# TT225 boost Problems, running full boost half a gear then hits a wall and drops and stays. .



## jason bouchard (Aug 25, 2005)

ok Ive got an 01 225 tt and i have a stage one chip tuned for 20 psi, i have a stock car other then the tune and a forge diverter valve.
so if i wanna do a pull with WOT and i go through a few gears, i will make full boost but at some point or another in at least one gear it will fall on its face and only hit 10 psi(after it was already sitting at 20 psi in the same gear)
it feels like it bogs so much and sits at 10 psi for the rest of the gear or until i let off the gas count to three and floor it again. . . at which point it will be right back to 20 psi.
i called the tuner but he wasn't much help, Thx guys


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## brian_216 (Oct 14, 2006)

*Re: TT225 boost Problems, running full boost half a gear then hits a wa ... (jason bouchard)*

Do a pressure test and look for a boost leak. how many miles on the car? could be a cracked hose somewhere. its pretty common.


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## jason bouchard (Aug 25, 2005)

*Re: TT225 boost Problems, running full boost half a gear then hits a wa ... (brian_216)*

68k miles, hmm where should i look because most of the time its making full boost its only at higher parts of each gear


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## ShockwaveCS (Jun 22, 2006)

*FV-QR*

may need an upgraded TIP/boost hoses. http://www.forgemotorsport.com/media/intake.mpg


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## jason bouchard (Aug 25, 2005)

*Re: FV-QR (ShockwaveCS)*


_Quote, originally posted by *ShockwaveCS* »_may need an upgraded TIP/boost hoses. http://www.forgemotorsport.com/media/intake.mpg

was that a 225 in the vid?? 
would that cause a sudden lose in bost pressure ?? thx


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## jwalker1.8 (Mar 4, 2008)

*Re: FV-QR (jason bouchard)*

It's stock except for the DV....that is the problem. The little turbos on these cars can't hold boost through the whole gear. If you do things like CAI, exhaust, and other basic bolt ons you may see your car holding to 14-15psi by redline...if you really want more boost get a bigger turbo


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## SteviLee (May 25, 2008)

*FV-QR*

turbo inlet pipe collapsing. upgrade it!


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## Krissrock (Sep 10, 2005)

new N75, or something to control the wastegate. I had the same problem. It's pretty much caused by over boosting. You car takes more time to hit peak boost than what the ecu is requesting. So when you heat peak, the ecu is already requesting something lower to taper it. So then, it lets the boost go to bring it down. it's a time discrepancy. At 2000rpm your ecu is requestion 20psi. You're only at 5 psi maybe. at 2300 you car may be requesting 20 still, but you're only at 15psi. then at 2500 you hit 20+ psi, but the ecu is requesting 17psi maybe as it tapers the boost...then you're overboosting...
I have Uni 1+ and this was happening to me all the time. try a different N75, or some kind of boost controller...
if u have a gauge, see if you go over 20 psi at all...it would only take mine to hit 21 or 22 for this to happen, and it would drop off to 14 and 10 psi consistently, just like you're experiencing...
i don't think it's TIP at all...
take a look at his pic...you ca see the sharp decline in the actual boost attempting to match the requested because it's takes longer to rise...










_Modified by Krissrock at 10:41 AM 9/6/2009_


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## jason bouchard (Aug 25, 2005)

*Re: FV-QR (jwalker1.8)*


_Quote, originally posted by *jwalker1.8* »_It's stock except for the DV....that is the problem. The little turbos on these cars can't hold boost through the whole gear. If you do things like CAI, exhaust, and other basic bolt ons you may see your car holding to 14-15psi by redline...if you really want more boost get a bigger turbo

no that is not it at all, other tts dont do this not modded ones or ones with just a stage 1 like mine. even stock my car would hold 15 psi till redline.


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## jason bouchard (Aug 25, 2005)

*Re: (Krissrock)*


_Quote, originally posted by *Krissrock* »_new N75, or something to control the wastegate. I had the same problem. It's pretty much caused by over boosting. You car takes more time to hit peak boost than what the ecu is requesting. So when you heat peak, the ecu is already requesting something lower to taper it. So then, it lets the boost go to bring it down. it's a time discrepancy. At 2000rpm your ecu is requestion 20psi. You're only at 5 psi maybe. at 2300 you car may be requesting 20 still, but you're only at 15psi. then at 2500 you hit 20+ psi, but the ecu is requesting 17psi maybe as it tapers the boost...then you're overboosting...
I have Uni 1+ and this was happening to me all the time. try a different N75, or some kind of boost controller...
if u have a gauge, see if you go over 20 psi at all...it would only take mine to hit 21 or 22 for this to happen, and it would drop off to 14 and 10 psi consistently, just like you're experiencing...
i don't think it's TIP at all...
take a look at his pic...you ca see the sharp decline in the actual boost attempting to match the requested because it's takes longer to rise...









_Modified by Krissrock at 10:41 AM 9/6/2009_

Wow there ya go that sounds like it. which n75 would be good for around 20 psi ? 
maybe i'll use the resistor mod to see if it stopped (if it does stop then its the n75 for sure seeing to much boost) 
some times it does spike to over 20+ and the next gear is when it does it so ya im gonna try a diode(resistor) for stage one cars and go from there 
Thx







http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## Krissrock (Sep 10, 2005)

I don't know if the Diode mod will help or not. I've never done it. 
If you're not using a stock n75, i would suggest getting a stock one. If you're using a stock one, maybe try a new one. 
otherwise, if you have a friend with some kind of boost controller (MBC or EBC), see if they'll let you try it out to see if that alleviates it.


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## jason bouchard (Aug 25, 2005)

*Re: (Krissrock)*

just checked the ecu got:
code 17965 p1557 - 35 - 10
came up on a look up of the ecu


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## Oh_My_VR6 (Sep 6, 2004)

*Re: (jason bouchard)*

I'm currently having the same exact issues. I have a MBC and diode as well. Have you come up with anything else? I was pointing to my DV or TIP at this point...it's very frustrating.


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