Guest cheesy-peas Posted February 23, 2007 hiya ive got a standard 1.9mi16 engine in my 205 and ive got a hole in the exhaust. Currently it is 3 inch dia the whole through. Im going to build my own system and replace it, what size internal diameter is best 3 or 2 1/2 or any other size?cheers Share this post Link to post Share on other sites
Ahl 4 Posted February 23, 2007 Im purely going by the general concensus on here, but most standard mi16's seem to make full power (and more) on the standard exhaust, 2.5" I'd go for a good standard make exhaust like Arvin-Mettler. Share this post Link to post Share on other sites
smckeown 1 Posted February 23, 2007 the stabndard pipe isnt as large as 2.5" is it ? Share this post Link to post Share on other sites
Ryan 99 Posted February 23, 2007 Standard I think is 2.5" in the downpipe, but it narrows to 2" before the joint with the centre section. Share this post Link to post Share on other sites
welshpug 1,626 Posted February 23, 2007 I think petert or someone said 2" for 8 valve and 2.25" for 16Valve Share this post Link to post Share on other sites
bales 1 Posted February 23, 2007 hiya ive got a standard 1.9mi16 engine in my 205 and ive got a hole in the exhaust. Currently it is 3 inch dia the whole through. Im going to build my own system and replace it, what size internal diameter is best 3 or 2 1/2 or any other size?cheers 3" Christ! Thats a HOOOOGE diameter for a standard N/A car, i'm pretty sure you wouldn't want anything much above 2" unless you have a seriously tuned engine. The downpipe may be 2.5" like on an 8v but I think it then reduces down to 2" and you would be better off maintaining that for the whole exhaust. You must have lost pretty much all your midrange using an exhaust that big I am using 2.5" on my car and that is a turbo!! Exhaust tubing generally seems to be given by OD so you need to know the gauge to work out the ID, but most people tend to just use the OD when the say what diameter the exhaust is. Share this post Link to post Share on other sites
Guest cheesy-peas Posted February 23, 2007 (edited) 3" Christ! Thats a HOOOOGE diameter for a standard N/A car, i'm pretty sure you wouldn't want anything much above 2" unless you have a seriously tuned engine. The downpipe may be 2.5" like on an 8v but I think it then reduces down to 2" and you would be better off maintaining that for the whole exhaust. You must have lost pretty much all your midrange using an exhaust that big I am using 2.5" on my car and that is a turbo!! Exhaust tubing generally seems to be given by OD so you need to know the gauge to work out the ID, but most people tend to just use the OD when the say what diameter the exhaust is. Thanks people. I thought 3" was too much aswell,its too noisy sat in the car aswell. Does anyone reccomend powerflows work becasue i was thinking either them or building my own from jetex products?Or maybe even a standard 205 system. Edited February 23, 2007 by cheesy-peas Share this post Link to post Share on other sites
sonofsam 5 Posted February 23, 2007 I can reccomend the Jetex products, built a complete system with them for my Turbo. They are a nice plug and play affair, as in one end of the pipe has been swaged out, so a pipe of the same diameter can easily be slotted in and clamped up, works a treat and doesnt cost the earth. Share this post Link to post Share on other sites
Guest cheesy-peas Posted February 23, 2007 nice one thanks,i reckon im going to get them from demon tweeks unless theres a better place out there? Share this post Link to post Share on other sites
sonofsam 5 Posted February 23, 2007 Yeah I think there might be, DT are notoriously expesnive on some products! Go direct http://www.jetex.co.uk/ and have a look through the dealer list The one I choose was http://www.coolmotion.co.uk/exhausts.php , may not be the cheapest now, but was at the time. Have fun! Share this post Link to post Share on other sites
sport1901966 8 Posted February 23, 2007 General rule is for anything up to 2.0 is 1.5'' to 2.25'', then from 2.0 about 2.25'' to 2.5'', then obviously when you get to massive engines/tuned engines/forced induction 2.5'' and up Share this post Link to post Share on other sites
Guest cheesy-peas Posted February 23, 2007 just out of interest what diameter is a standard 205 system?Because i might be better sticking to one of those with matbe a different backbox for abit of roar? Share this post Link to post Share on other sites
bales 1 Posted February 23, 2007 I think ph1 is 1 7/8 and the later models were 2" My omp grp N is actually 1 7/8" Share this post Link to post Share on other sites
