Benefits of the X-pipe on LS V8 exhaust

[RigsLS]

Wanted to ask you guys opinion on this as I'm soon (next week or thereafter) making an effort on getting my exhaust system redone.

As some you may know I'm currently running the following,

2.5" SS piping from the cats back,
2.5" magnaflow x-pipe (#10791),
Bassani mufflers (#4820)
Magnaflow tips (#35121)


As some of you may also know, a drunken sailor put this on and I was not happy with the work.
It needs to be much straighter, cleaner welds and the Bassani's need to be hung/aligned correctly,
tucked upwards and inwards more, Chrome tips will be nixed and hope to have just plain SS tips, which I will rattle can flat black with high heat temp paint.

The Bassani's are only a couple of seasons old, in great shape and absolutely want cleaned up at the welds and reused.


Two questions ...


1) What is the benefit of running the X-pipe and can/should I attempt to straight bank pipe it instead?
(don't want to trouble the guy with having to clean that up also or ordering yet another x-pipe.

Any issue with not running the x-pipe, what is it's benefit if any at all?


2) Would it be a smart idea to have him clamp bolt the piping coming from the CATS, in case I might need to get to the transmission, so as not to have to cut into the exhaust again. Meaning, it would be easy to undo the clamps and drop a section of piping out of the way to make room for transmission removal? Bad idea?



What you all think, would really appreciate your thoughts on both counts if possible.

~ Thanks in advance.

 

[2002_lincolnLS]

With a properly placed x pipe it will help scavenge the exhaust from each bank.

this increases the vacuum pulling the exhaust pulses out of each cylinder. In turn the engine can fill the cylinder with more fresh fuel and air. As we do not have scavenging headers on our car the x pipe benefits us more than a car with proper headers. However the proper placement is key.

Now our cars not really being all that powerful and not pumping out huge volumes of exhaust, it won't make a ton of difference. More difference would be seen by going back to stock pipe sizing after the x pipe to keep the velocity up. Bigger pipe means slower moving gases, unless of course the volume is restricted. 2 inch pipe has more than enough volume for a 3.9.

my 2 cents, backed by fluid dynamics...

 

[2002_lincolnLS]

also, for clamping, if they are tightened enough to hold they have ruined the pipe for reuse, unless you resize the pipe with an expander. Really welding would be fine, it will better. Also the Cats themselves should be removed to remove the trans. It may be able to be done without, but any shop will drop them as well as they are very much in the way. So weld the pipes.

 

[De-marko]

I know the x is supposed to smooth out the exhaust pulses and to help with scavenging and reducing back pressure. I used to have the classic H-pipe set up on my 89 GT mustang and then went to the X. The sounds was quite a bit different being more high pitched when up in the RPMs. Plus, it cancelled out the highway droning that the H inherently had. I'd say go for it.

From what I have read the placement of the X crossover is important as well. Every car, combo, etc. has it in a slightly different place.

EDIT: Ah, 2002 beat me to it!

 

[RigsLS]

With the comment of "properly placed", I could assume where the old stock H-pipe was located, now directly replaced with the Magnaflow x-pipe.

So looking like I should get my hands on a new fresh x-pipe if I want to do it right, may have him look at it see if he can re-use current.

 

[elephantrider]

whatever you do, DON'T straight pipe it ( meaning no x or h pipe ).

 

[RigsLS]

Just looking at some old pics, can't really be sure the Magnaflow x-pipe got placed directly where the original H pipe was.




Got me wondering where it is supposed to sit now!

 

[joegr]

Pretty sure that's an "H" pipe. (last picture)

 

[RigsLS]

Yes Joe!
... and I was looking at the H and checking/comparing to where the X pipe now sits.




EDIT ----

oh wait, you thought I was being a dumb dumb and not realizing there is an H in the old stock exhaust (last pic),
No I did realize that, as above I was looking and not too sure if the X pipe was put in it's location of where the H was.

 

[joegr]

Got it...

 

[RigsLS]

Sorry to bite like that, it's that time of the month again!

 

[2002_lincolnLS]

I don't know that an x pipe an h pipe would be in the same place. They flow gases differently. Really I would place an x pipe closer to the cats. An h pipe is just a balance tube, doesn't do quite as much.

I don't know on our car, but usually x pipes are closer to the manifolds on cars I've seen.

also I would bet running 2 inch after the xpipe would really raise the exhaust velocity as the temp (energy of the molecules) lowers.

 

[joegr]

I would expect that the diameter of the pipes would be a factor in the location of the cross over. Probably there are a few correct places that it could go, and the places in between those would be incorrect. You are trying to place it where the exhaust pulses from each bank interact in a complimentary way, instead of interfering with each other. (If I understand this correctly.)

 

[RigsLS]

Hmmm, so do we have any spec for the LS on this or best bet as 2002 says to just go closer to the CATS with the X pipe.

To me by just looking at the pics, I can't help but notice the X pipe was placed just shy of further up then where the original H sat.

I have some old photo's from mlara's exhaust, which I brought to that drunken sailors shop but it looks like it's not in the same location.

Anyone have any further pics of where they placed their X pipes.

I do think I will be staying with the 2.5" ... I understand the reduced piping thing but then I should have not gotten an LS or the 2.5 inlet Bassani's

at the end of the day, the LS is not enough racecar (as m4rk once said)

 

[2002_lincolnLS]

I would expect that the diameter of the pipes would be a factor in the location of the cross over. Probably there are a few correct places that it could go, and the places in between those would be incorrect. You are trying to place it where the exhaust pulses from each bank interact in a complimentary way, instead of interfering with each other. (If I understand this correctly.)

what you want is to find an area where one bank will cause a vacuum behind it to pull the other banks gasses down. Really the best way is with scavenging headers, but we don't have that so x pipe is he next option. There is also no need to go back to two pipes at this point other than old guy gotta have duel exhaust appeal. You could equally join the pipes at that point and keep a singe larger pipe, but it would have to be the same or slightly smaller over all volume as the two primary pipes or the exhaust will slow dramatically once introduced to the larger volume.

We have really long exhaust systems which is why they ran smaller pipe after the balance tube to keep the velocity.

And putting the x pipe any where in the exhaust that the pulses would be fighting would have no benefit to the system. Also two far back and he pulses don't have the velocity to create the vacuum behind them to actually benefit the system. I would error further forward than needed than back. Really with out doing tons of complicated math, there is no way to know where the sweet spot is on the car, especially with the possible variables such as wear in the motor causing exhaust to no fully evacuate( worn rings, valve seals), leaks in the exhaust, cat conditions and so on....

 

[2002_lincolnLS]

Hmmm, so do we have any spec for the LS on this or best bet as 2002 says to just go closer to the CATS with the X pipe.

To me by just looking at the pics, I can't help but notice the X pipe was placed just shy of further up then where the original H sat.

I have some old photo's from mlara's exhaust, which I brought to that drunken sailors shop but it looks like it's not in the same location.

Anyone have any further pics of where they placed their X pipes.

I do think I will be staying with the 2.5" ... I understand the reduced piping thing but then I should have not gotten an LS or the 2.5 inlet Bassani's

at the end of the day, the LS is not enough racecar (as m4rk once said)

If you aren't too worried about pipe size, I wouldn't lose sleep over the xpipe. I agree you may never notice the different in our cars. It should be fine either way, still better than no x pipe.

 

[LS4me]

Magnaflow put the "X" pipe right after the cats. They did prototype the V6 system on my old 2000. Oddly enough, it's the same as the V8.....

 

[elephantrider]

when i redo my exhaust, i'm going to put the x pipe as close to the cats as possible, then the muffs
as close to the x pipe as possible. my ls drones quite a bit when low rpm 5th gear is had due to the
muffs being at the very end of the system.

 

[2002_lincolnLS]

Magnaflow put the "X" pipe right after the cats. They did prototype the V6 system on my old 2000. Oddly enough, it's the same as the V8.....

my guess is they went for the best for both to lower production cost, bit of sacrifice for profit. I don't blame them, setting an extra line of jigs to make two different exhausts for the 1hp gain on either would have been a waste and cost us 10-15% more on the final product.

 

[RigsLS]

Ok, thanks for the feedback all for sure, I will work on getting a new X-pipe or see if the guy can clean this one up and re-use it.
I'll ask him to place if further upwards towards the CATs and have everything straight welded as apposed to my idea of clamps in the event of Trans-go shift kit +tranny work, worry about that if and when the time comes.

Many thanks 2002_ and others!

 

[cammerfe]

You might try to get pictures of an entire Magnaflow cat-back system and attempt to duplicate the component locations. By the way, there are 'band-clamps' available that don't do any crushing of the pipes.

FWIW, I installed both a Magnaflow cat-back system and an aftermarket intake duct tube and cone filter between my first and second trips to Maxton. Although the combination resulted in a VERY nice sound, it made no difference at all in my terminal speed. When I got the NX system and the methanol auxiliary fuel system working right, the exhaust and intake modifications might well have made an improvement but not at all on an otherwise stock engine. With the NX system/methanol engaged, about an additional 150 HP+/- was flowing through the exhaust.

KS

 

[RigsLS]

You might try to get pictures of an entire Magnaflow cat-back system and attempt to duplicate the component locations.

Brilliant!!!

I'll have a look, makes total sense. BTW this guy that's going to be doing the work, from what I've been told, knows what he's doing, so I'll value his input as well. Troubles with that is of course it's how the last guy was recommended, whom turned out to apparently enjoy drinking before yielding a torch on a bright sunny Saturday morning! Why I gave that guy money I do not know!

I understand from this thread that I should work on getting the X pipe closer to the CATS as apposed to eliminating it completely. I'll look into the 'band-clamps' and see if the installer agrees.

+1 thanks!

 

[hite337]

Band clamps leak. I have them attaching my exhaust together just after the cats and I hate them. Im just too busy to weld the exhaust in properly

 

[LS4me]

Band clamps leak. I have them attaching my exhaust together just after the cats and I hate them. Im just too busy to weld the exhaust in properly

Mine don't.........

 

[1LoudLS]

when I did the exhaust on my 1st gen, I put an X pipe right where the third cat (if you have it*) was, since it is a single chamber that pretty much did the same thing.