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Hi,

Just wondering if you guys think 20-25PSI boost is too much for a stock RB25? At the moment i have the following:

HKS3037 Pro S 0.68 Rear.

Apexi Power FC

Apexi PFC Boost Control Kit

Hybrid Front Mount

Z32 AFM

TurboSmart Stage 3 Plumb Back BOV

HKS Induction Piping

HKS Dump

Blitz 3" front Pipe

XForce 3" Highflow Cat

Straight Through 3" Exhaust

Exedy HDCB Clutch

740cc Nismo Injectors

HPI Stainless Low Mount Manifold

Walbro 255L/h In Tank Fuel Pump with Direct Feed Relay Setup (14.4V 2 pump)

(Splitfire Coils) ??? Planning on purchasing but in 2 minds, i think ill wait till i get any breakdown on the dyno

Anyone got any idea of a power figure they think ill make? I compression tested the motor dry and got 141 -142 on all cylinders as well so i think its a decent motor.. Runs well just rich as anything (the highflow cat will be put in once they have a decent basemap that wont kill it)

Thanks!

stock motor on 20 psi. lol

Thicker head gasket and it should be ok. I know of a few people who have run their RBs on 20psi just with a thicker head gasket and a decent tune in it. I run a GT30R and have kept it in the 1-1.1bar range and the car is at 150000km, having run up a good 30,000km on ~270rwkw and loving it still.

i agree. i have seen and heard of a few out there running 20psi and have lived to tell. it all comes down to how well ya tune is. good luck.

hi Mate, i run 20psi all day long with similar mods.

i tried running 24psi and the ring landing broke, 20 psi is just fine keeping an eye on Afr's and knock.

20 PSI it is... think i might wait till i build a new motor before going to 25+. I was just trying to learn from other peoples experience before costing myself huge amounts over a stupid mistake. The tuner said he flow tests the fuel system before tuning it so we will see how it goes. Im starting to think the 400HP at the wheels mark is going to be a little unrealistic just yet.

Like its been said a million times before, its not boost pressure you need to worry about, its the power it makes on that boost pressure, AFR's and knock. Boost pressure on its own means jack when it comes to "safe pressure". 20psi on a T25 is a lot different to 20psi on a T04Z, its relative to the amount of airflow it is pushing and therfore the corresponding power it makes. Run it on 20psi, see what power it makes on the dyno, watch the AFR's and make sure its not running dangerously lean, make sure your fuel system isn't struggling to keep up and make sure it doesn't knock. Simple as that. Knock, heat and excessive rev's kill a motor, not boost pressure.

End of rant.

the higher the boost you run, the bigger the restriction you have in the setup

if you can make the power you want at 14psi instead of 24psi the car will be much better overall

Thats exactly what it comes down to, how safe it is in the tune.

As long as you can keep knock down through the rev range you can tune it to ideal boost pressure for your application.

As was said above there is defiantly no 'cut off' for too much boost. it depends on your turbo and tune :)

Good luck getting the power you want mate. the HKS 3037 is a nicee turbo for the 25.

Cheers :)

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