Project Thirty Four: Chasing Power In A GT-R – Is It Really Worth It?

With great power comes great responsibility. Unless the power comes from an RB26; then it comes with great anxiety.

When I decided to rebuild my R34 Skyline GT-R’s engine in late 2018 – a decision made entirely by the fact an exhaust valve was embedded within the cylinder head – it felt like the perfect time to aim for big power.

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You know the kind of engine I’m talking about – one with a dustbin-sized turbo strapped to the side and a power band similar to the F1 Twitter feed during the Abu Dhabi GP. Nothing, nothing, noise building… absolute carnage two seconds later.

The car came from Japan with 650 horsepower, so it wasn’t exactly slow, but how much of a rocket ship would it feel like with another two hundred thrown on top…?


The quest for big power isn’t as simple as just winding up the boost; not on a 22-year-old Skyline whose history is documented entirely in kanji. Plus, I think we’ve all become slightly poisoned by modern car power outputs. 500bhp seems relatively normal now. 700bhp is an RS6 with an ECU flash, while 1,500bhp is the result of twin-turbocharging a Huracán with a few YouTube stickers down the side.


Maybe I’m glutton for punishment or just a bit envious, but a ‘build’ should require more than just software and a pair of downpipes. It should be approached in stages, growing both with your driving ability and urge to continually scare yourself. But I have to say that – I own a Skyline. Tuning in stages is the only way to avoid complete bankruptcy.

It’s all just part of the journey. Picking a power figure is well and good, but what about the power delivery? The drivability, and the engine’s characteristics? If a car is an extension of yourself, surely the engine needs to feel that way too.


I realise this is immensely contradictory having said several paragraphs back that I want 800bhp. But that does come with a disclaimer: 800bhp from a highly-strung RB that basically hates its own existence. Otherwise, I’d just swap in a supercharged LS motor and spend every spare minute telling strangers how superior it is.


But what kind of sadist actively wants pain? I’ve got my hand in the air, because I’ve bleated on countless times about the Skylines I obsessed over growing up – those that did top speed runs at Yatabe in the ’90s. They had boost levels to make you wince, tyres were an afterthought, and if the car stayed on the road that was cause for celebration.


Then you’d look at the engines. There would be an odd anticipation as each tuner popped open the bonnet revealing what turbo setup they’d gone for. Would it be a giant single, or the holy grail of top-mounted twins? Oh the irony that low-mounted GT2530s felt almost disappointing despite producing north of 600bhp.


There are many reasons why bigger doesn’t equal better. Lag is obvious, getting it to fit another. The response has never bothered me with RBs because shifting the power band a few hundred RPM lower doesn’t suddenly bring a load more drivability. However, if that big turbo is on full boost by 5,000rpm – and your engine has been built for 9,000rpm – now we’re in business.


These were the dilemmas being juggled around my brain while trying to choose a replacement for Project Thirty Four. The HKS T04Z fitted felt maxed out at 680bhp, and the obvious choice would be a T51R for maximum noise and JDM snobbery. But that’s 20+ year old tech now, so would it really be the best choice when everything else going into the engine is new?

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Step forward Xona Rotor. Actually, step back for a second, because prior to this latest rebuild, I’d never heard of Xona. I knew of TiAL Sport (who are behind the brand), but they otherwise sounded like something you’d find on an eBay search. That’s partly down to my own ignorance, and partly because Xona hadn’t explored much of the Japanese tuning scene (at the time).

Stuck in my ‘bigger is better’ mentality, I was ordering a giant 60mm wastegate when an e-mail came back from technical specialist Mike Franke at TiAL Sport asking what kind of application it was being used on. Mainly to check it wasn’t unnecessarily large, and also to introduce me to the world of Xona Rotor turbos.


I’d not seen any used on RBs so understandably had my reservations. But my knowledge here is dated and limited at best; I’ll always take time to listen to someone with much more experience. Mike was keen to run through the proposed engine specs and goals, not least the type of power delivery I was after too (worded slightly better than mad Japanese-spec). What he recommended made a lot of sense. Of course it would, he works for the company… so what’s the science behind it?

An easier way to look at it is bigger equals bigger,” Mike opened with. “As it applies to compressors, the inducer size doesn’t set a specific limit for the compressor flow rate, but it is possible to leverage the exducer size to provide either higher flow, higher efficiency or a combination of both.”

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“But with a larger exducer also comes a reduction in safe shaft speed, and this all ties into how the turbo can power that compressor most effectively. Where you’ll see the most benefits from modern turbo design is in the aerodynamics. Take for instance the move from cast compressors to fully-machined billet designs which allow blade shapes simply not possible when casting wheels. We’ve been able to leverage our own manufacturing capability to bring design changes to market rapidly, which is why you’ll see such a broad range of compressor and turbine housing designs from us.”


Back on the subject of intended use, my less-than-typical goal has always been to make the GT-R feel unhinged and a bit frantic. It’s just what I find entertaining, far beyond having the most responsive throttle or peak power lower down the rev range. For an engineering mind like Mike’s, that requires some deciphering. But again, he was quick to make sense of it all.

“The best indicator of peak power capability is always the actual compressor flow rate (at the required pressure ratio and efficiency percentage) so we encourage our customers to use that data rather than inducer size value.”


“For a road car, or road/track use, we often recommend a size smaller than what a customer typically has in mind since the majority of use will be focused on drivability and less on peak power. But for dedicated track vehicles, the focus becomes more about placing the power band where it can be used with response being less of a priority. In the case of your GT-R, we’re going to be looking at something which sits in the middle of those.”


We decided on a XR 105-68 which boasted a max compressor flow of 105lb/min with a turbine outlet of 68mm. This utilised Xona’s X3C frame which is surprisingly compact given its maximum power rating north of 1,000bhp. In other words, it looked about the same size as the T04Z which came off. My brain still assumed it’d run out of steam way too early despite Mike’s reassurance.

Ron at RK Tuning shared a similar concern, but in typical Ron fashion he simply used words that were a bit easier to hear: “Well, at the very worst you’ll just have a really responsive 650bhp.” he said. The man speaks sense, and only sense.

I’m not a talented driver; I don’t need even half that power on the road, let alone 800+. Maybe I need to manage my own expectations and stop watching ’90s tuning videos. Right, dyno time.


Preparing myself for the worst – which wasn’t power related but total engine detonation – Stu at Rotor Torque called me around lunchtime with some news. “Right mate, we’re at 700bhp,” were his words. ‘That’s fair, to be honest I thought it’d be about that,’ I replied, masking first-world disappointment in the most obvious way possible. “What? No, we’re only at 1.3bar currently,” Stu quickly added. “I was phoning to see what kind of boost you wanted us to push too.”

‘Just keep going until you think it’s not safe,’ was my reply. You’ll likely all agree that it’s a good thing I don’t map cars for a living.


There’s a big gap between the finished engine build (late 2019) and the final mapping with Stu and Jaydee earlier this year. A global pandemic – and becoming a dad for the first time – will do that unsurprisingly. Throughout 2020, the GT-R just wasn’t a priority. Plenty was being done to it, including new fuel pumps, R35 coil packs and a crank trigger kit – but it sat down at Ron’s until life slowly resumed to some kind of normal.

I think the best delay of all was when Stu and Jaydee started doing the on-road mapping. Due to guidelines, they weren’t actually allowed to sit next to each other meaning it had to be finished later in the year. What a truly bizarre time we’re living through.

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Back to the actual mapping. 750bhp was dispatched at 1.5bar and by 1.8bar we’d now cracked through the magic 800bhp barrier. In the end, high boost was left at 1.9bar with a peak reading of 833bhp at the flywheel. That’s 706whp for the lets-not-dispute-transmission-losses dyno warriors.

Best of all, the Xona 105-68 still had more to give. My clutch on the other hand, not so much. Being rated to 850bhp I (wrongly) assumed it wouldn’t need replacing as the end figure wouldn’t reach that high. With 833bhp, anything beyond third gear now results in slipping. And it’s far from a two-minute job to rectify.


Not that it bothered Stu. “The power delivery is completely savage,” he laughed. “We just took it out with a mate’s 650bhp F80 M3 and even on low boost it left it for dead. At 1.9bar it’s a monster.”

That right there is music to my ears. Everything about this engine I wanted to feel savage. From its appearance with exposed pulleys and RB20 cam covers to the noise and power delivery. The only thing missing was a quiet Yokohama road to drag race down, although a similar thing did happen on the A14 just past Kettering followed by an undercover Audi S3 pulling me over. Probably not a story for here…


833bhp on the road, what’s it like? I’m aware this kind of power is far from outrageous in 2021, especially when you see the kind of builds Nitto Performance put together and the various ‘modern’ sports cars cracking four figures without their engines being opened.

But in a 22-year-old Skyline using a 32-year-old engine design it’s beyond brutal. The switch to a huge single throttle body makes it a pig to idle when cold. The cams shift the power band high up the rev range, and when it comes on boost the noise is deafening. But it’s pure theatre; it’s more power than you could ever use on the road properly, but that’s what makes it so entertaining.

I was wrong about the Xona Rotor turbo, too. I assumed it’d build boost early and tail off by 7,000rpm. In reality, it comes in hard from 4,500rpm and then goes completely wild until the 8,500rpm limit. These words could be better described in say, an actual video. So, here’s a short clip of it going through the gears during mapping earlier in the year.

Was it all worth it? Now I’ve had the car back for a few months, absolutely. But it’s taken years to reach this point, multiple mapping sessions, several heated e-mails and Brexit levels of cash being spent in the process.


Would I do it all again? Absolutely not. And this isn’t even an ambitious build in the land of GT-Rs either. But it is for me; I take pictures for a living and this is the most I could achieve, and I’m pretty proud of that.

Ironically, in a point-to-point race, I’d put money on a mapped Golf R making a mockery of it – especially on track. But do 10 laps in each and I know which one I’d be fighting to get back into, even if the lap time was slower. Because this is my problem with aspects of modern performance cars; they’re ferociously fast but they’re not always engaging.

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If you’ve got £300 a month for some finance and £599 to flash the ECU, you can have a car faster than just about anything else on the road. And I’m not knocking that – that’s the most sensible way to go fast and if I had that option when I was younger, I’d have been all over it.

But what makes the GT-R entertaining is the complete sense of occasion it has. Yes, 833bhp will do that, but the way it delivers that is unlike any modern road or race car. The noise is deafening; but it’s a good noise, not a DSG fart. The tacho goes up to 10,000rpm because the engine wants to rev all the way there.

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It feels like it’s about to self-destruct because it probably is. But every noise is a by-product of the job each component is trying to do. Nothing feels artificial; it’s not been tuned for pops and bangs – those flames exist thanks to the volume of fuel being thrown in at full throttle. That alone makes (most of) the pain worthwhile.

And as every year goes by, I can’t help but think we’re a year closer to these cars being nothing but memories on YouTube. That’s not even a dig at EVs; how are we supposed to encourage the next generation of cars fans into Skylines and Supras when their current values put them beyond most supercars?


Racing brought Nissan Skyline GT-Rs into the mainstream, but the world of tuning cemented their popularity. The fact they’re now judged by mileage – rather than their potential – doesn’t seem very fair. Because fundamentally, they’re actually a bit crap when left standard. But everyone loves an underdog, and while an EV or modern supercar can reach this power with ease, very little will beat the sound of an RB screaming to 9000rpm with all the boost.

Mark Riccioni
Instagram: mark_scenemedia
Twitter: markriccioni



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A very unsurprising realisation at the end. Personally, I have OE development experience (JLR at gaydon) and I can vouch for the levels of testing every part is subject to before being signed off. I currently work at a diesel injector test equipment machine manufacture in Buckingham, UK. Now the Japanese namely Toyota started the whole approach to quality, so Japanease parts are generally some of the best in the world, more so from a durabilty perspective, less so out and out performance (unlike Germans, UK, USA, etc).

The notion that we are "upgrading" these parts is foolish, we are "exchanging" these parts, and not necessarily for a "better" option.

I'm not super JDM but an overall enthusiast. At present I am aquiring as newest OE parts as possible for my Fiat Uno Turbo projects (hard little cars to own because the quality is so poor) because I want box fresh, not modifed hahah.

The JDM companines that stand out for me is HKS and Mines, HKS because they design cast components (a sign of durabilty) and Mines because that old video of there R34 GTR shows that they don't change too much, like OE's do. For example Range Rover Sport 5.0 S/C Autobiography vs SVR, SVR isn't 50% different.


If JLR do that level of testing, just imagine what the level a car company with a reliable product must do!! ;-)

Well written article, enjoyed both the tone and the content. I have a mk7.5 Golf GTI with a map and some other bits, apparently it’s just over 300bhp to the wheels. It’s also massively dull and I roll around in eco mode because what’s the point. My old 350z was much more of an event to drive, despite having less power and consequently I enjoyed it much more (and I think I learnt more as a driver).

I’m old enough to remember how 500bhp was the number to hit with your sierra cosworth - most managed it for about 10 minutes then melted and it cost a fortune to get there. If I had the choice now I’d far rather drive one of those than an RS3 with a map and a set of down pipes. It’s not rose tinted glasses (imo) it just feels like you’re doing more with less


That last point - do you think that's mainly down the understanding certain tuners have of these cars, as opposed to a 'balls to the wall' throw everything at it?

Both can (and do) exist in the same world and ultimately only exist if there's the demand. But with that in mind, what's your take on the increasing amount of 'restomods' being produced as low-volume specials, taking those cult cars and essentially exchanging those parts with the odd upgrade thrown in the mix? Obviously there's some who absolutely nail it, and others who seem to have jumped on the bandwagon after seeing the potential value involved. But i think all of it comes down to that understanding of the car you're starting with, and that's not easily disguised.


I don't know who to write to Mark and therefore use this opportunity to 'appeal' to you folks at Speedhunters to feature articles about bike. After all the name speedhunters applies to those on 4 wheels and 2 wheels don't you think?. My stock R6 is quicker than many modified cars here to 1/4 mile. Motogp. World SBK are both very exciting to watch.


Thanks but no thanks. Bikes are boring and it's culture is just like you just proved : all about bragging who dares death the most and measuring their gentlemen sausages. Bikes (especially modern) might be enjoyable as an personnal hobby, but its extremely boring from any other point of view. That's another world, not the one we are following here. Fortunately for you, there are other websites that cover that subject.


In 1986 a Fiat Uno Turbo ran at Bathurst, it qualified last though. Cecchele Motors in Northbridge had the Fiat Uno raced at Bathurst on display in the showroom as well as a Lancia Delta Integrale race car and a red stock one as well as a red Fiat 132 Abarth... I wanted all of them :)

El Capitan Obviouso

Well, there’s a couple age-old sayings that fit a predicament like this.

-“Absolute power corrupts absolutely.”
Of course you’re gonna get thrown curveballs when trying to push a car beyond 650hp. Aside from the ecu-flashbabies mentioned, when has that ever been easy OR cheap?
Top tier, first-world problem.

-“A fool and his money are soon parted.”
If you can’t afford it, don’t spend it.
Enough said. Stop whining.


It looks like you've got the wrong end of the stick of this story - and maybe that's down to the tone and style of writing i've used. But what you've described as obvious points may not be so obvious to everyone else - especially younger generations of car fans.

It is entirely first-world problems. But the amount of people who expect X power figures from certain cars (like GT-Rs) without any understanding of the work involved may also need the obvious stating to them. Albeit in a fair, articulated way rather than a pseudonym on the internet and a screen grab from Clueless.

El Capitan Obviouso

I’m truly flabbergasted!

Was I unfair and inarticulate in my succinct summary of events?

Was my critique one that could also be levied against at least one other article which painstakingly detailed the nightmarish TORTURE of Riccione-modded, R34 ownership?

Am I being accused of whine-shaming? Well, I’d certainly hope so! Someone outta do it.

Anyway, I’m back to writing a draft article for the youth tentatively titled...“Automotive Unicorn Problems: why I’ve invented them and why you should care. Part I”

It’ll point ‘em in the right direction.


Perfect - when you're happy with it, ping us an e-mail to and we'll let you know if your submission is successful. You can find more info on the link below:


I don't think the author was whining, just explaining. It was a great insight into why people do it, well at least I thought so.


Basically this. It's a 20 year old performance car.
Also amuses me that old bud feels like 830hp is ground breaking, when shops here in Aus are doing 1500hp packages that come with a warranty.


Couple of things here, firstly i'm fully aware that 830bhp isn't ground-breaking for GT-Rs - i even reference that within the story. What is being done by the Aus & NZ tuners especially is bonkers, but ultimately i don't have pockets that go that deep. So the build above is a result of what I've been able to achieve right now - albeit over several years.

Too often on the internet/social media we're shown big-power GT-Rs without really giving much insight into the process or (potential) pain that can be faced. If you're in a position to go drop $100,000+ into an engine for more power and reliability, more power to you. But that's not a position most will find themselves in.

Last of all, 800+ horsepower in any Skyline is still stupidly entertaining and way more than you really need on the road. And if you think otherwise - or think that 800 is boring - I dread to think what you need to drive to feel entertained.


"But what makes the GT-R entertaining is the complete sense of occasion it has"

This speaks to me. I love my 99 WRX for the drama. Sure, my neighbours' mk VII Golf GTi is faster almost everywhere...and it's a nice place to sit when you're not driving it fast...and it's easier to drive fast...and it isn't super loud all the time...and and and!
The golden era tuner cars were all about the sense of occasion and I love them for that. But only a fool would disagree that the world has moved on


How long have you had the WRX for now? There's a car that's gone from being almost commonplace on the roads a few years back, to now being a rarity (in good nick). It's amazing how many cars you suddenly wish you'd love to own once the prices start getting a little spicy, it does feel very reactive currently and not very long-term.

That being said, these cars do feel like occasions because of how nice, safe, usable and good most modern cars are now. Very few are genuinely crap from the factory, so what was once described as bad can now be looked at as 'character' with a bit of time. Funny world.

Dino Dalle Carbonare

Totally worth it. People that buy these cars to collect are missing the point. You'll have to take me out in that beast next time I'm in the UK!


When you're next in the UK, it'll be your Avis Rent-A-Car for the trip (fuel expenses not included)


Really enjoyable reading, and an insane sound on the dyno!


Definitely need to get some proper footage/film of it in action, that's a promise


Perfect amount of power for Skyline GTR. Would be massively entertaining especially with a H pattern. Nowadays providing it’s been well built and is maintained you should get decent reliability from the engine.


Cheers Dan and you're absolutely right - this engine isn't even comparable to what it came with from Japan, mainly because i know exactly what's been done and to what level. That's just one of the risks you take with buying someone else's tuned car, but it's 100% worth it in the end.


You're not done! The car (engine) deserves new license plates!
Great write-up on a great car. For me it sums up what Speedhunters is about: to each his own! Build your car for you and enjoy it!!


That's a very good point! Although the way license plates seem to be selling in the UK currently, it'd be cheaper (and easier) to get a different engine at this point...


Totally bonkers!!!


Sounds like a proper GTR!! Love the article and I can completely relate to this, the new cars are quick but there's no real sense of occasion


My thoughts exactly. I love my '94 Evo 2 and its always a sense of occasion even when just turning it over because I've not had the opportunity to take it our for a while. My daily drive 123d is ok performance-wise but it doesn't have the "fizz-factor".

I loved following the build, Mark and hope to see more as it progresses. Everyone has their own idea and opinion but please, always always build for yourself. The best ones are these, not the ones done for likes and views. TBH, those bore me as its childish and very "look at meeeeeee! I need to be the center of attention". Those wheels look great, its not stupid "oops I must avoid that ant or I'll scrape" low and I love that the bodywork is understated (insofar as it can be!) Keep it up and I hope to see it in the metal one day.


I think the 90's thing has to do a bit with AI optimized design tools, I first saw something related to harmonics in tire design and AI-ish stuff in early 2000's so cars started getting safer etc, but some of the grit sort of gets lost. I would like to go with older chassis but then you have more of a problem integrating modern stuff. Anyway you can rebuild/mod or reproduce anything if you want to. You can also start a collectors market with anything remember the classic orchid boom. Hope the clutch holds for a bit, dont forget to find a supply of old tires and wheels.


Absolutely loved reading this article, and I too can completely relate. I’ve spent 4.5 years getting mine, oddly enough, to 705whp except I went with Precision’s 6870 and used HKS’s Step 2 vcam, so full boost on a v-band setup hits at 4k.

You’re totally right, it’s the theatre of the car that really makes the different.

I was out with SC:UK a few months ago and even an owner of a 720s McLaren who was behind me on our putting came over and said ‘now that’s a fast skyline’. I took that as a huge compliment, and many of the other supercar owners said they loved seeing it and watching it spit flames out on the drive (like you say, as part of the fuelling process and not a pop and bang map).

It’s a car that’s a piece of history, and should be enjoyed as so. Like you, I got mine for driving, not for garaging :)

Great article - keep up the great work!


Outing ** not putting