NHRA 101: How To Run A 10,000hp Nitro Car

Nitromethane, it’s a word that strikes up ideas of calamity or rapidity. The funny part is that both can be observed at a NHRA national event in the Top Fuel and Funny Car classes as they shake the ground and pass the 1000-foot mark in less than 4 seconds, or explode into bits when it all goes wrong.

The idea of getting down a drag strip seems so simple as it’s not that far; you can see it and it’s a straight line. However, the process of getting a nitro car down the track is far more complicated than what you see from the stands…

Larry_Chen_2017_Speedhunters_NHRA_101_17

The first thing is not even a part of the car. Track prep is vital to making sure all cars can go down the strip without ‘blowing their tires off’ or that smoke show you see those Top Fuel and Funny Car guys do when it does go wrong. While it looks more violent for them, all cars can encounter tire shake and cause traction loss. A chemical is sprayed down the track to help enhance the traction of the concrete and asphalt the racing surface is made of. This also must be done every time a car ‘oils down’ when an engine or drivetrain lets go.

Larry_Chen_2017_Speedhunters_NHRA_101_19

Prior to every run, crew members check the track’s condition from the heat, humidity, and atmospheric condition.

Larry_Chen_2017_Speedhunters_NHRA_101_20

The traction available is also determined by a very specific and special tool known as a track meter. A member of the crew will stand on this cross-looking device and attach a torque wrench to the top of it. What that is attached to is a piece of rubber that’s like the drag tires they use. By turning the torque wrench to certain degrees, the crew chief can get a better understanding of how much traction is available and how quickly they can apply the slider-style clutch along the track before traction is lost. It’s a very interesting tool but one needed by teams to ensure they run consistent times and run the car to its maximum available grip.

The Start & The Smoke
Larry_Chen_2017_Speedhunters_NHRA_101_24

Before performing the crowd-pleasing burnout, you must start a nitro car, and that’s not as easy a task as it might seem. You can’t just light up the mix like you can a gasoline or even an alcohol car. The fuel is a methanol composition with up to 90 percent nitromethane as mandated by the NHRA. The nitromethane, interestingly, is created by either treating propane with nitric acid at 350°C to 450°C (662°F to 842°F) or can be created with a reaction of sodium chloroacetate (which can also be used to make PVC plastics) and sodium nitrite (most commonly used as a food additive against microbial growth) mixed into a water solution. It’s not the same as nitroglycerin, though, as that’s more of an organic nitrate than a man-made nitro compound like nitromethane is. Nitromethane can also be used in anything that needs a monopropellant, like rockets, since it contains its own oxidizer like nitrous oxide. You can also use nitromethane to create hydrazine, an unstable monopropellant that is forbidden for use in the US.

Larry_Chen_2017_Speedhunters_NHRA_101_14

Nitromethane is very, very powerful when it burns. In fact, it’s 2.3-times more powerful than gasoline for the same amount of oxygen used. Also, because nitromethane contains its own oxidizer, less oxygen needs to be introduced to burn the nitromethane/methanol mix. The problem with it as a fuel, though, is that it burns very slowly, which is an issue when you’re trying to start a nitro car. The first thing you see before and during that start up is a crew member squeezing a bottle into the blower hat, the part where you see the butterfly valves that open on the top of the engine. Once fired and the engine is running on the gasoline, the member will then turn the valve from the fuel pump to start feeding the nitromethane mixture. You can even hear when it does because the pitch will change and become deeper. That slow burn is also why you’ll see some sprays of white liquid coming out of the header pipes before the burnout is done. That’s unburned fuel being sprayed out.

Larry_Chen_2017_Speedhunters_NHRA_101_48

Once these guys and gals are strapped in, they can only see out the front and sides. There are no mirrors so another crew member aides the drivers back to the starting line, making sure the car is in the groove that the crew chief feels is the right one for that run. Again, this determined by all the data he or she has acquired throughout the weekend and even events prior. You don’t really get a chance to put the car back right, especially with the longer Top Fuel cars. You’ll also find crew-members wiping down the tires in an effort to rid them of any rubber, dirt, debris, and even any leftover water that may have gotten on them as the car reversed back. Nitro cars need all the grip afforded to them and any loss of traction that wasn’t planned can be devastating.

Larry_Chen_2017_Speedhunters_NHRA_101_51

Before pre-staging, the crews do one final look-over and pull a pin on the blower hat. That is a limiter that doesn’t allow for full fuel during the burnout. Up to this point, only enough fuel has been allowed to flow into the engine to keep the blower cool and run the engine while the tires are heated.

Larry_Chen_2017_Speedhunters_NHRA_101_50

Running at full fuel increases the chance that a failure will occur, and when failure happens in a nitro car, it’s enormous to say the least. At this point, crews will also begin to turn on any data-logging and change the mapping of the slider clutch from burnout to the one for the pass.

Staged For The Battle
Larry_Chen_2017_Speedhunters_NHRA_101_23

Now, we’re finally getting to the point you can pre-stage the cars. This is just before the stage beam and is used to show the driver is nearly prepared to make their run. The driver is aided by a crew member to find the pre-stage beam. That indication between driver and member is unique to each, so there is no right or wrong way except if the car staged too early. Though, you can play mind and mechanical games here. Stay in pre-stage for a while and you can start messing with your competitor’s head. You usually don’t want to be the first guy staged, but you can also ruin a driver’s groove by staging quickly.

Larry_Chen_2017_Speedhunters_NHRA_101_25

You also normally only want to just cross the stage beam. It may only be fractions of an inch, but you are given that much more space to react to the .400-second pro tree light scheme. However, the theoretical advantage of the deep stage – where you cross so far that you turn off the pre-stage light but the stage light is still on – is that you’re that much closer to the finish line. That comes at the cost that you need to be dead on with your reaction time or risk a disqualifying red light and ending your run before you even get to the 60-foot mark.

Larry_Chen_2017_Speedhunters_NHRA_101_53

Once a driver (in a bye-run) or both drivers stage up, the starting official presses the button to begin the timing equipment of the run. Once that button is pressed, the three yellow lights of the tree all light up nearly at once and then the green light turns on. The time between the top yellow light to the green light is only .400-second. That used to be how the NHRA described a perfect light, however, now it’s the measurement of the reaction by the driver to just before the green light turns on to the time the front tires break away from the stage beam. A perfect light is .000, however most reaction times range from .022- to .115-second in the pro classes. An average person’s eye blinks in .033-second, just to give some indication on how fast they are reacting to that light.

Larry_Chen_2017_Speedhunters_NHRA_101_54

Once that throttle goes all the way down, 10,000 horsepower is unleashed at its full fury. The driver experiences a full 8Gs on their bodies at launch and it flattens out to 4Gs in the middle of the run. During that time, the driver is fighting the car to keep it going straight. Each time a cylinder lights off, it pushes the car in the opposite direction. Yes, the exhaust is coming out with such force that it not only aids in acceleration but keeps the chassis planted to the ground. When a cylinder fails to fire, the car will begin to move towards that side as more force is being applied to the opposite. Oh, that yellow-white color coming out of those headers is also burned hydrogen. When nitromethane burns in the absence of oxygen, which happens in the combustion chamber of that 8.19-liter (500ci) engine, it produces hydrogen which is then ignited upon its exit.

Even When It All Goes Right, It Can All Go Wrong
Larry_Chen_2017_Speedhunters_NHRA_101_58

Catastrophe is ready to strike every time the nitromethane mix ignites in the cylinder. Spark plugs can melt down and make a cylinder no longer fire. If that happens, the engine can hydraulic. So, instead of hydrolock and engine shutdown, the compression of the nitromethane that doesn’t get burned can force the head of the cylinder to lift off with enough force that it’s an explosion, one so hard that it can knock a driver unconscious, lift the car into the air, and even cause the rear tires to explode (if the shrapnel didn’t get it first). If the mixture backfires into the supercharger, it can blow it off the block.

However, if none of these happen and the run goes perfect, a Funny Car can cross the finish beam in 3.8-seconds at 330mph (531km/h). A Top Fuel car, on the other hand, can turn in an average ET of 3.7 seconds at 335mph (539km/h).

Larry_Chen_2017_Speedhunters_NHRA_101_04

Now, you must slow it down and turn off the track. Brakes alone won’t be enough when you’re still traveling at 4Gs and 300mph (482km/h); it can be done, but you’ll probably end up in the sand trap at the end of the track, too. That’s where the parachutes are deployed and that’s no easy ride either. When fully deployed, a parachute can pull 7Gs in the opposite direction and slow the car to more reasonable speed for the friction brakes to slow the cars further and be more manageable for the turn in.

Larry_Chen_2017_Speedhunters_NHRA_101_43

Parachutes can also aid when things start to go wrong during a run, as deploying them during a sashaying moment (aka a ‘tank slapper’) can help slow and straighten the car out. Yes, doing so ends the run, but you don’t destroy the car. Maybe.

By the way, all those g-forces are more than astronauts experience on even the harshest of launches as they only see about 4Gs to 5Gs on average.

Larry_Chen_2017_Speedhunters_NHRA_101_08
Teardown & Rebuild In 40 Minutes, Or Else

While the driver is done and the car is towed back to the pits, the crew still has work to do. After each round the engine must be torn down, inspected, and rebuilt before it can hit the strip again. The forces exerted on these cars are tremendous and the wear and abuse is even more impressive.

Oh, when we say ‘torn down’ we mean the block is stripped of everything; blower, pistons, crankshaft, fuel system – it’s all got to come off be inspected, repaired and/or replaced. The clutches are surfaced, parachutes are repacked, and everything is put back together and warmed up before making another run. This is also done in 40 minutes and is a time mandated by the NHRA, too. You can’t take longer or your competitor will be given a bye-run and a free win. Well, not a free win.

Larry_Chen_2017_Speedhunters_NHRA_101_27

Each time a Top Fuel or Funny Car goes down that 1000-foot track, it costs, on average, $4000. Well, that’s if everything goes right. Where does the money go? Well, nitromethane costs about $35 to $40 per US gallon and a nitro car goes through it at about 65 US gallons per minute. Each spark plug is used up in the engine and each one costs anywhere from $5 to $9 each and there are two per cylinder per run. Copper head gaskets are replaced after every run, and those are about $200 per side per run. Tires usually last about four to six runs and cost $900 each. So, you can see the costs begin to add up. It makes you wonder how any self-funded team can do it, though there are a few.

Larry_Chen_2017_Speedhunters_NHRA_101_05

It was a private team, Dote Racing, that allowed Leah Pritchett to get her start and now she’s the fastest woman in the NHRA and the fastest driver (unofficially) in Top Fuel’s 1000-foot history having recently run a 3.654 elapsed time at 331.85mph (534km/h) in testing. John Force was once a privateer Funny Car driver before he became the household name for the NHRA and the 16-time Funny Car champion.

A career in nitro cars doesn’t always work out, but when it does there is nothing quite like it. Fitting as it’s exactly like a run in a nitro car – flirting between that fine line of glory or disaster. There is nothing like them and it’s why crowds gather into the stands when these cars fire up.

Written by Justin Banner
Instagram: jb27tt
Facebook: racerbanner

Photos by Larry Chen
Instagram: larry_chen_foto
larry@speedhunters.com

Cutting Room Floor
Larry_Chen_2017_Speedhunters_NHRA_101_06
Larry_Chen_2017_Speedhunters_NHRA_101_09
Larry_Chen_2017_Speedhunters_NHRA_101_10
Larry_Chen_2017_Speedhunters_NHRA_101_13
Larry_Chen_2017_Speedhunters_NHRA_101_16
Larry_Chen_2017_Speedhunters_NHRA_101_22
Larry_Chen_2017_Speedhunters_NHRA_101_29
Larry_Chen_2017_Speedhunters_NHRA_101_31
Larry_Chen_2017_Speedhunters_NHRA_101_32
Larry_Chen_2017_Speedhunters_NHRA_101_33
Larry_Chen_2017_Speedhunters_NHRA_101_34
Larry_Chen_2017_Speedhunters_NHRA_101_35
Larry_Chen_2017_Speedhunters_NHRA_101_39
Larry_Chen_2017_Speedhunters_NHRA_101_40
Larry_Chen_2017_Speedhunters_NHRA_101_42
Larry_Chen_2017_Speedhunters_NHRA_101_45
Larry_Chen_2017_Speedhunters_NHRA_101_49
Larry_Chen_2017_Speedhunters_NHRA_101_52
Larry_Chen_2017_Speedhunters_NHRA_101_41
Larry_Chen_2017_Speedhunters_NHRA_101_55
Larry_Chen_2017_Speedhunters_NHRA_101_56
Larry_Chen_2017_Speedhunters_NHRA_101_57
Larry_Chen_2017_Speedhunters_NHRA_101_38
ADVERTISEMENT

Comments

Add comment

E-mail is already registered on the site. Please use the Login form or enter another.

You entered an incorrect username or password

Sorry, you must be logged in to post a comment.

22 comments

by Oldest
by Best by Newest by Oldest
1

Really cool article and amazing pics Larry! I've been to one of these events before and there's nothing else like it in motorsports. The engines are monumentally and indescribably loud - they will rattle your organs from a safe distance from the track. Spectator access is pretty much unparalleled too - you can watch them tear down a car and meet most drivers. No special pit pass is needed, just stay out of the way!

2

Plus everyone can get a face full of nitro to see what it feels like. haha.

3

Absolutely! The best is when the driver is wearing the gas mask and laughing at all the spectators crying and coughing, haha.

4

Oh man getting goosebumps just thinking about it. As a spectator there in nothing else like it on the planet. If you accidentally are down wind of the nitro you can't breathe, your nose starts running and your eyes water. Standing near the line when they launch hits you in the chest like a punch. Your peripheral vision blurs. I had been to almost every form of racing before finally going to a top fuel event. For sheer awe and violence nothing else comes close.

5

Monster trucks are the only thing that come close to being that loud (well apart from jet fighters at an air show). Really amazing spectacle without a doubt!

6

Monster Trucks! Yeah!

7

People really have a hard time understanding it having never been. Gut punch.

8

If anyone has not gotten out to see some NHRA action... do it. These Nitro cars shake your soul when they launch. Its simply a physical feeling that can't be described with words until you've seen it!
Thanks for the great pictures as always Larry!

9

Big fan of speedhunters I've been reading for a while. I mean this as constructively as possible and without malice but I found this article really hard to follow. There were parts where I lost track of what I was reading between two sentences and some key concepts were glossed over that even as a motorsport fan I didn't understand, for example: slide clutch. Maybe thed editor didn't work as closely as necessary but I hope that you can consider these comments when you write you next article.
Cheers

10

From how I understand it, a slide clutch in NHRA determines how hard the launch is and the "bite" is determined by the "clutch guy" on the crew based on the available grip on the track. Similar to how you can modulate the clutch whether you want a smoother or harder launch. Kind of like how a slipper clutch on a motorcycle softens the blow to the rear wheel when downshifting, but the opposite if that makes sense.

11

Without a doubt, the most captivating writing I've read on SH. Ever. The photography isn't half bad either.

My introduction to motorsport was drag racing back in High School. We cajoled the school's SRO to be our "faculty administrator" and ended up racing just about anything with four wheels. Great times and memories, can't wait to get my two little boys out to watch.

12

NHRA may not be my thing but I never knew how complex running a Nitro Car is. 0.o

13

Awesome article! Very informative!

14
Rapee Leepraditwan

Really Interesting and eyes open article.

Thanks for great article Justin. (And great pics too Larry.)

And I never know that top tier drag racing is that costy!!

15
Kamill Targoński

Great article! Im not a big fan of drag racing but you made this post so intresting that i fell like i am now. Great pictures, great writing!

16

Awesome pictures, but man that writing was hard to follow.

17

Awesome article! I remember the first time I heard a top fuel car run, no earplugs, I damn near pissed myself. I was about 13 and like other people have said it is an unreal experience. One thing to think about is if a hyper car going 220 mph crosses the start line at the same time a top fuel car leaves, the top fuel car would still beat it in a 1/4 mile.

18

Just a small correction about hydrazine. It is most definitely used in the US. Just not necessarily in very large quantities.

I have a roundabout dealing with it in my day to day job as an F-16 crew chief, as it's used as a monopropellant fuel to run the emergency power unit (EPU) on the jet. It gives about 10 minutes of bleed air and power to help steer into something soft to crash into.

There are other uses for sure, but I don't deal with them. It's just not factual to list it as "forbidden for use in the US".

Otherwise a very interesting article on a form of Motorsports I don't have too much interest in normally.

19

The clip that is removed after the burnout, is a throttle stop. The driver uses a lever to change the fuel mixture to full flow after the burnout and just as they are staging.

20

Awesome article and photos!

Too bad you guys only get 1000 foot runs. Here in Australia, governed by ANDRA, we still run 400m passes. Even with the Top-Fuel & Nitro Funny Cars :)

21

Actually, the Clutch Pack on current nitro cars can run either 5 disc or 6 disc setups with the new tech. being the 6 disc. However, on a 140 degree F. Starting line temp.
it makes it very hard for the Crew Chief to decide how hard and at what point on the
track to "Weld" the clutchpack, ie make it lock up and run 1:1 with the 11,000 HP motor. Recently, "Laid Back Headers" have improved Nitro FC's 60 foot times dramatically, and thus parlaying the launch into speeds thru the 1000 ft that is faster than a Top Fuel Dragster!
If you find motorsports interesting, you HAVE to see a NHRA NATIONAL EVENT in person!!! :)

22

Loving the over head shot of the mechanics working on the motor, Larry. Nice work! Was it hot? haha

OFFICIAL SPEEDHUNTERS SUPPLIERS