Stepped headers
Thread Starter
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Stepped headers
Which way do they normally go ? If you had long tube undercar headers like say Hooker Super Comps with 1 3/4" primaries would you gain anything buy stepping the pipes up to 1 7/8".
What I mean to say is you start with 1 3/4" and step them up not down, anyone know ?
Obviously I have never run them but I always thought you stepped them down ?
What I mean to say is you start with 1 3/4" and step them up not down, anyone know ?
Obviously I have never run them but I always thought you stepped them down ?
Race Director
Joined: Nov 2002
Posts: 12,142
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From: Taylor Michigan
I use the super comps and the primaries are 2 1/8 into 3 1/2 collectors....only problem is the ground clearance is close...But the tracks are smooth and flat so that issue is not much of a problem....some return roads/lanes are bad however...Just watch for holes and bumps......
Le Mans Master
Joined: Nov 1999
Posts: 5,768
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From: San Diego CA
Stepped headers start large at the heads and get smaller as they progress away from the port if I'm not mistaken. I believe the concept is as the exhaust cools, you reduce tube size to keep velocity up to enhance the scavenging effect.
At least thats how I understand it.
At least thats how I understand it.
Thread Starter
Race Director
Joined: Apr 2000
Posts: 17,673
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Can you do it both ways or is the smaller to bigger the way to go.
I have a guy that is going to make some stainless headers exactly like the Hooker Super Comps but step them up to 1 7/8" from 1 3/4" at the head. He wants to know if this would work well.
Sound like a good idea ?
Racer
Joined: Dec 2008
Posts: 300
Likes: 0
From: Toms River NJ
smaller to larger. starts out small to maintain velocity which increases torque, and then goes larger for higher rpm flow. stepping them down would just be adding a restriction right after the head. at least thats what i read in one of the mags. who knows if they are correct or not. i think hedman calls theirs Tork-Step headers for that reason tho.
also, I'd love to buy a pair for my small block but cant find any for C3s
also, I'd love to buy a pair for my small block but cant find any for C3s
Burning Brakes
Joined: Oct 2008
Posts: 955
Likes: 50
From: Jersey Shore
I would think that stepping them down will increase exhaust gas velocity, but at the expense of creating more back pressure. Stepping them up creates a venturi effect which pulls more exhaust gas out to fill the larger volume of the tubes after the step.
small world dp9, Im at exit 109 on the GSP. Not too far from you
small world dp9, Im at exit 109 on the GSP. Not too far from you
Last edited by vette427-sbc; Oct 16, 2009 at 03:47 AM.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Can you do it both ways or is the smaller to bigger the way to go.
I have a guy that is going to make some stainless headers exactly like the Hooker Super Comps but step them up to 1 7/8" from 1 3/4" at the head. He wants to know if this would work well.
Sound like a good idea ?
I have a guy that is going to make some stainless headers exactly like the Hooker Super Comps but step them up to 1 7/8" from 1 3/4" at the head. He wants to know if this would work well.
Sound like a good idea ?
Last edited by Little Mouse; Oct 16, 2009 at 05:02 AM.
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Thread Starter
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Le Mans Master
Joined: Apr 2006
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You can put a rat motor in a vette chassis with 2 1/8 primaries but you can't put a SB in the same chassis with 1 7/8 primaries.
All the money your going to spend on custom headers may as well get picky get everything you want.
Last edited by Little Mouse; Oct 16, 2009 at 11:06 AM.
Thread Starter
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
No room to put the bigger pipes between the bolt holes on the normal 23 degree heads, ever noticed how close the bolts are to the pipes even with 1 5/8 primaires ?
BTW this guy is going to sell these headers to C3 owners, if he ever gets them made
BTW this guy is going to sell these headers to C3 owners, if he ever gets them made
Last edited by MotorHead; Oct 16, 2009 at 11:38 AM.
Race Director
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From: Corsicana, Tx
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You step them up larger as you go. Several things come into play. It reduces reversion pulses back up the header. *Where* to put the steps is a little scientific to be correct. Many variables to get it perfect...but you can get close enough.
Do a search on PipeMax and Larry Meaux.........great stuff on exhaust flow.
JIM
Do a search on PipeMax and Larry Meaux.........great stuff on exhaust flow.
JIM
Racer
Joined: Sep 2003
Posts: 258
Likes: 1
From: Memphis TN
This may be a little off topic, but I have wondered if changing from my Hooker Super Comps with 1 7/8" primaries, 3" collectors, and a 3" system all the way back to side-mount Hookers with 2 1/8" primaries and 4" collectors & pipes would make a big difference in HP on my mildly built 454?
Have you other guys that have gone to Hooker side pipes seen a big HP increase on a big block?
Have you other guys that have gone to Hooker side pipes seen a big HP increase on a big block?
Le Mans Master
Joined: Apr 2006
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Ok that makes sense. Looks like you will have to come out a little ways then step up to 1 7/8.
Last edited by Little Mouse; Oct 16, 2009 at 02:39 PM.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
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From: columbus oh
smaller to larger. starts out small to maintain velocity which increases torque, and then goes larger for higher rpm flow. stepping them down would just be adding a restriction right after the head. at least thats what i read in one of the mags. who knows if they are correct or not. i think hedman calls theirs Tork-Step headers for that reason tho.
also, I'd love to buy a pair for my small block but cant find any for C3s
also, I'd love to buy a pair for my small block but cant find any for C3s
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
These are polished stainless with equal length tubes into a 3 1/2 collector and out through 36 in megaphones. Larson Engineering made them for me and did most of my custom work on the ski and drag boats...the equal length tubes are the important item and hard to get under a Vette...
