Shorties vs. Long Tubes
Team Owner
Joined: Apr 2005
Posts: 27,596
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From: YOU SEE ... I'M NOT CRAZY ...I'M JUST AHEAD OF THE CURVE
St. Jude Donor '09-'10
From what I have been told by reputable shops, the issue with long tube headers is that it relocates the factory position of the cats ... by interpretation of the law, that is "modifying" the OEM design and thus (regardless of emmission effect itself) illegal.
The Calloway shorty headers maintain the OEM cat location - and if you were to use the factory installed cats, you would be complying with the fed reg since you are using the original cats and the exhaust manifold/shorty headers are not part of the emmission system.
The Calloway shorty headers maintain the OEM cat location - and if you were to use the factory installed cats, you would be complying with the fed reg since you are using the original cats and the exhaust manifold/shorty headers are not part of the emmission system.
Team Owner
Joined: Oct 2004
Posts: 27,420
Likes: 64
From: San Clemente CA
From what I have been told by reputable shops, the issue with long tube headers is that it relocates the factory position of the cats ... by interpretation of the law, that is "modifying" the OEM design and thus (regardless of emmission effect itself) illegal.
The Calloway shorty headers maintain the OEM cat location - and if you were to use the factory installed cats, you would be complying with the fed reg since you are using the original cats and the exhaust manifold/shorty headers are not part of the emmission system.
The Calloway shorty headers maintain the OEM cat location - and if you were to use the factory installed cats, you would be complying with the fed reg since you are using the original cats and the exhaust manifold/shorty headers are not part of the emmission system.
Team Owner
Joined: Apr 2005
Posts: 27,596
Likes: 0
From: YOU SEE ... I'M NOT CRAZY ...I'M JUST AHEAD OF THE CURVE
St. Jude Donor '09-'10
Le Mans Master
Joined: Mar 2002
Posts: 5,253
Likes: 50
From: Sandy Eggo Calif.
St. Jude Donor '06-'07-'08-'09-'10-'11-'12, '16
(However, enforcement of this requirement is almost non-existent and is the primary loop-hole that allows the usage of so-called "high flow" catalytic converters. Many of these units are sold with the disclaimer as being a "race" component and are not intended for street use.) Due to the hundreds of vehicle models produced over the years, it is virtually impossible to determine by glancing under a car whether the converter is the original unit, a legal OEM replacement, or a non-legal aftermarket "high flow" performance unit. Unless CARB or the EPA decide to take more aggressive enforcement action, the installation and usage of these non-exempt "high flow" catalytic converters will likely continue.
Drifting
Joined: Jun 2005
Posts: 1,837
Likes: 4
Well, there is some information available.
Callaway claims 19 HP for "power group 1", which is a Honker and catback. They claim 47 HP over stock by adding "power group 2", which is the headers, an intake manifold and wires. And they claim 90 HP over stock by adding power group 3, which is a cam and heads.
So, just assuming that its half intake and half exhaust, that makes the headers worth about 14 HP (by their claims).
Which ain't great, but it ain't nothing either.
Most folks seem to get about twice that from longtubes, but there is one other factor ...
The longtubes are used with replacement high-flow cats, or no cats. So how much of that 30 HP or so gain is from the headers and how much from the cats? Random claims about 10 HP for their cats, so the short headers with Random cats could be around 25 HP or so - pretty close to the long tube headers. Of course that isn't legal either, with the replacement cats, but the cats would be fairly easy to swap out for inspection day.
Of course these are manufacturer's claims, and you milage may vary. But Callaway is pretty reputable, and Random's been around for a while, so it isn't like something advertised on late-night TV. Callaway's overall numbers - CAI, headers, intake, cam and heads adding up to 90 HP - is easy to believe - if anything, that sounds a little low. On the other hand, 19 HP from intake and catback sounds a little optomistic.
There's certainly one advantage to the short tube headers over the stock manifolds - they're equal length tubes, which the stock manifold isn't. I'm not sure that the equal lengths aren't more important than exactly what that length is. But I don't have dyno numbers to prove that, so ..
Callaway claims 19 HP for "power group 1", which is a Honker and catback. They claim 47 HP over stock by adding "power group 2", which is the headers, an intake manifold and wires. And they claim 90 HP over stock by adding power group 3, which is a cam and heads.
So, just assuming that its half intake and half exhaust, that makes the headers worth about 14 HP (by their claims).
Which ain't great, but it ain't nothing either.
Most folks seem to get about twice that from longtubes, but there is one other factor ...
The longtubes are used with replacement high-flow cats, or no cats. So how much of that 30 HP or so gain is from the headers and how much from the cats? Random claims about 10 HP for their cats, so the short headers with Random cats could be around 25 HP or so - pretty close to the long tube headers. Of course that isn't legal either, with the replacement cats, but the cats would be fairly easy to swap out for inspection day.
Of course these are manufacturer's claims, and you milage may vary. But Callaway is pretty reputable, and Random's been around for a while, so it isn't like something advertised on late-night TV. Callaway's overall numbers - CAI, headers, intake, cam and heads adding up to 90 HP - is easy to believe - if anything, that sounds a little low. On the other hand, 19 HP from intake and catback sounds a little optomistic.
There's certainly one advantage to the short tube headers over the stock manifolds - they're equal length tubes, which the stock manifold isn't. I'm not sure that the equal lengths aren't more important than exactly what that length is. But I don't have dyno numbers to prove that, so ..
Team Owner
Joined: Oct 2004
Posts: 27,420
Likes: 64
From: San Clemente CA
Well, there is some information available.
Callaway claims 19 HP for "power group 1", which is a Honker and catback. They claim 47 HP over stock by adding "power group 2", which is the headers, an intake manifold and wires. And they claim 90 HP over stock by adding power group 3, which is a cam and heads.
So, just assuming that its half intake and half exhaust, that makes the headers worth about 14 HP (by their claims).
Which ain't great, but it ain't nothing either.
Most folks seem to get about twice that from longtubes, but there is one other factor ...
The longtubes are used with replacement high-flow cats, or no cats. So how much of that 30 HP or so gain is from the headers and how much from the cats? Random claims about 10 HP for their cats, so the short headers with Random cats could be around 25 HP or so - pretty close to the long tube headers. Of course that isn't legal either, with the replacement cats, but the cats would be fairly easy to swap out for inspection day.
Of course these are manufacturer's claims, and you milage may vary. But Callaway is pretty reputable, and Random's been around for a while, so it isn't like something advertised on late-night TV. Callaway's overall numbers - CAI, headers, intake, cam and heads adding up to 90 HP - is easy to believe - if anything, that sounds a little low. On the other hand, 19 HP from intake and catback sounds a little optomistic.
There's certainly one advantage to the short tube headers over the stock manifolds - they're equal length tubes, which the stock manifold isn't. I'm not sure that the equal lengths aren't more important than exactly what that length is. But I don't have dyno numbers to prove that, so ..
Callaway claims 19 HP for "power group 1", which is a Honker and catback. They claim 47 HP over stock by adding "power group 2", which is the headers, an intake manifold and wires. And they claim 90 HP over stock by adding power group 3, which is a cam and heads.
So, just assuming that its half intake and half exhaust, that makes the headers worth about 14 HP (by their claims).
Which ain't great, but it ain't nothing either.
Most folks seem to get about twice that from longtubes, but there is one other factor ...
The longtubes are used with replacement high-flow cats, or no cats. So how much of that 30 HP or so gain is from the headers and how much from the cats? Random claims about 10 HP for their cats, so the short headers with Random cats could be around 25 HP or so - pretty close to the long tube headers. Of course that isn't legal either, with the replacement cats, but the cats would be fairly easy to swap out for inspection day.
Of course these are manufacturer's claims, and you milage may vary. But Callaway is pretty reputable, and Random's been around for a while, so it isn't like something advertised on late-night TV. Callaway's overall numbers - CAI, headers, intake, cam and heads adding up to 90 HP - is easy to believe - if anything, that sounds a little low. On the other hand, 19 HP from intake and catback sounds a little optomistic.
There's certainly one advantage to the short tube headers over the stock manifolds - they're equal length tubes, which the stock manifold isn't. I'm not sure that the equal lengths aren't more important than exactly what that length is. But I don't have dyno numbers to prove that, so ..
Good information, thanks.
Race Director
Joined: Oct 2004
Posts: 10,516
Likes: 2
From: Virginia Bch VA
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06
5-7 RHWP loss with the shorty vs Long Tubes. Long Tubes scavenge mo betta.
Last edited by JFTaylor; Jun 25, 2007 at 04:00 PM.
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