How free flowing should the XJ exhaust be?

[Boostwerks.com]

lol. I'm afraid there is no way that a gain of 18-22% is going to happen simply from any header swap. That would be a gain of nearly 30-40hp. When that happens I'd be willing to poop my pants in public.

BTW, the later model TJ's have a dual outlet header from the factory. Does it make 30-40hp more than our motors? Hell no.

With that being said, it will definetly make slightly more power depending on the cam profile. It isn't due to scavenging however, but because it prevents cylinder reversion between the cylinder that is ending it's exhaust stroke and the cylinder that is just begining to open the valve on beginning it's exhaust stroke. However, if the cam profile isn't very aggressive this isn't a big issue (most vehicles).

Not "flogging" you, but simply saying that the twin collectors really isn't going to give you that large of a gain.

 

[BBeach]

lol. I'm afraid there is no way that a gain of 18-22% is going to happen simply from any header swap. That would be a gain of nearly 30-40hp. When that happens I'd be willing to poop my pants in public.

BTW, the later model TJ's have a dual outlet header from the factory. Does it make 30-40hp more than our motors? Hell no.

With that being said, it will definetly make slightly more power depending on the cam profile. It isn't due to scavenging however, but because it prevents cylinder reversion between the cylinder that is ending it's exhaust stroke and the cylinder that is just begining to open the valve on beginning it's exhaust stroke. However, if the cam profile isn't very aggressive this isn't a big issue (most vehicles).

Not "flogging" you, but simply saying that the twin collectors really isn't going to give you that large of a gain.

Im pretty sure that 00+ 4.0's had the two piece exhaust manifold design. I had a "few page" debate dunno, maybe pages 6-10ish area on the matter haha. It obviously Y's down into a single pipe that goes into the cat.

On the note of 18-22% gain....id say myself that our exhaust manifolds are decent as is.....so a gain with a header should be ballpark of 10hp, which is 5%......

 

[alex22]

The 18-22% gain could only be true if they were going from the old cast iron log style manifold to a new steel tube manifold. Did they say what manifold was on before they put theirs on and re-tested?

~Alex

 

[BBeach]

The 18-22% gain could only be true if they were going from the old cast iron log style manifold to a new steel tube manifold. Did they say what manifold was on before they put theirs on and re-tested?

~Alex

I'd almost doubt that too, unless this was a very poorly designed cast manifold going to a properly engineered steel tube manifold. In any case, the stock xj manifold seems to be a decent design (with the exception of cracking of course) and for them to claim a 30-40hp jump is rediculous.

 

[PurpleCherokee]

I doubt the 18-22% also from first hand experience. I believe what they're talking about is on a built motor. Who knows what it is on a stock motor. I do know however that it is a SERIOUS power gain and I love it. Not to sound too mean but I'm tired of retards tryin to argue that dual exhaust is pointless, it's just moronic to think that, but I really don't give a F*CK who believes me and who doesn't. Oh well, your loss. You can sit around and argue with me all you want, I'm gunna be driving around enjoying all my newfound power

 

[alex22]

Purple, did you ever get dyno numbers with your dual exhaust setup?

~Alex

 

[wolfpackjeeper]

yea, i was still waiting on this too

 

[Boostwerks.com]

I doubt the 18-22% also from first hand experience. I believe what they're talking about is on a built motor. Who knows what it is on a stock motor. I do know however that it is a SERIOUS power gain and I love it. Not to sound too mean but I'm tired of retards tryin to argue that dual exhaust is pointless, it's just moronic to think that, but I really don't give a F*CK who believes me and who doesn't. Oh well, your loss. You can sit around and argue with me all you want, I'm gunna be driving around enjoying all my newfound power

lol. So. Tell me exactly how in fluid dynamics those two tubes are going to produce more overall exhaust velocity compared to a single pipe? I would rather have a single 2.5" exhaust compared to dual 1.25" pipes. Why? Anyone who understands engine dynamics, and fluid dynamics will agree with me. Dual exhausts = dual exhaust manifolds. Simple as that.

Why stop there? Why not go with quad exhaust? Surely the more the merrier.

 

[alex22]

i'm just going to do 6 zoomies on my stroker. maybe some of the flapper things like tractors have to keep the rainwater from entering....

~Alex

 

[wolfpackjeeper]

...my boss has those sticking out of the hood of a mud runner he built in NY. granted it also has a 454 in it...

 

[wolfpackjeeper]

I am leaning towards an lsx platform somtime in the future. I want to build another motor for the fun of it. The stroker is not as fun now that it is all together and troubleshooted.

 

[turpehar]

18-22% is the typical sales blow

 

[wolfpackjeeper]

I got 10% on my camaro with long tubes.

 

[Boostwerks.com]

I got 345% on my turbo manifold

 

[PurpleCherokee]

lol. So. Tell me exactly how in fluid dynamics those two tubes are going to produce more overall exhaust velocity compared to a single pipe? I would rather have a single 2.5" exhaust compared to dual 1.25" pipes. Why? Anyone who understands engine dynamics, and fluid dynamics will agree with me. Dual exhausts = dual exhaust manifolds. Simple as that.

Why stop there? Why not go with quad exhaust? Surely the more the merrier.

Ok, there's a lot more to exhaust systems than "exhaust velocity", such as backpressure and scavenging. But I guess in all your infinite knowledge about exhaust systems, you failed to realize that. And don't even start about "fluid dynamics" cause you don't know shit about it, OR engines in general if you think that dual 1.25" pipes equal the area of a single 2.5" pipe. It's called MATH dumbass, there's this little thing called PI... so you're tryin to argue that you know more about "fluid dynamics" than I do, yet you don't even know that diameters and areas of circles are NOT a fixed proportion. HA
Also, in all your infinite wisdom, you failed to realize that a 2.5" single exhaust system would flow TWICE as much volume as a dual 1.25" system :dunce:

Dual exhausts = dual exhaust manifolds. Simple as that.

Wow that's weird... cause I DO HAVE DUAL EXHAUST MANIFOLDS. WOW you're dumb!

And let me know when you figure out how 4 can go into 6 dumbass

 

[wolfpackjeeper]

did you jbweld another manifold to the other side of the block?

 

[BBeach]

OR engines in general if you think that dual 1.25" pipes equal the area of a single 2.5" pipe. It's called MATH dumbass, there's this little thing called PI... so you're tryin to argue that you know more about "fluid dynamics" than I do, yet you don't even know that diameters and areas of circles are NOT a fixed proportion. HA

If you're talking about it not being a fixed proportion, then why did you said "there's this little thing called PI". Its the squaring of the radius that makes the non proportional jump not pi which is a constant. I know what you meant though.
:cheers:

Wow that's weird... cause I DO HAVE DUAL EXHAUST MANIFOLDS. WOW you're dumb!

And let me know when you figure out how 4 can go into 6 dumbass

Dual outlets....that is, unless you jb welded another to the other side haha.

 

[alex22]

Wow that's weird... cause I DO HAVE DUAL EXHAUST MANIFOLDS. WOW you're dumb!

\

Thats too bad, everybody knows that headers are better than manifolds...
and BTW 4 goes into 6 .6(repeating) times

~Alex:spin1:

 

[PurpleCherokee]

did you jbweld another manifold to the other side of the block?

Dual outlets....that is, unless you jb welded another to the other side haha.

Ok... how many times do I have to say, or put pictures up to show that I have TWO MANIFOLDS with ONE outlet each, that makes TWO OUTLETS. Please read, or at least look at the pretty pictures before you go mouthin off about shit you don't know about. Thank you

and BTW 4 goes into 6 .6(repeating) times

Ya, that's intelligent, why don't you come up with a header design that utilizes 2 and 1/3 downpipes...

 

[BBeach]

Ok... how many times do I have to say, or put pictures up to show that I have TWO MANIFOLDS with ONE outlet each, that makes TWO OUTLETS. Please read, or at least look at the pretty pictures before you go mouthin off about shit you don't know about. Thank you

I said dual outlets. You have two, therefore it's correct for myself to say dual ,as in two, outlets.