FuglyHippo

Ok... I just ordered LS7 manifolds/H-pipe from our Forum Vendor Jeremy Formato (Which was an extremely enjoyable transaction, and he had the exhaust to my front door step 2 days after payment!!!). I wanted an X-pipe like that of the ZR1. But, thinking about it has made me really consider that it might not be all that worth while, and I need some experienced intelligent insight with it.

When I picture an Xpipe giving power, it's all about flow. Now IMO, not all X-Pipes are created equal. I think if the x pipe is in conjunction with the angled direction from the headers, it WILL help by making a straight path for it to cross over with the turbulence not hurting it too much. (Please refer to my professional quality diagram at the bottom of the post, it's the first drawing in the diagram.) However, I don't see the point of doing an "X" down the mid pipe where the stock "H" is. And if my thinking is incorrect, please explain to me why.

Let's start with some visuals.

Here's a stock Z06 exhaust. Notice the placement of the "H" on the midpipe.


Here's an example of an X-Pipe that IMO is USEFUL for power numbers, flow etc. Notice how the angle of the headers is INCLUDED when the "X" on the mid-pipe is made. It's virtually a straight line from the collector on one side to the other side's Pipe on the Mid pipe, creating an "X".


Here's what I will do to my C6 Z06 H-Pipe if I find it worth it with an X-Pipe insert from Ebay as depicted in this photo. This IMO might just not be worth the conversion from "H" to "X" as it already bends parallel to the chassis well before the "X". Again, PLEASE if this is not true (I honestly want to be wrong), explain to me why.



I made a quick drawing of what I'm trying to say in paint during class... Hopefully this will settle all confusion on what I'm asking/trying to express.


In accordance to this^ photo, if the air is flowing down an already straight pipe (parallel to the chassis), while make it arch to the other side to cause more turbulence? I understand the X on the "Useful" version way above, but this just doesn't add up for me. I'd love to do this "X" insert modification if it's worth it, but I need some convincing.

Thanks in advance!
-Hippo

Lothar34

The crossover is most beneficial at the point where exhaust flow is restricted the most.

The difference in power is going to be pretty much negligible on a street car. If you're really worried about that, then why not get long tubes?

FuglyHippo

Because I want to retain the "Stock" look of everything. I also want it to sound stock. I'm feeding the LS7 Manifolds and Midpipe into my stock 2.5" catback. I will be putting Low Profile cutouts on the end of the 3" Midpipe just before the flanges like so:


So you're saying the "X" insert is not worth it?

Thanks,
-Hippo

Lothar34

I think the gains will be negligible. That said, cutouts sound way better with an x-pipe IMO.

lionelhutz

Your reasoning for how to place the X-pipe is wrong. Typically, further back than right afte the headers is better.

FuglyHippo

Why?

RonSSNova

So AR headers do it wrong?

blackdak318

IMO this is up for debate. I've read on here people say the further back the X the better. When getting my car tuned my tuner asked where the X was and says he's personally seen as much as 7-10RWHP more with the X pipe located CLOSER to the headers.

Someone should do a back to back dyno run to prove it.

FuglyHippo

To my thinking, this is exactly what I would expect. Hence my entire argument/post. It doesn't make sense to me to put it farther back, and seriously need a technical, detailed explanation as to why further back X-pipes help at all.

Bill Curlee

How about this one:







BC

FuglyHippo

That would follow under my "Useful X-Pipe" depiction in my MS Paint diagram. I believe that would give every power. But again, needs some experts in here to verify some of the debates here.

Bill Curlee

XS Power makes that same exhaust for the C5 as well as the C6 and its one of the best X pipe designs.

That system worked outstanding on my C6 and my buddys C5 04 Vert.

BC

FuglyHippo

I have no doubt that the design above is stout. But I'm not sure the "X" I'm wanting to put on my Midpipe is worth it.

Bill Curlee

If you dont like the X pipe,, consider the O pipe.. Far superior!!!

Bill Curlee

They make the same O Pipe for the vehicle with single pipe exhaust.

FuglyHippo

Thanks.

Bill Curlee

But wait,,,,,,,,, I saw this the other day and it looks like it will catch on!! Keep your ears and eyes on this system!! Some SERIOUS POWER potential there!

FuglyHippo

Thanks.

RonSSNova

I've been using X pipes on my hotrods ever since I read about them from Dr. Gas. I tried to look up his web page, but I gather he sold his business and it is now gone. Too bad, I have used his pipes for years.
The theory is that it allows both banks of the engine to see both mufflers. It also aids scavenging. His liturature said keep it as close to the collector as possible.
That works in our Corvettes because there is no transmission in the way.

The H you show in your example is so short, it is nearly an X. An H pipe on a traditional car is much longer, and only serves to drop the sound level a bit.

The coolest thing about an X is the sound they cause the engine to make. It won't do that placed way back in the system.

Back to back testing would be great, but a guy would have to build an X and an H that go in the same location. Rather expensive and time consuming for a few HP.

So Bill, draw us up a Z pipe!

BTW....here is what I'm doing with my used XS power system to tame the Borla stingers a bit. Muffs are 3" by Pypes and are stainless packed. I hope it takes the edge off. It works on my Nova.



Ron

FuglyHippo

So since the H-Pipe on my setup is so close... It works damn near the same. Putting in an X in that area would be not be worth the extra $100?

Aside from power, my next goal is for it to sound as close to stock as possible. Since the stock Mid Pipe is an H, I think I'll leave it that way.

Thanks for the input!
-Hippo