Why round exhaust pipe?

[TC]

http://speedtalk.com/forum/viewtopic.php?t=848

Ya tell me something I don't know........

[TheSilverBuick]

Ya tell me something I don't know........

Elementary Physics.

[chevy3100truck]

Elementary Physics.

[TC]

Elementary Physics.

Though flat edges produce more flow than a radiused edge.......... Well at least when it comes to valves........ Maybe turbulence is a good thing.......

Thing I'm getting at is a well designed exhaust system, whether it is round or square can be made to work, you just need to know how to design it right........ I posted a pic of a Nascar exhaust earlier, don't think it's just designed like that for clearance, it's designed like that cause it makes more HP..........

[JeffMcKC]

I cant beleive this is still going, a little real world info

1. My car 4 inch into a DR Gas 4" X pipe ( so it has even less back pressure 20" back from the collector into a 4" bullet ( see thru) out a 4" outlet in front of tire. Took them off gained 2.5 and 5 MPH at the track

2. Docs SEERED Car, 4" into a Borla 4" muffler into a 4" turn down took the mufflers off 2.0 and 4 MPH faster.

Both cars have like no "Restriction" its does change the tune lenght of the exhaust maybe its more about the tune lenght than the shape of the exhaust......

[Bob Holmes]

Just bought a Nascar boom tube to finish the plumbing on the Red Furd.

3" to a 3" Dynomax VT, to the boom tube located on the passenger side in front of the rear tire.

Its a street car so I don't care about the science on this one. I figure that if it exhausts half of 850 hp, then it won't have any trouble with my 300rwhp.

[dieselgeek]

75% it's just out of the box thinking that you guys can't keep up with. lol

[PatricksDad]

Well Nascar doesn't have a problem using square exhaust.......

That's kind of old-school, since most are oval section now. They use flattened outlets to clear the framerails and still maintain the maximum legal circumference.

[SuperBuickGuy]

I cant beleive this is still going, a little real world info

1. My car 4 inch into a DR Gas 4" X pipe ( so it has even less back pressure 20" back from the collector into a 4" bullet ( see thru) out a 4" outlet in front of tire. Took them off gained 2.5 and 5 MPH at the track

2. Docs SEERED Car, 4" into a Borla 4" muffler into a 4" turn down took the mufflers off 2.0 and 4 MPH faster.

Both cars have like no "Restriction" its does change the tune lenght of the exhaust maybe its more about the tune lenght than the shape of the exhaust......

I'll buy that, but to ask the question which won't make a bit of difference to the Corvette (in short, to learn a bit) - what about Vizard's assertion that there's a reflective wave that comes back through the exhaust from the tip?

[JeffMcKC]

I'll buy that, but to ask the question which won't make a bit of difference to the Corvette (in short, to learn a bit) - what about Vizard's assertion that there's a reflective wave that comes back through the exhaust from the tip?

Its not "Vizzards assertion" there is well known intake and exhaust pressure wave /pressure recovery(Helmholtz) I think the first I know trying to bring it into Drag Racing was Billy Shope ( High and Mighty Ram Chargers) . Pipemax with show the best size and lenght as a baseline of both. But its just a baseline not the rule of law, there is no magic number.

[CDMBill]

I cant beleive this is still going, a little real world info

1. My car 4 inch into a DR Gas 4" X pipe ( so it has even less back pressure 20" back from the collector into a 4" bullet ( see thru) out a 4" outlet in front of tire. Took them off gained 2.5 and 5 MPH at the track

2. Docs SEERED Car, 4" into a Borla 4" muffler into a 4" turn down took the mufflers off 2.0 and 4 MPH faster.

Both cars have like no "Restriction" its does change the tune lenght of the exhaust maybe its more about the tune lenght than the shape of the exhaust......

The pick up in ET and MPH tells us that the complete systems are robbing power. When we ran in '07 removing the the exhaust after the Dr. Gas x-pipe was worth .25 seconds and 4+ MPH so there is some consistency despite a fair amount of variance in performnce and engine design and output. My collector tapers from 4" into the Dr.Gas 3.5" frame clearance tubes to a 3.5" x-pipe. The full exhaust tapers to 3" after the x through 3" DynoMax Ultraflo mufflers, over the axle to 18" bullets as resonators. The goal there is quiet, at the track his year it all comes off in favor of 4" dumps after the x. That's 70# of weight loss and we'll see what we pick in HP as refected in MPH.

There is a reason real race cars don't have mufflers and other stuff hung onto the exhaust.

[TC]

The pick in ET and MPH tells us that the complete systems are robbing power. When we ran in '07 removing the the exhaust after the Dr. Gas x-pipe was worth .25 seconds and 4+ MPH so there is some consistency despite a fair amount of variance in performnce and engine design and output. My collector tapers from 4" into the Dr.Gas 3.5" frame clearance tubes to a 3.5" x-pipe. The full exhaust tapers to 3" after the x through 3" DynoMax Ultraflo mufflers, over the axle to 18" bullets as resonators. The goal there is quiet, at the track his year it all comes off in favor of 4" dumps after the x. That's 70# of weight loss and we'll see what we pick in HP as refected in MPH.

There is a reason real race cars don't have mufflers and other stuff hung onto the exhaust.

How much of the gain was from shedding weight??, the mufflers and exhaust system do weigh something.....

Also IMO if the collect is 4" you need to run 4" pipe all the way back, anything smaller is just creating a restriction, which I guess you already figured out.........

Which brings up the question, is back pressure really needed in a performance application??.....

[jcharliem]

I cant beleive this is still going...

I can. Any thread with TC vomiting on it, is like the Energizing Bunny...just keeps going on and on. Because the fool is hell-bent on proving himself correct with his 75% out-of-the-box thinking and Google links.

[TC]

I can. Any thread with TC vomiting on it, is like the Energizing Bunny...just keeps going on and on. Because the fool is hell-bent on proving himself correct with his 75% out-of-the-box thinking and Google links.

Did you read the link to SpeedTalk and how they were talking about he effects of putting angles on valve seats.... Some of the top engine builders in the country are discussing it, they've even done comparisons....... Angles always made more HP..... Hmmm, wonder why................ Oh that's right they tell you that to..........

Get a clue and quit fishing, as the only troll is the troll that calls people out.......

Though who goes down a mountain faster, a guy sliding on his ass or a guy tumbling head over heels??........

[BBR]

Ya tell me something I don't know........

You're on my ignore list?