are they worth the coin?? does the bottom of the car get all carboned up form the exhaust since the exhaust exits under the car? do u smell the fumes?

 

1 cutout freed up 20hp on my old catback. But that was on an F-bod.
You have an X-pipe setup, sweet. Any Vette guys with some thoughts? Is it worth bypassing the Vette mufflers?

 

All I know, if it doesn't gain Hp, it sounds damn good anyways, but they are known for freeing up 5-10rwhp, even more on modded car. Some carbon will accumulate on the underside of the car, just get a turndown welded in to point it down.

 

i have 3 cutouts, 2 on the y-pipe, one on each side and then a 3rd on the i-pipe.

when i dyno'd. i did one with all closed, one with just the back one open and then the last one with all 3 open.

with just the back one open i gained 19rwhp and then with the other 2 open (all 3) i gained another 25rwhp.

its crazy, everybody at the dyno couldnt believe it.

 

Wicket, you tellin' me you gained 44 RWHP with the cuttouts open? Sorry, gotta wave the flag on this one.

I gained 28 RWHP with a single cuttout open (423 RWHP) compared to running through the stock muffler (395 RWHP) which is VERY restrictive compared to most aftermarket muffs. Gee, I guess if I'd had two more cuttouts I would have been the first A4 tranny 346ci LS1 to dyno close to 450 RWHP with a 224 cam!

 

i feal no power increase but the sound is worth every penny... espesually under a brige or a tunnel.....it will scare the **** out of people ...i can smell it alittle but i have no cats... get it.

 

This One Is An Electric One And Comes Withe Dumps

 

Yes

A little

Not if you have cats

 

I think you would pick up alittle.

 

i have no cats...so will it still make an improvenment

 

i have high flow cats. so will the under of the car get all blck???

 

Yes, you should.


Less so than if you had no cats at all, but still some I would think.

 

i decided not to get them. emissions seems like a problem up here in mass

 

Your better off switching your cats to the offroad pipes if you want power.

I run a cutout but only gain 1hp with it open compared to my Corsa..Now I run the cutout when my stock exhaust is on only.

 

you can raise it as high as you want, you can look at the dyno sheet, is in my other thread in the "internal section". its the "finally dyno's my 231/237 cam w/ pp heads.

first pull was with all closed
2nd pull was with just the back one open
3rd pull was with all 3 open.
there was about 30 people there and everybody was amazed including my self. its crazy i have to admit, but it happened.

 

i love my QTEC cutout..that thing rocks.. i still have the stock muffler so the cutout gives me huge gains..

 

Believe Me U won't regret having it once u get it

 

On my combo, the cutout is worth 15rwhp and 17rwtq over the B&B Tri-flow.

 

I checked again today what the cutout was worth.On my car the loss was 15hp/20tq across the rev range compared to running through my SLP dual dual..Now running my Corsa I gain no hp..

 

"first pull was with all closed
2nd pull was with just the back one open
3rd pull was with all 3 open."

I hope you take this in the helpful manner in which it's intended but here's a suggestion so that you get a more accurate understanding of what really happened.

1. Get the engine and drivetrain (drivetrain takes longer) up to normal driving temperature. This means driving it for a good half hour I would think.

2. Dyno 4 pulls with the single cuttout open. Take the highest reading.

3. Allow the engine to cool back to the starting temp of the first pull.

4. Dyno 4 pulls with all three cuttouts open. Take the highest reading.

Be sure to use a diagnostic scanner to monitor timing advance and O2 readings. Better yet, use a wideband. Keep the fuel/air mixture between 13:1 and 13.3:1.

I think you'll see that there is little to no difference in power between 1 and 3 cuttouts UNLESS you have a restriction between the 2 cuttouts and the single, such as a restrictive sized I-pipe.