ok so ive heard from un confirmed source that rotary's dont need back pressure.. is this true and if so or if not then why. somone whos not DUMB awnser please.

 

I am pretty sure a NA car needs back pressure but a turbo doesnt

 

Well on piston engines the back pressure is req for the valves, If the back pressure is really low to none then you will have burnt valves.

Thus Rotary engines dont have valves so nothing to worry about.

 

Less backpressure on a turbo means a faster spool. IE faster moving exhaust flow thru the turbine.

 

so your saying the NA doesnt need back pressure? The Turbo doesnt either?

 

^^ X2

Turbos need nothing. they'll run BEST w/o any downpipe at all.

there's infinite discussion as to weather or not a naturally aspirated engine requires backpressure.

 

ok just had me questioning myself for a minute there.

 

huh, I always thought n/a's needed some...

 

Despite the often posted erroneous information, the cat and back pressure have nothing to do with aux port operation on a S3 or S4 non turbo.

The aux ports work off exhaust velocity/ pressure. With the proper exhaust design you can run with no cat or air pump and they will work fine.

Back pressure is always a bad thing. The mistake is when people put bigger exhaust or mufflers on (like a 3inch dia. exhaust on a non turbo), and the aux ports stop working. It is not from reduced back pressure, but rather reduced exhaust velocity. But people think that reduced back pressure from the larger piping. They of course think wrong. The larger pipe actually slows down the speed of the exhaust leaving.

 

Nope, LOUDER is FASTER in my mind that is........ Is that my car starting

 

ahh, that makes sense. thanks for the expliation.