95K miles on the allroad now. In for service today to take care of a bunch of issues

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Jan 30, 2008 | 03:02 PM

#11

skidmark

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Seems guys with piggy pipes have overboost problems compared to guys with aftermarket DPs.

AWEs allroad code was tuned with Milltek downpipes and exhaust. I have no problem with overboost and hold 20 psi to redline with no problems.

Just thinking out loud, I really doubt there is any performance difference, but seems like there could be a backpressure difference which causes driveability issues.

Jan 30, 2008 | 03:08 PM

#12

gragravar

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very well could be

Jan 30, 2008 | 06:41 PM

#13

Nappy

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I don't see how piggies vs. actual dp's could possibly make a difference but, could happen.

Jan 30, 2008 | 07:52 PM

#14

skidmark

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You have never seen posts of differences in exhaust backpressure changing boost?

AWE has a different code for the S4 with no main cats because of backpressure drop.

I am just confused as to which(more or less backpressure) causes which result(boost spikes, or lags).

I know Milltek downpipes are 2 3/8" all the way from turbo to exit inside diameter were stock pipes are 2" inside diameter to main cat, the 1 7/8" from main cat to outlet. Milltek downpipes are also 200 cpi metallic cats were stock are 400 cpi ceramic.