I have an rb header that I want to install with a straight pipe instead of a presilencer..The question is how long should the straight pipe be..I guess I could also find get the length of the rb presilencer and go from there..
So does anybody know the length of the rb presilencer?

 

You will absolutely want some kind of a pre-silencer on an NA.

A straight to muffler NA exhaust is WAY loud.

Check out the pics & sound clip links in my sig below.

 

loud I like...

 

Gres86,

From my notes, "racing beat presilencers are 20" long, and 2 of these will fill the space between the standard header (16130) and the Y-pipe." I recommend at least one presilencer.

I have a friend in Plano. I suspect she'll know when your on the road. Loud is one thing, obnixious and deafening is another.

 

We are talking "voice of God" loud.

An NA rotary (especially with a header) is way louder than any turbo or piston engine.
Besides, it's not a good idea to **** off cops & girlfreinds.

You can try it & see for yourself, but keep some cash available for a presilencer later.

 

I'm talking loud like a thousand weed whackers.

An uncorked rotary is not the nicest sounding device. Trust me, you NEEEEED a prelencer, or stock rear muffler. The system needs to be able to change the sound to a nice note. With a good exhaust system, it will still be a little loud, but you might amlost get a little rumble out of it (no not really... lol)

Go ahead, dont' use a presilncer, but wait to hear what it sounds like with those headers! Headers are LOUD. (Again, not good loud- *** loud)