crg53

I had the full RSR system on my car for about a week, and returned it for a refund. Can you say "DRONE"

Makmov

Yes.

Tuned systems generally work best on open systems. I.E. header + straight pipe out the back. No mufflers, cats, resinators, or bends.

They really work best on two-strokes.

crg53

To my ear, one of the best sounding systems I have heard was one a 3.0L with SSI's and a Dansk sports muffler, nice growl, very different from our engines with cat/primary bypass or cat/secondary bypass.
I just bought a set of 993 heat exchangers that I will fit to my car, thought I would try to hook them up to either a Dansk or a Monty muffler and see what kind of sound will emit from a system like that.

evoderby

Ahum....do a search on David Vizard exhaust science, exhaust tuning on 4-stroke engines has such strong effects/potential DV goes as far as calling it the 5th stroke.

NineMeister

In my experience any reasonably well designed equal length header system (including SSI's) has the potential to make more power than a stock cat-free 964 system. Two examples below, one back-to-back test of a 964RS on 9m Motec with a set of B&B headers & the other a similar back-to-back of a 964RS 9m Motec +3 (billet heads, 3.8, cams, Motec) with 9m headers.

The Flying Dutchman

The well-known tuners are in this thread, good to see that! I think it is very logic that non equal lengths of exhaust sytems (for porsche this means headers) for left and right cilinder bank are a better solution than the 964 uses.

( I did a lot of tuning on 2-strokes, which is much less complex than 4 stroke and exhausts are a more important factor to consider on 2-stroke, but from what I can apply to 4 stroke is that unequal length exhausts is very suboptimal)

Steve Weiner-Rennsport Systems

Well sir,........tuned systems (headers) are specifically designed to scavenge the cylinders in a particular RPM range so these can be configured for a street or race engine. Straight pipes are NOT required to see the gains, IF,...... IF the headers are correctly designed and a good muffler system is used. This is a very complex subject and there isn't room here for a thorough discussion/treatise on this. I can tell you that these engines are more sensitive about header/muffler systems than most people know and there are many systems that do not work very well.

Due to local noise restrictions for many years, we are required to muffle our exhausts and as such, have a header/muffler system that makes very good power on these engines. Naturally, its not for everyone due to noise levels, however one needs to understand that there are many options for street and track cars.

Two strokes AND four strokes both benefit from a well designed exhaust.