The R35 platform was destined for greatness the day it rolled out of the hermetically sealed factory. Handmade bi-turbo charged powertrains coupled to dual clutch gearboxes quite a recipe right? What ensued was around 480bhp at the crank and a 4-wheel-drive system to die for. The R35 is a heavy beast weighing in at 1750kgs but this was for a reason. Mass delivers traction and grip it’s not the enemy if it can be controlled. In virtually every generation of the GT-R and skyline models there’s been a vast tuning scene and in the UK at least we have “stage” upgrades. But what do these mean?

Stage 1 – 590bhp

With most vehicles a “stage 1” package is typically a remap, what this does is calibrate the ECU and “unlock” extra power and torque once the car has been released to the public. This is very similar with the R35 platform with power typically raised to 590bhp (crank) regardless of which iteration it is. Using software and replacing the “Y pipe” removing a set of secondary catalysts this reduces restriction and opens up the V6 soundtrack.

Stage 2 – 610bhp

Stage 2 power again consists of a software tweak the “Y pipe” coupled to a full exhaust thereafter. The aftermarket system is typically of larger bore and dependant on your budget can be made of titanium to save weight, although stainless steel units are also of high-quality. Stage 2 power is typically around 610bhp

Stage 3 – 615bhp

Stage 3 only gains you 5bhp however you get better sound and throttle response thanks to larger intakes and increased MAF size. Coupled to the earlier modifications the GT-R is starting to become a very different proposition altogether.

Stage 4 – 640bhp​

Stage 4 is where things start to get both serious and expensive (I know from personal experience this is where my R35 is currently sitting). 1050 or 1100cc Injectors are fitted (standard size is 570cc) these coupled with intakes and full exhaust system transform the car totally into a 640bhp monster.

Stage 4.25 – 650bhp

Stage 4.25 is a very simple transformation as all that’s required is downpipes and a map tweak. Back pressure from the standard cats means you actually run more boost on a stage 4 tune to “push” through the Cats. With these being removed you can alter the map and boost pressure while again gaining more power. Most cars at this stage will run 650bhp plus. The early cars have smaller turbo intakes so are maxed out at slightly lower power. However later cars with an intercooler can get as high as 680bhp.

Stage 4.5 – 700bhp

Ah the engine drop time. Stage 4.5 adds the addition of hybrid turbos coupled to everything else on this list and high-pressure fuel pumps. This state of tune is good for 700bhp. However the upgrade from stage 4.25 is still around £6700.

Stage 5 > 700 bhp

Stage 5 is as far as Litchfield will go in the catalogue (they’ll take you much higher but that will be price on application levels of tune). Larger Borg-Warner turbos are fitted with a much much larger race intercooler which has been proven to be good for around 1200bhp and larger turbo intakes. You can add upgraded differentials to this to help your GT-R use all the power. Engine Remains on standard internals but this is the last stage it will do so.

So there you have it guys that is your explanation of the stage system in reference to the R35 GT-R. If there are any Americans screaming in the corner stage 4.25 is equivalent to Full-Bolt-On (FBO). Although we don’t really have the option in the uk to run flex-fuel or E85 exclusively. Hope you enjoyed reading this and it helps put into context just how much tuning an R35 GT-R costs.

Details and figures were sources from Litchfield Motors UK one of the renowned GT-R specialists.