PSk wrote:
Gee, that valve is a lot of hassle for no gain.
Just make the car so it is just legal noise wise and you will get most definitely enough noise from the drivers seat from the inlets anyway. Those valves are for posuers driving by people/hopeful audience members not for real cars like this one.
Seems like show when I thought "we" were building a go

Pete
LOL
The gain is my neighbors don't hate

There is also a decent chance that the small restrictive mufflers help damp the damaging reversion pulses around 3500 rpm. Remember these are very fast acting vacuum valves controlled by the ECU that OEMs like ferrari and BMW now put on everything, not the slow manual controlled electric valves popular with the ...ummm...cruiser crowd

Also when I planned all this I couldn't find a 3.5" multicore muffler like the 3" versions I have. The multicore is important to get rid of the "fart can" sound you get from big diameter exhaust pipes.....and I REALLY didn't want it to sound like it had fart cans on it. Borla does make them now so that will be fall back I guess if my fancy valve system turns out to be a failure.