grandspt

Hi guys, as some of you know from my previous posts I got the ARH 1 3/4 headers for my 96 LT4 GrandSport. I am using my stock exhaust system which I will have to cut after the resonators. Now the ARH headers and cats. come with an X pipe but my exhaust has a small H pipe after the resonator (which unfortunately after the cut will be connected to the new ARH system). Will there be any kind of flow issues having an X pipe and then an H pipe all in the same exhaust?

Thanks!

DanielRicany

That's not how it's supposed to be I don't think. I think you're supposed to replace the H pipe with the X pipe. You may get an interesting sound with it, you may lose power, you may gain power, I have never heard of anyone doing it this way before.

Klyde

The purpose of the X pipe is the sound pressure waves cross each other and cancel or mellow each other out. The purpose of the H pipe is to equalized the back pressure between the left and right side of the engine. The X pipe also does this of course. So you will have the noise canceling, pressure equalizing X pipe feeding the pressure equalizing H pipe. It's over kill but I see no problems that it would cause. If you think about it the earlier C4's run everything through one pipe for awhile and then split it back into two and they work just fine.

grandspt

I was told that the ARH system is suppose to bolt up to my stock exhaust system. So I can't remove the H pipe unless a muffler shop bends up new tubing. But then it is not my stock exhaust anymore.
I never really thought about this until I removed the exhaust system and found a H pipe on it!
Klyde, do you think I would lose any power running both?

Klyde

I don't think it would lower your horse power. On most systems the X pipe replaces the H pipe or resonator and the system hooks where the H pipe used to hook before its removed. If they said it hooked to a stock exhaust it should link up after the H pipe. The headers plus X pipe combined length should equal the stock manifold plus cats, plus the resonator H pipe. As others have said something doesn't sound right. I also have never seen this complaint by anyone else. Are you sure you have your facts straight? I have an LT1 96' and it had a resonator not a H pipe. Here is a pic of my old system.

grandspt

Klyde, you see where the welded strap is at th rear before the mufflers? Well mine has a welded pipe in front of it.

grandspt

I don't know if this picture will show.

STL94LT1

Pretty sure only LT4's got the H section.

Klyde

That's odd that they added that H connection. I've seen the resonator piece right before it cut open and they share the same cavity with holes in both pipes so there is no reason to add that. The header company may not be aware of the added cross connection. You may have to get some pipe work done if the X pipe attaches to close to the H. I do not see this connection as being power robbing or any other ill effect. If you can land the X pipe I think your good to go.

SteveDoten@ARH

The H or Xover section will not affect the performance of the ARH system.

Klyde

Steve: I think his biggest concern is will the new system (headers + Xover) mate up correctly with that H pipe located where it is.

grandspt

Well the X pipe will be further up stream right after the cats. The H pipe will have to stay. I am not happy with having both cross over connections in one exhaust system but I don't feel like spending any more money on a muffler shop! Hopefully no flow issues!

Tonight I found that my stock exhaust manifold bolts will not work with the headers as I was told!
The stock bolts have a long shoulder because the cast iron manifolds are thicker than the ARH (3/8") header flanges!
Steve any way you can send me some header bolts? Or do I have to buy some (if I buy some I will go with ARP Stainless bolts) Though I'd rather not!

AR Headers

Grandspt, to clarify further, our system extends pretty close to the rear axle. I don't believe you have a choice but eliminate the H altogether. Our systems requires the you mark and cut the factory exhaust that's 2-3/4" OD and slip that portion of the system into our outlets and clamp them. The H should be further forward of where that connection is made. I've never seen an H that far back in the system. Please take another look and give me a call to confirm either way. For what it's worth, if the H had to stay it wouldn't be a problem regardless. I just don't see how both could be used. Thanks.

Nick
631-608-1986.

grandspt

Hi Nick, I will attach a few more pictures with my stock exhaust on the bottom and the ARH on top.
I aligned the front equally at the hanger mounts.

CDN/AZ LT4

Grandsport, I'm thinking of doing what your undertaking. Is there any way you could have saved the stock resonator and spliced the x pipe into the resonator? I'm concerned about drone with the resonator replaced by straight pipes. Good luck with your install.

grandspt

CDN/AZ LT4, I don't see any way of leaving the resonator in the system unless you have a muffler shop splice the outlets of the Cats to the stock resonator. Look at my last picture. The crossover from ARH is too close to the resonator and the inlet of the resonator pipes are not the same distance as the ARH crossover pipe outlets.
They won't mate up. As far as resonance, I am hoping the stock mufflers will take care of that along with the crossover pipe.
But I won't get a chance to drive the car until after winter.

grandspt

Nick, can you see that the H pipe can't be eliminated?
If you say there is no problem with running the Crossover and the H pipe together then that is what I will do.
Let me know if you have any suggestions, it seems like I am the only one using your headers with my factory exhaust system. I have been here before with aftermarket parts and to be honest I don't like it!
Also no one has addressed my header bolt situation. Steve told me to reuse my old header bolts. Unfortunately the Cast iron manifold flanges are 1.5" thick. Your header flanges are 3/8" (or .375" thick). The shoulder on the bolts are about 0.860" (micrometer reading).
If I use my stock bolts the shoulders will bottom out on my cylinder heads (.485" difference) without ever getting the header to seal up!
So again I must be the first LT4 install for the ARH headers.
Not trying to put you guys down, the headers look fantastic, the workmanship is top rate. But I didn't want to have installation issues, this is why I called you and emailed you several times before I purchased the headers.
Can you at least send me some header bolts that will fit my application?

CDN/AZ LT4

Grandspt, thanks for the reply. I'm following this thread carefully. I've following all ARH related threads looking for an LT4 application. The ARH advertising suggests that it's a bolt on/splice on to the factory system. I take that to mean splicing into the stock resonator from the ARH x pipe. I did see your pictures but I could not tell if that was the alignment required from the engine block back to the H pipe. I was thinking this would be my winter project, however now I'll wait to see how you make out. Unfortunately most ARH related threads speak to the quality of the product but not so much the actual fitment.
Please keep the pictures coming. Thanks,again

grandspt

CDN/AZ LT4, the stock resonator is eliminated with the ARH system.
In the pictures I aligned the front exhaust hangers of my factory system and the ARH system with a pushrod going through the mounting holes. As you can see the resonator is replaced by the ARH Catalytic converter/X (or crossover)pipe setup. And where you also have an LT4 engine, you will end up with the factory H pipe in the system as well! This may help with your worry about drone. But I have no idea as it seems I am the first with an LT4 install that has tried to keep the stock mufflers with the ARH system!
As far as fitment, I still don't know because I don't have any bolts to mount the headers with!
I am getting frustrated, this was going to be a good weekend to work on the car but now I am at a stand still because I need header bolts.

Kevova

The resonator is actually a crossover of sorts the placement of the "H" is so far back I don't think it helps anything performance wise.