I have been working and reworking my exhaust. I finally came to a system that I really like.

I have (single) Dutra Duals (ceramic coated), and a custom Y pipe, 2" runners to 2.5" collector, see here: http://s785.photobucket.com/user/67dart ... rt=3&o=107

From the collector I run 2.5" back to the muffler, where I reduce to 2.25" in and out of the muffler. I'm using a larger stock replacement muffler, and then 2.25 inch pipe back to a glass pack with a SS tip, which I made:

http://s785.photobucket.com/user/67dart ... sort=3&o=4

http://s785.photobucket.com/user/67dart ... sort=3&o=3

I used 16 gauge 2.25" pipe inserted well into the glass pack and the SS tip. I tacked the SS tip to the glass pack (I cut off the glass pack's outlet tube so they abutted, saved me about 3"). The glass pack slips onto the pipe that comes over the axle, no clamps, it fits snugly.

NOTE: after the system was in place, I noticed this garbly awful sound, (not the leak, I'll get to that) which was the gas at the collector dumping into the 2.5" pipe. The exhaust system sounded great at cruising speeds and highway speeds, but at acceleration it sounded like crap. So, I cut my 2.5" pipe before the muffler, and tacked in a SS 2" perforated tube about 3 feet long: http://s785.photobucket.com/user/67dart ... sort=3&o=2

This is like an internal muffler or resonator in the 2.5" section of my system. This worked like magic! The garbly ugly sound at acceleration was gone! No issues with restricted flow, runs great!

Now that my exhaust is quieted down and sounds awesome (I get a wonderful throaty rumble at highway speeds, no drone whatsover), I'm now facing a new issue. Under load I have an exhaust leak at the flange of my homemade header. Last weekend, I removed one of my oxygen sensor bungs and installed a rubber hose and blew cigarette smoke (yuck cigs are nasty) in the pipes to find my leak. Sure enough the front flange was leaking, it wasn't aligned well. I realigned, used a new remflex gasket. did the smoke test, it seemed like I had fixed the leak. Took it out for a try....no leak when it was cold, even under load. But, once warmed up, the "tick, tick" of an exhaust leak came back.

I'd think this is consistent with a cracked manifold, no leak cold but when hot the crack opens and voila, leak. But I can't find any cracks and clearly I had found a misaligned flange previously. But why no leak when cold, only when hot? Aaaargh! I hate leaks!! I'll try to realign the flange again, but geeze, I can't seem to get this right. At least my system is finally (after four tries) what I was looking for. I'd be happy to share pics of the system if anyone is interested, it took me months and several tries to get a system that I really like.

Brian

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Could be your flange(s) is/are not just misaligned but also warped. Get a good look at the flange and gasket surfaces when you take them apart next; look for penetration of the black carbon across what should be the seal area.

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Too many people who were born on third base actually believe they've hit a triple.

Yes, the flanges are not warped (they are 3/8" thick) but are not perfectly parallel to the manifold mounting surfaces. I'm using Remflex gaskets which have a lot of crush, but the other issue is that I've reconfigured my system so many times, the flanges don't exactly align where they used to. The issue is the front one, can't seem to get it centered, it's either too far forward or backward in order to get the rear one bolted on. I may have to bend my pipe a bit; I'll try not to mar my ceramic coating, but that's not the main concern, it's that ticky tick exhaust leak under acceleration that bugs me...

brian

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https://tinyurl.com/yynpj4v2