Header help! does size really matter?
Thread Starter
Drifting
Joined: Feb 2003
Posts: 1,714
Likes: 2
From: of mind, NY
Header help! does size really matter?
Lots of " talk" regarding 1 3/4 -vs -1 7/8 whats the deal. I see lots of guys here with dynatechs and they only come in 1 7/8 and everyone seems happy with them. Any one able to jusify Not getting the smaller tube ? I mean,does the 1/8 of an inch make that much difference on a car without forced induction?
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
the 1 7/8s is for the 427. the 1 3/4 is for the LS6 and LS2 blocks.
The 1 7/8s on the LS2 blocks will work, but most likley there will be better performanc from the 1 3/4 on the LS2.
The 1 7/8s on the LS2 blocks will work, but most likley there will be better performanc from the 1 3/4 on the LS2.
Thread Starter
Drifting
Joined: Feb 2003
Posts: 1,714
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From: of mind, NY
Originally Posted by AU N EGL
the 1 7/8s is for the 427. the 1 3/4 is for the LS6 and LS2 blocks.
The 1 7/8s on the LS2 blocks will work, but most likley there will be better performanc from the 1 3/4 on the LS2.
The 1 7/8s on the LS2 blocks will work, but most likley there will be better performanc from the 1 3/4 on the LS2.
I see american racing putting larger tubes on also. I feel theat this will reduce backpressure, which up to a point is good. I would like to hear from a tech the merits of pro and con
Le Mans Master
Joined: Nov 2004
Posts: 7,242
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I'm no expert, but I remember this was discussed. Too large of a chamber will create some kind of turbulence, which is counterproductive to the goal of getting the exhaust out as quickly and efficiently as possible. Or something like that, I think. 
CF Senior Member
Joined: Feb 2006
Posts: 23,313
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From: Tucson Arizona
I don't know that 1/8" is going to be a critical difference but I was lead to believe the 1 3/4" design provides optimal benefits for the LS2....perhaps a slight edge in low-end torque. Hopefully someone more knowledgeable will jump-in with definitive proof.
There are many good brands but after doing a little research, I went with (coated) LG Pro long tube headers with high-flow centers. IMO they were the best choice. I'm very happy with them.
FWIW, I'm not a proponent of forced-induction on a stock, cast-piston engine (irregardless of the size of headers used).
There are many good brands but after doing a little research, I went with (coated) LG Pro long tube headers with high-flow centers. IMO they were the best choice. I'm very happy with them.
FWIW, I'm not a proponent of forced-induction on a stock, cast-piston engine (irregardless of the size of headers used).
Safety Car
Joined: Dec 2004
Posts: 3,565
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
imo, you shouldn't select header size solely based upon the block/head size.
imo, you need to know the flow characteristics of your particular combination, in order to select the proper size.
however, most 1 3/4 will work well, as will 1 7/8. 1 7/8 will give more room for growth (additional airflow mods).
the difference in gains between the two don't justify a difference in cost.
imo, you need to know the flow characteristics of your particular combination, in order to select the proper size.
however, most 1 3/4 will work well, as will 1 7/8. 1 7/8 will give more room for growth (additional airflow mods).
the difference in gains between the two don't justify a difference in cost.
Drifting
Joined: Nov 2002
Posts: 1,651
Likes: 125
From: laguna niguel ca
It mostly depends on where you spend your time...
Both headers work. It's just that on the street in the rpm range where most of your driving is spent, the 1 3/4" primaries give you the best torque off idle and up. Yes you might give up a few HP at top of the rpm scale, but who but drag racers seek that rpm range all the time.
Just remember that torque talks the loudest on the street. Not high rpm HP. High rpm HP is for sustained high speed driving. So, both 1 3/4"
and 1 7/8" work well; they just work well in different places of the rpm scale. I choose 1 3/4" Kooks, my car is a daily driver making 461rwhp/435rwtq. They worked for me.
andreas g
Just remember that torque talks the loudest on the street. Not high rpm HP. High rpm HP is for sustained high speed driving. So, both 1 3/4"
and 1 7/8" work well; they just work well in different places of the rpm scale. I choose 1 3/4" Kooks, my car is a daily driver making 461rwhp/435rwtq. They worked for me.
andreas g
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Safety Car
Joined: Jun 2004
Posts: 3,563
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From: Dallas Tx
Originally Posted by RDunn
what about for a car thats a daily driver(very daily unless it snows) sees the track once 2 twice a year. only mods planned for the car are cai,headers and catback
Bigger is not always better. Matched to the application is better. Tubing size is only one factor, length, equal length, x pipe... go for the system optimized for that engine. Low end torque is your best bet for a street driver.
Drifting
Joined: Jul 2005
Posts: 1,969
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From: NJ
One of the things I see people looking for in daily driven street cars is a huge advertised RWHP number. That is not going to give you the best "feel" on the street. Area under the curve and TQ are going to give you "happy" street cars. Peak hp @ 7k rpm will not. Look at headers that give good tq on a stock cube motor, you will have more fun.
Drifting
Joined: Nov 2002
Posts: 1,651
Likes: 125
From: laguna niguel ca
Originally Posted by RDunn
what about for a car thats a daily driver(very daily unless it snows) sees the track once 2 twice a year. only mods planned for the car are cai,headers and catback
I would build my car for the street ,not the track. It's not top end power, that's just a number on a dyno. it's the power under the curve that moves you. What is it GM used to say, "horsepower sells cars, torque moves them". And since you only plan the above mentioned mods, the 1 3/4" primaries would be the better choice. Even with ETheads,224/228 cam, headers , tunning, and cat back, I still choose he 1 3/4" Kooks, and I don't regret it.Hope the info is helpful.
Melting Slicks
Joined: May 2006
Posts: 2,891
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From: NJ..."the way I saw it, everyone takes a beating sometimes."
Originally Posted by andreas g.
Both headers work. It's just that on the street in the rpm range where most of your driving is spent, the 1 3/4" primaries give you the best torque off idle and up. Yes you might give up a few HP at top of the rpm scale, but who but drag racers seek that rpm range all the time.
Just remember that torque talks the loudest on the street. Not high rpm HP. High rpm HP is for sustained high speed driving. So, both 1 3/4"
and 1 7/8" work well; they just work well in different places of the rpm scale. I choose 1 3/4" Kooks, my car is a daily driver making 461rwhp/435rwtq. They worked for me.
andreas g
Just remember that torque talks the loudest on the street. Not high rpm HP. High rpm HP is for sustained high speed driving. So, both 1 3/4"
and 1 7/8" work well; they just work well in different places of the rpm scale. I choose 1 3/4" Kooks, my car is a daily driver making 461rwhp/435rwtq. They worked for me.
andreas g
The best explaination I've ever read hazchris:
Since you're in the NY area give Chuck over at Corvette's Of Westchester a call. He's a big fan of the LGs and I'm sure he can help you make the best choice for your set up.
Drifting
Joined: May 2005
Posts: 1,254
Likes: 0
From: Ft. Liquordale Florida
1 7/8 here too. But I knew I was going to go FI eventually, and didn't want to have to change them out.
All depends on where you want to go with your mods. If SC or NOS is in your future, then go 1 7/8 - keeping in mind you will lose some bottom end TQ. Personally, I didn't really find it very noticable before I put the blower on...
Rick
All depends on where you want to go with your mods. If SC or NOS is in your future, then go 1 7/8 - keeping in mind you will lose some bottom end TQ. Personally, I didn't really find it very noticable before I put the blower on...
Rick
Le Mans Master
Joined: Feb 2006
Posts: 5,762
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From: Chandler Arizona
Don't let anyone fool you, size does matter! But in this case, the 1 3/4" is about right for the LS2. However, I wouldn't lose any sleep over using the 1 7/8" primaries. However, Lou claims that they made more power under the curve with the 1 3/4" primaries even on an LS7.
Racer
Joined: May 2005
Posts: 344
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From: Rancho Santa Margarita CA
Originally Posted by andreas g.
Both headers work. It's just that on the street in the rpm range where most of your driving is spent, the 1 3/4" primaries give you the best torque off idle and up. Yes you might give up a few HP at top of the rpm scale, but who but drag racers seek that rpm range all the time.
Just remember that torque talks the loudest on the street. Not high rpm HP. High rpm HP is for sustained high speed driving. So, both 1 3/4"
and 1 7/8" work well; they just work well in different places of the rpm scale. I choose 1 3/4" Kooks, my car is a daily driver making 461rwhp/435rwtq. They worked for me.
andreas g
Just remember that torque talks the loudest on the street. Not high rpm HP. High rpm HP is for sustained high speed driving. So, both 1 3/4"
and 1 7/8" work well; they just work well in different places of the rpm scale. I choose 1 3/4" Kooks, my car is a daily driver making 461rwhp/435rwtq. They worked for me.
andreas g
PS
I beleive the Dynatechs also have the smaller 2 1/2" collector where most other designs have a 3"
Instructor
Joined: Dec 2005
Posts: 162
Likes: 0
From: Bergen County NJ
Remember, the key here is to maintain velocity out of the exhaust port and scavenge on the next cycle. It is not a backpressure issue, it's velocity and 1 3/4s are better for the LS2. The increased velocity and scavenging are what provide better torque throughout most of the RPM range.
Thread Starter
Drifting
Joined: Feb 2003
Posts: 1,714
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From: of mind, NY
Originally Posted by DaddySS
Remember, the key here is to maintain velocity out of the exhaust port and scavenge on the next cycle. It is not a backpressure issue, it's velocity and 1 3/4s are better for the LS2. The increased velocity and scavenging are what provide better torque throughout most of the RPM range.
