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View Full Version : Square exhaust tubing is NOT better than round.


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FattyBoomBatty
06-21-2008, 09:09 AM
Sadly I will be in Canada for a race Saturday. Talk to Brian next time you come up, I would be interested to talk to you about some of the things we have been disscussing that's 2.4 related.

Dave figured out that with a square tube primary, you have more surface area than with a round priamary. Kinda like a kicker square solo baric sub woofer vs a round one. Using a square tube you can use a smaller primary for the those tighter areas and still have the same volume that a larger round pipe would use. He also figured out that with a tight bend in a round pipe the exhaust starts to "roll" over itself and begins to spiral, slowing the exhaust speed. With a square tube, it doesnt spiral and actually the tighter the bend the better. On the inside of the bend exhaust speeds will actually increase and draw the exhaust out.

He has huge patents on anything automotive related that uses a square tube for exhaust, etc. Currentley he works with chevrolet and ford using this technology and you will also see his square tube headers allot in dirt track racing. Look at a new corvette, cast square tube exhaust manifolds.

Any way, sorry to wander off the subject


This is by Archertsi, who knows nothing about fluid dynamics or corvette exhaust manifolds.

Look at this picture, LS2 (new corvette engine) exhaust manifold next to some aftermarket header. Yes, I know there's a head shield on it, but it uses ROUND tubing for the little runners. From the factory, because it's better.
http://images.highperformancepontiac.com/tech/0706_hppp_03_z+ls2_power_package+exhaust_manifold. jpg

Meow, that dummy who told Mr. Archertsi that square tubing flows more air that round, especially in an extremely tight radius bend apparently works for DPengineering, who obviously don't engineer anything at all.

I am not a mechanical engineer, but I did spend two years at college for it, and can list many, if not hundreds of examples where square tubing would not only not fit, but inhibit air or exhaust flow more than round tubing, while adding unnecessary weight.

Look, if you will, for any measure of time, at a jet engine. Take a brand new engine from a boeing 777, perhaps the pinacle of current jet engine technology, at least when it rolled out, not but a few years ago.
http://www.rolls-royce.com/civil_aerospace/images/photos/trent800_cut.jpg

Do you see anything remotely square about that design? Why do you think that is, Archertsi? It's because air flows better through a round tube than a square tube. If you really want, I can spend some time looking up air mass properties in a tube vs. a square, but I'll ask you to try first.

Also, just to make sure I wouldn't make a fool of myself (unless you were joking, in which case, I am a fool for reacting to what you said), I searched for a while for pictures or stories about square tube exhaust headers. Couldn't find any. If they are so good, and he's got deals with ford and chevy, why might I not find anything about it? I checked here: http://www.circletrack.com/enginetech/index.html and found an article comparing headers, none of which were square. Anyone who patents something in the automotive field and doesn't have it purchased by an auto manufacturer or an oil company must not have a very good product.

HiImBrian
06-21-2008, 11:47 AM
All I can say, is that was very well written. All statements were somewhat supported and the bashing meter barley even flinched. Nice little write up.

tpunx99GSX
06-21-2008, 04:18 PM
lol square tubes. what about rectangle tubes with rounded edges. such as the ports on the intake and exhaust sides of our heads. if you followed that shape all the way down i wonder what the result would be.
Im not saying its going to be better or anything or if im going to even try it but it would be kinda fun to put in into a program that measures fluid dynamics and see what the result would be vs a round tube design.

xveganxcowboyx
06-21-2008, 04:30 PM
You do make a good point about shape consistency. I wonder which causes more restriction, the more restrictive design of an oval or rectangular shape that continued through from start to finish or the turbulence caused from changing size and shape to round tubing.

I guess it's not very relevant to boosted applications. :)

311evo
06-21-2008, 04:51 PM
even if it would flow better (which was pretty well explained that it doesn't) it would look dumb as hell on a car.

Kevin 1G Drummer
06-21-2008, 06:21 PM
If anyone remembers that turbo Geo Metro at the spring dyno day, He had a square "tubing" exhaust manifold, and I bet that thing flowed like hell! ;)

BLaCk_1cE
06-21-2008, 06:33 PM
If anyone remembers that turbo Geo Metro at the spring dyno day, He had a square "tubing" exhaust manifold, and I bet that thing flowed like hell! ;)

That thing was bad ass as hell.

FattyBoomBatty
06-21-2008, 11:52 PM
Well, I got pretty riled up about this, that's why it's kind of like a rant, but there really is a reason most of us have never seen square tubing for any kind of airflow, or liquid, for that matter. Manufacturers would be using it if it were more efficient at all.

tpunx99GSX
06-22-2008, 10:14 PM
I just got done helping a buddy install a dnperformance tubular manifold and was kinda shocked as to how small the runners were. I would think it would actually be a lot more efficient if it used the same shape runners as the exhaust ports on the head. but it may require a lot of work to get all of the runners in that shape.

FattyBoomBatty
06-23-2008, 09:34 AM
Runner size can be important in a high powered car, or one where there is a lot of exhaust per cylinder. If you go too big, the exhaust will tumble over itself creating backpressure. In a square tube, that type of thing would seem almost unavoidable, given the shape of the corners. I do know that if you slightly flatten a round tube (make it an oval), the flow capability goes down.