Why round exhaust pipe?

[38P]

Check out page 144 in David Vizard's "How to Build Horsepower." He shows a long rectangular "pressure wave termination box" after the tuned collector length. Both pipes flow into the box and there is no X or H pipe. Install was for a 700-h.p. 1986 Corvette. Vizard asserts that the headers will see this as open atmosphere because of the dramatic cross-sectional increase, thus the mufflers and tailpipes are invisible to the headers/collectors (if they're of sufficient flow capacity) and do not change the tuned length of the system. He does point out on an earlier page that the exit of a pressure wave box needs to be funneled or properly radiused to prevent flow losses.

[Deaf Bob]

With how low my Corvette is, square will be the cat's pajamas. Especially since I'm not hearing anyone who's convinced me that there'd be any kind of performance loss.

I may even make a new muffler into the last 2 or so feet of the rectangular tube. Although, I do care a bit about apparances, so it'll go from 1x5 at the frame to 2 1/4 x 4 or 5 at the side of the car

Why make a muffler?
On my Gold Wing I had 1 1/2 inch pipes with 3/4 inch baffles inside drilled a bunch of holes in the baffle pipe (the stock outlet was 3/4 inch) welded a big washer on the 1 1/2 pipe and put the baffle pipe in it.. I flattened and rolled the inner end so exhaust had to go thru the drilled holes.. The total holes were more than the 3/4 inch outlet.. I never got looked at by a cop as long as I drove normal.. But once I twisted the throttle, it would jump and bellow!
Always wanted to try to do it on my flatbed.. Just to see...

[skullbucket]

Imagine going down a water slide that has square hills and valleys instead of smooth rounded off ones!
Round tube exhaust is better.

[TC]

Imagine going down a water slide that has square hills and valleys instead of smooth rounded off ones!
Round tube exhaust is better.

Then why do they put "angles" on intake and exhaust valves??.........

[TheSilverBuick]

Then why do they put "angles" on intake and exhaust valves??.........

Because they are easy to machine for sealing. Notice that most performance setup have higher angle counts? 3, 4, 5 and I think I've even heard of 7? The more angles there are the better it simulates a curved surface.

[SuperBuickGuy]

Imagine going down a water slide that has square hills and valleys instead of smooth rounded off ones!
Round tube exhaust is better.

you misunderstand the question? Nothing is squared off, it still smoothly transitions as the pipe flows to the tip; just the shape of the pipe is square.

[TC]

Because they are easy to machine for sealing. Notice that most performance setup have higher angle counts? 3, 4, 5 and I think I've even heard of 7? The more angles there are the better it simulates a curved surface.

Then why not make it curved??.... Why have the angles at all??......

[TheSilverBuick]

Then why not make it curved??.... Why have the angles at all??......

Because they are easy to machine for sealing. With out an o-ring or something, its difficult to seal a curved surface against another. Flat surfaces are a piece of cake to machine two surfaces flat.

[SuperBuickGuy]

Then why not make it curved??.... Why have the angles at all??......

because keeping a stone sharpened to give a consistent radii is nearly impossible. Yet you are thinking along the right lines - The ports that lead to the valves are generally square, squared, or have sharp edges (IMO it helps direct the flow). Cylinders and valves need to be round because of the materials used and what they're required to do.... will we see ovoid or square cylinders as material tech gets better? I doubt it, but I'm sure that out there somewhere is someone who has built a better mousetrap

[hauen]

Look up The late '70's early '80's Honda Motorcycle GP engines for an exercise in oval cylinders. It led directly to the creation of the V-4 engines. It's always cool to see thinking outside of the box, even if it often leads to spectacular failure.

[Scott Liggett]

get it shaped like this?



oh wait - that was just a dumb response, not a great idea.

I cash money for anyone who lives near him to weld a few of these on his cars one night.

[jcharliem]

Then why not make it curved??.... Why have the angles at all??......

Dude, please pack it up and go home for good. While you're worth a snort or two...you always end up embarrassing yourself.

[TC]

I'm going to have to say it doesn't make one god damn difference in what shape your exhaust system looks like........ The only thing that matters is the area of the space the exhaust has to move in........ As long as nothing is creating a restriction I can't see an exhaust system made up of square tubing being any more restricting than one made up of round tubing, even if you have sharp 90 degree turns in it, the engine will just push the exhaust past it............. And the fact that a 3" square tube has more area that a 3" round tube should make up for any flow impairments from the bends not having a radius..... It's not like the way the exhaust flows through the pipe has any bearing on how much HP has been made since the Power is made before the exhaust enters the exhaust system...... When in doubt, increase the area of the tubing that the exhaust has to pass through.......

And SBG I think you just gave me an Idea of how to run the exhaust on my '71 Camaro........

[skullbucket]

Dude, please pack it up and go home for good. While you're worth a snort or two...you always end up embarrassing yourself.

Well its too late he just wrote down the stupidest thing I have ever heard

I'm going to have to say it doesn't make one god damn difference in what shape your exhaust system looks like........ The only thing that matters is the area of the space the exhaust has to move in........ As long as nothing is creating a restriction I can't see an exhaust system made up of square tubing being any more restricting than one made up of round tubing, even if you have sharp 90 degree turns in it, the engine will just push the exhaust past it(AH THIS IS CALLED A RESTRICTION)............. And the fact that a 3" square tube has more area that a 3" round tube should make up for any flow impairments from the bends not having a radius..... It's not like the way the exhaust flows through the pipe has any bearing on how much HP has been made since the Power is made before the exhaust enters the exhaust system...... When in doubt, increase the area of the tubing that the exhaust has to pass through.......

And SBG I think you just gave me an Idea of how to run the exhaust on my '71 Camaro........

Why is the earth round instead of square?

[TC]

Well its too late he just wrote down the stupidest thing I have ever heard

Why is the earth round instead of square?

If round is so good why in HVAC is the duct work square, with 90 degree turns??.......

I'm not expecting you to understand the mechanics of it and what has to be done to make square bends flow more efficiently......... But I do feel the same principles do apply..... In either instance you are forcing air through a venting system....... You do understand that 2"x4" square tubing has more area than 3" round tubing and thus will flow more exhaust with less restriction........ What you fail to realize is the exhaust doesn't know if the pipe is round or square it just wants to flow and it'll take the path of least resistance every time..............