Oval exhaust tubing?

[carbuff]

Has anyone here constructed their exhaust using oval tubing rather than round? Eric is going to rebuild the front section of my exhaust from the headers past the crossmember, and we are planning to use oval tube to gain some clearance.

I'm specifically looking for ideas on flanges. I think we'll use 3" oval tube (which is 2 1/4" x 3 1/2" or so). I found these at Spintech:

http://www.spintechmufflers.com/images/uploads/Oval%20flanges%20good.jpg

but I'm not really excited about a slip-fit design. I also found these with some Googling:

http://i100.photobucket.com/albums/m23/carbuff69/flange_zpsd2374305.jpg (http://s100.photobucket.com/user/carbuff69/media/flange_zpsd2374305.jpg.html)

but my guess is that you have to seal those with a handmade gasket or high-temp RTV.

So I'm looking for ideas or suggestions here?

[Ketzer]

I am in the process of doing same.

Where are you flanging and why?

http://pic40.picturetrail.com/VOL267/1824562/21668057/408828820.jpg

Jeff-

[Revved]

I've done Oval but only where I needed it for clearance issues... where it met back to other components I changed it back to round and used V-Band clamps. Vibrant Performance sells everything you need... you can buy them from Summit.

Don't forget to build in flex sections to cut down on vibration and help things last longer. Vibrant sells those as well in different lengths and diameters.

[Ketzer]

... where it met back to other components I changed it back to round and used V-Band clamps.

Same here, that's why I was asking the OP about those flanges. I hate changing exhaust gaskets.


Jeff-

[carbuff]

The tentative plan is to cut off the current 3" round collectors from the headers and come straight out to oval. The reason that will work is that I have a set of tri-y headers, so I have 2 2" round pipes side by side which will transition into a natural oval.

I want to flange at that point, where the original collector flange would be. We will run about 2-3' of oval back to tuck up above the frame rails and under the crossmember, then transition back to round for the rest of the exhaust. I'm only running as much as I need to in order to gain ground clearance, since I am scraping with my current 3" round setup.

So I'll need 1 oval flange point where the header will meet the intermediate pipe.

[WSSix]

Good info as I'm wanting to go oval for clearance too. Admittedly, I'm nowhere near needing it but I'll need this info when the time comes. I'm already planning to have to build the entire system including headers myself too. Thanks for this.

[Flash68]

Brett is doing a similar section on my exhaust in oval. I am 3.5" round though converted to something like 5.25" x 2" I wanna say.

[Panteracer]

Bryan,
We cut the flanges off my collectors (3 1/2") and then welded
a short piece of round.. then opened up a piece of 3" so that
it slips on.. my whole exhaust comes off in one piece... it goes
under the rear end... a couple of bolts welded to each side and
it holds it together

I do not have Tri-Y headers (not made for oval pontiac heads)
so they do hang down a bit but my bellhousing is actually the
lowest point.. need to square that off next time the motor is out
(frequently on this car 12 times now)

My subfame connectors are also very low so I raised the car
slilghtly from 1 1/2" clearance to 2 1/4" clear.. really tight but
not too bad on the streets now

They make a spin type fitting that is fairly small and ss
that you can use. one of the Pantera Race cars has them
as we change from straight pipes, to two different types of
mufflers depending on where we run...My Ford truck actually has
these

Good luck and have fun running the car.. I am taking mine out
for some more test runs to see if the pushrods will stay in the
motor this weekend

Panteracer Norcal Bob

[riles]

This may be what you're looking for.

[6D9 Matt]

I put a 3" oval Xpipe on my Camaro bc of clearance issues. Got my stuff from Spintech.

[Revved]

Same here, that's why I was asking the OP about those flanges. I hate changing exhaust gaskets.


Jeff-

Once you go V-Band you never go back... I got tired of fighting bolts in around the pipe on some of the systems that required crazy angles.

[carbuff]

Agreed, I don't like flanges either. But you don't have much choice on oval tubing. And the V-Bands add about 3/4" on each side for the diameter of the tube. That's 3/4" less ground clearance for me.

Eric and I spent some time checking out everything and making a plan today. I'll be ordering up the parts on Monday. I'm going to go with the Verocious 4-bolt flanges, 3" oval tube (2 1/4" x 3 1/2"), and a couple of transitions. We'll have to cut the collectors off the headers, which means having them coated again unfortunately... But we'll be able to tuck things up to the point where the subframe should be the lowest point on the front half of the car. The mufflers will still be the low-point on the rear, but there's just no where for those to go, short of cutting out the floor (which I'm not doing!!!).

[WSSix]

What about making your own mufflers? Eric clearly has the skills. Just use stainless steel for the muffler wadding like Magnaflow does. I bet you could use 0 gauge stainless steel wool, or I'm sure some company can supply you with what you need. I figure I'm going to have to make my own mufflers too as I don't want to cut up the floor either. Though I might be able to use a transverse muffler if I stay with the leafs out back.

[carbuff]

There are other options as well, other mufflers which are not as tall as these. To be honest, at this point, I don't want to remake the whole exhaust system unless it continues to be a problem. We've got a lot of time and $$$ tied up in it. So I'm going to see how things are after this job where we gain clearance, and I'll dive into the back half later if we have to... The mufflers are about 3/4 - 1" higher than the v-bands were, so I have more clearance there. .

[WSSix]

Understood. It sucks to have to redo or change parts on completed cars. Especially when a lot of time and care has been put into it versus just grabbing it off a shelf somewhere.

Good luck with it Bryan.

[carbuff]

I picked TOW up this afternoon after Eric wrapped up the exhaust and other work. We didn't have time to get the new sections coated, so I will have to do that after the GG show this weekend. For now it's just sprayed with some high-temp paint.

We ended up using this flange:

http://i100.photobucket.com/albums/m23/carbuff69/flange_zpsd2374305.jpg (http://s100.photobucket.com/user/carbuff69/media/flange_zpsd2374305.jpg.html)

That turned into a problem because there were only 3 available at the Vibrant dealer in the states. I do have to give them some serious credit for helping me out though. They are located in Canada, and they stock parts in Detroit. When the one I needed arrived there, the rep had it overnighted to Eric so we could make progress. Much appreciated!

Anyway, strangely the oval pipe is smaller than I expected. Eric though the same, and when he first saw the flange, he was worried I had ordered the wrong ones. ;)

This job ended up taking more work than we expected to get it right, but in the end, it was the right choice. I have plenty of clearance now, the frame rails are the lowest point. I don't have any pics yet, hopefully Eric took a few. But since we need to disassemble for coating, we can get some then if not.

One interesting thing Eric did was to cut off the collector housing from the tri-y headers and transition the 2 2" tubes directly into the oval pipe. To do this he cut up the original collector transition which worked almost perfectly, just a bit of reforming required. He also cut the header tubes to shorten them to raise everything. Again, more work, but better end result.

I know this sounds odd, but the sound of the exhaust is different now. Eric noticed it too. The car has always has a 'crackle' sound: little pops, raspy. That is gone now, and it sounds much smoother. We can only hypothesize as to why, but it's definitely different after driving it for a while...

[waynieZ]

Looking forward to seeing it when you take the pictures.

[Sieg]

Sounds like a success. :thumbsup:

Sound is amazing......I changed the tailpipes on my car from straight OEM style tips to turn-downs between the rear spring shackles and rear wheel opening with the same 2.5" diameter and it changed the exhaust note quite a bit.

The bends/angles were also changed slightly but not enough that I thought it would be a significant difference. The changes took a lot of the mechanical rasp out of it from low mid-range to redline.

I'd had the previous tips for 20 years and really liked the sound but after a few months with the new tips I'd have to say it is an improvement.