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Boost not holding till redline

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Old Dec 9, 2003, 11:53 AM
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Boost not holding till redline

Hey i have had my turbo xs boost controller installed for a while now and my boost does not stay solid till redline. it still drops down to about 16 when the revs get up. Does anyone know how ican fix this. This is the whole reason i got a BC in the first place. Is it my stock bov? i use 91 octane. Thanks
Old Dec 9, 2003, 12:00 PM
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Thats pretty normal.

People pay money to get the car tuned to hold boost like that.
Old Dec 9, 2003, 05:29 PM
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I had mine dyno'd with the TurboXS HP MBC. It still dopped off from 19 - 17 psi at redline. Tuner guy says the turbo can't keep up at high rpms.
I've seen posts on here where stock turbo holds 19.5 til redline?
I do know the stock turbo is more mid-range oriented, and falling off makes sense.
I don't know the A/R of the housings, but most stock turbos are smaller and designed to be most efficient at "normal" driving speeds, (mid range).
I see Turbocharges.com has an upgrade for the stock turbo.
The bigger wheel should move the effective boost window up the rpm scale. (more lag, but higher boost at redline).
They said they are testing it currently and will post results on their website when complete.
Everybody wants their cake (top end) and eat it (burn outs) too.
Old Dec 9, 2003, 07:28 PM
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?????????????????????????????????Mine holds whatever I set it to, you may be getting a BIG spike and have it set to what it is really set at., BIG 16G can Hold 25PSI to redline, no problem.



!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!BUT!!!!!!!!!!!!! !!!!!!!!!!!!!

I bet I knwo what your problem is. Mistu techs are morons, and when they were manufacturing your car, they neglected to TIGHTEN your IC clamps hard enough, so they leak, just like mine did from the factory, so open your hood, and tighten every clamp you see, and your car will hold the boost, really.....
Old Dec 19, 2003, 11:32 AM
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U mean those metal bracelet things on the intercooler piping? Ill try and tighten the screws on them to see if it helps. I noticed that when i pump my boost up to about 21, it holds boost at about 19.5-20 at reline, but when i set the boost to 20, the boost drops to about 16 by redline.
Old Dec 19, 2003, 12:18 PM
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When you routed your MBC did you remove the stock actuator from the system entirely? If not, it will kick in and start to pull boost.

When I first hooked my MBC up, the stocker was still in the loop and the taper effect came into play. Once I took it out, the taper went away.

Jason
Old Dec 19, 2003, 01:15 PM
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Originally posted by bishiboy
I had mine dyno'd with the TurboXS HP MBC. It still dopped off from 19 - 17 psi at redline. Tuner guy says the turbo can't keep up at high rpms.
I've seen posts on here where stock turbo holds 19.5 til redline?
I do know the stock turbo is more mid-range oriented, and falling off makes sense.
I don't know the A/R of the housings, but most stock turbos are smaller and designed to be most efficient at "normal" driving speeds, (mid range).
I see Turbocharges.com has an upgrade for the stock turbo.
The bigger wheel should move the effective boost window up the rpm scale. (more lag, but higher boost at redline).
They said they are testing it currently and will post results on their website when complete.
Everybody wants their cake (top end) and eat it (burn outs) too.




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