Exhaust 2xX's
 

Im slowly making my way up the learning curve for the LS1, im used to ford's 4v 4.6. I know for us (atlest mark8's) The optimum ballance for the exhaust is to use duel X pipes. It also makes for one amazing exhaust note.

I was wondering if anyone uses 2xX's for the LS1, and if so..do ya have any sound or vid clips. Have you noticed any more improvement over other systems you have had, or been witness to?

Personaly I have never heard pf using 2 x's but I can assure you that you wont find anything of the sort around here.

I've never heard of that before... I always thought you wanted the least bends as possible?

+1 for this topic I'm curious...

Well, from my experience with the mod motor, the exhaust system needs to be ballanced some way or another. The h pipe doesnt offer proper ballance all the time, and creates turbulance in the exhaust, the Y pipe compresses the gasses into one pipe which is ok, in my oppinion, but only if u are running a single large pipe afterwards. But the X pipe offers perfect ballance, and gives a good deal of backpressure, but when going with 2.5"pipes (on the 4.6 4v ford) you need more backpressure, so you add another Xpipe, which doesnt nessissarly restrict airflow because of the bends, they are light sloping bends for free flow. Not to mention, the flow of the gasses creates an amazing exhaust tone

heres a sound clip of the tone...

http://www.lincolnmotorsport.com/xpansionx2.wav

http://www.lincolnmotorsport.com/jimspipes.mpg

but its mostly for the performance.

Some people have used dr.gas x-pipes on their LS1 dual setups. This is the best design i have ever seen in terms of an x-pipe. I prefer the h-pipe setup i currently have :D . I must say that i admire the sound made by the 4.6L 4V Ford motor.

yeah, its extreemly agressive.

http://www.lincolnvscadillac.com/sho...ust+commercial

http://www.lincolnmotorsport.com/xx2.wmv

I definatly would testify as to how good a duel X setup is. Most people dont like the single X because of the noise and the vibration caused by the noise, but with the duel x it makes the car a nice sleeper at idle, and make it sound like the gates of hell opened behind you at WOT.

First off... let us define what a "true X-pipe" really is.

The individual who designed, and then sold the rights to Dr.Gas, is a lifelong friend of mine. Back in the day, we did extensive research and probably constructed 150 variant systems using an "X" member, including the use of more than one in a complete system. What is attached below is a 'stick figure' drawing which lightly explains the difference.

If you talk about an "X" pipe, at least say and mean "true X-pipe" or state "Dr.Gas type X-pipe". There is a huge difference. :bang:

I've heard of Vettes using an X-pipe up front and an H-pipe by the axle to help with resonance.

Chicane, do you have any photo's of the "true x-pipe"? Any reason you think you never seen this style used? Interesting idea. :)

yeah, "true" x pipe.

hmm yes interesting. i wonder how much if any power a true x pipe setup would be worth on an LS1 over a dr gas type, it doesnt seem *too* hard to make. chicane would you care to expound a little more on the true x-pipe?thanks

Photos... yes, but I have to get them from my laptop, which is at work right now. I'll post a picture or two hopefully in a day or two..... as SEMA starts tomorrow and I most likely wont be online for a couple of days dealing with everything there.

It is used. I have three chassis with this system, an old partner of mine has it on his 70 and in his race trucks and there are a few others in southern California, as well. Why isnt it seen much more than that ?? Well, most likely because we have kept it under wraps for so many years. If I remember right, I did my smallblock 67 back in 1989...... and thats is the system I have pictures of...... only due to the fact that I have had to re-do the system to accommodate the new 3.5" system for the 7.0L.

Initially, the mule engine picked up 38 ftlbs, from the standard ole dual exhaust set-up. I couldnt tell you about the difference between the DG set-up over the true X, only because it just made more power "under the curve" and all over the place..... under the curve, and we never looked back at it again..... and then he sold the rights to DG.

Sure, what specifically would you like to know ?? I'll bring the tech, but, this can get into some heavy theroy about flow, frequency, negative pulse scavenging, pressure vessal volume, divergent and convergent ducting, frequency tuning a system including the mufflers and temperature effects on flow and gas speed.

I just need to know where you want me to start....

If the True-X made more power than the Dr. Gas style, why didn't Dr. Gas buy the True-X design instead?

Because we didnt sell it to them....... nor did we tell them about it.

no need to get too in depth, any thing you want to talk about. maybe a little bit about pipe sizing of the x portion in relation to the rest of the system and maybe ideas on where to place it in the system which i guess would touch on negative scavenging and the thermal aspects?? how feasible would it be for someone to create this setup themselves? thanks
under the curve is the place to be :jest:

With this type of X design, there is enough 'plenum' volume from the 'four seperate tracts' that the individual sizing is the same in all four tubes. Testing showed this to be where it need to be. It does however, have to symmetrical, as this has to do with pluse phase timming.

I would place it in the same position as shown in the drawing..... I havent done one on a late model, but I do think it would be..... "challenging".

The scavenging aspect should be looked at from the exhaust collector and also going into the muffler. Its not that big of deal with the true X design. A chambered type (Spintech/Flowmaster) muffler works better with a smaller size outlet to improve muffler scavenging (because of the volume difference). A flow thru muffler (Borla/Burns/Dynomax) can use either. I'll give you two examples which depend on the type of muffler being used.

1. Same tubing size throughout. 2.5" collector to 2.5" muffler inlet, with either a 2.5 or a 2.0" outlet.

2. Larger tubing after 'merge' collector. 3.5" collector to 3.5" muffler inlet, with a 3" muffler outlet (which acts as a 'merge' out of the muffler).

If you have access to mandrel bends or even crease bends, it shouldnt be hard at all to fabricate it..... if you have the room to fit it.

i was thinking this is gonna be the rub :jest:, esp. with our cars and the knock sensors. i would still like to try something like this, thanks for the reply.