difference for the LT headers in 1 7/8 or 1 3/4

[cris]

I need to know if you guys know the difference and which one is better, because I just buy the 1 3/4 LT HEADERS and I see other brands who make this in 1 7/8 to.....

thanks

[hapisok]

1 3/4 if you don't plan on making ridiculous HP...1 7/8 for ridiculous HP...and 2" for INSANE HP.

[Juiced1]

Generally when you use a header that is to big for your application you lose some torque down low. For LS3 applications a 1 7/8 tube seems to be a great blend for top end power and torque and doesn't seem to lose anything down low. The 1 3/4" seems to be lost to the LS3 Camaro's but would actually be suited just fine for a bolt on car but at the same price you'd be better off with the 1 7/8". I wouldn't recommend the 2" header to anyone under 800 HP or so.

[geaux_tigerss]

Originally Posted by Juiced1

Generally when you use a header that is to big for your application you lose some torque down low. For LS3 application a 1 7/8 tube seems to be a great blend for top end power and torque. The 1 3/4" seems to be lost to the LS3 Camaro's but would actually be suited just fine for a bolt on car. I wouldn't recommend the 2" header to anyone under 800 HP or so.

Grrrrr, show me some dyno charts that validate your claim of "loss of low end torque." You are perpetuating a myth!

The only drawback to larger primaries is cost (and fitment to a lesser degree). You do not lose low end with these cars with increases in primary diameter.

[caverman]

I have 1 3/4" because I got a smokin' deal on a set of used ones. No way I could've turned them down. I don't have true back to back comparison because I've never switched them out. However, I can say my car still runs good at the track. I've even beat other Camaros that had the same basic bolt-ons but with 1 7/8" headers (difference being that I had suspension work and they didn't). My car dynoed about 3 less HP than the average 1 7/8" on the same shop's dyno.

All in all there is nothing wrong with 1 3/4" headers. You'll never notice or feel the difference in 3 or 4 hp. That being said, if I were to buy brand new and money not being an issue I would still lean towards 1 7/8" just in case you were to add a big cam or super charger down the road. If you know for sure you won't do that or you found a good deal on 1 3/4" then stick with that.

[IndeedSS1]

Originally Posted by geaux_tigerss

Grrrrr, show me some dyno charts that validate your claim of "loss of low end torque." You are perpetuating a myth!

The only drawback to larger primaries is cost (and fitment to a lesser degree). You do not lose low end with these cars with increases in primary diameter.

Actually Juiced1 is correct. It is way down low though.

I went from SOLO cats to 1 7/8 headers and immediately noticed a difference. The way to maximize testing this, would be to cruise down the hiway at 65 mph in 6th gear (LS3), quickly increase the throttle position by a very small percentage and not only pay close attention to how much squat you feel but how quickly the mph increases. There is a noticable difference. Once you move up in the rpms it no longer is noticable and the opposite happens.

It is hilly around and I noticed I had to give it more throttle to maintain a climb or downshift where-as before the headers it would climb no problem. Don't get me wrong, once up in the rpms the headers really shine.

[nighttowl]

if you have ported heads, go with the bigger ones. i went with 1 7/8 because that is how big the exhaust ports were. stock heads, go with 1 3/4.

[SUX2BU]

Originally Posted by geaux_tigerss

Grrrrr, show me some dyno charts that validate your claim of "loss of low end torque." You are perpetuating a myth!

The only drawback to larger primaries is cost (and fitment to a lesser degree). You do not lose low end with these cars with increases in primary diameter.

Exactly. I did a true back to back dyno back in the day on my LS1 bolt on 98 SS. I had 1 3/4 headers and then swapped to 1 7/8 headers. The dyno curves were EXACTLY the same from just under 2,000 all the way to about 4,500. After 4,500 rpm the HP and TQ both started climbing on the 1 7/8 headers. The difference was only about 5 hp 4 tq but remember this was only a bolt on LS1 so anything with more power like our LS3 will have a bigger gain.

I think 1 3/4 are a waste on these cars unless you get them for a CRAZY good price, like $100. I went with 1 7/8 but would swap to 2" on my bolt on car in a heartbeat if they weren't so expensive.

[Mr_Draco]

Originally Posted by Juiced1

Generally when you use a header that is to big for your application you lose some torque down low. For LS3 application a 1 7/8 tube seems to be a great blend for top end power and torque. The 1 3/4" seems to be lost to the LS3 Camaro's but would actually be suited just fine for a bolt on car. I wouldn't recommend the 2" header to anyone under 800 HP or so.

Originally Posted by IndeedSS1

Actually Juiced1 is correct. It is way down low though.

I went from SOLO cats to 1 7/8 headers and immediately noticed a difference. The way to maximize testing this, would be to cruise down the hiway at 65 mph in 6th gear (LS3), quickly increase the throttle position by a very small percentage and not only pay close attention to how much squat you feel but how quickly the mph increases. There is a noticable difference. Once you move up in the rpms it no longer is noticable and the opposite happens.

It is hilly around and I noticed I had to give it more throttle to maintain a climb or downshift where-as before the headers it would climb no problem. Don't get me wrong, once up in the rpms the headers really shine.

Actually, dyno tests have shown ZERO low end difference between the 1 3/4, 1 7/8 and 2". The HP and Trq curves are identical until you reach the 4k rpm range. After 4k, the 1 3/4 begins to drop off from the other 2.

[MarylandSpeed]

No one really runs 1 3/4" on these cars. 1 7/8" are pretty much the same powe wise, and give you room to grow. The only exception is stepped headers. When designed right, a 1 3/4" stepped to 1 7/8" header can out perform a straight 1 7/8" header.

[dekan513]

i seen test from someone i think it was jannetty racing that did a comparison

[geaux_tigerss]

Originally Posted by dekan513

i seen test from someone i think it was jannetty racing that did a comparison

Yep, and that test showed that bigger primaries had higher tq and hp all the way through the rpm range. I want to see a single dyno that shows otherwise. Back pressure is a myth on modern fuel injected cars.

[Whitehambone]

Look into Kooks stepped headers if you can't decide. They start at 1 3/4 and step up to 1 7/8. My tuner showed me several dyno sheets with the same mods compared to mine on one sheet. Mine did better than the others in HP and TQ.

[BlackM6RS/SS]

ARH 2" wouldn't be bad on a all out Heads Cam build like I see shops run on big builds!