that it provides race-fuel properties at bargain basement prices. It’s quite possible to see your engine power literally double in some cases when switching from pump gas to E85. Obviously there’s a bit more to consider than just the fuel, but stay with me and we’ll get to the good bits.


How does E85 make more power?

E85 isn’t magic, and there’s some basic science behind why you can expect more power. The real merit of the fuel is in two of its properties: its octane rating and its cooling ability. Octane rating is a measure of a fuel’s ability to withstand detonation or knock. Too much boost or too much ignition advance can lead to detonation on pump fuels and hence the fuel’s octane rating often limits the power we can make. Increase the octane rating though and we can often make more power. The octane rating of E85 is in the region of 105, but when combined with its cooling properties, the actual knock resistance of E85 is much higher than the octane rating would suggest.


E85 also has a very high ‘latent heat of evaporation’. If you failed chemistry, don’t stress. In plain English this means that when E85 is injected into the engine, it goes through a phase change from liquid to gas and during this process it absorbs a lot of heat from the intake charge. A colder intake charge is denser and improves power, but also has the effect of making the engine less prone to detonation.


Can you just fill up at an E85 pump?

Unless you have a Flex Fuel capable vehicle, the answer is no. Normal gasoline has a stoichiometric air fuel ratio of 14.7:1, while E85 is 9.8:1. ‘Stoichiometric’ is a chemical term that refers to the required ratio of fuel and air for complete combustion. Again, if you failed chemistry this means that on pump gas we need 14.7 parts air to mix with one part fuel. On E85 however, we now mix one part fuel to 9.8 parts air. So on E85 the air/fuel ratio needs to be significantly richer, which means it contains a larger volume of fuel. To achieve this we need to inject around 35 per cent more fuel to mix with the same volume of air when we switch from gasoline to E85. In short, your car needs to be tuned to run correctly on E85.


Our MoTeC M150 ECU pictured can monitor the ethanol content and then automatically account for the changing fuel properties including stoichiometric ratio and fuel density thanks to an ethanol content sensor.


What you need to upgrade to run E85

As we just saw, even just supporting the same amount of power you were making on pump gasoline will need around 35 per cent more. Considering most people will be changing to E85 to improve power the actual fuel demands can be much higher than this. This can be a problem if your fuel system isn’t built with E85 in mind. In particular, larger injectors and a larger fuel pump are usually a necessity. In high-power applications multiple pumps and dual sets of injectors may be required. It’s also worth mentioning that since you’re burning more E85, your fuel economy will take a hit.


E85 care and maintenance

E85 isn’t all plain sailing and does require some care. For a start E85 is very hygroscopic, which means that it will absorb moisture from the atmosphere. This moisture can cause corrosion of your fuel pump and injectors leading to some serious issues down the track. How quickly E85 will absorb moisture depends on the humidity, but if you aren’t using the car regularly it’s always best to drain the E85 and run some gasoline through the system.


Another concern is the changing ethanol content of pump E85. While it’s called E85, the actual fuel specification allows ethanol content to vary anywhere from 51 per cent to 85 per cent. Particularly in colder regions, the gasoline percentage is increased to help increase the fuel’s volatility which aids cold weather starting. While it’s great to have a car that starts when there’s snow on the ground, if your engine is tuned for 85 per cent ethanol and all of a sudden you have a tank with 51 per cent ethanol, your tune will be off the mark with potentially dangerous results.


What is Flex Fuel?

Flex Fuel is common on many newer vehicles and this system uses an ethanol content sensor to tell the ECU the percentage of ethanol in the fuel. With this system you can run a car on pump gasoline, E85 or any mixture of the two and the ECU takes care of the necessary changes. Flex Fuel functions are also available in many aftermarket ECUs and this can allow you to take advantage of the same technology for your own car. For those without regular access to E85 this gives the freedom to swap between fuels without visiting a tuner or breaking out the laptop each time. We mounted a Continental ethanol content sensor to the strut tower of our Toyota 86 and plumbed it into the fuel feed line using some AN adaptors. The ethanol content sensor can also accommodate tank-to-tank fluctuations in ethanol content and ensure safety for those running dedicated E85.


Tuning on E85

Just tipping E85 into the tank and retuning the ECU to deliver the correct volume of fuel isn’t going to really harness the power potential of E85. If you want to take advantage of the fuel you’re going to need to add some ignition advance, increase the boost pressure, or both.


We did some testing on our turbocharged Toyota 86 and optimising the tune in the MoTeC M150 ECU netted an increase in power from the 198kW (265hp) the car made on pump gas to 267kW (358hp) at the rear wheels. Even with the high 12.5:1 compression of the FA20 engine, E85 allowed us to increase the boost from 7.0psi to 9.5 psi with no detonation. The only thing stopping us going further was the stock internals and a little mechanical sympathy.


Is E85 just an advantage for boosted engines?

The advantages E85 offers play out perfectly for any engine that is very sensitive to knock or detonation on pump gas, which is why E85 lends itself so well to boosted engines. So how about if you’re naturally aspirated and you aren’t really being effected by knock on pump gas? Well the news is still good! Even without taking advantage of the knock suppressing characteristics of E85, we can still expect to pick up around 5 per cent power and torque from the switch to E85.


Precautions when tuning on E85

E85 sounds like the perfect fuel and for those who are power hungry it’s hard to argue with the notion. Some care is required though if you’re considering tuning your car for E85. Aside from the ethanol’s ability to absorb moisture, the variable nature of the ethanol content is a big concern if you are tuning for maximum power. As well as the ethanol content at the pump, variable ethanol content is a danger for those who regularly swap between pump fuel and E85. It’s almost impossible to completely drain a factory fuel tank, and this may leave as much as 5 or more litres of fuel in the tank when you swap from E85 to pump fuel. The result is a potentially dangerous variation in the ethanol content of your fuel. The best idea is to use an ethanol content sensor so your tune can adjust automatically. Failing that, an onboard ethanol content gauge and wideband air/fuel ratio meter are wise investments. This way you can monitor the quality of your fuel and prevent potential damage.


If you’re looking for more performance out of your car, tuning to suit E85 can provide impressive results for a modest investment. But it does demand some respect to ensure good performance and reliability. Hopefully I’ve been able to give you a better understanding of this fuel and its benefits, but if you have any further E85-related questions, or you’d like some advice on your fuel setup, feel free to comment below and I’ll do my best to answer any questions.

Andre Simon
Instagram: hpa101

E85 Photos by Ben Silcock
Additional Photos by Bryn Musselwhite



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Great article. I've always heard that using E85 with a stock car can lead to serious engine problems, I think that is when you use it often, but what if you use it ocasionally, let's say a few track days a year? Without any mod to the car, I mean.


EvolveWRC The only engine problems that comes from E85 are ones related to tuning and the properties of the fuel, E85 absorbs lots of moisture and can eat through certain kinds of rubber fuel lines clogging up injectors with black sludge.

Of course, If you do not tune your car for e85 and track it, you'll probably grenade your engine in addition to making much slower lap. As stated in the article, you need more fuel in the combustion camber than regular gas to make the same power. You'll get terrible idle, gaps in the acceleration and terrible performance overall at the very least.


One thing worth mentioning when tuning with E85 is to be careful with how much you advance timing. You will hit MBT before seeing knock with ethanol. So it's important to keep an eye on the power and torque curve to see when MBT has been reached otherwise excessive ignition advance will result in high EGT.


I have a wideband gauge and I've never really gotten the nitty and griddy of how to really understand it. I run 100 octane as well. I just know there's a good area and a bad area, so the question is What am I really reading on a wideband and what's some things I can look out for?
Very very good read. Love this


Hayden Evans The wideband gauge will tell you the current air fuel ratio your engine is running at. The problem is that there is no single value that is 'correct'. It will depend on whether your engine is naturally aspirated or turbocharged, what fuel you're running and even how the engine will be used.

The best idea is to chat to your tuner when the car is being tuned and ask what AFR they have tuned for under full power. This might be perhaps 11.5:1-11.8:1. Then you can keep an occasional eye on the gauge and make sure that when you're driving hard that the AFR is safe.


RMutt You're quite right. The aim of optimising the ignition timing is to reach MBT (Maximum Brake Torque) timing. In many instances on pump gas (particularly with factory turbocharged engines), you will reach the knock threshold before you reach MBT - This is one of the reasons E85 can offer more power.

On E85 we are usually relatively immune to knock (this isn't always the case so care is still required), and hence as you point out, it's possible to over advance the timing and actually make LESS power. This is why a load bearing dyno is the best place to optimise your tune.


How about a quick tutorial on how you are able to modify the Continental sensor to accept a #8 an lines -- I've been wanting to install one on my car and have never been able to get pass the funky small diameter tubing they are set up for

Thanks in advance, My 300HP ACVW thanks you also.....


I'm finishing up my first EFI engine install this week. Built a MegaSquirt ECU and went full standalone.  Talk about a learning curve!  I'm nervous about the first crank. Hopefully it will start and not require countless hours of troubleshooting.  After that...I'm counting on countless hours of tuning.  More learning! It's fun, but a long hard road for this old carburetor and distributor guy.


You said E85 colds the intake charge, does that means that you should move your air intake temperature sensor? Because the way I see it, taking the temperature of the intake air before the E85 seems pointless if the E85 is going to change it.


therealnecroscope  Just buy the best stuff and invest in someone that knows how to tune on a dyno and the learning curve will shorten up considerably (talking from experience)

Wife favorite line when I've hit a road block on my build -- "Don't you wish you still had a carb and MSD???" Damn Wives LOL


@Fiatdude The AN adaption is pretty easy. We used a Speedflow -6AN to 3/8" EFI fuel line adaptor. Part number 715-06-06. Similar adaptors are almost certainly going to be available from most hose and fitting suppliers.


therealnecroscope Sounds like a great project! There is a lot to learn compared to carbs and a dissy but the end result will be worth it. It's all the more satisfying when you've managed to do the whole job yourself and the skills you will pick up along the way are invaluable.


py4age Even injecting pump fuel will have a cooling effect on the intake charge but E85 does a much better job. It's not really possible to measure this effect with an air temperature sensor though so the sensor needs to be located in a conventional spot - Either the intake pipe pre throttle or the inlet manifold. 

Many ECUs include a 'charge cooling gain' parameter or similar which can be used to tell the ECU how much the fuel is cooling the intake charge. Other than this though the cooling effect will be accounted for in your tuning.


Ive got a question. Everyone around here runs e85 in their supras, wrx and evos, but Ive heard of many downsides such as no start in the cold (20°f), injectors failing, fuel lines leaking, cylinder walls rusting, and fuel pumps failing. I'm planning on tuning my AEM standalone for e85 with the help of a tuner, but from what Ive heard cranking injector pulse should be somewhere in the area of 500%-1000% of gas in cold weather, is that right? As far as fuel lines leaking I should be fine with new factory lines or something better(volume not being an issue)? Fuel pumps and injectors should be e85 friendly, or is it just a gimmick? And cylinder walls rusting could only be prevented by running gas through the system once in a while?



AlexLobanov You have some great questions and there is a lot of misinformation about E85. First of all yes, the cold start performance is worse than petrol and this is why in cold climates the ethanol content of pump E85 is reduced. At temperatures of 20 F (-7 C), cold starting can be a real problem for you if you are up around 80-85% ethanol. 

At a minimum you will need to dramatically increase your cranking enrichment. Post start and warm up enrichment generally need to be increased too but not nearly by as much. Here in NZ we don't regularly see temperatures as cold as you but I would start by doubling your cranking enrichment from what you are using on petrol. It's then a case of tuning from there to see how much more (if any) is necessary. 1000% however is more likely to result in massive over fuelling and you'll still have poor staring.

Most modern factory fuel systems are ethanol compatible but it always pays to check your factory handbook regarding compatibility. Split lines and leaking injector seals etc are more related to older cars that aren't ethanol compatible. Sourcing new lines and fittings that are ethanol compatible is easy but it's still worth confirming with your supplier.

The biggest problems with E85 and injectors/fuel pumps are due to the hydroscopic nature of the fuel. In humid climates it can attract significant moisture levels in as little as a week or two. It's the moisture that is most often responsible for damaging your fuel components. That being said, many fuel pumps now are available that are 'E85 rated' so I'd start with one of those.

Lastly if you're using your car regularly then E85 won't be a problem for you. It's a real issue for those using their cars perhaps once a month. In this situation you need to drain the E85 and run the car on pump fuel before letting it sit.


if the car is tuned solely on e85 or e98 and only used for racing so not often should I still drain the tank and run petrol through? Can I just fire it up once a fortnight and bring up to temp or are there additives to put in it?
Alternatively is there any type of heater that can be installed to keep it warm?


@Fiatdude Because the sensor only measures fuel composition and temperature, and not fuel flow, you can put the sensor in parallel with another fuel line.  Split the (large) fuel line with a T (or ideally a Y).  So some fuel can flow through the sensor to determine composition and temperature, and the rest of the fuel can flow through another line and then merge back together.  It's pretty easy because you can go from a HUGE single fuel line and split into two smaller lines, then merge back to a HUGE single line, or split and then use two ports into the next fuel device, or whatever works best for your setup.

The size of the sensor and bypass lines should ideally be the same so the velocity through the sensor and bypass line are pretty equal, making everything equal and easy for flow properties, and to limit the amount of adapters and line sizes you actually need.


@Jack Yes if you are using the car infrequently then I'd definitely recommend draining the fuel system and running petrol through it before storing the car. Simply starting the car and running it occasionally won't fix the issue of the fuel absorbing moisture. Likewise it's not really related to temperature - It's simply the moisture content of the fuel that can cause corrosion on your injectors and fuel pump internals.

Changing fuel is a little frustrating but it's no different than if you were running a methanol drag car for example. Just all part of the fun :)


Hi Andre
First up thanks very much for your informative article. Ive heard good things about you your company and your tuning schools.
I live in NZ also and am building up a A70 supra. Which is currently limited by the factory fuel system and ECU. These upgrades will come this year in the form of a Storm Link, But regarding the fuel system. I am interested to set the car up with the ability to run flex fuel E85 for track events and occasions but most likely most of the time just on normal pump fuel. What fuel pumps and sizes are required for E85? are your average 300lph intank AEM, DW pumps ect enough? and injector sizes?

Thanks very much


@Nick Thanks for the kind words Nick. The fuel system requirements are totally dependent on how much power you intend to make. A set of 1000 cc injectors on a 6 cylinder engine for example would be able to support somewhere in the region of 700-800 hp on E85. If you are aiming for significantly more than this then you would need to size accordingly.

As for the fuel pumps, it depends if you are going for an in-tank or external system. I've used the DW300 in tank on E85 with great results although this pump will likely top out around 650-700 hp on E85 depending on fuel pressure and boost. If you're going to aim for higher than this then you're probably best to consider an external pump and this opens up you to almost infinite possibilities


Good reminder of E85 being hygroscopic. Probably, why I don't see it being sold here in Seattle, too much moisture for nine months of the year.


so glad Andre be writing for speedhunters !!!!!! should be twice a month ...... great write up and information .... Great thing about information the mind can absorb it all !!!!! 

i am liking this section a lot .this is better than reading specs of someone engine n not knowing how it works ..

waiting to see your evo on speed hunters soon !! keep up the good work as always guys !!!


Fantastic Article Mr. Simon. I enjoyed reading it for sure, I actually sent this to a friend who had some mininformation (more or less a lack of understanding) and it cleared things right up. Thanks for the info! One Tidbit, I believe Ethanol's relative increase in cooling ability compared to gasoline is that it's specific heat is greater than gasoline!  


Question about how a compatible ECU handles the ethanol content you have to create a fuel map for pump gasoline, another map for E85 and the ECU interpolates values between the two maps based on the sensor reading, or is it just one map and the ECU applies a correction factor based on the sensor reading?


I run E85 with a Flexifuel Kit on both car and motorbike, which is very far from the tuning options you are mentioning, but just with this setup I've seen a 15% power increase. I live in Thailand so the cold start is not a problem, almost all gasoline has 10% Ethanol, plain Gasoline is not available at all stations. Good to know about the hygroscopic factor since we have a quite long rainy season, although I use both vehicles on a regular basis and alternate between petrol and E85 regularly. I have a friend who constantly uses E85 on a older EG6 Honda with a K20 engine (parameters adjusted through ECU) for more than 2 years and he hasn't had a single problem. On my motorbike which is modern (2011) components fully compatible for Ethanol based fuels also not a single problem in about a year now.


hey there, do we have to take any extra care when storing e85?


@Fabrik8  Thanks -- That thought had crossed my mind, but I haven't pursued it -- but with you seconding it I get after it -- I'm installing an AEM EMS4 right now and I'll make sure to allow for wiring it into the harness


@Sunj there isn't much to do with storing E85 that differs from any fuel. It is important that it is stored in a sealed container so that it can't absorb moisture from the atmosphere though.


Hydrolastic the humidity of some regions could be problematic for E85 users. Another consideration is how long the fuel has been stored in the tanks at the pump as this can effect it's moisture content and makes E85 suitable for very high humidity climates.


zemanski thanks for the kind words! I will do my best to keep producing helpful technical content :)

Not sure my old EVO will make it onto Speedhunters any time soon. It's well and truly retired although you never know what could happen in the future ;)


johnygezony thanks for the feedback - I'm glad that the article hit the mark! 

It's the latent heat of evaporation that defines how much energy a liquid will absorb to go through a phase change (liquid to gas). In the case of E85 this is approximately 850 KJ/kg vs about 550 KJ/kg for gasoline.


Slackinfux different ECUs deal with flex fuel in different ways. One technique is to have a second fuel table or a fuel trim table and this is 'blended' or added onto the primary petrol map based on ethanol content. Ignition timing and boost can be handled in the same way. Alternatively some ECUs actually track the change in the fuel's properties based on its ethanol content (stoichiometric AFR, density etc) and then can make the required changes in the background.

There isn't really one technique of dealing with flex fuel and the options will depend on the ECU being used.


Retro fitted my gc8 with e85 system. Running Zeitronix flex fuel sensor. My system has 3 fuel pumps (one uplift and 2 feed pumps from surge tank) all braided lines (Teflon) and through to black ops 1400cc injectors (did have 800cc injectors but they maxed out pretty quickly with ethanol). I have to say if you're going to run ethanol I don't get why people don't use the flexi system? it's so much easier to live with day to day and means you can easily mix any percentage of 98 to e85 you wish. I  made 300kwatw with 98 (22psi boost) and by just switching to e85 this increased to 330kwatw at 22psi boost on fully built ej207 motor. If you care about mpg I would not switch fuel economy decreases hugely.


How much does that costs you to install the Flexifuel kit? I live in a shitty country where E85 isn't available yet but i just wanted to know.


What are the concerns in regards to degradation within the fuel system regarding E85. A compatible fuel pump, lines, and injectors would understandably be required, but are there any concerns within the engine that the fuel could possibly 'eat' away at?


@jcs32089 the fuel system components are really the primary concern and as discussed, provided they are ethanol compatible this isn't a problem. It's worth remembering that E85 is not just used in the aftermarket, but brand new vehicles are produced that are E85 or flex fuel compatible, hence it's fair to say that long term effects of E85 are deemed acceptable by OEMs.


RussClarke I personally am a big fan of a flex fuel system but not just for the ability to run both E85 and petrol - The more important consideration I believe is the ability for a properly tuned flex fuel system to account for the day to day and tank to tank fluctuations of ethanol content. 

Failing to account for these inevitable fluctuations is one of the main reasons for engine reliability problems even on dedicated E85 vehicles.


Bima Leksono Here in Thailand it costs around 180 U$ for a 4 cylinder car and around 60 U$ for a single or twin motorcycle. The systems that auto detect and auto adjust according to fuel mixture are more expensive though.


Aside from larger injectors and a bigger fuel pump, where can I get a system that I can run any amount of ethanol? I would like to find an ECU and ethanol sensor to put in my car. I'm not looking for major performance gains, I just like ethanol and I know my car would love it.


This read made me happy


One thing that is not mention here, is that you see power gains from idle to redline. Mostly torque gain, wich helps overall driveability, for the majority of us whom comute or like to cruise.

I really enjoyed the read, i would love to see more often such articles.


romanrobbert you're right, the gains from E85 can be noticed throughout the rev range. I'm glad you enjoyed the article and I look forward to bringing the Speedhunters community many more.

The turbo on the Toyota 86 is a Borg Warner EFR 6758. Keep in mind that the Dynapack dyno is displaying torque at the hubs. This is the engine torque multiplied by the gear ratio and final drive which is why the figures may seem unrealistically high.


dragonfoot you're going to need a flex fuel compatible ECU and an ethanol content sensor like the one pictured in the article. There are a pretty wide range of ECUs that offer flex fuel compatibility - Haltech, AEM, Link, Vipec and MoTeC are just a few that come to mind. What you choose to run will depend on where you are in the world, what ECUs are available and what your tuner is familiar with.


Andre Simon RussClarke  this is one of the main reasons  I went flexi as the ethanol content as you state various considerably at the pump.


Thank you very much for this super helpful article! My inner science/chemistry nerd always wanted to know the applicational properties of ethanol and E85 fuel! Look forward to more technical articles!


Awesome write up. Any insight to the next couple topics coming up?

I cant even remember the last 98 fuel setup Ive installed. E85 is just the standard these days for street/strip cars. Rotaries love it!


well-written article, especially for those who hated chem in HS and as a college elective (guilty as charged hahaha) - just enough tech to not make us lose interest and making sure your terms are given easily-understood explanations.  looking forward to your next article!


So the torque value has to be divided by 5.530. Impressive numbers for just 9,5 psi, cool turbo, this will rock on a 2jz in terms of power and driveability spool at 2000!? On single turbo setup with decent boost.


Shame we cant get e85 in the uk :(


I am surprised that timing and AFR differences were not discussed. 

Here is the thing with tuning timing on E85, use a dyno. Since E85 has such great knock resistance, you can easily surpass MTBT with no signs of knock and melt internals due to increased cylinder pressure. I've made this mistake on one of my old engines. 

My two was of tuning E85 are focusing on AFR or timing, one or the other. If I do not have a dyno at my disposal I will leave timing almost unchanged (maybe add 1-2* at peak torque) and target 0.5-1 AFR leaner than with the gas tune. For example if I was targeting 11:1 AFR on pump gas, I would target 11.5-12:1 AFR equivalent on E85. While this is not going to make the maximum amount of power, you will still see a noticeable gain in power and torque due to increased cylinder pressure.

On a dyno, I tend to target a sightly leaner mixture (in the range on <0.5 AFR) and focus solely on timing. Each car is different, so no best amount of timing to add (advance) really exists. On Subaru EJ engines I tend to add anywhere from 6-10* of timing before the car stops making more power and torque. Once you find how much timing you can add before you stop making more power, I tend to back it off 1* as most of the cars I tune are for street and road racing use. This is good insurance to prevent melting a piston if the customer decides to be at high load for extended periods of time (highway or top speed racing.) If you are planning on drag racing only, feel free to leave the tune right on the razors edge.

My two cents


This is a great starter article for those wishing to gain knowledge on fuel properties :)  You could have added a little something about the oxygen content of the fuel too, a bit like MTBE but not so bad for you!
With E85 not available in the UK I had to Look in to toluene and xylene, not nice things for your skin (nitrile gloves!), but extraordinary knock resistance.  It is what gunwash thinners is made from and around 112 octane.  It is a normal fuel additive used by the petrol manufacturers to change the octane through the seasons, and has the added advantage that the Stoic AFR is virtually the same a pump petrol. 
BMW and Honda thought it good enough to run 5 bar boost in their 1980's f1 engines ;)

My Hillman imp made enough combustion pressure to push the gasket sideways out of the head joint without any knock using this fuel, 13:1 compression and 1 bar boost from a supercharger :D


nugundam93 thanks for the kind words! If it's any consolation I hated chemistry at college. Amazing when some of the seemingly pointless aspects of a subject like that become useful in later life though :)


AirLift_Lucas thanks for your comments. The article did touch on the need to optimise timing on E85 although due to space I couldn't elaborate too far. Regardless of the fuel though, the dyno is the only way to properly calibrate the ignition advance and find MBT.

As you mention, with E85's properties it's often possible to advance the timing past MBT without knock. This however won't necessarily melt the internals. Provided that you aren't encountering knock, over advancing the ignition simply results ins a reduction in torque - The combustion pressure begins fighting against the piston as it's still rising on the compression stroke as the cylinder pressure rises.

Personally I don't change my AFR target between petrol or E85 although due to the cooling properties of E85 and it's knock suppression, it's certainly possible to tune a little leaner. Typically I don't see any power advantage from doing so and would prefer to maintain a bit of a safety buffer from the cooler combustion charge.

I couldn't mention it in the article but it's also important to understand the settings of the wideband meter too. As discussed, E85 has a vastly different stoichiometric AFR than petrol (9.8 vs 14.7). Fore the wideband to accurately display in units of AFR it must be programmed with the stoichiometric AFR of the fuel you're running. Most tuners don't bother doing this and leave the stoich set to 14.7:1 regardless of the fuel.

It's critical to know how the wideband has been programmed otherwise your targets may be a long way off - For example on petrol we may want to tune for 11.5:1 at full boost. On E85 using a stoich setting of 14.7:1 this would still be a target of 11.5:1 but if the stoich setting was changed to 9.8:1 you would be targeting 7.7:1.


James_Turbo I've used toluene back many years ago and it does a pretty good job. As you mention it was the major component in many of the special blends of F1 fuel back in the turbo days.

E85 shows similar problems with head gasket integrity - In essence any time you're raising cylinder pressure, the head gasket will have a hard time. In your situation the composite gasket construction wouldn't be helpful either :(

In my own experience with our import drag engines running 50 + psi boost on methanol, head gasket integrity is the limiting factor on engine power. It becomes exponentially more difficult to keep the head sealed to the block.


@Fiatdude therealnecroscope That's great for people with a budget that will allow it.  I can't afford a top shelf ECU and days worth of dyno time. Besides, I'm the type of person that really wants to understand "how the sausage is made". My recreational time is free.  I'll get it running good on the street and then spend a couple hours at the local dyno to get the last 15%.


Andre Simon AirLift_Lucas Thanks for the reply! Hopefully someone reading through this article scrolls down and reads this conversation as well :)

I mentioned the melting of internal engine parts (specifically pistons) as this is something that I personally experienced. I saw my EGTs climbing rapidly but no knock so I kept my foot in it which in turn caused the pistons to expand in to the cylinder walls. I agree that this doesn't always happen, but it is something to watch out for, especially if you are using stock cast pistons. 

Regarding leaning out the mixture; I have noticed an ~100*C increase in EGT by going 1 AFR point leaner. I honestly have never done much experimenting with AFRs on a dyno, but I can say the butt dyno tells me it yields marginal gains. I tend to keep the higher revs rich but lean out the mid range. That way if someone is doing extended high load/high rpm runs the internals will stay cooler. This is especially important on engines with stock cast pistons.

Most widebands will work with no setting changes out of the box running E85. A wideband oxygen sensor only cares about the stoichiometric of the fuel it is using. The thing to note is that the WBO2 may read 14.7:1 AFR on E85, when in reality the actual AFR is 9.8:1 due to the stoichiometric ratio differences between the two fuels. The best way to read AFR when using alternative fuels is Lambda. 1.0 lambda on gasoline is 1.0 lambda on E85 (1.0 lambda = 14.7:1 with gasoline. 1.0 lambda = 9.8:1 with E85). I personally find is easier to just keep my wideband set to gasoline settings as that is the scale I learned to tune on.

Again these are my experiences, your results may vary. 99% of the cars I've tuned are in the 200-500whp range, with one 600hp EJ25 under my belt. Most people I deal with are looking for reliable street tunes. The guys aiming for high HP numbers usually have the cash to go to a real shop and pay a reputable tuner. Just speaking from my hobby level experiences with tuning over the last 10 years. I find tuning fun as it can be extremely difficult, but the reward of a perfectly running engine is well worth the headache!


AirLift_Lucas while E85 is much more resistant to knock, you will still run into trouble with a lean mixture. The other aspect where a lot of people come unstuck is that E85 (and alcohol fuels in general) are much more susceptible to pre-ignition. 

What you will find with any fuel is that it provides a reasonably wide range of AFR over which the power/torque remain reasonably constant. Go too rich or too lean and the power will drop off but the 'sweet spot' is usually quite wide.

Widebands will generally ship with the stoichiometric setting configured for pump fuel (14.7:1), but many people don't understand the consequences when swapping to different fuels. Personally I always tune using lambda so it doesn't matter when I swap between different fuels. I find however the US market in particular seem to only use units of AFR.

The reason I still love tuning is because no matter how much you know, there is always more to learn :)


Andre Simon Thanks! But I believe the reason many components fail with the use of e85 is the low lubricity level, which makes fuel lines dry out then crack and fuel pumps/injectors wear faster due to increased friction.


Andre Simon Thats great information thank you.
At this stage the turbo setup im running will only support around 500hp. So sounds like you say a intake fuel pump upgrade and some 1000cc injectors would flow enough E85 for my needs.

Is it true you can end up with corrosion issues with factory fuel tanks, factory lines and factory aluminum fuel rails? or is this a longevity thing where E85 has been present for years



Andre Simon zemanski Pretty sure everyone will like to see pics of it and a little article probably name retired and still strong etc... even doh it retied we will luv  to read what was done to it etc...


romanrobbert correct, divide by 5.53. Yes I was quite impressed with the numbers it made as well as the low boost threshold and fast spool. You might find a single 6758 is a bit on the small side for a 2JZ. In twin turbo form it would be a monster but in single form I'd be looking at either the 7670 or even the 8374.


scibO thanks for your comments! I can't give too much away but I'm sure over the coming months I'll do my very best to create more interesting and relevant tech content :)


Bima Leksono A full flex-fuel conversion can get quite expensive and will depend on the hardware you already have. The flex fuel sensor alone can be purchased quite cheaply ($50-100 USD), but you will also need a flex fuel compatible ECU, potentially larger injectors and fuel pump and then tuning to suit. This can easily add up to $2000 + USD depending on your starting point.


AlexLobanov you're correct, ethanol has a lower lubricity than gasoline. E85 blends generally have additives to help with lubricity although I couldn't comment as to how closely this ends up resembling the properties of pure gasoline.

When running drag engines on pure methanol which is a very dry fuel, we use a fuel system additive to lubricate and reduce wear. 

I don't believe you will see any long term issues from modern alcohol compatible fuel system components though. Again it's worth remembering that many current cars are produced to run on E85 and hence the fuel system reliability needs to meet OEM standards.


I see. What about the fuel economy? I usually got 8-12L/100km depending on the conditions, and you said that the fuel economy will decrease significantly, but by how much is that? Thanks for the reply!


Like others noted. Great article for those just getting our feet wet in the world of Ethanol.
I recently acquired my newest drift rig powered by 2012 ford racing 5.0 coyote with a 2.9L wipple SC.
It has been run on E98 since new but still retains the Ford Racing ECU and has a heck of a time with cold starts.
Im in talks with my shop to switch it over to a Vipec or the newest infinity to aid in cold starts, DBW driveablitly and overall potential.
I opened the dry sump reservoir the otherday after running it up to operating temp and noticed a fair amount of condensation built up on the reservoirs walls and cap.
The oil is fresh but im afraid there may be moisture hiding in lower areas im not able to inspect.
Could this be due to a high Ethanol content that has washed down into the scavenge sump?
Any input on ecu options and moisture in the oil is greatly appreciated.
You guys rock!


Andre Simon I concur, this engine in particular is very prone to head gasket issues, the hillman imp.  The head to block interface is not strong enough to compensate for either an MLS or gas filled ring solution, the dry liners drop in the block and cause even more issues than with the fiber gasket!
The solution that is well proven, is larger head studs rather than bolts, wet liners and then 'wills rings' (a type of gas filled malleable steel fire ring).  This allows these little engines to run a bore for 998 or 1040cc and make well over 100hp, from a non cross-flow 8 valve head!

Mine was supercharged and injected, but is now no more, as I came to the limit of all the other 1960's components.  With no aftermarket support for the car, the project became unviable.
Thanks for your input :)


Great article, and thanks for answering all the questions below - they really added lots of useful info.


@matt t  Good evening,

Water in the sump, and fuel for the matter is an issue in engine that don't get hot for prolong periods of time, if you do a reasonable amount of motorway (highway) driving, you will get the oil plenty hot enough to evaporate the water in the engine and deposit it via the breather system.

Ethanol holds a number of issues compared to normal petrol, partly because it burns cooler than petrol so engine temperatures generally don't get as high. 
Because the fuel also has a lower AFR, you are more likely to have fuel washing down the bores and into the sump directly, this will deposit and dissolved water in the fuel into the oil, as the ethanol evaporates at a much lower temperature (around 76 to 78 deg centigrade).

Finally combustion of ethanol is really quite different to petrol, and even discounting any water dissolved in the fuel, it will still produce 33% more water. 

If we look at the oxygen balance for petrol -
CH4 + 2 O2 -> 2 H2O + CO2 + Energy

And the same for Ethanol -
C2H5OH + 3 O2 -> 2 CO2 + 3 H2O
Some of that will always make it's way into the sump through the process of blow-by, something unavoidable on a high combustion pressure engine.

Finally, just as a point of interest to those that don't know, you can only distil alcohol to just over 97% ethanol to water by volume.  If you want to get rid of that last 3% you need to use 'drying' a molecular sieve or reverse osmosis :)


great article, unbelievable that you can get 90+ hp from just another fuel.
I just wondered if e85 can also increase power on a 2 stroke that runs with a carb?


jdmRob  It sure will, you will be able to run leaner without it 'nipping up' because the fuel burns colder.  More advance and more primary and secondary compression without detonation.  All of these will be great for a two smoker :D


James_Turbo thanks for the quick answer, would be interesting to have a two stroke project run on e85...


jdmRob I don't have any familiarity or experience with 2 stroke unfortunately so I can't give you any solid advice from first hand experience. I would however expect to see similar gains on a 2 stroke as what we see on a naturally aspirated 4 stroke engine.


@matt t depending on your ambient temperatures you may struggle to get clean starting on E98 regardless of the ECU. Of course a quality standalone will help with the ability to quickly and easily make live changes to the cranking/post start/warm up enrichment tables.

Either the AEM Infinity or Vipec V88/i88 will do a great job with the Coyote engine. I've personally used a V88 on a Coyote Boss engine here in NZ with great results.

The moisture in the reservoir is probably quite normal. This will particularly noticeable after regular starting and stopping without gaining sufficient oil temp. You will find that on E85-E98 that you may end up with a reasonable amount of fuel contamination in the oil and it's worth performing more regular oil changes.


HI & thanks for a tech article.
I have to correct you on one point, based on my own experience & others around me.
Your point on having to swap fuel if the car if not used regularly is a bit misguiding.
I have had my car standing/running for 6 years with E85 in the system, summer & winter, in the harsh conditions Swedish climate has to offer, and i´m not alone doing like this.
The tank will most surely have to be drained after a long stand still. This is noticed when trying to start the car after 4-6 months with no just wont start, or it will hardly be able to stay alive if it starts.
Drain & swap to fresh E85 in the tank & open the return line to flush the system by running the pump & the car will start.
As long as the mechanical parts in the system, pumps & injectors, are intact & filled nothing will happen. This is my conclusion. When taking apart the system put the parts in E85 or spray some WD40 into the injectors & pumps. This will prevent the parts from getting damaged/oxidization.
There are also rumors saying that Walbro pumps, among others, will not withstand E85, which is false. Most likely broken pumps are a result of non proper handling i.e not using filters, bad wiring or dismantling the system & not squirting some lubricant into the pump.

Thanks for the tech article & keep´em coming :)


James_Turbo jdmRob I have run a competition two stroke engine on AVGAS in the U.K. It allowed me to run more compression & advanced timing, ran cool too. I ran that engine for 3 seasons without a hitch!
Did need to invest is a decent programmable ignition, had a pipe made too. Some of the guys also ran powerjets as well.


what about toluena addition on gasoline? is it ok?


The sheer amount of rainforest cleared and also existing arable land used to grow the biofuel crops basically more than cancels out any reduction in emissions from using this stuff :

Source: I'm a petrol-powered dinosaur.


Found myself reading through the comments today out of curiosity and I
have to say you have a thorough understanding of your field. It's the
little things you mention like cranking enrichment initial pulse, use of
lamdba vs afr for stoich et al that get me as it shows we can have a
discussion at more technical level, something that seems to be missing
on SH. I love tuning my own vehicle and learning more as they years go
by. The feeling of doing your homework and getting your car to cold
start on e98 on the first try with solid closed loop afr is something I
don't think most enthusiasts get to enjoy. Most gravitate toward the
mechanical aspect of things but I grew up in the age of the computer and
a laptop has always been more common to me than a wrench. Of course the
two go hand in hand but tuning is an art form in of itself and it's
amazing when everything comes together and you have a car that's not
only powerful, but tame and smooth enough that anyone can drive it.I'm glad to see someone writing articles of this nature and look forward to more.


RMutt thanks for your comments :) 

I think my love for performance tuning comes from the challenge that it offers and there is always something new to learn. In particular the challenge of taking a heavily modified vehicle and getting it to the point where you can replicate factory driveability/cold start/idle performance etc is particularly satisfying when you can get it perfect. 

From the comments it seems like this technical series has hit it's mark and I look forward to bring the speedhunters community many more articles like this.


Slappy_Pistons I don't have any data that would let me support this argument either way, however I am aware that the E85 production takes it's own toll on the environment. Whether this is better or worse for the environment than burning fossil fuels I'm simply not in a position to state. 

For better or worse though, E85 is a reality and this article is simply here to discuss it's relevance and importance to engine performance.


gilaroda2 absolutely! Toluene was a major component of many of the specialised F1 fuels back in the F1 turbo era and it's ability to suppress detonation is well known. These days with the range of race fuels on the market, as well as E85, it's not so common. Depending on your location in the world, often getting hold of an easy supply of toluene can be difficult too.


BuddyDavies just a point from my own experience that's worth mentioning. Here in NZ avgas was banned for sanctioned motorsport events about 5 years ago. At that time I ended up with a large number of cars across my dyno that I retuned from avgas to run on our unleaded 98 octane pump fuel. Almost without fail I found that we could make marginally more power on the unleaded 98 than on avgas (I'm talking a hand full of killowatts at best) although this usually required a little timing to be removed to guard against knock.

The lead content of avgas however does give a nice safety margin as it helps suppress knock. I can't comment about the relevance of this to 2 stroke though as it's outside my own experience.


barre the potential for corrosion due to the hydroscopic nature of E85 is a real concern. The reality of how serious this may be will depend however on many factors - Humidity level, how much fuel is in your tank, and how well sealed your fuel system is to the atmosphere.

I'm happy that you're having no trouble with your car and what you're doing is working for you. I personally tend to be a little more cautious though. My concern is that corrosion damage to components such as the injectors may not be immediately apparent. For example mild corrosion may reduce the opening of the injectors which will still allow the engine to run but may result in a lean AFR.


i saw you working with nigel petrie on his blog, anyway looking foward to reading more!




Andre Simon BuddyDavies I'm glad to hear that you had the same results with the change from AVGAS to U98 Andre, I found the same result in a high compression (13.5:1) pushrod Nissan A15, that I gained power and torque with the switch to the high octane unleaded fuels.


Slappy_Pistons The rainforest isn´t cut with this purpose in mind. In africa is done to grow rice adn not only, is basiclly colony v 2.0, to feed the chinese and indians, or to  feed cows - proces called grazing 

Why do you think that after o many speaches and programs (SaveAfrica, blablabla) there isn´t any improvement, they dont want educated people, they want farmers) put it simply its because this isn´t at their best interest.

Dont blame it on ethanol, you are just beeing ignorant. Is not the chinese and indian people fault aswell, its just hypocrisy of the cannibal like capitalism who want just to produce braindead workers and consumers with no sense of criticism, smart enough to type and work on a computer but dumb that can´t see through the layers and put the pieces togheter, the kind of people that get easelly influencieted and sometimes manipulated, and forget after 5 minutes.. love to watch bullsh*t TV  and soo on...

Dont want to include you as is beeing rude, but what you stated is nonsene... 
See my logic: You complain about the rainforest beeing deforestated and state that your source is petrol-powered dinosaur..

Dont get me wrong i love petrol power -  but i have a diesel 1.6 that gets 60 MPG (US), is comfy and has a 600 liter trunk, however, i use my bycicle every day to move around city, go to university, even on rainy days.  I use train to comute and not V8 powered cars that get max 20-22 MPG. 

I save the money for a coyote build and with this on my mind i go to sleep every night.  

To produce Ethanol you need plants tha feed themselfs with CO2 and water  to produce C6H12O6.

BTW  As Jeremy Clarkson once said cows are the world biggest enemy. more if you consifer that to feed them you deforest the rainforest. 

I do prefer that we do ethanol from corn that feeding cows..



Great article & good to see this kind of content on SH.
I know there's a broad spectrum of car culture and interests that gets covered here on SH, but this article really touches on the 'fundamentals' that leads to well-thought-out and considered modifications.
I teach people about this stuff pretty regularly; I invariably get great reactions when you can bring the theory into a 'real world' relevance, like for modifying. Once someone can relate to the material, the hard parts over...
Oh, but one criticism :)
'E85 also has a very high ‘latent heat of evaporation’
- this isn't chemistry. It's physics.
But I'll shut up... :)
Great stuff


MSTech Andre Simon BuddyDavies Keep in mind though that E85 is alcohol based and 2 stroke engines need to use oil in the fuel to lubricate themselves. Alcohol is a great cleaner, which also happens to clean the oil film that is needed for a good seal of the piston. I would use Avgas for it, since it is a carbon based fuel with a rather rich lead content (have seen as much as 145 octane) , but I wouldn't recommend E85 for 2-stroke engines . It's ok on race engines with a service life of hours compared to thousands of miles, but not for street use, since reliablity will be an issue....


James_Turbo Andre Simon : Try using copper headgaskets. They are expensive, but can be used more then once. It should help a lot:
E85 tends to corrode it a bit, but thats not much of an issue. The real advantage is that its mallable, and its very ductile. When you clamp it down it already seals good, but once it heats up it expands a bit so it's very good when used on high compression engines. Mayor drawback is cost involved, since most need to be custom made....


romanrobbert Slappy_Pistons Thanks, yes I'm aware of the wider issue.  Ethanol production in some parts of the world contributes to the wider environmental issues that we are already facing.


MSTech Slappy_Pistons yes, very true.  I just don't think that Ethanol is an answer, but like the man said, it's here, so let's talk about it.  A lot of corn ethanol is grown in the USA, am I right?  How about growing food for people!?  Govt. subsidies have been keeping corn ethanol growing up for decades.


You can, Anglo American Oil import the Sunoco Racing E85 (indy car fuel)


James, you can buy the Sunoco Racing E85-R from Anglo American Oils.


Hi. Over here in South Africa we only get E96. I noticed most countries and most of Europe use E85. Is there a big diffrence. Obviously the tune will be much different. Will E96 cause more harm the plesure? Otherwise what is your thoughts on Methanol?


Jannie16v The higher ethanol content will negatively affect your cold start performance (which I can only assume isn't a huge issue in South Africa). In hot climates this isn't a concern and there are some minor benefits to the higher ethanol content as it further raises the octane rating. A minor downside would be that your fuel consumption will be slightly increased beyond what you'r expect on E85.

Methanol as a fuel is really only suitable for race use. It will produce more power than E85 (or E98), but with a stoichiometric AFR of 6.4:1 you are burning around 2.2 times more methanol than what you would expect on pump fuel to make the same power. Methanol is also very corrosive to aluminium and can't be left to sit in the fuel system for long periods. The shear quantity of methanol you need to inject also ends up with quite a lot of dilution of the oil in the sump, requiring regular oil changes.


SlipDiff thanks for your comments. I hope that over the coming months I'll be able to add some real value and insight to the Speedhunters community. People shy away from some of the technical aspects because they fear that it's too hard or complex to understand. I believe that when it's laid out in a straight forward manner most people find that many of these topics are actually pretty easy.

Latent heat of evaporation is a thermodynamic term, however I was taught the concept in both chemistry classes and physics and hence I'm quite comfortable using the term in this way. If my memory serves correct I believe the term was actually introduced by a chemist :)


Hi Andre. This is a good article and thanks for taking the time to write it. I've had the pleasure of running my car on 100% methanol and since the temperatures in Malaysia can be pretty high, I've not had any issues with cold start. But what I do have an issue with is my engine getting contaminated after runs. Any advise on what I should look out for when looking for lubricants next time


Awwwesooome. Andre's doing tech articles for SH, I know i'll be visiting this site more often now and I definitely know I'll be learning a thing or two. Thank you Andre for your time and sharing your knowledge with us.     Bring On The Tech !!
Pity here in NZ we get deprived of having 85 at the local pump unlike some other countries. Stink Bro


Good article and lots of good comments.  Just a note, most of not all "E85 sensors" are not that at all.  They are gasoline sensors and that's how they determine the ethanol percentage.  This can be problematic in extreme cases.


Most cars in the 80´s hear in Brazil used a E100, and they engines running out the factory with 13,5:1 compression, today our flex fuel cars runing about 12:1 compression, but we dont have E85, its only E100 and our gasoline have a 27% ethanol.


Most cars in the 80´s hear in Brazil used a E100, and they engines running out the factory with 13,5:1 compression, today our flex fuel cars runing about 12:1 compression, but we dont have E85, its only E100 and our gasoline have a 27% ethanol.


I 'm hoping to modify the ECU map of a 2.5 1998 V6 Ford Mondao hope I'm


RodolfoMazari  Is it a conspiracy, hard  to believe a major car maker would deliberately make cars do poor mileage


I'm also re-building an older British Essex V6 with a CR of 16.51 to 1, I'm going to run on e100 indoors in a stand It's got an original DGAS Weber and a FoMoCo Distributor my Web site is at where I'll post what happens even if it blows up.


I have a flex fuel avalanche, it's a daily driver, would i benifit from switching? would I have to have a tuner installed? Or professional tune? Or does my ECU take care of that stuff? should I keep running 92 octane for power?


Slappy_Pistons the renewability of biofuels lean in the fact that the rhythm of compsumption of those is lower than the rhythm of production of raw materials. At the end, biofuels are the same as fossil fuels, but you don't have to wait millions of years till the resource is ready to use. Regard the emissions issue, when you burn biofuels, the CO2 produced is the same the plant settle in their body to grow up, so thats an advantage respect the use of fossil fuels. Ofc biofuels should originate from non-food crops or wide biodiversity areas. (forgive my english, is not my native language)


Im running a yamaha nytro with a turbo (snowmobile) and i can run 6psi on 93 and about 10 to 12 on 110 i wanted to see if i can tune it to run on e85 because of the cooling effect and the price i called capol a sled tuners and non of them have tryed it do you have any suggestions on how to get the right a/f ratio tables im running a power commander 5 pti which is a 3d tuner that recognize boost and self tunes thanks


superbad773 First and foremost you need to make sure your system is capable of delivering up to 35% more fuel. The simple and not accurate way, increase fuel pressure by 30%. The best way would be to add ~30% fuel to all of your maps then tune from there. If you do not have access to all of the maps on your engine I would really just stay away from E85 and stick with 110oct. You will actually see a marginal loss of power (~1-3%) over 110oct, what you are gaining is availability and much cheaper cost/gal.


superbad773 I'm not familiar with the power commander so I can't really advise accurately I'm afraid. Tuning for E85 would require you to be able to make quite large changes to the fuel tables. You're also going to need to almost certainly fit larger injectors and perhaps a fuel pump. If you can increase the fuel system's flow by about 35-40% by fitting larger injectors then the changes you will need to make in the ECU actually won't be too great.


AirLift_Lucas I wouldn't advise trying to account for the required fuel flow increase by adjusting fuel pressure. Firstly the relationship between flow and pressure isn't linear so raising fuel pressure by 30% will actually only increase fuel flow by about half that. Secondly when you raise the fuel pressure the pump needs to work harder and this can mean you run out of fuel pump flow and end up back in the same situation with insufficient fuel.


Andre Simon AirLift_Lucas I agree that this is not the best solution and I also do not know about his power commander. The thing that caught my eye in his post was "self tunes" which to me sounds like an automatic tuning feature. A bump in pressure may be enough for a system that can make WOT adjustments on the fly to dial itself in. I should have been more clear by saying "I don't recommend this, but you could..." I have heard of powersport vehicles with these types of systems installed.

Raising fuel pressure can make all sorts of headache for a tuner as it will change injector latency as well as shift the amount of fuel injected per MS. I 100% agree that the best way is to verify that your system can flow an extra 30-40% more fuel over the current tune, then create entirely new fuel tables to provide the extra required fuel.


Slappy_Pistons MSTech
Most of the corn used for ethanol production in the US is not particularly suitable for human consumption. 
It is either a specific engineered variety of corn grown specifically for ethanol production that does not look good, is more fibrous and does not taste as good as food corn, or it is damaged corn that is not suitable for consumption. 
"How about growing food for people!?" 
In the US corn is grown for people too, but it is usually a different variety than is used for ethanol, no one in the US is hungry because of ethanol production, that is a popular and often repeated politically motivated lie. There is no shortage of corn or corn based products in the US because of ethanol production. 
"Govt. subsidies have been keeping corn ethanol growing up for decades." 
That is a mostly true statement, but not a complete statement, the government has provided subsidies for the ethanol industry, but the oil and gas industry has also received and is currently receiving government subsidies. 

Ethanol as/in US fuel is not new and has been around since the late 1920's. 
US ethanol subsidies are not new and have been around since the early 1980's. 
In the mid 1970's there was a big push from state and federal government to develop a domestically produced fuel and reduce the US dependence on foreign oil, there was renewed interest in ethanol as a fuel, ethanol was selected and development funding was appropriated in the early 1980's. 
Ethanol subsidies picked up momentum in the late 1980's and increased greatly in the early 1990's. 
The ethanol subsidies are not cash given to the ethanol industry, it usually comes as low interest loans for development/research, plant startups or existing plant expansion, tax credits and production credits. 
US ethanol subsidies have totaled approximately $2-4 billion annually ($0.5 billion annual average 1994-2012), but that Dollar amount of subsidy has only been at that level since about 2003. 
US oil and gas government subsidies total approximately $4-24 billion annually ($5 billion annual average 1994-2012) and as of 2016 the oil the gas industry has received government subsidies for 100 years. 
Most oil and gas subsidies are in the form of industry specific front-end depletion and overhead tax credits, tax credits, foreign tax credits, production credits and tax offsets. 
Comparatively, the oil and gas industry has received exponentially greater subsidies than ethanol and all of renewable energy collectively. 

Relative to this article on ethanol/E85, I did not read anywhere in the article that ethanol is the answer to anything except as an affordable high performance fuel for certain high performance engines/vehicles that is superior to pump gasoline in performance and an alternative to very expensive boutique race gasoline/fuel. 

What is your proposal for a superlative alternative performance fuel?


Slappy_Pistons MSTech From what I have found with a quick Google search, more Corn was used to product High Fructose Corn Syrup in the US that was used for Ethanol Production, and most of the corn product that was used for Ethanol is not what would have been able to be used for human consumption anyway, where as the HFCS does use the same part of the corn plant as is used for human comsumption.  I would say that the reduction of production of HFCS would be much better overall than Reducing Ethanol production.


What is the safest lambda range for a non turbo Yamaha running Alcohol? Thank you!


I'm looking to Buy the new Honda civic RS here in Thailand but I'm put off with E20 Fuel which they run it on over here.. In the US it doing nearly 6-5 seconds to get to 60 MPH but it's struggling to get under 9 seconds in Thailand because it's run on other Fuel.. How can I boost power with that fuel or is it best just to Buy the new Ford Focus that runs on E85 and takes 8 seconds to 60MPH.. Is it easier to get more power from the Focus with the E85 fuel rather than the civic on E20..
Thanks David


Thnking about changing over. Have a 502 big block Chevrolet eng close to 600 hp natural aspperate .street and strep on nitrous 200 shot.not looking to gain 10th at the track . look for more tork /timeing fuel savings /cooling running on the street maybe more hp. Is it really worth the cost for the gain


Hi Andre, I am making the swap to an ethanol blend for my SR20VE engine ( naturally aspirated, 12.7:1 static CR). What sort of ethanol content in the fuel will give me the most power / torque ? Is it a case of more is better or is there an ideal ratio ?
Thanks - Wade


What about using E85 in aviation?
Thank you for your help.


I would like to build a Continental O-200 with a lot more bang... Which fuel would you recommend??



can you mix e85 with some octane booster like  toluene? to get higger octain level.

my 4age turbo sees some knock already on e85


RobertsRode E85 doesn't knock like petrol.


Warakon E20 has no gains. It needs to be higher rating than 60 to start having gains


Hi Andre,

Great article, thanks for the science and advice behind running E85.  We have upgraded our fuel pumps, injectors and installed a flex flo system for our 09 GTR R35 and have been researching other issues associated with the pitfalls of using E85. Our next concern is the filters - our pumps have a combined flow of 680l/h and the 1150cc injectors have a combined flow of 414l/h - how can we tell what inline or additional filters we will need to efficiently and safely run E85?

Any advice or direction would be appreciated.



Hello there im kire ive got a rb26 in vl im gonna convert it to e85 have u had any problems with the e85 getting to hot and the car running ruff ? What fuel pump set up do u use?


Hi André,
My car isn't e85 compatible (2010 Audi A4 ) but I'd like to find a way to make it compatible. Are their any kits to enable a car to safely run e85? Can a shop successfully achieve this?


My question is on mixing the grades 93 with the e-85. Is it recommended to mix them for more horsepower, and would it damage anything in the process of doing so. And the car is a 2016 gt mustang.


My question is on mixing the grades 93 with the e-85. Is it recommended to mix them for more horsepower, and would it damage anything in the process of doing so. And the car is a 2016 gt mustang.


hi  would i get beter results by mixing e100 and avgas 50/50 as it should give a higher octane rating than e 85 witch should allow me to turn the boost up to 2.5bar with 10/1 cr on a lexus v8 i am currently running 50/50 toluene and 95 octane pump gas with max timing of 28 deg and a afr of 11.5 but 1.5 bar seems to be the limit before detonation sets in.and with the e100 and avgas should i aim for a afr of 10
and what would a safe max timing adv be
thank you kindley


We are changing over to E85 in our racecars. Here in Kansas City I'm finding out that it's only 70%. What can we buy to increase the level back up to 85% ?


how rich is to rich in your experience with e85 at cold start and idle?


I have a twin turbo 4.6 DOHC Ford running on E85, I get IAT as high as 200 degrees, I am not using any air to air intercooler or methanol, Can I assume the E85 is cooling the combustion chamber enough that the 200 degree IAT is not a problem? or do you recommend and intercooler or Meth?

Thanks Rick


I have a b20 vtec fully built @11.1 cr. On e85. Im on 11lbs boost. Question is on a gasoline aem wideband what do i need my numbers to be at boost... spark plug heat range would be nice to know too. Im running ngk bkr6e-11 @ .030 gap... thanks


what is the basic technique used in the ethanol content sensor?
Like is it capacitive sensor/ultrasonic sensor/something else?


Should you run a cooler spark plugs for E85?


Poor guy posts an informative article and is forced to answer questions for 9 months. Pick up a book suckas


I’m no “sucka” dickhead and is that even a word ?
We are not all looking at the same time and some of us would really value the help or advice. I’m sure if the guy didn’t want the questions or feedback he’d have removed the post....information is not forthcoming from any or many sources and your comment and childish attempt at koool spelling pisses me off


Really Interesting read...
I’m about to finally take delivery of a brand new car that has been modified with flex fuel capability, twin injectors and the British Syvecs ECU. The car has been tuned on E85 to peocsuce some good bragging numbers but has maps installed to run pump and all variants in between..
Im asking the following questions because I’m am absolutely clueless about the everyday running and how to use it and how much to use..
No one seems to ever mention addIng an amount (say 2-10L) to the fuel tank ?? It’s only ever E85 or pump. For us in the real world I want to know am I wasting my time putting litre after litre in that’s not enough or will anything make a difference ?
If the car achieves say 550hp on good fuel and 700hp on E85 is it as simple as basic maths when deciding to add say 2-3 or 5 litres to calculate the HP gain .....or just not worth the hassle of standing funnelling it in and carrrying boxes of the stuff with me on long journeys ?.....also is all Ethanol you can buy of the right quality and is there something I should be checking on or looking for when purchasing ?
One last question.....would it be easier for an everyday car to sack it off or have a meth injection kit installed and forget the Ethanol except for the occasional sprint or drag fun day ?
Thanks in anticipation


if i get 30 miles per galon on unlead 91 what would i be getting on e85