can a muffler do this....

[rollingwithdubz]

I have a 93 SOHC, and a long while ago I got a universal muffler put on. Its basically a 2.5" diameter tube with no hindrance in the pipe at all. I noticed that it gave a lil more pull in the low RPM range, up to bout 3500rpm... but from 4500 on it seems like my engine is completely robbed of power. Can a muffler do this... or does the engine just not have to power in that range?

[peanotation]

are you sure your engine feels robbed or power? or is it the lower sound you're hearing. when you take off your muffler for I4s (galants that is) there's some power/torque loss through the entire powerband, so maybe at the higher bands it's undergoing the same principle. right now my muffler is off for the car about to get painted, and it feels so power-less.

[rollingwithdubz]

well... hears a lil more detail. (I have an automatic trans)... If Im accelerating hard, the engine pulls real nice up to 5500rpm through 1st gear, and 2nd gear... As soon as I hit 3rd gear tho, it'll rev till about 3500 then automatically shift to 4th, even with the gas pedal floored and the car in POWER mode. I can feel a loss in engine power whent that happens.
Same thing when Im takin a hill goin around 70.... the transmission stays in 4th and I start losing speed. So I tap the gas pedal to get the tranny to downshift to the higher end of 3rd, as soon as it shifts to 3rd tho, the engine rpm drops out and the car shifts back to fourth (again, with this happens with the gas pedal floored, and the car in POWER)

[ken inn]

read this article, especially the part about scavenging exhaust gasses:

http://www.dalhems.com/engine/ssheader.html ('http://www.dalhems.com/engine/ssheader.html')

if you were to remove the entire exh system, the car would run even worse.

[4-G-rim]

2.5 inch piping for a N/A SOHC 2.0L A/T car is way too big especially if its mostly in stock form motor wise. You need some backpressure and I would reduce the size of the piping...at most 2.25 diameter in piping.