Well now that i am getting a street-port motor I have to re-think my exhaust and one guy told me this one setup with the collector at the end will make more power then having the collector at the front. i made a diagram of what he said.




Will exhaust one be louder and make more power or will exhaust 2 be better

 

I would run 1&7/8th"- 2" extractors to 1&7/8th" twins with resonator for each pipe. merge after back of gearbox (further back the better) to perhaps 2" or 2.25" pipe over the diff into muffler

 

Long primary systems are reported to make better power. However, if you already have the short primary setup with 2.5" pipe, just stick with that. The HP difference between the 2 is not enough to offset the cost of having it done a second time.

 

what about sound?

 

Assuming both setups are using the same single muffler, and neither has any additional silencers, the sound will be nearly identical. Start adding additional presilcencers, and it becomes a different story.

 

i want my drawing back cody....

 

no its mine

 

What happens if you leave them un-collected?

 

true dual?

 

Yes, if you compared a true dual system to a long-runner type, how would they differ in performance?

 

Well, a true dual does have many benefits on a rotary, one of which is removing the crutial tuning of exhaust pulses, which if you get wrong kills power. One major disadvantage is that you don't get any of the scavaging effect. There is a reason why RB makes the high end exhaust for the FC a true dual. The sound is unique too, kinda like a high revving harley. I know there will be debates on this.

I'm personally going true dual on my S4 NA swapped 82. I have 2" pipes all the way back from my paceshitter header. I'll have magnaflows at the back, not sure if I'll use presilencers though, but if i do it will be 2 4" round magnaflows. The rear mufflers will be 5x8 magnaflow with same end in/out.

 

I run twin 2" with resonator per pipe into collector just before diff then 3" over diff with single Rotaflo muffler. This is on 13B PP and is still streetable