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Jezz
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Can anyone translate 9 and 14 psi into old money? Ie, Bar? Also can anyone tell me how a de-catted car should boost? Basically first turbo is at 9 psi then at 4000 rpm second turbo comes in and stays dead on 14 psi. But between 3000 and 4000 rpm the boost seems to drop off a touch. Does this sound right? :blahblah:

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9 psi = 0.620528 Bar

14 psi = 0.965266 Bar

 

When my car was BPU .. I used to get 0.8Bar on Turbo #1 .. then at 4K RPM it then boosted to a limited 1.2 Bar.

 

I think the slight drop in power, I remember reading a techie thread on here... between turbo #2 coming online is normal ..

 

But a fully decatted Jspec ... should boost alot higher than 0.9 Bar. Perhaps a boost leak ?

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Just looked at the small pipes around the turbo area, and they're all cracking and really hard and brittle. It seems to have gone pants under boost since those hot weeks in july. Anyone else had probs with stock pipes going hard? As far as i know, it has a restrictor ring, FCD, and the pipe is a fully de-catted stainless jasma sp. Otherwise, fairly standard.

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Sounds normal mate, thought the pressure is a little lower than you'd expect from a properly decated car. Do you have any of the following done:

 

- Walbro fuel pump

- colder grade (eg ik22) plugs

- New fuel filter

- Fuel cut defencer

 

Which Decat pipes do you have and do you have a restrictor ring?

 

Check this graph for a 'normal' bpu car, its bhp vs afr. This was before the FMIC and new FPR (which gained 40rwhp :D )

 

BTW: Jasma is just a Jap standard, kind or like the Kite or E mark on European products. What is the back box you have, the stock ones and non-straight through can be quite restrictive.

 

Edit: re-attaching the attachment ;)

dyno1 afr.jpg

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It may sound weird, but i dont really know alot about my car! Its my third supra but my others have been standard and i have been able to mod from scratch. The exhaust is a straight through 4 inch stainless pipe, but it has no name on it other than the tag saying jasma sr, with a 5 inch backbox, the fuel cut is the one everyone raves on about (cant remember the name), and i persume its running a stock fuel pump. I guess i need to get in my tank tomorrow and check! Anything else i should look for?

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Any chance you could post a pic of the rear box and the pipe work underneath. Might also be worth posting come pics of the 'decat' pipes, from under the car and also from the engine bay, I’m sure a few people here can help you identify what you have. Its a start at least!

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Excellent, i'll do that cos i'd like to know what pipe it is! (so would everyone who's heard it so far!!) In the mean time i'l check plugs and fueling tomorrow and let you know what i find. Is there anyway to tell if a restrictor ring has been fitted, cos i'm just taking someones word for it?!

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The restrictor ring will be fitted in two possible places, either between the 1st decat pipe and the 2nd one, of either between the 2nd decat pipe and the cat back system. As far as I know its best to have it between the 1st and 2nd cat as it has a small effect on limiting boost spikes.

 

Difficult to tell if there's one fitted without unbolting the pipes, but something like the shiny metal gasket here is what you are looking for:

CW decat pipes.jpg

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