My Exhaust s0unds like a tin can!!

[LordWorm]

Originally Posted by deusexmacaroni

With regards to simply replacing the tip, every exhaust expert I have spoken to (including people who aren't working for exhaust shops) has said that playing with the tip does little for the noise, and that the muffler and piping are responsible for most of the issue.

As Lordworm says, the piping does the most when it comes to backpressure and torque, and big pipes = crap performance on the 4cyls. This I know first hand, as the previous owner of mine upped the pipe size and the muffler size and it kills the low end torque, and makes Skitz beat me off the line running stock.

Just to clarify...i'm not a proponant that backpressure is a good thing... its NEVER a good thing

Velocity is what you want.. big pipes affect velocity..hence why big pipes are bad on smaller engines (unless u are reving the living sh!t out of them).

Backpressure refers to gas being pushed BACK down the pipe (due to restrictions, basically backing up the exhaust system)... this is bad because it will lead to starvation of the engine as exhaust gas is not being evacuated completely from the combustion chamber.....

But yeh, overly big pipe = bad... you need to find the sweet spot between velocity and flow...too small will give stacks of velocity but not enough flow, then you get restrictions and stuff stops working... too big means good potential flow but poor velocity so gas isn't expelled quickly enough and you are back to the same old problem... perhaps twilightprotege can answer any questions on this matter tho.. he explains things far more elequently (i know spelling!) than I

[platypus]

and there was me thinking that it was actually best to have the exhaust flowing the greatest volume at the correct RPM... ie work out your current highest RPM and work around that with your exhaust shop

not whatever big pipe = bad is...

[LordWorm]

Originally Posted by platypus

and there was me thinking that it was actually best to have the exhaust flowing the greatest volume at the correct RPM... ie work out your current highest RPM and work around that with your exhaust shop

not whatever big pipe = bad is...

Not so much... the "work" in an exhaust system is done at the header
you have the headers designed (or you buy one thats close enough to) tuned to a specific rpm band..

once the exhaust gas has left the collector cone, there is little or nothing you can do to positivly affect performance... u just go for the least possible restriction to maintain the most possible velocity. Too small a pipe and all the hard work done in the header goes to waste as the gas cannot flow out of the collector cone at the speed it has generated through scavanging... it backs up, you restrict the primary pipes, you suffocate the engine...you may have insane velocity but it wont do you any good once the revs start to pick up

Too big a pipe, and the gas slows down in the big pipe... yes you can shift a stupid amount of it, but you wont have enough force behind it to push it out until you are up high in the rev range.

its all a balancing act....thats why i say, its a trade off between maintaining velocity, and maintaining flow... a tiny pea shooter is just as bad as a dirty great big 6in exhaust pipe