I know, I've done a search on this and am still confused. I know that there are quite a few of you guys running the cutouts, so let me know. Where'd ya putem. I am still running cats and I am going to definitely put them behind there. But should I go before the X-pipe or behind it. Obviously, I want it to be loud, but not at any sacrifice to a ton of power.

Oh, and I will be welding these in Friday afternoon sooo.

 

In theory, the further back you put them, the less power you will lose. The closer to your headers you run them, the more power you are going to lose. With the power you are making, an open exhaust system will not benefit you, only noise. With today's exhaust technology, you need to be making a TON of power to warrant running an open exhaust. We did a test on my last Mustang I had at the track, and I made some 10.80 passes on motor, unbolted the 3" exhaust, and took it off, and ran open headers, we slowed to 11.00's. That motor was making in the neighbor hood @ 500-525 HP.

 

i agree, when i un cork my cutouts, i can feel a huge SOTP difference in power.....a loss

PS. as far as putting cutouts on with your cats in place, i wouldnt even waste your money. i had my flowmaster 50s cut off at one point, replaced with straight pipe(no mufflers at all) and dumped before the rear axle, and i was still running my stock cats. the sound difference was barely even noticable, i was very dissappointed. in my opinion, if you wanna get cutous, get rid of your cats too. some people may have had differnt experiences though.

todd

 

i disagree. my dyno results on a stock motor showed from 5hp down low up to 20hp up top just from unbolting the cat back. with all the extra noise you may not feel the power but i bet you gain .1 in the 1/4 with it even on a stock motor.

check out this old thread and you will get my $.02 on the subject and even a dyno chart. >> https://ls1tech.com/forums/showthrea...ghlight=cutout

 

Do you think cut outs are worth 1/10 on an aftermarket exhaust such as Magnaflow? With and without cats? Thanks for the info Parish8 the dyno sheet pretty much sums it up. For me at least.

 

I dynoed my truck with the cutouts open and closed and gained around 16RWHP with them open. I will agree that driving with them on the street it feels like you lose some low end. I have cats and you can definitely notice when the cutouts are open. Sounds like a Nascar car!

 

You say stock motor on the dyno...meaning a stock ehaust system? I could see open exhaust picking up over a stock exhaust sysyem, but an open exhuast system over a modifed one at those power levels?????? Man I just find that extremely hard to beleive. I have seen it to many times (including my own testing at a race track) that a free flowing exhuast system be better for a motor as opposed to an open header. That is my experience.

 

the general thought is yeah you loose low end but nothing i have seen leads me to belive it. on any set up i have ever had i picked up hp and lowered ET with the cut out. this is back to back runs on the dyno or street with gtech. the results have been very repeatable and consistant.

that chart starts at 2500 and there is a 3hp diference then. with a super tight stall maybe you could loose a little power before 2500 but i really dont believe it. to me track runs are not very consistant. typicaly there is an hour between runs and my launches very but on the street i can do much better testing. showing a slight loss or gain at the track with an hour between runs would proove nothing to me.

i have seen the discusion come up many times and usualy post up my experience. so far no one has posted up any conflicting dyno numbers. with a free flowing cat back i would expect to see the exact same thing but with about 1/2 of the gain as no cat back at all.

this has nothing to do with this discusion but here is a chart under boost. i think this was with the 6.0. 55hp with a cut out!

 

I used to feel a slightly weaker low end, below 2000rpms. But above 2000rpms it always felt a little faster. And i gain nearly .3 in the 1/4 with them open.

That is with no cats, dual 2.5" pipe, through dual 2.5" mellow tone race mufflers. So i cant imagine how much better an open cutout is than a stock exhaust.

 

I agree with Parish..
I ran with mine closed, and then ran with them open.
ran 2 tenths faster with them open..

and Curtis I have mine bfore the x-pipe but farthest from the headers as I could get them.