danpug 1 Posted February 25, 2008 (edited) I need to find an exhaust system for my turbo engine, i've been offered a 2 1/4 inch system cheap but i'm not sure if its big enough or not. I noticed in G.Bells forced induction book he recommends an exhaust diameter of 2 1/4 - 2 1/2 inch for 1.6 engines producing 120-150 bhp per litre. My engine is a 1.8 and i'm hoping for around 110-120bhp per litre. Does the exhaust i've been offered sound too small or could i get away with it? Spec is below. 1.8 8v 1.9 SRi head/cam (light h/work) Turbo Technics T25 Turbo Technics Exhaust manifold Dta management Cossie 2WD intercooler Gti6 injectors 9:1 Compression Edited February 25, 2008 by danpug Share this post Link to post Share on other sites
Rob Turbo 3 Posted February 25, 2008 When I went to get the parts to build my exhaust they talked me out of getting 3" because it wouldn't gain any power but would loose torque, they reccomended 2 1/2" and said it's good for 350bhp easily. So that's what I went for in the end, worked out cheaper and easier to fit under the car than my original plan of 3"! Share this post Link to post Share on other sites
inferno 1 Posted February 25, 2008 2 1/4 will be fine my 2litre turbo home brew pipe was 2 1/4, and as rob said, i was also talked out of 3inch original plans by another sports exhaust making company Share this post Link to post Share on other sites
welshpug 1,661 Posted February 25, 2008 what you'll also find (I heard from Neal at DES) is that 2.25" pipe is so much cheaper than 3". Share this post Link to post Share on other sites
danpug 1 Posted February 25, 2008 The maths (my appaling maths lol) suggest 2 1/4 inches will be ok. Perhaps i will just buy it, when it comes to mapping i'm sure it'll be noticed if something is holding it back. Thanks guys. Share this post Link to post Share on other sites
bales 1 Posted February 26, 2008 I have used 2.5" on mine aswell, 3" is very big pipe to fit under your car especially if it is lowered. Share this post Link to post Share on other sites
vern 0 Posted February 26, 2008 I have a 3" downpipe, and a 2 1/2" system. Share this post Link to post Share on other sites
Hilgie 16 2 Cars Posted February 26, 2008 2.5" will be fine.... Share this post Link to post Share on other sites
tom_m 0 Posted February 26, 2008 I have a 3" downpipe, and a 2 1/2" system. ditto, well thats the plan anyway Share this post Link to post Share on other sites
vern 0 Posted February 26, 2008 Speak to Neal at Des developments, as he supplied mine. Share this post Link to post Share on other sites
