Does anyone have solid info on N/A short primary exhaust that collects right after header into a 2.5" pipe, then 2.5" RB presilencer, and 2.5" muffler after the axle?



Vs. the traditional 2.0" long primary exhaust, dual RB presilencers, that collects right before axle into a 2.5" muffler?



In terms of:

Width of Powerband

Peak HP

RPM Peak HP is at

Amount of noise supression

Tone quality





This is for a 13b Streetport 4-port N/A.

should work really nice! no hard numbers though, remember the off the shelf RB stuff isnt apples to apples.



the long system has a 2" pipe into the muffler, the short system is 1.75"



if you compare the 2 on the same engine, this is what you get. car was a gsl-se, with an s4 engine.



peak power: almost the same



peak power rpm: power peaks at a higher rpm with the short system, shorty was more like 7200, long was more like 6800



width of power band: sub 4000rpms, the long system was much better, the difference was like having working 6 ports or not



i think if they both had the same tubing size after the collector, the power levels would be more even



as far as tone quality, i like the deeper darker tone of the long system.