Is it true that in order to get the full benefits from an X pipe you should be running a high compression engine? If so what is considered high?

You don't need a high compression engine to derive the benefits of an x-pipe.

Almost every single multiple cylinder engine will gain from the use of a 'balance tube'(Dr.Gas and common 'H' pipes), and the better design of them all the true 'X' pipe.(see attached link for further detail)

In balancing the signal and pressure of each cylinder bank, you improve the total signal to the induction system. Also its common properties of negative pressure scavenging help evacuate the spent gasses into the exhaust system. There are NO requirements for running any of these types of systems, even the most stock set up can benifit from the use of one of these.
http://www.geocities.com/tholt67/exhaustsystem.html

[This message has been edited by chicane67 (edited 01-22-2003).]

you don't need a high compression engine to see the benefits, but a high compression engine will probably get more benefit, percentage-wise, than one of a lower compression ratio. but that holds true for pretty much any modification that frees up air flow into or out of the engine. imagine spending $6000 on your dream 600hp big block, then putting stock intake and exhaust manifolds on it with a single snorkel air cleaner 2" stock exhaust..

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see dirty pics here of a car that gets driven http://community.webshots.com/user/novaderrik

[This message has been edited by novaderrik (edited 01-22-2003).]

Chican67,
Your link above mentioned that Dr Gas x pipes are more suited for racing applications and is not a true x. I was planning on purchasing a dr gas package. However the last diagram in that link shows a different type of "x" more suited for street cars. Where can I purchase somtething like this?

Chicane67,
I was just curious how the middle of the X is joined in the diagram that is in the link,does it flow from both sides through the middle of the X ? Is the X similar to that of a Bassani X pipe? Or do you just have this fabricated out of aluminum tubing? I currently have 1 5/8" headers and dual 2.5" exhaust,what size X pipe would give me the best gains in HP/TQ?I've been meaning to add one.Thanks

tommyg- The Dr. Gas 'X' is more suited for a specific RPM, not just racing.....but a race car per-say usually runs in a specific RPM band. The volume of the exhaust port, the individual primary tubes, the collector volume and the exhaust system tubing diameter all play a role in where this 'powerband' will become effective and wide the powerband is.

You can not really purchase a true 'X' pipe off the shelf. It has to be fabricated. The gentleman whom I share the rights of this design is also the designer of the Dr. Gas device. The 'true' x-pipe is not only suitable for street cars, it works great for racecars as well. The real reason that you dont see this design on race cars is mainly due to space considerations, weight and overall ease of fabrication. That and most racecars run in a specific RPM bandwidth. The reason it works so well in street cars is that it works in a VERY broad RPM bandwidth, just like our cars operate on an everyday basis.

Luke805- The middle is joined together by cutting a hole in the two seperate tubs with a plasma cutter before assembly. This design allows flow/pressure/sound through all tubes at once. It has similar characteristics to that of the design of the 'mixing chamber' in the C-4 Corvette exhaust system. The Dr. Gas and Bassani systems are almost identical, with the exception of the bassani system uses two formed halves and it is then put together. The Dr. Gas system is two seperate mandrel tubes connected......

The material in the entire exhaust system is of a heavier wall steel tube than what 95% of exhuast shops use....this is a durability issue. In just about every exhaust system I have done (with the exception of a few experiments), I use the same diameter tube for the 'X' as I use in the entire system.

FYI, the main concerns in fabricating this type of system are as follows:

1. The second turn coming off of the collector (the one turning to the trans tunnel **AS IN THE DRAWING**); The OD should transition into the ID of the forward part of the 'X' pipe. This is the most critical part of this system.

2. The back part of the 'X'; The exits should be in line (line of sight) with the entrance (forward part of the 'X').

3. The center joint of the 'X'; The joint itself should be smaller than the ID of the exhaust tubing being used. The cut out should be about 120* but really no more than 140*.

The drawing is a fairly close representaion of how and where it is shaped. I wish I was in a position to take pictures of what I have on my chassis, but unfortunately I dont have that luxury at this time. I'll have to dig to find the fabriaction pictures from 14 years ago...........

Hey Chicane, (digging up an older post here) I was looking at the drawing listed in your link and was going to attempt to duplicate the "true x pipe" Do you think that i will have any luck using a Dr Gas as the center section of the assembly? I know it isn't exactly what is depicted but i think it will save my muffler man mucho grief. I am going to rotate it 90* from a standard gas x application and try and accomplish a similar effect. Thanks for your help in advance. I'm basically broke after the new motor and tranny and this seems to be a compromise.
-Dave

[ 04-15-2003, 05:54 PM: Message edited by: dceresa ]

I guess it could be done, but I would find it more difficult than actually fabricating one while building the exhaust system. I mean a couple scrap pieces of tubing and a bender to 'fit' the tube is eaiser than trying to build the rest of the system around a pre-fabricated peice......and I think cheaper.....

BTW, you're exhaust system is just as important as the engine you built......this isnt a time to take short cuts for something you will never have to do again.....

[ 04-15-2003, 09:49 PM: Message edited by: chicane67 ]

Good point, i am a big fan of doing it right the first time. I will stop by the shop this morning to talk it over with my installer. After looking at your home page i wish i saw some of your mounts before i fabricated mine looks great, nice work. Thanks for your help.

chicane,
are there any guidelines on where to locate the X in the true X-design? distance from collector affect torque and sound? i've only run a h-pipe before but plan on fabbin the true X up.
thanks
kip

For all of you planning on installing an "X" pipe set up, don't forget to ask the muffler shop to install another set of collector flanges behind the "X", just before the mufflers. It will help a lot when time comes to remove the tranny. Been there done that graemlins/clonk.gif

Good suggestion Orench. I read a past post of yours and bought them too from Dr. Gas.

Kip- Its in my second post of this thread. Its location is less important than that of an "H" pipe, because of it only being conntected in two places. The "X" having four points is more about the position of the transition tubes being attached so as not to be a restriction in flow (as in the drawing), not really a distance from the collector thing.....

I am running the Dr Gas x pipes and love them. Experiencing much harder pull through most of the rpm range and the sound is very healthy. Great resonation, and the install was easy. Chicano, my pipe setup only looks vaguely like the drawing on your link, but I guess that really is of no consequence. Sounds like you know much more than I about the building of the systems, I only know what I have and I am very very happy with it. :cool: