Whats the diff horsepower wise between 2 cats and no cats on x-pipes?

[SonicB]

i had bassani o/r x on my 02 gt. i took it off recently and put the stock back on. heres the difference, the car with bassani did lose a little snap in the lower rpm range. i mean so little it really didnt matter, and by 3 thousand rpm and up the car was moving like a rocket ship. i think it helps alot up top end!

i had a similiar experience going from a stock exhaust to a catted magnaflow x-pipe and catback. the engine is stock and the low end torque has disappeared can't even chip 2nd anymore but above 4k rpm the car picks up.

 

[Solid Snake]

Yes, thank you. I tried to explain it but couldn't so I gave a link to a post were Voldamont discusses this. Now others can simply read your reply. Again, thanks for the explanation.

Yeah, I'm Volldamort

 

[93civ]

well im not gonna argue agianst you solid snake or blev and im not flaming either one of you guys BUT when dealing with little 4 bangers if you remove the cats you loose torgue and gain some HP. I wish i could have access to the dyno printouts but i dont as of now(ill see if i can get to any or if my friends still have theirs) but a honda with a cat and a no cat (both stock cept exhaust and intake and without or with cats) the honda without a cat gained a MINIMAL amount of hp buyt lost torque. the other had more torgue than the honda without a cat. every car mechanic i have ever talked to has told me that takin away the cat means more hp less torque. im not flamin either one of you or sayin i've just talked to ALOT of credible people on this. i will see if i can get some mechanics i know to post under my name in the next couple weeks with their knowledge on the topic.

 

[01Black_46]

I noticed a very significant GAIN with o/r magnaflows and packs and dumps(which would take near the most backpressure away compared to stock) I had a superchip put in at the same time and I noticed much more response and much better torque (would chirp hitting the gas under 2K in second) Thats just me-reminds me of the guys that lose power from K@N filter.. Seems like once they get it tuned its a whole nother story (gained 22 ft pounds at 2500 after tune w/ exhaust then before)

 

[00VERT GT]

i had a similiar experience going from a stock exhaust to a catted magnaflow x-pipe and catback. the engine is stock and the low end torque has disappeared can't even chip 2nd anymore but above 4k rpm the car picks up.

Yeah i noticed i can't chirp second as easily as i used to. kinda sucks but whatever...too late now.

 

[Blev]

Quick question. Did you guys get a tune after the exhust change?

Volldamort, sorry I screwed your name up in the first post bro. I had a few Jack and Cokes and wasn't paying much attention. Will a tune help with some of the other issues as far people saying they feel a loss in tq? I know there are no changes to engine components, but will a change in the flow effect anything that a tune can fix?

 

[Solid Snake]

Quick question. Did you guys get a tune after the exhust change?

Volldamort, sorry I screwed your name up in the first post bro. I had a few Jack and Cokes and wasn't paying much attention. Will a tune help with some of the other issues as far people saying they feel a loss in tq? I know there are no changes to engine components, but will a change in the flow effect anything that a tune can fix?

Possibly. One thing that people have to remember is that altering exhaust is not only going to affect peak HP/TQ, but it will also alter the powerband. In most cases, people think TQ is lost because they are looking at peak #'s. What happens is that the TQ is "redistributed" (for lack of a better term) throughout the powerband. They don't actually lose TQ, they may lose peak TQ but gain it elsewhere in the powerband. Do you see what I'm saying?

 

[Blev]

Possibly. One thing that people have to remember is that altering exhaust is not only going to affect peak HP/TQ, but it will also alter the powerband. In most cases, people think TQ is lost because they are looking at peak #'s. What happens is that the TQ is "redistributed" (for lack of a better term) throughout the powerband. They don't actually lose TQ, they may lose peak TQ but gain it elsewhere in the powerband. Do you see what I'm saying?

I think so. Basically they have a smoother acceleration brought on by adding some tq and hp to the lower RPM's?!?!?!

 

[travis0712]

Can anyone back this up with dyno graphs? Lots of reports... but the basic question is still unanswered. I would like to see if someone has a dyno of before and after with an x-pipe with cats and one done without cats. This would be a graph to refer people to.

 

[twogts4us]

I'd still prefer the catted pipe because of the sweet V8 noize that with an off road pipe, unfortunately, just gets to be too much for a daily driver...IMO. I love the sound of an off-road pipe - it's just not for me. (Maybe I'm just getting old!)