Standard Supra Boost Pressure

June 10, 2004

My friend has just bought a very very nice silver Supra TT with full Blitz bodykit + TRD style wing,blitz induction kit and NUR zorst + Volk wheels. Looks !Removed! sweet and best of all its a 6sp getrag job 54k miles.

BTW the manul box is !Removed! slick! Not at all clunky as people think...not as bad as my mr2 anyways(suppose anythings smooth after experiencing an mr2 tubby box!)

I drove it today and noticed the peak boost was sitting bang on at 7.5psi is this correct? Im sure it should be higher no? Its a 1993 model.

also he is of course going to tune it...whats he expecting if he decats? Any overboost probs? Also should he remove both cat pipes?

June 10, 2004

Hi there. The standard boost on a Supra TT should be 7psi on the the first turbo (or up to 4000rpm) and then 12psi when both are running (after 4000rpm). The fact your mate's car is only making 7.5psi means either, the boost gauge is wrong, the second turbo is buggered or you have a boost hose/control problem. Advise him to get it checked out asap at a decent garage. Let me know if he needs a hand.

He can remove the 2nd cat no problem, Blitz and HKS do decat pipes for the Supra. However you should strongly advise him against removing the pre-cats if he is retaining the standard twin turbo setup. The pre cats acts as a form of boost control and if removed must be replaced with a restrictor ring otherwise he will get bad boost creep which can cause the ceramic tubos to break up. In my opinion there is no point in replacing the pre cats with a restrictor ring as the car will then fail the emissions test.

June 10, 2004

BTW the manul box is !Removed! slick! Not at all clunky as people think...not as bad as my mr2 anyways(suppose anythings smooth after experiencing an mr2 tubby box!)

MR2 is very clunky... lol

Looking forward to that Supra test drive buddy !

June 12, 2004

Hells yea Jimlad youll like it loads! Nemesis the car still shifts I think it could be a dodgy gauge or something but he is taking it to Dastek for them to do a full check on it should reveal any probs. Tar for the info :thumbsup:

Emissions is not a problem either m8 he knows a friendly mot man :yes:

You therefore recommend removing both cats and precats?

June 14, 2004

I wouldn't recommend removing both cats unless you are running both an aftermarket turbo and aftermarket management. As I said the first cats work as a form of boost control and removing them will cause damage to the standard turbos. Also what benefit will you get by removing the precats? The car will quite happily run 500bhp on standard internals and hybrid turbos with the front cats in!

Jon