MY STI VS MY BPU SUPRA.... sti boost issues now..
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This is a discussion on MY STI VS MY BPU SUPRA.... sti boost issues now.. within the Comparison: WRX vs World forums, part of the Community - Meet other Enthusiasts category; I own a 2005 sti and a 1995 supra auto bpu. I never tested them both together because the Supra ...

  1. #1
    Registered User Mikeysti's Avatar
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    MY STI VS MY BPU SUPRA.... sti boost issues now..

    I own a 2005 sti and a 1995 supra auto bpu. I never tested them both together because the Supra I had stored back in New York City and my Subaru Sti was down here in Dallas TX. So finally I took a flight and picked up my supra and brought it to my guy and had everything tuned and changed for the long road trip back. Long story short it made it no problem. When I arrived back in Dallas my buddy said " hey bro, what do you think this little subarea will do to that ?.. I said, you know what, lets find out... We went out on ... ahem.. Highway... we went to 40 mph roll.. and the subarea immediately jumped up in front, but once the supra made full boost it was a steady walk passed the sti especially overtime my buddy shifted the sti i gained a half a car.. i stayed in one or two gears most of the race... we went to about 135 and i had my Sti by 7 lengths.. pretty bad.. so we decided to switch.. because only I can drive my Sti right, and all my buddy would need to do in the supra is brake boost and floor it... so same race,, 40 mph we went and i pulled ahead fast on the jump.. by the time i was going 80-85 the supra was pulling past pretty steady . and same thing.. when i shifted it jumped ahead.. i stayed in it until about 130 ish again.. and he had me by 4-5 lengths.. so we decided to do the dead stop race.. thinking the sit would dominate/.. we found a good road.. lined up,, he heated the radials.. began to build boost by braking with the supra and gassing half way.. i kept revs around 4000 rpm.. dumped and gunned.. slammed 2nd,, slammed 3 rd,, i demolished the supra.. off the line the sit will keep up with anything, and my supra even with a torque convertor, just isn't that impressive, and even the stock twins, have considerable lag. by the time he had full boost an grip in the supra i was zoo far ahead, that i can see he would pass me, if i was next to him, but 4-5 lengths is what a 1/4 mile would've ended as. was pretty fun.. but now my sti is having boost issues.. its boost low, it doesn't spool fully, you can hear and feel a considerable power loss.. and when i reset the ecru it'll boost fully again, but when the turbo starts spooling past the plateu of the low boost it does.. the car shudders, stutters and feels like it pulls back and then kicks in kinda,, and thats not flooring it,, if you floor it to redline and shift,, by then the boost will be low again.. and the turbo isn't at all noticeable. and the power is gone... SUCKS.. my supra is still a beast,, bottom line,,.. a big turbo subaru would have problems with my supra on a roll race with stock twins.. especially literally no shifts, overtime you shift im in full boost pulling linear.. but i want my sit to rip my supra a new one.. so need help with the boost issues..

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  3. #2
    Registered User John M's Avatar
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    A full BPU Supra auto should trap around 117 mph, utterly decimating an STi after 50 mph. You don't mention any mods on the STi but you'll have to spend some change to get it into that neighborhood.

    My brother's Supra had a SP57 single with a good converter and built auto. It beat many larger singled cars from a roll for the first 10 seconds or so and still trapped 122 mph.

    To find out what's going wrong with the STi you'll need a logging cable and the Learning View software (free). It'll give you a snapshot of what your ECU has seen to reduce boost and/or timing.

    AWD vs 2wd is always fun, even with a really built car.

    My old Stealth vs Supra with basic mods

    I lose but he's got to earn it!
    John M
    2000 Lincoln Continental - slow DD with the DOHC 4.6 and a Superchips tune
    1992 Lexus SC400 - slow resto project
    2005 Legacy GT Limited - SOLD Feb 2011 - Forged internals, FP HTA Green @ 22 psi.

  4. #3
    Registered User Mikeysti's Avatar
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    Dallas Texas / New York City
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    My sti has Cobb stage 2 with some extra goodies. Lightweight pulley. Pro drive cold air. Aps bov. Y pipe. Shifter bushings. Short shifter Cobb suspension. My supra is bpu. No boost control. Just greddy BC. Hka exhaust downpipe intake etc. But both cars are not running like they should. Brought the supra to the track this past weekend and ran 13.5s. Should be running 12s. Sti is running like crap boosting low still. And had a hard time starting the other day. I'm at a loss.

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