Exhaust Science Demystified
Thread Starter
Team Owner
Joined: Feb 2005
Posts: 32,519
Likes: 1
From: central America
St. Jude Donor '08-'09
Exhaust Science Demystified
I found this while checking up on some mufflers I was thinking about buying, and I remembered that a bunch of people were pretty interested in this article when it first came out several months ago...just thought I'd post it for those who are interested in reading it.
trw
http://popularhotrodding.com/enginem...exh/index.html
Shoot, this belongs in general, mods could you move it for me, thanks.
trwhttp://popularhotrodding.com/enginem...exh/index.html
Shoot, this belongs in general, mods could you move it for me, thanks.
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Vizard seems to have become a wizard at trotting out 1980's era advice and calling it new.
Granted most people havn't a clue about exhaust systems but telling people, for example, that equal length headers don't make a difference is a gross disservice.
It's an OK article but it's not the only thing you should read.
Granted most people havn't a clue about exhaust systems but telling people, for example, that equal length headers don't make a difference is a gross disservice.
It's an OK article but it's not the only thing you should read.
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
Originally Posted by 427V8
Vizard seems to have become a wizard at trotting out 1980's era advice and calling it new.
Granted most people havn't a clue about exhaust systems but telling people, for example, that equal length headers don't make a difference is a gross disservice.
It's an OK article but it's not the only thing you should read.
Granted most people havn't a clue about exhaust systems but telling people, for example, that equal length headers don't make a difference is a gross disservice.
It's an OK article but it's not the only thing you should read.
For street use, Tri-Y headers are MUCH more effective.
Dep
Thread Starter
Team Owner
Joined: Feb 2005
Posts: 32,519
Likes: 1
From: central America
St. Jude Donor '08-'09
Dep,
Glad to see you back on the forum.
What company makes a tri-Y header for C3 vettes?
I'd be interested, since I'm more in the street/strip crowd then anything else.
trw
PS: Do you need a set of Hooker super comps for your 302 you're going to build? If you do I've got a set.
Glad to see you back on the forum.
What company makes a tri-Y header for C3 vettes?
I'd be interested, since I'm more in the street/strip crowd then anything else.
trw
PS: Do you need a set of Hooker super comps for your 302 you're going to build? If you do I've got a set.
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
Originally Posted by 72 stingray owner
Dep,
Glad to see you back on the forum.
What company makes a tri-Y header for C3 vettes?
I'd be interested, since I'm more in the street/strip crowd then anything else.
trw
PS: Do you need a set of Hooker super comps for your 302 you're going to build? If you do I've got a set.
Glad to see you back on the forum.
What company makes a tri-Y header for C3 vettes?
I'd be interested, since I'm more in the street/strip crowd then anything else.
trw
PS: Do you need a set of Hooker super comps for your 302 you're going to build? If you do I've got a set.
That's the tricky part. Most likely they will have to be fabbed by an exhaust builder. People are so sold on the 4-tube equal-length that that style header gets major coverage.
Here's some websites that give more details on the Tri-Y headers:
http://www.clearimageautomotive.com/...haust/TriY.htm
http://www.autocandy.com/triy.htm
http://www.stans-headers.com/tri_y.htm
Stan's (the last website) shows a Tri-Y for a Vette, but not sure which year it fits.
Doug Thorley is big into Tri-Y headers and he may have a set for a C3 Vette. Summit carries Thorley headers.
I could sure use those headers you have, but I'm getting ready for a big move to New Mexico and don't want to accumulate any more stuff.
Dep
Last edited by DJ Dep; Jul 15, 2005 at 11:27 AM.
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Thread Starter
Team Owner
Joined: Feb 2005
Posts: 32,519
Likes: 1
From: central America
St. Jude Donor '08-'09
For those interested: here is a pic of the tri-Y header from stan's headers-and they sell for cheaper then ceramic coated Hooker super comps.
http://www.stans-headers.com/Photos/109y.JPG
Anybody have any experience with Stan's headers?
trw
http://www.stans-headers.com/Photos/109y.JPG
Anybody have any experience with Stan's headers?
trw
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Originally Posted by DJ Dep
Gross disservice or not, it happens to be TRUE. Equal length headers are more suited to RACE engines where the headers are run wide open.
For street use, Tri-Y headers are MUCH more effective.
Dep
For street use, Tri-Y headers are MUCH more effective.
Dep
Equal length is most important on the street. The biggest difference they make is not in Max HP but rather in tuneability.
The exhaust contributes 100x more to the manifold vacuum than the intake does ( Vizards own words ). Haveing unequal length tubes means some clyinders are running lean, some rich, none where you want them.
( this is one of his many contradictions )
Tri-Y headers have never been proven to be better than a properly designed set of equal length headers. They may be better than 90% or the garbage out there but that doesn't mean they are good!
When I switched from non equal length headman side exit headers to a set of properly designed headers I ganed 5" of vacuum. Thats what matters in a street car. Oh, and that is through the mufflers.
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
Personal experiences aside, it's been common knowledge among most hot rodders for MANY years that the Tri-y design is superior to 4-tube for street use.
4-tube headers are great...uncorked and running wide open at the strip.
For the street, the best thing they do is reduce weight over the stock manifolds. Some folks just refuse to face facts and prefer to be brainwashed by advertising. Ah well...someone has to keep those 4-tube header companies in business
BTW...I'll take useable HORSEPOWER over vacuum any time!!!
Dep
4-tube headers are great...uncorked and running wide open at the strip.
For the street, the best thing they do is reduce weight over the stock manifolds. Some folks just refuse to face facts and prefer to be brainwashed by advertising. Ah well...someone has to keep those 4-tube header companies in business
BTW...I'll take useable HORSEPOWER over vacuum any time!!!
Dep
Melting Slicks
Joined: Jul 2002
Posts: 3,000
Likes: 22
From: Boulder Creek California
"trotting out 1980's era advice"
If that 80's advice was no longer relevant, I'm sure he would have noticed while he was continuing to win races and actively involved in research...
http://www.coe.uncc.edu/college/vizard.htm
So I'm a little biased, I'm starting there in the fall
-Chris Newport
If that 80's advice was no longer relevant, I'm sure he would have noticed while he was continuing to win races and actively involved in research...
http://www.coe.uncc.edu/college/vizard.htm
So I'm a little biased, I'm starting there in the fall
-Chris Newport
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Headers by Ed is one of the better header manufactures in the nation. It's a good read.
http://www.headersbyed.com/
http://www.headersbyed.com/
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
Originally Posted by Techno
Why don't car makers use "Try whys" if they work so well on the street?
I mean they use "headers" don't they?
I mean they use "headers" don't they?
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
It's because tri-Why's aren't any better. It's been proven over and over on the dyno and on the track.
Contrary to what most hot rodders think...
Besides if a car is strictly street a pair of shorties is probably the best solution. Not like you need every last hp out of the engine...
Contrary to what most hot rodders think...
Besides if a car is strictly street a pair of shorties is probably the best solution. Not like you need every last hp out of the engine...
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
Originally Posted by 427V8
Headers by Ed is one of the better header manufactures in the nation. It's a good read.
http://www.headersbyed.com/
http://www.headersbyed.com/
Melting Slicks
Joined: Jun 2003
Posts: 2,802
Likes: 241
From: Niles, MI
Originally Posted by 427V8
Vizard seems to have become a wizard at trotting out 1980's era advice and calling it new.
Granted most people havn't a clue about exhaust systems but telling people, for example, that equal length headers don't make a difference is a gross disservice.
Equal length is most important on the street. The biggest difference they make is not in Max HP but rather in tuneability.
Having unequal length tubes means some cylinders are running lean, some rich, none where you want them.
Granted most people havn't a clue about exhaust systems but telling people, for example, that equal length headers don't make a difference is a gross disservice.
Equal length is most important on the street. The biggest difference they make is not in Max HP but rather in tuneability.
Having unequal length tubes means some cylinders are running lean, some rich, none where you want them.
"For many years we stressed the importance of equal-length primaries, but it is important to realize that equal length is not the only consideration in header design. The ultimate test of a good header is equal flow through each primary tube. Even though all the primaries may be equal in length, if some of the tubes have more bends in them they will be more restrictive. As an example, if one tube has two bends in it and another tube of equal length has four bends, the one with four bends will not flow as much volume as the one with two bends!
So it is very likely that a properly designed racing header will have primary tubes that are not all equal in length. You may want to keep this in mind when you buy or have a set of headers fabricated. Unfortunately, it is impossible to just look at a header and tell how efficient it is—the only sure way to tell is to use flow testing—but the important thing to remember is that equal length doesn't necessarily mean equal flow."
Smokey Yunick's Power Secrets by Smokey Yunick with Larry Schreib, copyright 1983