HEADERS : 1 3/4 vs. 1 7/8
06-01-2013, 03:13 PM
#41
Tri-y design doesn't require the same size primary as a 4-1 design to make good power - you're missing the point 
LS2 = 1-3/4"
LS3 = 1-7/8"
** with a 4-1 header which is what most manufacturers make
I don't care if you believe me or not get the smaller headers if you have an LS3 and go slower
LS2 = 1-3/4"
LS3 = 1-7/8"
** with a 4-1 header which is what most manufacturers make
I don't care if you believe me or not get the smaller headers if you have an LS3 and go slower
06-01-2013, 04:37 PM
#42
I posted a similar thread (regarding LG streets 1 3/4 vs. Texas Speed 1 7/8) for my bolt on 05. I am adding a FAST 102 at the same time and probably a cam later on. The Texas Speed headers/x are a great deal, saving around $500 to go that route instead of the LG's. This thread as well as info posted in my thread have led me to lean towards the 1 3/4.
06-03-2013, 12:43 PM
#44
Drifting
Its very simple in my eyes..
NA LS3
FORCED INDUCTION /NITROUS = 1 7/8
NA: 1 3/4
Will you make max HP in an NA application w/ 1 3/4 ? NO but you will make more TQ and HP under the curve...MORE TQ then HP ...that will be the biggest notice
NA LS3
FORCED INDUCTION /NITROUS = 1 7/8
NA: 1 3/4
Will you make max HP in an NA application w/ 1 3/4 ? NO but you will make more TQ and HP under the curve...MORE TQ then HP ...that will be the biggest notice
06-03-2013, 01:11 PM
#45
Safety Car
From what I have read here posted by Pfadt (for one example) is that it's the amount of HP that the car will make i.e. 900+ that will decide what size primary header tubes to use, PERIOD... 
06-04-2013, 09:52 AM
#46
this is a before and after dyno with the maff doing the tuning 1 3/4 cattless vs 1 7/8 only a 4 hp gain at 7000 rpm no gain across the band and a 20 rwtq loss and a loss across the whole band. i would think the numbers are pretty high for an LS2 A4 AUTOMATIC big converter and 373 gears. if it gained 4 hp and loss no tq then it would be worth it to me, im not willing to trade off tq
if it gained 4 hp and loss no tq then it would be worth it to me, im not willing to trade off tq
06-04-2013, 10:52 AM
#47
Safety Car
Looks like it lost HP & Torque across the whole band! and only gained that 4 hp at the very end on just the one pull of the two; also looks like a 25/30 HP loss @4500 RPM'S to me with the 1 7/8" headers & about a 50 HP loss if you use the lower 1 7/8" header pull. WOW!!
Last edited by C7/Z06 Man; 06-04-2013 at 11:55 AM.
06-04-2013, 12:35 PM
#49
Race Director
Looks like it lost HP & Torque across the whole band! and only gained that 4 hp at the very end on just the one pull of the two; also looks like a 25/30 HP loss @4500 RPM'S to me with the 1 7/8" headers & about a 50 HP loss if you use the lower 1 7/8" header pull. WOW!!
that was with no tuning changes, we let the cars computer adjust and those were after it adjusted, i would love to try some other brands if some companies would like to step up!!! i would hate to do this test and only the kooks prove to show tq and hp gains with no loss. I know it would be great for business if the 1 7/8 header could put a H&C C6 automatic into the 500rwhp range
06-07-2013, 12:16 AM
#50
Team Owner
If your content with second, than go with the larger diameter headers.
If you like first, than go with the smaller diameter headers.
From reading some posts on here from those who build HP 1 3/4" will make more torque which gets you to the finish line first and it's not until 700/800 hp that the larger headers finally inch ahead. Also remember power over the curve.
How much HP is your final setup going to make??? 
PS: Maybe that's the difference why the guy in second place in the GS bolt-ons with all the same equipment runs 1 7/8" to my 1 3/4" first place.
If you like first, than go with the smaller diameter headers.
From reading some posts on here from those who build HP 1 3/4" will make more torque which gets you to the finish line first and it's not until 700/800 hp that the larger headers finally inch ahead. Also remember power over the curve.
How much HP is your final setup going to make??? PS: Maybe that's the difference why the guy in second place in the GS bolt-ons with all the same equipment runs 1 7/8" to my 1 3/4" first place.
More important is that they are 3 inch (x-pipe) catback over 2 1/2 catback. Oh by the way it's power UNDER the curve.Whats the FIRST PLACE STUFF!
Last edited by 3 Z06ZR1; 06-07-2013 at 12:20 AM.
06-07-2013, 12:29 AM
#51
Team Owner
A&A kit and the SAME tune!
Last edited by 3 Z06ZR1; 06-07-2013 at 12:35 AM.
06-07-2013, 01:31 AM
#52
Safety Car
I run 1 3/4" SS headers with a 3" X-pipe & no cats back to 2 1/2" stock (430 hp) LS3 mufflers.
This thread I believe is about "header size" with the rest of the system the same and not apples and coconuts.
This thread I believe is about "header size" with the rest of the system the same and not apples and coconuts.
Last edited by C7/Z06 Man; 06-07-2013 at 10:43 AM.
06-07-2013, 09:34 AM
#53
Former Vendor
always love this debate btw..haha
No right or wrong answer, the decision to choose 1-3/4" or 1-7/8" should be decided on a few factors such as how you actually use the car, what current modifications the car has and where you want to be in the future. Seems like these questions/answers aren't commented enough. Next set of questions are based around how long do you plan on keeping the car, how many miles do you drive per year and what your budget is. If you put a lot of miles on the car you should be choosing a stainless steel header with lifetime warranty, otherwise save the money. Obviously we could go on and on, like who will do the install and what about the tune??
Sorry just our 2 cents as there are many important components to look at besides basic primary size. Thanks for listening.
Paul G.
Stainless Works
No right or wrong answer, the decision to choose 1-3/4" or 1-7/8" should be decided on a few factors such as how you actually use the car, what current modifications the car has and where you want to be in the future. Seems like these questions/answers aren't commented enough. Next set of questions are based around how long do you plan on keeping the car, how many miles do you drive per year and what your budget is. If you put a lot of miles on the car you should be choosing a stainless steel header with lifetime warranty, otherwise save the money. Obviously we could go on and on, like who will do the install and what about the tune??
Sorry just our 2 cents as there are many important components to look at besides basic primary size. Thanks for listening.
Paul G.
Stainless Works
06-07-2013, 11:01 AM
#54
Melting Slicks
I was told by my tuner to get 1 3/4 headers, then I decided to go with a mild cam. Tuner said better get a 1 7/8 header and a 160 thermostat at this point, sound about right? Cam must have made a difference.
06-07-2013, 11:08 AM
#55
Former Vendor
Does the cam have an aggressive profile? A cam will change the volumetric efficiency of the engine, slightly but all depends on cam specs. Again, all depends on how you use the car. If its just a cam, use 1-3/4". Seems like the cam is probably mild since you didn't mention upgrades heads and intake.
06-07-2013, 03:05 PM
#56
Melting Slicks
vararam Intake, cam is 232/234 .595/.598 comp cam grind
Does the cam have an aggressive profile? A cam will change the volumetric efficiency of the engine, slightly but all depends on cam specs. Again, all depends on how you use the car. If its just a cam, use 1-3/4". Seems like the cam is probably mild since you didn't mention upgrades heads and intake.
06-07-2013, 03:20 PM
#57
Race Director
Member Since: Mar 2007
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There is/was something horribly wrong with that car in the first pull if the only change was headers.
06-07-2013, 03:22 PM
#58
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my guess is that for 98% of the people the decision between 3/4" and 7/8" won't make a difference nor will it be noticed in daily driving. if you are going to go cam or supercharger in the future or if you are not sure then go 7/8's.
06-07-2013, 06:54 PM
#59
Team Owner
I've built several high horsepower cars...never even seen anything close to those gains by swapping headers....I think someone is pulling your leg. Right now I have a 402 with 15lbs of boost. I'm swapping my headers out for some 1 3/4....I honestly don't expect to see loss ( I haven't in the past). I'm only swapping them because my Kooks have a crack in them right now
Kook's 1 3/4 with 2 1/2 inch x-pipe.
Switched to ARH 1 7/8's with 3 inch x-pipe.
Then redyno'd on the same tune. No one pulling ANY LEGS HERE!
The obvious here is the 2 and 1/2 xpipe sucks on a blower car.
Everyone says Phaft says this! Nick at ARH which has sold 10,000
to one of Phaht's. Tells you the 1 7/8 beats the 1 3/4. Plus PHA
FT's Tri-y opens up quickly from 1 3/4.
06-07-2013, 06:56 PM
#60
Team Owner
So wrong!