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Jul 14, 2000 | 11:10 AM

SwifTT

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Junior Member

Joined: Jul 2000

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This may be a ...

dumb question but, I was talking to a friend of mine who does a lot of mods on imports(yes, rice burners :P) and he was telling me how big of an improvement it would be to remove the cat and let air flow more freely. I don't know much about it, but was wondering if anyone was thinking about it or heard about it or actually done it already. The only downfall to it is that it may be having problems passing the environmental air tests in 2 years(here in BC, Canada at least), but of course you may put it back on before heading in for the exam. Any input will be helpful!<p>Blue/Blue 180QC w/MKII suspension/Madico "Cool Chrome" tint/Growing list

Jul 14, 2000 | 11:21 AM

TTrophy

AudiWorld Member

Joined: Apr 2000

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I think turbo cars have a backpressure issue........

On normally aspirated cars I've seen guys at the track with custom 4" exhaust (crazy) but everybody knows engines are air pumps, more in/more out=more hp. Seems like I read somewhere that turbo engines have to have a certain amount of restriction for turbo efficiency???? Always questioned this myself though. I bet Bracket would know.

Jul 14, 2000 | 11:51 AM

smallTTs

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Joined: Apr 2000

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Modern cats sized for the engine output cause very little loss..

If you try to pump 300+ hp through a cat designed for 150 or 180, you'll get losses. Go to a higher flow cat.
Just taking the cat off isn't worth the effort if your not boosting the power over 30% or so.

Does anyone know if 225 cat is different/larger than 180 cat? Inquiring minds want to know.