4.6Gtconv

Well, basically here’s the deal.. I have done lots of research on this lately and basically what I could find seemed back and forth from true and false, “removing” mufflers and running a straight piped catback with stock midpipe and all 4 cats supposedly will lose HP and Low end torque for you. I don’t really see how. Now aside from the sound preference, I’m not asking what some people think it sounds like. Everyone has their opinion… personally I think it gives the 4.6 2v some character. So how can removing the mufflers lose power and low end torque with just removing the mufflers? The stock 2 pre cats and 2 cats = 4 cats.. That’s more than enough so called “backpressure”, possibly even more than mufflers... if it were true then why not running a O/R h or x with mufflers cause the same problem? Your removing cats with the “O/R” mid pipe.. which from my experience holds a lot more back pressure than a muffler so Wouldn’t you lose power and low end torque? If this were true then all the “straight through” mufflers are losing you low end torque and Hp too ?.. for example Slp LM1 is just a hollowed out piece of pipe basically.. or what about magnapacks or any other bullet style muffler.. or any straight through muffler. ? It dosnt make sense ?. Why do some of the top suppliers carry “ muffler delete kits” for 05-13 mustangs but not the new edge ?Currently I’m running a bbk O/r H and 2 flow master single chamber super 10’s but here in the next couple days I need to get my car smogged so I have to put the cats back on, I was thinking about trying the “muffler delete” with cats for a little while since I was putting the cats back on to smog anyways. Regardless of how it sounds I just want to get to the bottom of this. Anyone know the true and false info ?? Let’s hear some answers or experience!

boduke0220

My neighbor has to stock mid pipe and straight pipes/muffler delete...sounds like crap. Yea you will lose low end torque but you wont even notice it it will be such a minimal difference. No cats gains you power in the mid-upper RPM range, idk if you'd honestly even lose power down low unless you went from stock exhaust to open headers or something extreme.

school boy

you will have no trouble running muffler deletes.

RHuckster

You will lose a bit of low end torque but gain some mid to high end horsepower.

Rick

Bpohlman13

What everyone else is saying. Theres a guy at my school with stock midpipe and muffler deletes and it sounds like poop flapping out of a butthole. Run some sort of muffler. It can be a straight thru design, but please run a muffler.

99GTvert

My guess is with freeing up the flow of air means moving the power band to higher rpm's which might feel like a loss in the 'low end'.

Cristoff

here is the problem with a muffler delete in good ol California.

Division 12 / Chapter 5 / Article 2 of the California Vehicle Code:

27150. (a) Every motor vehicle subject to registration shall at all
times be equipped with an adequate muffler in constant operation and
properly maintained to prevent any excessive or unusual noise, and
no muffler or exhaust system shall be equipped with a cutout, bypass,
or similar device.


for California

LilRoush

In CA you're already begging for ticket/impound for running without cats... why risk more attention with deleting mufflers as well?

As for backpressure, somewhere on here there is a good thread about matching intake/exhaust ability to move air.... if you have one over powering the other, the end result is lower performance because of improper air flow into/out of your combustion chambers.