First does anybody know about KERKER exhaust mufflers. Also I heard that if you go with a true duel exhaust that you need to install the inversion cones. what is the lowdown. Thanks Terry[X(]

 

A quality system will come with all the reversion you need engineered in.

 

Hope someone elaborates on this... Not familiar with inversion or reversion cones.... Sounds like something to adjust back pressure?

How about expansion chambers? (ok, being funny here... don't flame me)

 

I have the factory system that I eliminated the H pipe on. I got the parts from ebay and they were real nice, and it looks nice. BUT I was told that since I eliminated the cross over I should put the cones in to assist in reversion/ or inversion. Was hoping someboby that was mecanical could expound on the ?.

 

Found this on a website.

"Cones help to restore the performance lost when the stock exhaust is replaced with drag pipes. Cones are known by several names and are available from several manufacturers. The appearance and price varies greatly, but the size and function is almost constant. Improvement is felt in torque and in reduced stumbling when the throttle is opened."




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I'm not an engineer, but since there has not been much response here, I'll take a shot at it. Reversion (as I understand it) is when the exhaust pressure "bounces" back from the restriction (muffler) and tries to get back into the engine/exhaust valve. This is bad, and won't allow the next exhaust "pulse" to get out efficiently because the two pulses are fighting eachother (one trying to exit, the other trying to bounce back in). Ideally, you want a certain amount of "scavanging". Scavanging is where the exhaust pulses bounce out at the right frequency in order to actually pull the last pulse out of the engine. Reversion cones attempt to block the bad, improperly timed exhaust pulses from bouncing back into the engine. It's supposed to act like a one way valve, if you will.

As far as true duals (with no cross-over pipe), I suspect (nope, can't prove it) that they are worse for performance. A cross-over allows the spent gasses to exit essentially through both pipes, releiving some of the back-pressure. Like an H-pipe on a performance street car, it lets the exhaust benefit from both mufflers/pipes instead of being squeezed out of each individual side. This not only allows for less restriction, but it also makes for a mellower tone as the frequencey of the pulses is balanced between the sides (more of a rumble, less of a "blat" sound).