anyone running a 4" exhaust. any driveability problems. turbo lag . any down sides.
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From what I read it would be really tough to fit 4".//-\\ ((_)) //)) // -
4 in side exit would be easy....as long as you mind the speed bumps..Comment
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i have noticed slightly less low end response with my 3in single box side exit system without cats,but it revs much more freely and pick up at high revs is much beter,also get that nice 5 cyl burble with the one silencer,its no louder than the standard exhaust until about 4k rpm either...Comment
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On a turbo engine, there is little exhaust tuning to be done as you're not relying on backpressure to scavenge the cylinders as with a NA engine (there's a turbo in the way!) I'm surprised that the low end response is worse? The main thing you want to do with turbo engines is clear the gases as quickly as possible, so a bigger exhaust should be the way to go, but there's no need to get silly with sizes! Shorter systems are the next step after bigger diameters.
__MDC__Martin Cutting
aka Keeper of "The Teutonic Kitten"
It's not better than sex, but it runs it a close second.Comment
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This is a good read and may be of interest?
Cheers
ChrisAudi 90 quattro (Typ 85)
20v turbo conversion
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It is a good read, for sure - my comment about backpressure as posted above should really read as per the post by RSCoupe (Mark), ie the exhaust velocity is key to scavenging on NA engines, and the backpressure goes hand-in-hand with it (though not desirably so). The downstream of turbine thing is entirely valid, bigger is better.
I am in the process of switching to K26/K27 turbocharging, and I have already been told about the conical diffuser coming out of the turbine, having read the linked post I now understand more about it. Well worth the time spent reading it!
__MDC__Martin Cutting
aka Keeper of "The Teutonic Kitten"
It's not better than sex, but it runs it a close second.Comment
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thanks guys for the help
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Got a car with 4 inch down pipe and 3.5 inch for the rest of the system with rear exitAelredComment
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Here is a 4" downpipe on Elijahs car. This is my turbo setup, but he graciously let the fabricator make my setup on his car.
The fitment is damn tight on the s2 chassis. The downpipe touches the tie rod at full lock. I'm just running a straight dump at this point ahead of the front axel
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