ok so I got brave today (not really since I have two of everything including the stock exhaust) and I welded a muffler I had off a car that was a flowmaster 4 series.... well needless to say I might as well run with no muffler at all cause this thing is beyond all reason of loud... its coming off tomorrow but non the less I wanted to ask why this is happening... when I am in 4th gear around 5-6k RPM the motor starts stalling like its missing on a cylinder (if it had them but that is the best example I can think of) I dont know if this is cause of lack of back pressure or what but its pretty bad and it is way way way to loud... and also when I am just driving in say 4th gear around 45mph and I let off the gas but DO NOT push the clutch in it starts doing that missing thing again as the revs drop.. like there is an engine break...whats up with my car....

 

Could be a vac leak...or it could just be the engine...mine didn't used to sound too good when I let off the gas...but It was that huge rats nest of emessions stuff...something in there was jacked up...it go to the point where my tranny would shake really bad when I let off from high rpm's...the engine would lug...miss...whatever you want to call it...sounded AWFUL...



now...is this actual...missing...or is the engine backfiring a bit?...mine used to backfire like crazy with the stock exhaust system after I cut the cats off...the stock muffler didn't have any...uh...muffle?...left...just all burned out...rattled bad too



Then we welded a glass pack on and it sounds good...runs good...just a tad on the loud side



actually I think mine did that stalling thing really bad in 5th..but it did it in 4th too...it was really noticible on the interstate going about 80 when i'd let off...the engine would shutter...transmission stick would be shaking around violently...just kinda scary...then when i finally came to a stop it would die...and i could barely start it with the key...took like 3 mins or longer



but I could get it rolling and enguage 1st gear...started it up every time...stupid emissions...praise the emissions removal tutorials!

 

In theory, due to rotaries not having a valve train or any of that similar bullshit that pistons engines have, back pressure is not an issue.



--Open to correction--

 

That might be the case...but...I think it does have some effect...my car backfired a lot more when I didn't have any backpressure...ie...stock burned out muffler...and I didn't get very good gas mileage...but my style of driving has changed some too...so i guess you'd have to figure all of that into the equation



Perhaps there is some sort of test we could run to prove/disprove the theory...or even better...find someone thats already done a test :P