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Discussion Starter #1
I've been saving up for a new custom turbo back exhaust: 2.5 or 3" dp, hi flow 3" cat, 3" cat-back, and some kind of nice muffler. The thing is...I've heard rumours that the boost creep after doing this can be killer, eg- 19psi. I DON'T want to run 19psi on my mostly stock 90 laser (K&N, no aircan/silencer, 2nd gen exh manifold). Is this a risk at all, or can I safely add the full exhaust with no worries?

Note that I don't have a boost guage or a boost controller as of yet :rolleyes:
 

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Search.

If you're not getting one then port your stock O2 housing.
 

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Discussion Starter #3
I did search...

...just not very much :rolleyes:
Most of the posts I found with this problem were with larger turbos or were 2g's. I'm mostly curious if this is as common with 1g's running stock turbos, with no o2 housing porting and no wastegate modification. Any one in this position?
 

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If you go to www.dsm.org and search you'll find that Boost Creep is a common problem with big exhausts even on stock turbos. The problem was discovered early on in the days of the Talon Digest but the cause wasn't clearly understood until later. It's caused by the new exhaust flowing better through the turbine than exhaust gasses flowing through the wastegate bypass. If the backpressure in the wastegate bypass is much higher than the backpressure past the turbine wheel then the wastegate can open all it wants but enough exhaust gas won't flow through it verses past the turbine causing increasing boost feedback. The solution is to port the wastegate and the wastegate passages in the O2 housing and seems to be completely eliminated by upgrading to a larger wastegate flapper which requires porting the wastegate hole to install.

Steve
 

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Boost Creep

Hi,

My first two mods where a K&N and Buschur 2.5 mandrel bent turbo back exhaust with test pipe. Boost creep occured. I put a hi flow cat on and the boost creep stopped.

I now have an EVO Ported Hdr and O2 housing and no boost creep with the test pipe. Porting worked for me.


Speedlimit
 

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i have a 3" turbo back exhaust with a 3" hi flow cat and don't have any boost creep on my 1g with the stock turbo :)
 

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Discussion Starter #7
thanks for the feedback
hmm...I think I'll get guages and an mbc installed first...I don't feel like gambling with burnt out valves and seals and such :p
 
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