BIG BANG THEORY
GT-R tuner turns its expertise to turbocharged 991 Carreras with quietly spectacular results
What does a man synonymous with tuned Nissan GT-RS buy himself for his 40th birthday? Why, a Porsche of course! Iain Litchfield’s choice of a Carrera T is perhaps less surprising when you consider the history of the highly respected company carrying his name. Growth from an importer to tuner resulted in highly-acclaimed cars like the Cosworth-engined Type 25 Impreza. But as fashions changed and Subaru fans moved into Nissan GT-RS Litchfield was right there with them.
Whether you want a few more horses for your GT-R or a full, 1000hp-plus Time Attack monster with a billet engine block, wild aero and ’Ring record ambitions Litchfield is your man and his workshop, dyno and expertise are all in demand. But where do you go when you’ve scratched the GT-R itch, want something a little more mature but still crave the turbocharged horsepower hit? Well, you could do worse than a Litchfield-tuned Porsche. And upgrade packages for 911 Turbos were an obvious progression for both company and customers alike.
Litchfield fancied a 911 of his own though and had his heart set on a GT3. That didn’t happen but, rather than sulk about dealer allocations, he put the money into a Carrera T, spotting both a nice 911 to own and enjoy and a business opportunity to develop tuning packages for all second-gen 991 Carreras using the twin-turbo 3.0-litre engine. The only issue? Out of the box it was near-perfect.
“It’s one of the best cars I’ve ever driven!” laughs Iain, praising the suspension, steering feel, throttle response and expansive power delivery of the stock 370ps/365bhp engine. His personal car is a purist’s delight, with the carbon bucket seats, rear seat delete and optional rear-axle steering. The manual gearbox ticks the enthusiast box and scores him the T’s lowered final drive, his car already living up to the ‘driver’s Carrera’ billing. But there was untapped potential and it wasn’t long before Iain was working to unlock it.
Porsche offers its 3.0-litre turbo six in three states of tune. Starting with the 370ps/365bhp Carrera you can then go to the 420ps/414bhp Carrera S, which is identical bar slightly larger compressor turbines on the turbos. To that you can add the optional factory Powerkit that matches them with larger exhaust turbines, new map and sports exhaust for 450ps/444bhp. This is standard in the GTS and as far as you can officially go on a Carrera.
With a plug-in remap alone Litchfield can release a Gts-beating 460ps/454bhp from the base Carrera engine, as tested on Iain’s T and carefully tuned on the in-house dyno to maximise driveability as well as improved performance. For £1994 including VAT, and fully reversible if required, it’s a temptingly easy option if you want a bit more poke from your 991 Carrera and turns a GTS into a 500bhp-plus Turbo chaser. But this is just the first step.
Looking at the stock exhaust system Iain realised it was hugely restrictive. For those who prefer tuning to come from bolt-on mechanical parts rather than electronic tweaks even a ‘slip-on’ Akrapovic exhaust can release an additional 19bhp and 34lb ft, a result that impressed even the Litchfield boys. Sports cats release a little more still. A Remus equivalent achieves similar results at a more reasonable price. But the real choke-point in the system was the stock, pressed-steel manifolds. By accident or design these restrict the flow of exhaust gases to the turbos, capping both response and power. Admittedly there are few complaints about either when driving the standard car and Porsche has to preserve its range hierarchy. But Iain reckoned there were big gains to be made and had some tubular manifolds fabricated to test the theory.
Even he was pleasantly surprised at the results. “The turbos are now spooling up at least 500rpm sooner and we’re seeing 30lb ft more torque at 2000rpm and an additional 55lb ft at 2500rpm, plus peak power at 480bhp” Numbers are numbers though. Proof, as always, comes in the driving.
Straight out of Litchfield’s gate you hit the kind of bumpy, twisty B-roads on which 911s traditionally shine. And before the first mile the transformational effect of what are relatively minor modifications shine through loud and clear. Literally in the case of the engine, the breathing mods and Akrapovic exhaust singing a louder, more intense tune while the turbos whine and hiss in a way Porsche tries to mask in the standard car. But it’s the throttle response that really stands out.
Rather than sulk about dealer allocations, he put his money into a 911T
The standard engine is hardly mushy, especially when you hit the Sport button. But rather than a contrived, electronic tweak to the throttle mapping the improvements in this car result from mechanical changes and improved breathing. It’s not quite as sharp as the more exotic, naturally-aspirated 4.0-litre in the GT3 variants. But it’s not far off and matched with a much stronger torque delivery that gives you more options on how to drive the car.
Whether you haul from fifth, or enjoy shifting down a couple of gears for the simple pleasure of doing so, the Litchfield Carrera picks up instantly. With so much turbocharged grunt and a fat mid-range to exploit you might be tempted to just short-shift and leave it at that. But the improved breathing means the T is as keen on revs as it is boost, meaning a refreshing amount of your time is spent in the upper reaches of the rev counter. True, a GT3 has another 2000rpm or so to play with and that remains a core USP. But to drive a modern, turbocharged engine that revs like this one is a rare treat in this day and age. And given the good stuff is there in any gear, at any revs it’s easier to exploit than it is in a GT3, especially at road speeds you might consider responsible.
The engine package with the Remus exhaust, sports cats and the remap costs £7354, including VAT and fitting, or £10,363 with the titaniumakrapovic system. A chunk of money but not unreasonable compared with the £7172 factory Powerkit, which isn’t available on the T.
And that’s not all. Although delighted with his T’s handling balance following some track testing Iain reckoned there was a little room for improvement, the front ride height in particular robbing a little steering feel. Some custom springs and adjustable beds let him play with the rake, dropping the front by 20mm and the rear by 10mm while 7mm spacers help fill the arches and take the edge off the raised spring rates. Uniball lower front arm bushes meanwhile permit a tweak to the castor. Stiffer sidewalls on the Michelin Pilot Sport 4s also help, the package adding just a little extra bite to the front end and just a smidge more feedback through the wheel. It’s hardly a stiffly sprung handful but you can now sense the cambers and shifting grip levels through the wheel like you might on an older 911, this paired with the crisp throttle and predictability of the T’s standard mechanical LSD releasing more of the oldschool feel the T always hinted at. This package costs just over £2000 fitted but seems money well spent.
Litchfield’s upgrades are entirely respectful and simply unlock that final degree of interaction the Carrera T’s ‘entry level’ positioning wouldn’t otherwise allow. It’s a tactful package of upgrades, created and refined by people who really know what they’re doing. Best of all it can work the same magic on any turbocharged 991 Carrera, now or at any time in the future you may wish to consider it. Best driver’s 911 for road use this side of a GT3 Touring or R? With a light tickle that’s exactly the potential Litchfield has done to a T. PW
To drive a modern turbo engine that revs like this, is a rare treat
Litchfield 991 T sits 20mm lower at the front and 10mm at the rear, on custom springs. The track has been widened slightly, with 7mm spacers. Uniball front suspension arms allow camber change
Standard exhaust is typically restrictive. Litchfield has replaced it with a combination of Remus sports cats and an Akrapovic exhaust centre box
Below left: A simple remap will liberate over 450bhp. Below: Exhaust is a work of titanium art