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View Full Version : Cut-outs on a 4.6?



SWEET GT
04-04-2007, 09:50 AM
How would cutouts sound on a 4.6 with a off road h (pro-chamber)?

Not sure if it would sound good or not..I love the way my flowmaster 40 series sound..but wonder if I threw some cutouts in before the mufflers if it would make it sound alot meaner..or just plain bad.

bobtsgt
04-04-2007, 10:07 AM
probally sound more like a truck with no exhaust. I ran open H pipe one time and hated it. cutouts would be more benefficial if you had a turbo set up.

MADMOD
04-04-2007, 04:04 PM
The word Camaro comes to mind:tongue2:

Blackout
04-10-2007, 03:27 PM
The car won't run very well if you do. and sound like crap. The car has to have some back pressure to run any good.

08 Vette
04-10-2007, 03:41 PM
It will sound like ASS! Don't do it.

Tim

Black Hole
04-10-2007, 04:30 PM
I wouldn't consider it on a near-stock car.

Forced Induction or a big-block that would help it breathe would be the only way in my opinion.

2-8-1
05-01-2007, 03:56 PM
The car won't run very well if you do. and sound like crap. The car has to have some back pressure to run any good.

I disagree, and not to undercut you, but no 4 cycle engine should ever need back pressure to run its best.

On to that, I used to run stock open H all the time, made a crap ton more power than with a catback, but was droning in the cabin. I went with a o/r X and a mandrel bent Flowmaster setup and it pulled a little harder on top end, but lost nothing on bottom. I pulled the catback off for a local show and it lost a little on bottom, but top pulled good. I'm going to put dynomax bullets on and run like that. Tune it.

Soundwise...ever hear an SRT-4 with an open exhaust? Sounds JUST LIKE THAT, only louder. Kinda like a Farm Tractor...I agree that it sounds like ass...

5.0calypso93lx
05-01-2007, 04:11 PM
I disagree, and not to undercut you, but no 4 cycle engine should ever need back pressure to run its best.

On to that, I used to run stock open H all the time, made a crap ton more power than with a catback, but was droning in the cabin. I went with a o/r X and a mandrel bent Flowmaster setup and it pulled a little harder on top end, but lost nothing on bottom. I pulled the catback off for a local show and it lost a little on bottom, but top pulled good. I'm going to put dynomax bullets on and run like that. Tune it.

Soundwise...ever hear an SRT-4 with an open exhaust? Sounds JUST LIKE THAT, only louder. Kinda like a Farm Tractor...I agree that it sounds like ass...

I agree with blackout. There is no way an open exhaust on a stockish 01 GT will outperform a nice free flowing 2.5" exhaust. These cars really do need the backpressure.

You say you made a crap ton more power, was this done on a dyno, or were you just going by feel?

Blackout
05-01-2007, 09:23 PM
I have to say that a 4 cycle engine and a 4.6l are a little different (just a few more cylinders):). The 96-04 mustangs will lose about I say on average about 3-7 tenths in the quarter with open exhaust. I've seen this with my own eyes at tristate. The car sounded like it was tractor on roids. Just sounded bad. It has to do with the way the entire drive train is designed and the fuel injection tune. now if you have an 302 or 351 carbed you can sometimes get away with no exhaust. In my opinion, I would rather loose a couple of tenths in the quarter with full exhaust (on a old car that runs good with no exhaust) than to be totally deaf and gagging on exhaust smoke. Just my opinion.

2-8-1
05-01-2007, 11:06 PM
You say you made a crap ton more power, was this done on a dyno, or were you just going by feel?

In a case like this, I would think the ass dyno would be more beneficial, your not going to feel 3-5hp from a seat of the pants with a 250hp car...I've never dyno'd it, Im afraid Ill be disappointed.

I will be honest, bottom end felt a little sluggish, however, I could describe it as the feeling of a turbo spooling when it hit 3000rpm, picked up like mad, far more than with full mandrel exhaust.

I am no expert, and will be the first to say so, but I remain firm with this.


I have to say that a 4 cycle engine and a 4.6l are a little different (just a few more cylinders)

What? a 4.6L is a 4 cycle engine...they are not a little different, they are one in the same. Its an otto type 4 cycle V8, OHC. I hope your post was in jest, and understand that I am not familiar with you enough to realize when you joke.


The car sounded like it was tractor on roids.

Agreed 100%


and the fuel injection tune.

Agreed again, however, I still stand firm that a tune on open headers will make more power than on a car with full exhaust. Im not saying any 4.6 will make 35rwhp by cutting a hole in a downpipe, I am saying that high velocity, hot gases escaping a short distance from the head make for the best hp...in any 4 cycle engine.

There is the anomaly that is the Miller Cycle, and I haven't really played with one of those (friend's dad wouldn't let me put a pulley on it), but even with that type 4 cycle, I think less restriction would still equal more power...again, tune is the make or break.

Blackout
05-02-2007, 12:51 PM
281 Sorry man I didn't plan on you getting upset at some ones opinion.and jokes, but if so thats ok. I thoght we were one her to share our insight and to have a few laughs along the way.

Sweet GT,

Hey man try it with both at the track and deside for yourself with the numbers in hand. That way theres no question.

2-8-1
05-02-2007, 03:17 PM
281 Sorry man I didn't plan on you getting upset at some ones opinion.and jokes, but if so thats ok. I thoght we were one her to share our insight and to have a few laughs along the way.

No need to apologize, I did not take offence or get upset at all, I just didn't know if you were joking or if you didn't know what a 4 cycle was, Im new so I don't know when your joking or what. No harm no foul. Im simply sharing my opinion as well. After re-reading my last post, I see where your coming from in this one, the internet has a way of not conveying tone. My apologies for being unclear.


Hey man try it with both at the track and deside for yourself with the numbers in hand. That way theres no question.

I agree, what may work well for one, may not work so well for others, you may not see an improvement as I did. Tune means everything, sometimes you get lucky.

Im getting ready to run open again, Ill get some track times asap and we can compare. :)