Tim Stoughton
New Member
- Local time
- 9:50 PM
- Joined
- Feb 3, 2018
- Messages
- 6
W
I see you trollin . If you honestly believe what you say then do more research. Google 4 stroke exhaust theory. Here's the link: https://www.google.com/search?q=4+stroke+exhaust+theory&sa=Search . Over and over you will see that best efficiency is no back pressure and proper diameter pipe. Length tunes what rpm the vacuum wave hits the exhaust valve during valve overlap, basically doing almost what 2 stroke expansion chambers do, except instead of shoving unburnt fuel back in, it helps draw the intake charge in. Pick your length for the rpm it hits on. Back pressure doesn't help 4 strokes.[/QUOTE
When I used to race go karts I was in the Blueprint class 5 hp Briggs and Stratton on alcohol we ran a 12 to 14" straight pipe. That's been 25 years ago and I'm sure things have changed. We did wrap the pipe with fiberglass wrap and used Stainless Steel wire to hold it to the pipe."Backpressure caused by the exhaust system (consisting of the exhaust manifold, catalytic converter, mufflerand connecting pipes) of an automotive four-stroke engine has a negative effect on engine efficiency resulting in a decrease of power output that must be compensated by increasing fuel consumption."
Source: https://en.m.wikipedia.org/wiki/Back_pressure
Back pressure is a lie.