is backpressure really needed?

is backpressure really needed?

i'm just wondering because one of my friends runs his 95 grandam with no muffler and he hasn't noticed a drop in any performance.

my other friend has a lincoln ls and he took off the mufflers when he was working on new exhaust tips, he loved the sound his car made with no mufflers but he said it felt sluggish.

how does backpressure work then? if it is actually needed....

It's not backpressure that the car needs, it's exhaust velocity. The smaller the piping, the faster the velocity, which is why you shouldn't put 3" exhaust piping on a n/a 4 cylinder. Taking the mufflers off will only increase power.... and noise.

true. you need more velocity for 4's right? and less depending on the engine displacement. liek the accord has a 2.75 on the exhaust but that is with a 3.0 V-6 and the Rolla had a 2.75 but was later made smaller to a 2.25 on the beginning rightat where the flange is at is it a 3 inch in diameter then converts to a 2.25. is that good bad or what?

It's not that they need less velocity, it's that they're putting out more air!

I don't like the fact that they put out more air reason being is when i drive and its cold outside, it seems as if though it has two mini jetliners coming out of my exhaust and just shoots the air though. Imagine two lines of exhaust coming out the back of my car. thats what it looks like.

More air = more fuel = more POWAH!

Exactly

Backflow actually helps push more air out efficiently. With a 4-cylinder design, air does not travel continuously, there is a pulsing lag between each puff of air. Backflow in essence helps pull this lag of air more efficiently than say a system without pulses. backflow is, in essence, the ability for each pulse to carry the one behind it.

keep something else in mind...and i don't know the reason for it, so PLEASE don't jump me for it...but it seems that domestic motors respond VERY well to intake/exhaust work. my cav gained a noticeable amount of both HP and torque with just a straight pipe.

Maybe they got some very bad stock design intake and exhaust in the first place?

that's part of it, i'm sure...

i dunno...it really doesn't make sense to me...but i know the Colorado(S10 replacement) with the I-5 option responds REALLY well to a straight pipe.

Fords are the same way.

I'll second that. We own a ford and it responds very well with just an intake.

works the same way on 2.8L, as well...

ther is a difference in the firing order between some domestics and imports. the displacement if the ports themselves also make a difference from what i've seen.