long tube versus short tube headers
11-01-2006, 02:45 AM
#1
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long tube versus short tube headers I am trying to find some definitive data on the performance of long versus short tube headers. Most people say that long is better.
Is this just folk law, because I can't find any dyno data.
Logically one might say that the gases are in a less restrictive environment for longer in the long tubes, but I am not sure how much difference this would make given that the systems after the headers are usually twin 2.5-3 inch after the tubes anyway. Perhaps with forced induction where reducing backpressure is critical it may be significant
Anyone have any info.
Is this just folk law, because I can't find any dyno data.
Logically one might say that the gases are in a less restrictive environment for longer in the long tubes, but I am not sure how much difference this would make given that the systems after the headers are usually twin 2.5-3 inch after the tubes anyway. Perhaps with forced induction where reducing backpressure is critical it may be significant
Anyone have any info.
11-01-2006, 03:20 AM
#2
Long is more power yielding by a longshot. It is common knowledge around here. I know that sounds like a real ignorant way to answer your post, but you will find that is what everyone will tell you. Most sites/sponsors that sell headers can tell you dyno results.
11-01-2006, 04:07 AM
#3
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for n/a setups long tube all the way. It's about scavenging more so than flow!!!
Read the sticky (link in sig - induction/exhaust) read posts 6 and 13 onwards.
Shorties and mids will work well on FI as scavenging doesn't take place in this instance. But generally Lt's will still outflow in these conditions.
If you live in CA then shortie is legal.
Anywhere else in the world for pretty much any setup = LONG TUBE!
Read the sticky (link in sig - induction/exhaust) read posts 6 and 13 onwards.
Shorties and mids will work well on FI as scavenging doesn't take place in this instance. But generally Lt's will still outflow in these conditions.
If you live in CA then shortie is legal.
Anywhere else in the world for pretty much any setup = LONG TUBE!
11-01-2006, 09:05 AM
#4
shorties are known to give more torque but only like an 8hp increase over stock.
long tubes give you around 15-20whp over stock and also gives you a lil lower torque numbers than the shorties.
thats bout the best way i can answer that question hope it helps you out.
long tubes give you around 15-20whp over stock and also gives you a lil lower torque numbers than the shorties.
thats bout the best way i can answer that question hope it helps you out.
11-01-2006, 09:43 AM
#5
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Originally Posted by bjamick
shorties are known to give more torque but only like an 8hp increase over stock.
long tubes give you around 15-20whp over stock and also gives you a lil lower torque numbers than the shorties.
thats bout the best way i can answer that question hope it helps you out.
long tubes give you around 15-20whp over stock and also gives you a lil lower torque numbers than the shorties.
thats bout the best way i can answer that question hope it helps you out.
Shorties don't scavenge affectively within the operation rpm range of the LS1. I have heard claims of 10,000rpm being required to scavenging to take place with them.
The only time more torque in the lower rpms should be noticed is they myth of back pressure.
In truth you don't want any back pressure. Sure you need exhaust gas flow, but not back pressure.
On a stock tune if you remove the back pressure it will alter the fueling, and thus sometimes people see a reduction in performance (low end torque).
If tuned correctly though this will not be the case. And it's not a loss of torque, it simply moves the torque curve along to the right allowing PEAK torque to be higher in the rpms. This means that say at 1100rpm you are slightly lower down the torque curve than before.
11-01-2006, 11:28 AM
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Originally Posted by 300bhp/ton
I would have to disagree. Scavenging is the key to good header design on a n/a motor and the longer the primary the lower in the rpms the scavenging will take place.
Shorties don't scavenge affectively within the operation rpm range of the LS1. I have heard claims of 10,000rpm being required to scavenging to take place with them.
The only time more torque in the lower rpms should be noticed is they myth of back pressure.
In truth you don't want any back pressure. Sure you need exhaust gas flow, but not back pressure.
On a stock tune if you remove the back pressure it will alter the fueling, and thus sometimes people see a reduction in performance (low end torque).
If tuned correctly though this will not be the case. And it's not a loss of torque, it simply moves the torque curve along to the right allowing PEAK torque to be higher in the rpms. This means that say at 1100rpm you are slightly lower down the torque curve than before.
Shorties don't scavenge affectively within the operation rpm range of the LS1. I have heard claims of 10,000rpm being required to scavenging to take place with them.
The only time more torque in the lower rpms should be noticed is they myth of back pressure.
In truth you don't want any back pressure. Sure you need exhaust gas flow, but not back pressure.
On a stock tune if you remove the back pressure it will alter the fueling, and thus sometimes people see a reduction in performance (low end torque).
If tuned correctly though this will not be the case. And it's not a loss of torque, it simply moves the torque curve along to the right allowing PEAK torque to be higher in the rpms. This means that say at 1100rpm you are slightly lower down the torque curve than before.
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11-01-2006, 03:33 PM
#8
long tubes make more power due to their more ideal runner length (for scavenging) and better flow.
shorties are for people who want all the disadvantages of running headers, but the performance choking of manifolds...
seriously though, for the LSx motor family, the ONLY reason anyone should run shorties is that they have to meet inspections, or because of packaging reasons..... in either case its a non ideal compromise.
shorties are for people who want all the disadvantages of running headers, but the performance choking of manifolds...
seriously though, for the LSx motor family, the ONLY reason anyone should run shorties is that they have to meet inspections, or because of packaging reasons..... in either case its a non ideal compromise.
11-01-2006, 04:21 PM
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right now I have the JBA shortie headers and that was the biggest waste of money I have put in my car. I just bought some longtubes from pacesetter and I can't wait to put those in my car.
11-01-2006, 04:34 PM
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Originally Posted by import slayer
right now I have the JBA shortie headers and that was the biggest waste of money I have put in my car. I just bought some longtubes from pacesetter and I can't wait to put those in my car.
--- RIGHT ON MAN..GREAT..-- 
11-01-2006, 05:57 PM
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Absolutely no comparison, longtubes FTW. Only problem is they're not technically EPA/CARB legal anywhere (especially Commiefornia) as they relocate the cats.
Rob (Bad30th)
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11-03-2006, 02:10 PM
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Definately Long Tubes are going to out-perform shorties at any usable rpm, tq across the board.
But that's not to say you can't get decent numbers with shorties, it's all about the combo. Check my web site for a dyno graph of my old shorty dual exhaust combo, it put down 344 rwhp as a complete package.
But that's not to say you can't get decent numbers with shorties, it's all about the combo. Check my web site for a dyno graph of my old shorty dual exhaust combo, it put down 344 rwhp as a complete package.
