turbo headers primary tubes
so phil and intmd8 you both are saying use 2 1/4 over using 2 1/2 crossover tube? wow i was gonna use 2 1/2. I have a t6 flange turbo. im gonna contact intmd8 and see if i can use a different manifold on the driver side so i can fit under my motor plate and go from there. I do wanna thank all of you guys for your help. I will be sure to post any questions before i make any decisions. thanks.
Last edited by bumpin_records; Nov 6, 2010 at 09:56 PM.
Good info...BUT...home ported Truck mani's and 2.5 crossover on a 364 (1400hp), 447 (1800hp) and recently a 440 (2000hp) all with very good results.
BTW...the whole system is for sale,lol...can't you trim your motor plate to fit the manifold...I have pics of how I did mine if you are interested.
Mark
BTW...the whole system is for sale,lol...can't you trim your motor plate to fit the manifold...I have pics of how I did mine if you are interested.
Mark
Yes I am interested but not I have a mustang. I would like to see your set up, email me at Lfcoleman71@yahoo.com thanks.
Last edited by bumpin_records; Nov 7, 2010 at 07:54 PM.
Just my experience....
My 438" motor has 1 3/4" headers with a 2.5" crossover, LS7 heads and more compression than 90% of the turbo LS setups out there. With the 1 3/4" headers on my LS7 head/carb style manifold and the marcella, the combo spooled very quickly and was fast went 160+ to the 1/8 mile. We never really leaned on it hard with the 1.75" headers.
We switched to 2" headers(what you would run on a turbo BBC) and now its harder to spool and doesn't seem to make any more power.
I'm still learning at this but I dont understand why you would run a 1 3/4" header on a 370 and on a 438. A 438 is going to make more power than a 370 considering they have the roughly the same volumetric efficiency. The amount of power you make will give you a certain air speed number in each header tube which at some point will cause problems if the airspeed is too high.
A 370" motor with 90# VE will make X amount of power and yield X amout of CFM in each header tube.
A 438" motor with 90# VE will make X amount of power and yield X amout of CFM in each header tube.
I spoke with Corky bell about a year ago and he said that there are some key air speeds that should be used when sizing header and crossover tube diameter, too big and airspeed falls, too small and it gets turbulent. When I appiled the forumula to my setup it said that the 2" header was too big for my 438" and the track results/spooling said the same thing.
The difference between a 1 3/4" header and a 1 5/8" header is airspeed. I'd be willing to bet that there is very little power difference between the true 1 3/4" header vs the 1 3/4" header stepped to 1 5/8". The difference is going to be in the velocity or airspeed and that will show up in spooling, not TEC®.
I'd still use a 2.25" crossover into a megs 2 x 2.25" to 3" collector/tube to the turbo. We use a 2.5" to 3.5" and we're making enough power to go 165 to the 1/8 mile. The key is get as big of an exhaust after the turbo as possible, run the wastgates to the atmosphere. Just my .02
What is the cross section of a truck manifold at its smallest point?
My 438" motor has 1 3/4" headers with a 2.5" crossover, LS7 heads and more compression than 90% of the turbo LS setups out there. With the 1 3/4" headers on my LS7 head/carb style manifold and the marcella, the combo spooled very quickly and was fast went 160+ to the 1/8 mile. We never really leaned on it hard with the 1.75" headers.
We switched to 2" headers(what you would run on a turbo BBC) and now its harder to spool and doesn't seem to make any more power.
I'm still learning at this but I dont understand why you would run a 1 3/4" header on a 370 and on a 438. A 438 is going to make more power than a 370 considering they have the roughly the same volumetric efficiency. The amount of power you make will give you a certain air speed number in each header tube which at some point will cause problems if the airspeed is too high.
A 370" motor with 90# VE will make X amount of power and yield X amout of CFM in each header tube.
A 438" motor with 90# VE will make X amount of power and yield X amout of CFM in each header tube.
I spoke with Corky bell about a year ago and he said that there are some key air speeds that should be used when sizing header and crossover tube diameter, too big and airspeed falls, too small and it gets turbulent. When I appiled the forumula to my setup it said that the 2" header was too big for my 438" and the track results/spooling said the same thing.
The difference between a 1 3/4" header and a 1 5/8" header is airspeed. I'd be willing to bet that there is very little power difference between the true 1 3/4" header vs the 1 3/4" header stepped to 1 5/8". The difference is going to be in the velocity or airspeed and that will show up in spooling, not TEC®.
I'd still use a 2.25" crossover into a megs 2 x 2.25" to 3" collector/tube to the turbo. We use a 2.5" to 3.5" and we're making enough power to go 165 to the 1/8 mile. The key is get as big of an exhaust after the turbo as possible, run the wastgates to the atmosphere. Just my .02
What is the cross section of a truck manifold at its smallest point?
http://www.coneeng.com/pdf/4-1%20Collector%20PDF.pdf
I'd use the CL4-163-SS 1 5/8" to 2.5" and get a pair CL4-163-SS(2.5" to 2" cone reducer), throw some v-bands with aligning flanges on the header and put the cone on the other v-band.
I'd use the CL4-163-SS 1 5/8" to 2.5" and get a pair CL4-163-SS(2.5" to 2" cone reducer), throw some v-bands with aligning flanges on the header and put the cone on the other v-band.
Good info...BUT...home ported Truck mani's and 2.5 crossover on a 364 (1400hp), 447 (1800hp) and recently a 440 (2000hp) all with very good results.
BTW...the whole system is for sale,lol...can't you trim your motor plate to fit the manifold...I have pics of how I did mine if you are interested.
Mark
BTW...the whole system is for sale,lol...can't you trim your motor plate to fit the manifold...I have pics of how I did mine if you are interested.
Mark
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
I know the philosophy varies heavily........ I am building my headers with 1 7/8"- 1 3/4" after the first bend. I feel like the exhaust port needs the additional cross section to get out the opening. Well, with the consideration of a "weak" exhaust port. I have ported all pro cathedrals that will flow decent, but not enough to keep up with the boosted and well flowing intake side. Unless I were to "belly" the straight walls of the exhaust port around the guide it doesnt make sense to me. I would rather keep a straight line of site out the door. Mine is being set up for a 408 with decent compression and a 94mm. But I want the versatility to go up on cubes and turbo and build the garbage once.
here are a few pictures of what i got so far. notice the notch on the bottom passernger side plate. the notch would have to be way bigger to get the truck header to fit on the driver side. Im gonna make my way up to speed inc hopefully this week to check out there manifolds.
