I spent 3 hours last night pooring over the archives and the search oblivion, to come up with 100 or so half answers and 50 or so post of pure babble.

I have a LARGE modified RB header for my 2nd gen 13B that is in my Track car. The total length of the header is actually 6 ft long!!! They are two seperate tubes all teh way back. I am thinking of putting 2 stainless OBX fart in a foldgers on the end of each pipe and tapping in an o2 bung. Anyone have a solid # on the gain from running true duals? Also what are the drawbacks?

thanks

trevor

 

You want the pipes to collect so you can get exhaust scavenging affect.

 

What does that do? And what is the difference if it collects at the header or at the muffler? What are the pros and cons?

 

It would seem to me that the exhaust scavenging effect would be less pronounced on a rotary... or at the very least, not as important as the higher flow offered by true duals... though the car IS just a 2nd Gen 13b...

Honestly RRTEC, I can't offer any more than the speculation that you've already found. I would *guess* that going to true duals would only offer gains on engines which require much larger flow... Is your 13b ported?

Jon

 

LONG primaries have a propencity to be MUCH louder than a short primary set-up.

Long primaries also shift you power band up, you may get a higher PEAK hp # but the car won't necissarily be any faster.

I would suggest against a "true dual" set-up, esp on a street car
.

 

Long primary = pressue wave tuning for low rpm while short primary = pressure wave tuning for high rpm.

As for the noise issue, it really comes down to pipe thickness and muffling not header length.

 

This is a track car that will ONLY be driven to the track and also to local meets...

 

Checkout both exhaust tech articles Trevor, VERY good read.

http://www.yawpower.com/techindx.html

Anything n/a other than peripheral port should have long primaries that collect way back. Check out the RB catalog, has a good article on it there too.

 

Hey great read, Thanks Brad.