1 3/4 vs 1 7/8 headers and ORY what's deciding factor in correct size.
05-15-2013, 11:52 PM
#1
1 3/4 vs 1 7/8 headers and ORY what's deciding factor in correct size. I am building a iron LS2 6.0 for my 02 T/A Flat tops, 243 heads and GM ASA cam. Car has a borla adjustable catback on it already. I am really leaning toward going with TSP headers because of how affordable they are. Not looking to drop 1500 on headers and a Y
It will be a daily driver on nice day's and will never go to the track and not real concerned with total HP output. I just want a nice strong running good sounding reliable street DD motor and it does have a stick. With that said
1. What are the tried and proven reasons for going with one size over the other or is there a point at which x amount of mods and cubic inches and cams necessitate the 1 3/4 vs 1 7/8 header choice.
2. How much of a average loss in output if I were to just run OE manifolds and punched out cats on the above.
Keep in mind this combo is for a daily driver w average speed of 0-75 and mostly highway driving and a few WOT back road runs every blue moon or so.
It will be a daily driver on nice day's and will never go to the track and not real concerned with total HP output. I just want a nice strong running good sounding reliable street DD motor and it does have a stick. With that said
1. What are the tried and proven reasons for going with one size over the other or is there a point at which x amount of mods and cubic inches and cams necessitate the 1 3/4 vs 1 7/8 header choice.
2. How much of a average loss in output if I were to just run OE manifolds and punched out cats on the above.
Keep in mind this combo is for a daily driver w average speed of 0-75 and mostly highway driving and a few WOT back road runs every blue moon or so.
Last edited by 01WS6/tamu; 05-16-2013 at 12:29 AM.
05-16-2013, 06:28 AM
#2
even a stock ls1 will gain with 1-7/8 over 1-3/4. The larger primaries outperform the smaller ones period. They los no torque down low compared to the 1-3/4 and make more power up op so its a no brainer if you're buying new headers.
Also leaving stock manifolds on that car would be a major choking point, I'd estimate on the field of losing 25whp or more by not doing a good set of lt's.
Also leaving stock manifolds on that car would be a major choking point, I'd estimate on the field of losing 25whp or more by not doing a good set of lt's.
05-16-2013, 07:53 PM
#6
05-16-2013, 07:55 PM
#7
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you could do alot better in cam dept....a 228-232 split duration or some around there would be nicer....i personally would recommend the lunati 227-232 cam, performs very well, its quiet and easy on the valvetrain....
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05-21-2013, 04:24 PM
#12
Yep.
4 things to consider with headers: primary length, primary diameter, collector length, and exhaust valve/port.
Generally, a 1-3/4" longtube, like LG's Vette headers, make more torque, but they are also quite a bit longer than Kooks/ARH for the Vette. For the F-Body, primary length is sort of what it is due to the frame.
The only tunable variables, then, are the primary diameter, collector length, and optimization for the heads being used. And it turns out the shorter length primaries makes any torque advantage of the 1-3/4" have, moot.
So, that leaves the heads and collector length. Generally the collectors are pretty similar with Kooks, QTP, and ARH having high velocity merge collectors to help pick up midrange torque lost by the shorter primary length.
And as for the heads, 1.55" and 1.575" exhaust valves seem to favor the 1-7/8" at all RPMs. The only exception is AFR with the 1.60" exhaust valve. It's more of a wash on the F-Body, but on the Vette, the longer 1-3/4" primaries made more power (not much, but a little more). Why? Well, the 1.60" valve loses some velocity over the 1.55 or 1.575" valves and the long tube smaller primaries helped reclaim that lost velocity.
To sum it up, primary length is what it is on the F-Body, and most heads favor the larger primaries with no ill effects. The only thing left to decide is which stainless headers you want and if you're willing to pay extra for the HVMC to ratchet up the torque a bit?
4 things to consider with headers: primary length, primary diameter, collector length, and exhaust valve/port.
Generally, a 1-3/4" longtube, like LG's Vette headers, make more torque, but they are also quite a bit longer than Kooks/ARH for the Vette. For the F-Body, primary length is sort of what it is due to the frame.
The only tunable variables, then, are the primary diameter, collector length, and optimization for the heads being used. And it turns out the shorter length primaries makes any torque advantage of the 1-3/4" have, moot.
So, that leaves the heads and collector length. Generally the collectors are pretty similar with Kooks, QTP, and ARH having high velocity merge collectors to help pick up midrange torque lost by the shorter primary length.
And as for the heads, 1.55" and 1.575" exhaust valves seem to favor the 1-7/8" at all RPMs. The only exception is AFR with the 1.60" exhaust valve. It's more of a wash on the F-Body, but on the Vette, the longer 1-3/4" primaries made more power (not much, but a little more). Why? Well, the 1.60" valve loses some velocity over the 1.55 or 1.575" valves and the long tube smaller primaries helped reclaim that lost velocity.
To sum it up, primary length is what it is on the F-Body, and most heads favor the larger primaries with no ill effects. The only thing left to decide is which stainless headers you want and if you're willing to pay extra for the HVMC to ratchet up the torque a bit?
05-21-2013, 05:50 PM
#13
Yep.
4 things to consider with headers: primary length, primary diameter, collector length, and exhaust valve/port.
Generally, a 1-3/4" longtube, like LG's Vette headers, make more torque, but they are also quite a bit longer than Kooks/ARH for the Vette. For the F-Body, primary length is sort of what it is due to the frame.
The only tunable variables, then, are the primary diameter, collector length, and optimization for the heads being used. And it turns out the shorter length primaries makes any torque advantage of the 1-3/4" have, moot.
So, that leaves the heads and collector length. Generally the collectors are pretty similar with Kooks, QTP, and ARH having high velocity merge collectors to help pick up midrange torque lost by the shorter primary length.
And as for the heads, 1.55" and 1.575" exhaust valves seem to favor the 1-7/8" at all RPMs. The only exception is AFR with the 1.60" exhaust valve. It's more of a wash on the F-Body, but on the Vette, the longer 1-3/4" primaries made more power (not much, but a little more). Why? Well, the 1.60" valve loses some velocity over the 1.55 or 1.575" valves and the long tube smaller primaries helped reclaim that lost velocity.
To sum it up, primary length is what it is on the F-Body, and most heads favor the larger primaries with no ill effects. The only thing left to decide is which stainless headers you want and if you're willing to pay extra for the HVMC to ratchet up the torque a bit?
4 things to consider with headers: primary length, primary diameter, collector length, and exhaust valve/port.
Generally, a 1-3/4" longtube, like LG's Vette headers, make more torque, but they are also quite a bit longer than Kooks/ARH for the Vette. For the F-Body, primary length is sort of what it is due to the frame.
The only tunable variables, then, are the primary diameter, collector length, and optimization for the heads being used. And it turns out the shorter length primaries makes any torque advantage of the 1-3/4" have, moot.
So, that leaves the heads and collector length. Generally the collectors are pretty similar with Kooks, QTP, and ARH having high velocity merge collectors to help pick up midrange torque lost by the shorter primary length.
And as for the heads, 1.55" and 1.575" exhaust valves seem to favor the 1-7/8" at all RPMs. The only exception is AFR with the 1.60" exhaust valve. It's more of a wash on the F-Body, but on the Vette, the longer 1-3/4" primaries made more power (not much, but a little more). Why? Well, the 1.60" valve loses some velocity over the 1.55 or 1.575" valves and the long tube smaller primaries helped reclaim that lost velocity.
To sum it up, primary length is what it is on the F-Body, and most heads favor the larger primaries with no ill effects. The only thing left to decide is which stainless headers you want and if you're willing to pay extra for the HVMC to ratchet up the torque a bit?
Last edited by LilJayV10; 05-23-2013 at 01:37 AM.
05-22-2013, 10:16 PM
#16
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1 7/8's here also. I have the TSP y-pipe with cats welded in. Its alright the clamps they send with it suck so either pony up for some nicer ones or just weld it all together like I did.
05-24-2013, 11:52 AM
#18
Personally, I like it loud however it MUST have tone (pouring out of a cutout at the headers just sounds loud and louder). I think that setup would sound really good.
I love the deep Borla tone and the LT+ORY will help dial up the volume and you can adjust the plates if you find it's too much. I have a somewhat similar setup and would've gone with the Borla catback over the Magnaflow if I wasn't trying to get under a track's noise restriction.