60mm exhaust bore

[Brooky]

Hi people.

Could i get away with an exhaust system with a bore of 60mm on a tuned 1242 16v engine??

The only reason im asking is because i have got hold of some thin walled 60mm titanium tubing and it is very light.

Thanks Tom

[Guy Croft]

Well, based on my exp I wouldn't go that big. I'd use 38mm ID on that motor (1.5"). Even a 260 bhp 2 liter 16v engine will run with a 50mm bore tailpipe.

60mm ID is 2.5 x bigger in cross sectional area than that and it will reduce the ex gas velocity down the tailpipe by nearly half. In a pipe where, ideally, with a normally aspirated engine you want to keep the gas speed as high as you can get it. Otherwise the engine has more work to do to pump it out.


GC