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:



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



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?



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]

Originally Posted by Revved

... 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.

[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

[Revved]

Originally Posted by Ketzer

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!!!).