Why round exhaust pipe?

[TheSilverBuick]

lol.

[dieselgeek]

Reason number 439,214 that there should be a "members only" tech forum here. Members vote who gets in.

I hate it when somebody plagiarizes the work of someone else. I've found people quoting my posts as if their own before. Gotta love the fat sack-o-$h1t that does this kind of stuff.

TC = officially on ignore

[jcharliem]

^^^^ That's funny as hell. I can't recall a single piece of tech advise from ol' TC that wasn't Googled up from somewhere. There's no thoughts - that are worth a hoot - that originate from him.

[dieselgeek]

^^^^ That's funny as hell. I can't recall a single piece of tech advise from ol' TC that wasn't Googled up from somewhere. There's no thoughts - that are worth a hoot - that originate from him.

But he's been hotrodding for 15 years!!! he's an expert!!

[dieselgeek]

Given the elastic nature of air, I'm not ready to sign up for the proposition that low pressure/low temperature performance (i.e. HVAC system) is predictive of high pressure/high temperature performance (i.e. exhaust pipe). Certainly the slow-moving boundary layer is going to be influenced by factors such as the duct shape, duct wall finish, surface-to-volume ratio, density, flow turbulance and velocity.

x2

I stay out of this argument, but there are some pretty smart guys on speedtalk.com who have made a more than convincing argument that the a constant flowing air mass (as is the case when heads are "flow tested") is absolutely, totally, and unequivocally not relevant to what's going on in an internal combustion engine.

One look at the pressure wave simulations in Dynomation will make this clear. Or a view of the standoff in an IR intake helps us understand.

And I heard Ray Barton discuss his thoughts on airflow, and some of the ways he's tested and observed it, he says the same thing.

It sucks because in Wind Tunnel testing a race car, you DO use lower velocity airflow behavior to predict or model what will happen at higher speeds. But apparently it's the pressure pulses in the exhaust that throw all that right down the toilet.

I'm just an innocent bystander so, don't shoot the messenger on that one. Lord knows I got enough people pissing and moaning about the "Internet Lies" thing in Hot Rod this month -jeebus!! (I have yet to find a single doubter who ever did ABA testing on that issue, FYI)

[Loren]

x2

I stay out of this argument, but there are some pretty smart guys on speedtalk.com who have made a more than convincing argument that the a constant flowing air mass (as is the case when heads are "flow tested") is absolutely, totally, and unequivocally not relevant to what's going on in an internal combustion engine.

That's been my thought for a long time. A blob of compressable gas that's being pushed on, pulled on, speeded up, slowed down, heated, cooled and stored in a runner or primary and then stuffed together with other blobs at an uneven rate (normal V-8 header side) is sure not gonna behave the same as an even flow blowing through a hole. Push on anything compressable...poke a balloon on the side...it's going to move away from you but also a portion will bounce back when you pull away, just one of the type of things that would have to be considered when you dream up a port or header design.

Really the only thing for-sure common is that when you make a mass turn a corner (i.e. decelerate in one direction, accelerate in another, and change shape to make the curve) there's gonna be resistance.

[JeffMcKC]

Thats why I always laugh when someone gives a hard and fast Magic number on anything.

[TC]

You know what's funny DG, I found that same exact quote (by TC) on a Mustang Forum dated March of 2008. I shit you not, quoted word from word. The screen-name is 67mustang302 from California. I couldn't help but laugh and had to post it.... Ha Ha Ha!!!

http://mustangforums.com/forum/5-0l-1979-1995-mustang/423658-backpressure-i-might-need-to-change-some-things.html

Thought you'd get a kick out of it........ LMAO!!!

Fact is who cares where I got it from(and it wasn't from that site), I just used it to back up what I already know..... Back pressure is bad, that is fact. And pulse wave tuning has nothing to do with back pressure, to saying anything else just shows that you really don't know what your talking about........

And the fact here is not one person on this board, other than maybe Dynoroom has any experience with pulse wave tuning, so your all talking out your asses........

[TC]

x2

I stay out of this argument, but there are some pretty smart guys on speedtalk.com who have made a more than convincing argument that the a constant flowing air mass (as is the case when heads are "flow tested") is absolutely, totally, and unequivocally not relevant to what's going on in an internal combustion engine.

One look at the pressure wave simulations in Dynomation will make this clear. Or a view of the standoff in an IR intake helps us understand.

And I heard Ray Barton discuss his thoughts on airflow, and some of the ways he's tested and observed it, he says the same thing.

It sucks because in Wind Tunnel testing a race car, you DO use lower velocity airflow behavior to predict or model what will happen at higher speeds. But apparently it's the pressure pulses in the exhaust that throw all that right down the toilet.

I'm just an innocent bystander so, don't shoot the messenger on that one. Lord knows I got enough people pissing and moaning about the "Internet Lies" thing in Hot Rod this month -jeebus!! (I have yet to find a single doubter who ever did ABA testing on that issue, FYI)

Hey nice book report from the thread I read last night on Speed Talk.........

[dieselgeek]

Fact is who cares where I got it from(and it wasn't from that site), I just used it to back up what I already know..... Back pressure is bad, that is fact. And pulse wave tuning has nothing to do with back pressure, to saying anything else just shows that you really don't know what your talking about........

And the fact here is not one person on this board, other than maybe Dynoroom has any experience with pulse wave tuning, so your all talking out your asses........

#1 learn the meaning of the word "Fact" because you don't get it
#2 quit using other people's experience and passing it off as your own.
#3 I know more than I ever wanted to know about pressure wave tuning, ktanksbye

[TC]

#1 learn the meaning of the word "Fact" because you don't get it
#2 quit using other people's experience and passing it off as your own.
#3 I know more than I ever wanted to know about pressure wave tuning, ktanksbye

#1 You have no experience either and your post about pulse wave tuning having an effect on back pressure, was wrong......

#2 So your saying don't learn from others??........ Ya you go out and learn it all on your own, I have no problem taking the experience from other people's testing and applying it to what I know....

#3 Sure you do...........

[dieselgeek]

Guess how many people on this entire forum are interested in your posts Alex? that's right - ZERO. Congrats!

[TC]

Guess how many people on this entire forum are interested in your posts Alex? that's right - ZERO. Congrats!

I could care less who is interested in my posts.......

[skullbucket]

Is there really an ignore app on this site, because I have a few to add to it.

[Bucky67]

Fact is who cares where I got it from(and it wasn't from that site), I just used it to back up what I already know..... Back pressure is bad, that is fact. And pulse wave tuning has nothing to do with back pressure, to saying anything else just shows that you really don't know what your talking about........

And the fact here is not one person on this board, other than maybe Dynoroom has any experience with pulse wave tuning, so your all talking out your asses........

Fact is- you got called out on it and busted bigger than shit. Funny thing is; you even kept the same exact word capitalized in the quote. I mean word for word you stole that entire paragraph. If that's not bad enough, you typed it as if you wrote it. All you would have had to do is say, "hey from the research that I've done" and then provide the link.

As for talking out of my ass, never done that. One thing the Military has taught me, you better be able to back up what you say. And yes, I've built a ground pounding street car- from start to finish. I'd be more than happy to provide any pictures, videos, and/or documentation on Jade!!!