Cutout Vs. Catback....

**Raoul-Duke** · 09-12-2007, 07:49 PM

hey guys i have a 04 a4 gto with just k&n cai and dual cutouts...im planning on doin more bolt on's. however i dont know whether to get a catback and lose the cutouts. i have two 2 1/4 to 3inch cutouts right where those resonators would be.. so about midlength under the car...my question is, will i notice that much of a gain if i get a catback exhaust?? i cant see there being that much airflow freed up by a catback when it is opened always with the cutouts. i would think that, that was the most free flowing if anything. if you guys can let me know how much the cutouts are giving vs a catback and why...i would be greatly appreciated, thanks...p.s. i dont plan on getting headers

**01Z28M6** · 09-13-2007, 01:20 AM

I have a single cut-out with my hooker catback. All I've noticed with the cut-out open is more noise; but this is on an LT1, you have a different situation. At least this reply will bump your question up.

**Danger731** · 09-13-2007, 01:25 AM

If you never have em closed then I'de say save your money.

**Raoul-Duke** · 09-15-2007, 01:29 PM

does anyone else know anything about this situation..sarge?? help...lol

**Raoul-Duke** · 09-18-2007, 02:33 PM

anyone? need help here. any assistance?

**Danger731** · 09-18-2007, 02:36 PM

Already answered

**Raoul-Duke** · 09-18-2007, 04:31 PM

no its not. thats for a lt1. not a ls1 gto. a gto's exhaust is nowhere similar to a f-bods =)

**FantaZGuy28** · 09-19-2007, 06:59 PM

Dump the cutouts and get a after market cat back, you will save some weight...

**Raoul-Duke** · 09-19-2007, 08:55 PM

Originally Posted by FantaZGuy28

Dump the cutouts and get a after market cat back, you will save some weight...

yeah but 700 dollars just for freed weight is nnot worth it,lol....can someone please TELL ME IF A CATBACK WILL BENEFIT ME FROM CUTOUTS???? ANYONES PLEEASE!!!! I BEG YOU!!! and how much rhp??

**L3THAL_Z28** · 09-21-2007, 09:33 AM

with cutouts you will actually lose power in the low bands...i say u stick with a catback

**Raoul-Duke** · 09-21-2007, 04:57 PM

Originally Posted by L3THAL_Z28

with cutouts you will actually lose power in the low bands...i say u stick with a catback

yeah i feel the loss down low due to backpressure is lost right?? but i mean as far as...lets say i dyno with the cutouts...and then with a catback...what differences will i see as far as rwhp??

**richard head** · 09-21-2007, 07:52 PM

Originally Posted by blackz-lt1

yeah i feel the loss down low due to backpressure is lost right?? but i mean as far as...lets say i dyno with the cutouts...and then with a catback...what differences will i see as far as rwhp??

The loss down low thing is a myth... freer exhaust, more horsepower. Especially with stock manifolds. If you have enough pressure for your O2 sensors to work, you have enough backpressure and you will get more power from freeing it up up until this point. If you have 2 cutouts on the y-pipe, I think you're fine. A catback will help you some on the power issue, but not a whole lot. If it's really that big of a deal, just go have an exhaust shop chop the exhaust off right after the 2 pipes merge. It will give you an even pressure on each cylinder bank and the best flow possible considering that. Close the cutouts though... but the cut will help you a lot on weight too, i think the stock setups weigh like 50 lbs.

**Raoul-Duke** · 09-22-2007, 02:15 PM

Originally Posted by richard head

The loss down low thing is a myth... freer exhaust, more horsepower. Especially with stock manifolds. If you have enough pressure for your O2 sensors to work, you have enough backpressure and you will get more power from freeing it up up until this point. If you have 2 cutouts on the y-pipe, I think you're fine. A catback will help you some on the power issue, but not a whole lot. If it's really that big of a deal, just go have an exhaust shop chop the exhaust off right after the 2 pipes merge. It will give you an even pressure on each cylinder bank and the best flow possible considering that. Close the cutouts though... but the cut will help you a lot on weight too, i think the stock setups weigh like 50 lbs.

icic..yeah but i dont want my tail pipes to be missing,lol...

soo no one really knows exactly the difference in rwhp from having lets say a loudmouth catback vs. dual cutouts right before the resonators. like mid length of the car????