um.. no mufflers = less power ??

[JBeryleC]

Hey all...

I got sick of the stock exhaust.. and cant yet afford the MAC cat-back system...

So I cut off the stock mufflers and welded 2.5" tube in their place...

And now, it seems I lost a lot of mid range power... especially in 2nd gear or higher, from about 2200 - 4000 rpm's

I thought if anything, there would be a slight power gain, not a loss at all. Because, no mufflers = way better flow
Right? Wrong?

Any thoughts??

[Bri's ride]

whenever you lose backpressure you lose some low end torque. 2k-4k is a little high, i got a prochamber and magnaflow and there was a noticable lose before before 2k, maybe it is just a psychological thing, sometimes i get in my car and i think something is broken, but its fine.

just my .02$

[JBeryleC]

Well now I am going to throw on the MAC 2.5" cat-back system...

HELP PEOPLE::.. I do NOT want to lose any power at all.. especially low end power!

Is this still going to be a problem?

[Bri's ride]

that mac should help low end, since its not a strait through muffler. If you want low end get new gears, im thinkin about gettin 3.73's once i have the money!

[JBeryleC]

HELLO?? Exhuast specialists.. where are you??

If the back pressure is needed, then how is it that long tubes, off road H or X pipes, cat back exhuasts... all of which drastically reduce back pressure and they all claim horse power gains!?!?!

Especially the SLP system, which is pretty much straight through, I've heard.

Now... I still have stock headers, stock H pipe with 4 cats, and stock tubing... (mufflers removed) all the way back to the tips... including the major bends up and over the rear axle...
And I've lost A LOT of low-mid power...

If I cut out the stock cat-back, and bolt in the 2.5" MAC system, will I atleast have ALL of my stock horse power back??

Or do all catback systems reduce low-mid power?

[Red Mustang Gt 46]

The HP gained is usually in the upper RPM's...with an open exhaust. Since 4.6's have a mild compression ratio, back pressure is needed to have a complete burn within the cylinder, if you were running 10:5 compression or higher...back pressure has a minimal effect...in my experience. (I am no expert)...

[JBeryleC]

Originally posted by Red Mustang Gt 46
The HP gained is usually in the upper RPM's...with an open exhaust. Since 4.6's have a mild compression ratio, back pressure is needed to have a complete burn within the cylinder, if you were running 10:5 compression or higher...back pressure has a minimal effect...in my experience. (I am no expert)...

Ok.. did you lose any low-mid power when you did your exhaust?
I know that there is a claim of HP gains with exhaust systems, but thats just in the higher rpm's...

Wondering if you lose a little low end with a cat-back system, since it loses a lot of back pressure...

???

[Red Mustang Gt 46]

If your using your stock catalytic pipe, you shouldn't lose any low end torque. I've never heard of cat back sytem reducing numbers on a catted exhaust, not that it has never happened. If I may make a suggestion as to your exhaust choice...The mac cat back sounds really nice but the chromed tails stand a good chance of peeling (my first cat back back in 1998). The Flowmaster will sound nice too and the tails are stainless and virtually maintenence free (my set up in 2000). The Magnaflow is nice but too quiet (unless you get the magnapacks, my set up in 2002). As I mentioned before, I finally went with the Magnaflow stainless pipes with Mac stainless mufflers...the complete stainless set up sounds a tad different because of the stainless (deeper).

I'm sure you'll be happy with what ever you choose...let us know.

[JBeryleC]

Well MAC changed their kit... the 2.5" cat back now comes with 3" stainless polished tips

I'm gonna go with it, I cant deal with this straight through exhaust anymore.. way to much power loss

And I chose the MAC because I've heard that its the deepest, aggressive sounding cat-back, and thats what I want

I dont care for the other cat-backs sound because they seem to have a raspy-high-pitched sound in the higher rpm's

So, I'll let ya know when I get the MAC bolted on.. should be good to go with that!

[TARZAN]

Modulars NEED backpressure, whereas some Pushrod motors don't seem too need as much (or any other than that caused by headers).....

On a late model car, its best to do it right, or leave it alone man

-Will

[JBeryleC]

Well yeah.. I learned that one hahaha

Just had to see how loud it would be! lol

[Mercury]

The reason why Hi Flow X/H-Pipes help, and why headers help, even though they cut back pressure is because they Scavage.

Headers, help pull the exhaust gasses out of the cylinder by the Vaccum effect created by the exhaust pulse of other cylinders.

Open exhaust decreases back pressure without any real benefit to scavenging of the cylinder exhaust gasses.

Man...Straight pipes on a stock Mod motor (Or any motor for that matter)???? There are 3 GT's here in town with straight piped exhaust..I know two of them have Off-Road pipes, one of which has Long Tubes also....and they sound like Pure Crap. Pure Obnoxouis. Not a Performance oriented Loud at all.

No meaning to be harsh, but thats just my opinion.

A Mac Cat back system would sound sweet and be good for your car. You shouldnt really be conserened about Muffler Flow, that is until you start talking about 400-450+ Horse power. Then it would be time to think about a good flowing muffler.

Dumps wouldnt sound all that great unless you have Hi Flow Cats or an off-road cross over...and Long Tube headers with that...Otherwise they have this Garbage truck/Sanford & Son tone going on.

If you want that seat of the pants Low End Torque Feel....GEARS! YOu aint gonna get the Bang for the Buck FEELING with any other low buck bolt on like you do gears. It will make it feel like a whole new car.