ajazyasin Posted October 21, 2008 Share Posted October 21, 2008 Ive got a 3inch exhaust from turbo to tail. Im running a t78. Would a 4inch exhaust really have any benifit over the 3 on this setup? thanks;) Quote Link to comment Share on other sites More sharing options...
SteveR Posted October 21, 2008 Share Posted October 21, 2008 no Quote Link to comment Share on other sites More sharing options...
jonahjones26 Posted October 21, 2008 Share Posted October 21, 2008 straight to the point steve lol Quote Link to comment Share on other sites More sharing options...
uk-rich Posted October 21, 2008 Share Posted October 21, 2008 it will be much louder Quote Link to comment Share on other sites More sharing options...
JamieP Posted October 21, 2008 Share Posted October 21, 2008 According to the yanks it will spool better and make more power, i have a complete 4" exhaust and mine goes/spools pretty well. Quote Link to comment Share on other sites More sharing options...
SteveR Posted October 21, 2008 Share Posted October 21, 2008 According to the yanks it will spool better and make more power, i have a complete 4" exhaust and mine goes/spools pretty well. No better than mine, with a 3" setup. Look at the plots on Ryan's website straight to the point steve lol Yeah I could have elaborated I guess I spoke to a bespoke race exhaust manufacturer when I was trying to get my screamer pipe plumbed into my downpipe. We spoke about surrounding issues too, and he did a few calcs whilst we were on the phone that showed zero gain and also mentioned a 4" exhaust had nothing to offer a 3" setup for a race car he'd been working on, and that had 700bhp. He reckoned 800bhp~1,000 and you'd need 4", anything less and it's unlikely. 4" would just be noisier. Quote Link to comment Share on other sites More sharing options...
JamieP Posted October 21, 2008 Share Posted October 21, 2008 (edited) No better than mine, with a 3" setup. Look at the plots on Ryan's website ) You have a smaller turbo and vvti and my torque still out spools you by a few hundred rpm, it may make no difference but id like to see back to back testing over this side of the pond, few threads on supraforum say they are better for power and spool. Edited October 21, 2008 by JamieP (see edit history) Quote Link to comment Share on other sites More sharing options...
SteveR Posted October 21, 2008 Share Posted October 21, 2008 VVTi isn't doing anything on mine at present Quote Link to comment Share on other sites More sharing options...
Terminator Posted October 21, 2008 Share Posted October 21, 2008 Interesting thread. 4" is so yesterday, 5" is the way to go. Seriously I went for a 4" system to help with spool and yield the power my setup can deliver at high RPM. If someone makes up a 3" bung for my 4" system I will try it. I predict it would make the mixture richer due to back pressure and spool times will be stretched out and top end power reduced. I do have an induction side to match though, Jun style plenum, longer duration cams and 1mm OS valves. I would like to see any real data related to the 3"/4" debate. Quote Link to comment Share on other sites More sharing options...
TRACIE_LOU Posted October 21, 2008 Share Posted October 21, 2008 tracie said 4inch any day Quote Link to comment Share on other sites More sharing options...
paul mac Posted October 21, 2008 Share Posted October 21, 2008 now others may have a different experience but when i tried a 4" boostlogic exhaust on my car (T61 auto) it killed the bottom end torque stone dead, the car had a superdragger on previously but the 4" exhaust transformed it from a fast "street" car into a noisy dog slow awefull drive, when i opened the car up i got to about 5500 rpm and gave up as there was blood coming from my ears , i hear people say how "good" these exhausts sound, b*llox imho they sound utter sh*te, needless to say the 4" came off about 10 minutes later and back on went the rotting superdragger to be replaced by a 3" Greddy titanium, for me lesson learned Quote Link to comment Share on other sites More sharing options...
jonahjones26 Posted October 21, 2008 Share Posted October 21, 2008 tracie said 4inch any day around Quote Link to comment Share on other sites More sharing options...
michel lane Posted October 22, 2008 Share Posted October 22, 2008 For the larger turbo's setup, the 4 inch will benefit . I have used a 3 inch system and 4 inch on mine , the 3 inch was nice a quite, but when i placed the 4 inch systems on , the turbo did spool about 200rpm quicker, but for 200rpm quicker spool do i really need the noise to go with it . Iam thinking about changing back to a 3 inch system now, to make it more softer on the ears. Quote Link to comment Share on other sites More sharing options...
Robbie Posted October 22, 2008 Share Posted October 22, 2008 If you ask the guys at Boostlogic they'll tell that for anything over the t67 it'll be beneficial with the 4". That said there are plenty of guys running 3 to 3.5 " systems and big turbo's to race levels in the U.S with no probs. This is a good link to 4" systems: http://www.supraforums.com/forum/showthread.php?t=280947&highlight=clash+titans and 3" systems: http://www.supraforums.com/forum/showthread.php?t=451976&highlight=3inch+exhaust Quote Link to comment Share on other sites More sharing options...
SatSport Posted October 22, 2008 Share Posted October 22, 2008 10.66 1/4 at santapod can`t argue with you Robbie on that performance:) Quote Link to comment Share on other sites More sharing options...
ajazyasin Posted October 23, 2008 Author Share Posted October 23, 2008 thank all:) Quote Link to comment Share on other sites More sharing options...
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