rx7b13

im confused when it comes to rotary engines do they need the back pressure like normal cylinder engines. and if they dont which exhaust type would be best for function over fashion. i was thinking strait piping my 2nd gen n/a so it wouldnt have the resistance of the mufflers. and what do they sound like i heard they dont sound ricer when the strait piped

eriksseven

iTrader: (6)

umm...

To the best of my knowledge, they do need a certain amount of back pressure. On N/A's the back-pressure comes from resistance in the exhaust. On turbo cars, the turbo itself provides adequate back-pressure.

Also, on N/A's with functioning 5th and 6th ports, backpressure is needed to actuate the ports.

I'm assuming you have an N/A. It's been a while since I've dealt with N/A's, but if you don't mind disabling your 5th and 6th ports (and sacrificing a bit of low-end torque) you should be fine doing a full 2.5" straight pipe with a decent muffler... Perhaps someone with a bit more experience will chime in.

I don't really know what "ricer" sounds like. If you truly prefer function over fashion, sounding "ricer" shouldn't be a concern...

Regardless, it'll sound gnarly.

tie pilot

like the biggest chainsaw you've ever heard. if you drive it on the street, Jesus will cry.

by the way, search for "exhaust" in the 2nd gen section and you will find enough text to read for days.

vicious525E

i like the sound of a pissed off lawn mower i get from my car (since it is running just the turbo, and no down pipe right now)

Cowzzz

omg...hope you have friendly neighboors...

diagoro

omg... i hope you have flame friendly engine bay

MRX_Rotary

N/As need backpressure to open the aux. ports on S4s (86-88). The aux. ports open on S5s (89-91) with a solenoid using the airpump, so you don't need backpressure to open them on S5s.

ddub

The more free flowing the better from what I've seen with rotaries. For a long time I ran an RB collected header to 2.5" straight pipe back to dual BOMZ ebay mufflers (straight through n1 style) that eventually blew out. Essentially my whole exhaust seemed like straight pipe. I finally put in a straight through 2.5" in/out Borla XR-1 muffler to quiet the system down a bit. From straight pipe to that muffler I didn't notice a damn difference, for what it's worth.

Oh and here's what the system sounded like before the Borla, it's basically what a straight pipe system will sound like but possibly a tiny bit quieter since the blown out mufflers might still be doing something, however little it is.

http://home.comcast.net/~rx7pics/before.MPG

That's idle, holding at 3k rpms, and then revving to 7k. At the end you start to hear my friend say "Oh shi...." That's because he was the one taping it and basically felt like his ears had been blown out

The video doesn't give the whole feeling for how loud it truly was, and that's why I eventually put a Borla in

rx7b13

i cant get the link to work

rx7b13

well if i run rb headers with a rb presilencer would that be enought backpressure to open the aux ports.

Jager

iTrader: (10)

You will. Racing Beat uses a back pressure tube to actuate the ports.