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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
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1. Wastegate shouldn't (and usually cannot) shoot flames. Flames are unburnt fuel that goes into headers while deccellerating or letting off throttle. When throttle is shut, wastegate is shut...thus nothing can go trough wastegate. I believe flames are coming off the exhaust pipe and not wastegate. It's sometimes hard to see as it's a very transient occurence.

2. Bigger turbo and more free-flowing headers exhaust means less back-pressure. With other words, bigger proportion of exhaust gasses will find it's way trough the turbocharger instead of being vented trough the wastegate. This is a common thing. Wastegate spring tension should be adjusted downwards (and in worst case, bigger wastegate installed) if you expirience boost peaks.

Easiest way to diagnose too small wastegate is to watch the boost vs. revs. If wastegate is able to hold certain boost at say, 3500 RPM but boost starts "creeping" upwards at higher revs (as more gases are produced) then it's time to go up one size.

If you just expirience boost peaks briefly just when letting off the accellerator, your BOV might be faulty.

If your boost peaks when you step on the accellerator just to go down later on (regardless of revs) then it's time to check for:

1. Binding wastegate valve stem
2. Wategate piping

If it doesn't help, go with less sping tension. If it doesn't help, install EBC (electronic boost controll).
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Old 04-20-2007, 09:38 AM
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