With all the worry about ground clearence of pipes has anyone ever just gotten over sized pipes and flattent them..

The exaust passes thru the same volume its just oval Vs round....

 

ive done it several times on y pipes and duals...i just made oval pipe with standard 3" exhaust pipe by sandwhiching it in 2x4's and slowly pressing it into an oval in a hydrualic press.

 

I've done the same exact thing. It works suprisingly well.

 

Dr. gas makes several tipes of oval pipes. some might elp in making true duals clear the axle easier wihout sacrificing volume.

 

Thats wahat I was thinking...meke it look like the stock driver side pipes but just way bigger...to allow for greater volume...

 

Flattening a round tube to make it an oval, reduces the overall area (volume). If you think about taking it to an extreme, you can picture it. Keep flattening the tube, and pretty soon it won't flow anything... The closer to round it is, the more it will flow.

Here is a chart of roughly equivalent oval tube that corresponds to a fully round (nominal size) tube, from this site:
http://www.burnsstainless.com/OvalTu...valtubing.html

Oval Tubing Dimensions

Nominal Size: 3"
H x W: 2 1/8" x 3 1/2"

Nominal Size: 3 1/2"
H x W: 2 3/8" x 4 1/8"

Nominal Size: 4"
H x W: 2 1/2" x 4 3/4"

 

It would probally take some flow away but not sure if it would be enough to really make a difference if you really need the clearence Id do it.

 

wow that place has lots of cool stuff, but good god is it expensive...how is a 3" mild steel X-pipe worth $350?

 

This must have been SLP's idea when they designed the Dual/Dual. The pipe that goes over the axle is no where near round. It actually looks crushed.

 

unless its real flat or you are making tons of hp, it really isn't going to going to harm performance on a DD.

 

I've heard that even with sizes setup so it is not shrunk at any point the speed of the gasses is cut.

Interesting idea though.
I would agree with NHRAMAN and guess if any losses on a med or mild build up it wouldn't effect you.

 

How can that be..its that same...I understand maybe not having as laminar flow as a round..but not by much....but an decrease in area..I dont think so

if you take a 2x2 square and make it a 1x4 square the area is the same

 

If your worried about volume, buy a wider pipe.
How would an oval pipe affect sound?

 

Also, I think BitViper is wrong. Flatening a pipe does reduce its volume.
4x4=16, 5x3=15, 6x2=12, 7x1=7.
Do you understand what I'm trying to say.

 

thats what i was looking into since i dropped the **** outta my car with sportlines lol...but in the end i looked into dr. gas and burns stainless and another site that had a variety of real cool round to oval and oval to oval pipes etc but dam when i added it all up after getting a rough estimate of the measurements and bends i would need, it was alotta $$$money. So i ended up jus doin a custom round 3" made for my car all the way back to the tips, came out real nice IMO...

Oh and the sound, while i was researching all that y-pipe crap in oval and round etc, i spoke to a few of the people at dr.gas and other shops and they all told me the oval would make it sound higher pitch, would make it scream more bla bla, ...which is why i wanted to pursue it in the first place becuz of what i thought it would sound like....jus imagine high pitch sounding LS1's, picture something like a ferrari+nascar sound comin out of ur tips..sweeeeeeet

ill do it someday, probably when i turbo the car and destroy some of the exhaust piping lol

 

yes and no, becuz think of it, reducing how tall the pipe is but making up for it by making it wider would balance out in the end, its not really like flatenning it, its more like stretching it thus makin it turns out to be not as tall as a round 3", that immediately means awesome clearance...its not rocket science..and ok lets say some "area" is lost, what 1 square millimeter of exhaust lol cmon work with me pple lol

 

here's another exhaust tubing vendor FWIW

http://www.boyceindustries.com/boyce-racing-index.html

 

HAHAHAHAH!!!!! you cant possibly be serious?!? the 2x2 square has a circumfrence of 8, the 1x4 has a circumfrence of 10. It wouldnt even be the same tubing!

Anyway, yes, as you flatten the round pipe, the cross sectional area lessens. Imagine if you continues to crush it till it was completely flat. How much area would that be? Probably wouldnt flow as well as the original pipe, huh?

That being said, most of our exhausts are way overkill for our applications. You can easily get away with crushing some areas for added clearance.

Here's the formula for fiuring out the cross sectional area of a floval pipe (flat oval)

Original 3" tubing has an area of 7.065 (radius x radius x pi) and a circumference of 9.42 (diameter x pi)

Now lets crush it to 2 inches high. Now the easiest way to think about a floval pipe is to break it into easier shapes. Lets picture it as a rectangle with a half circle on each side. First lets figure out the area of the two half cirlcles (equal to one whole circle) on each side. 1 x 1 x 3.14 = 3.14. So the two half circles have an area of 3.14 sq. inches. Now lets find the circumference. dia x pi gives us 6.28. The circumference of the pipe wont change when you flatten it, so lets take the original 9.42 and subtract 6.28. This gives us 3.14 inches of circumference left over. Half of this will be the flat spot on the top, and half on the bottom, so lets divide by 2. (3.14 / 2 = 1.57) Now lets figure out the rectangular area between the two half circles. We know the pipe is 2" high now, and that we've got 1.57" of flat on the top and bottom, so 1.57 x 2 = 3.14. Now all we have to do is add the area of the two half circle sections to the area of the center rectangular section. 3.14 + 3.14 gives us 6.28 cross sectional area of our crushed pipe, where as the original has 7.065. See the difference?

Of course this example does not take tubing wall thickness into consideration, but you get the idea.

 

Everything you've posted is absolutely correct Guitsboy, but you're missing a critical component of what the OP has asked.

He's talking about using a 4" pipe that has been ovalled as opposed to a round 3" pipe. So you're absolutely right it wouldn't even be the same tubing.

Using your own formulas, which as far as I can tell are indeed correct, a 4" round tube has a cross sectional area of 12.56 square inches. That same tube flattened to 2" has a cross sectional area of 9.42", which is indeed greater than a 3" round tube, yet provides an additional inch of ground clearance.

There's still the issue of that 4" oval pipe having a greater surface area to volume ratio than a round pipe, which will create a greater resistance to flow as well, but the numbers tell me pretty confidently that it will still be far better than the stock exhaust, and absolutely viable for anyone looking for an upgrade that doesn't impact ground clearance.

Something like this would have to be custom made though, so you're either looking at paying somebody to do it for you, or putting in the time and effort to do it yourself, assuming you have all the equipment to do it properly.

**EDITE**

Sorry, hadn't really read the whole thread. I realize now you're responding to later posts regarding cross sectional area decreasing when you flatten a given pipe. Flattening a larger pipe is still a viable option though, as the numbers indicate.

 

Yes, yes, yes, i definately agree with you. I doubt the surface area to volume would make any kind of detectable difference. The bigger problem is when you transition fromthe 3" to 4" are you going to flatten the reducer cone or expand to round 4" then flatten in the problem areas. The first choice would be difficult to get the pipes to butt togather nicely once you start squashing, so break out the cutoff wheel, BFH and get ready for big messy welds. The second way would compromise ground clearance where there's full 4" round sections.