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Discussion Starter · #1 ·
wassup everybody, i'm new to this forum and the reason i joined is cos i'm having problems with my supra. i have a 98' jdm supra (2jzgte) with bpu mods. i recently swapped my twin turbos with new oem ones. after i did that the car keeps boosting up to 17-18 psi everytime. i tried dialing down the boost using the boost controller but it soesn't seem to work. i checked if theres something wrong with the boost controller but it seems fine. i just keep getting inconsistent boost. and also when the car gets hot i notice alot of hesitation in the acceleration. i'm using the ik22 plugs and an hks dli. i thought that would fix the problem but it didn't.

these are the mods on my car:

Greddy profec-2 bc
greddy speed limiter remover
greddy bcc
greddy turbo timer
greddy type rs blow off valve
hks intercooler
TRD LSD
TRD single plate clutch

i would really appreciate any feedback to help me solve these problems.
 

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SupraForums Sponsor
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1,020 Posts
Bypass your boost controller to see if your boost returns to factory levels. If it does, then the problem is definately with your boost controller head unit/stepper motor, or the way your boost controller is programmed (if it's a profec b spec 2 like it seems.)

About the hesitation, make sure your coil pack wiring harnesses aren't cracked (mainly the white piece on the inside of the harness that keeps the terminals in their places.) Also verify the spark plug gap is correct and that your DLI is hooked up properly with good connections.

And of course, the first thing to do any time you have a problem is pull your ECU trouble codes and start there (if there are any stored in memory that is.)
Good luck
 
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Discussion Starter · #3 ·
i did bypass my boost controller, but it still over boosts the whole time. my spark plugs are gapped at 0.035. before they were gapped at 0.6 but i don't see a real difference between the old and the new plugs. i will do what you told me to do and see what happens. i really appreciate your feedback. thank you.
 

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Last stock TT on Earth
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625 Posts
Personally I think your gap is too high. Typical BPU gap is 0.032 for the 6097's for example.
 

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Registered
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23 Posts
If it's a JDM TT that has been decatted the boost will run too high because the JDM turbos have a smaller wastegate than the US/UK/Euro spec TT Supras.
You need to fit a restrictor plate in between two sections of the exhaust so that the flow is reduced and the wastegate can cope.
There is a lot of info on BPU with the JDM Supra TT over at www.mkivsupra.net

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Jake
2000 VVTi Supra (JDM)
 
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