lucasl Posted June 20, 2007 Share Posted June 20, 2007 I don't think this has been discussed before, but what is the benefit having a 4 inch through exhaust to a 3 inch. I read somewhere that a 3 inch exhaust doesn’t make much difference till you get to about 500hp. Only asking because my 4 inch one hangs really low under my car because it’s so big ,that sounds rude as Quote Link to comment Share on other sites More sharing options...
Homer Posted June 20, 2007 Share Posted June 20, 2007 None really, 3inch is more than enough for a TT, in fact CW said 2.5inch is the most suitable size. 4inch exhausts are really only for BIG power cars, 800bhp+ range. The 3inch is lighter, cheaper and has better gorund clearance. Quote Link to comment Share on other sites More sharing options...
lucasl Posted June 20, 2007 Author Share Posted June 20, 2007 ok yea i thought a 4 inch was a bit overkill, you've got me thinking about a 2.5 now lol Quote Link to comment Share on other sites More sharing options...
michel lane Posted June 20, 2007 Share Posted June 20, 2007 4 inch is a bitch !!!!! clearance / noise / noise /noise /noise ...need i go further ??? noise /noise Quote Link to comment Share on other sites More sharing options...
Class One Posted June 20, 2007 Share Posted June 20, 2007 I have a 4 inch on mine. Noise isn't an issue. But the bucket sized outlet is. I hate it. Anyone want a Trial Racing Spirit S/S 4" cat back system? Quote Link to comment Share on other sites More sharing options...
Nic Posted June 20, 2007 Share Posted June 20, 2007 4 inch is a bitch !!!!! clearance / noise / noise /noise /noise ...need i go further ??? noise /noise PHR only had a 4" down pipe and mid pipe in stock when I was ordering mine, so went 4". Looking back I wish I'd have waited and fitted a 3" instead, as ground clearance can be an issue on road humps. No benefit on mine anyway as my exhaust is 3" It does look impressive though and I can smile to myself and think, mine's bigger than yours, which is very self satisfying Quote Link to comment Share on other sites More sharing options...
Cable Posted June 20, 2007 Share Posted June 20, 2007 I've gone for a compromise and got a 3 1/2 inch Quote Link to comment Share on other sites More sharing options...
couv3z Posted June 20, 2007 Share Posted June 20, 2007 I heard lades like 4inch over 3 so i'll b getting a 5 inch oval Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted June 20, 2007 Share Posted June 20, 2007 Anyone want a Trial Racing Spirit S/S 4" cat back system? For free Quote Link to comment Share on other sites More sharing options...
Joeatphr Posted June 21, 2007 Share Posted June 21, 2007 3" Is plenty for a lower hp application. We always use a 3" unless you are going with a 74mm Turbo or larger. Then that is when we include the 4 DP/MP in the Turbo Kit. Cheers, Joe Quote Link to comment Share on other sites More sharing options...
jevansio Posted June 21, 2007 Share Posted June 21, 2007 I went for 3" dp/midpipe & 4" exhaust, it's still loud, I have to put the bung in when doing early starts. 4" section still catches though over rough bumps etc but I can live with that for the sound of the HKS Ti Quote Link to comment Share on other sites More sharing options...
Wez Posted June 21, 2007 Share Posted June 21, 2007 3" all the way Quote Link to comment Share on other sites More sharing options...
paul mac Posted June 21, 2007 Share Posted June 21, 2007 remembering my HNC on gas flow i think we allways tend to get our exhausts the wrong way round the big section should be at the front where the gas is hot, as the gas cools and contracts the section can be reduced, i would suggest a 4" down/front pipe leading into a 3" mid/rear pipe would be the most effecient system and would keep noise/ground clearance good as well, this also applys to intercooler piping the big pipe should be the hot side Quote Link to comment Share on other sites More sharing options...
SupraPL Posted June 21, 2007 Share Posted June 21, 2007 I went for 3" dp/midpipe & 4" exhaust, it's still loud, I have to put the bung in when doing early starts. 4" section still catches though over rough bumps etc but I can live with that for the sound of the HKS Ti That's the only reason why i kept this exhaust. Quote Link to comment Share on other sites More sharing options...
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