[ScratchAce]

Looking at options for headers from my local shop an there is quite a difference in price between the two sizes. Are their significant differences or reasons to pay the extra for 2"?

[BradfordCamaro]

Good testing done by Jannetty Racing... about 20 threads before This One.

http://www.camaro6.com/forums/showthread.php?t=472259

[boostednut]

4whp. -2tq

I think that's actually considered within the noise. But either way 7/8th's wont be an issue until you're near what the block it's self will hold. Well, depending on power adder exactly. There are lt1 cars over 800whp on 7/8ths.

[KonigWolf]

EFI Tuning 2" Kooks.
http://www.camaro6.com/forums/showth...85#post9540185

Pray Performance compared two cars with similar mods, one with 1 7/8 and the other on 2".
https://www.facebook.com/prayperform...111973/?type=3

[62nalide]

I will recommend a 2" header any day all day

[oneredry]

I thought that 2" was more designed for the boosted applications (or should I say yield better results) 1 7/8 for N/A

[62nalide]

We have been making 8whp 3wtq more vs the 1 7/8s......these LT1s like the bigger headers. We will not sell nor install any 1 7/8s at our place.

[danhr]

You can make 800 rwhp with 1 7/8. Hell.. you can make 900 rwhp with factory manifolds. There is no HP limit on exhaust manifold/headers, but more a hinder.

The more power you make, the more smaller primaries/shorter lengths will hold you back. Sure you made 800 rwhp on a supercharged setup with 1 7/8ths headers.... But you would of made more with 2". It all depends on how much you want to leave on the table

Personally, I would just get 2" and be done with it. Just like 20 years ago, people would always argue 1 3/4 vs 1 7/8 on an LS1..... 10+ years later, it's finally widely accepted that 1 7/8 is the standard.

Learn from the past.

[boostednut]

Originally Posted by danhr

You can make 800 rwhp with 1 7/8. Hell.. you can make 900 rwhp with factory manifolds. There is no HP limit on exhaust manifold/headers, but more a hinder.

The more power you make, the more smaller primaries/shorter lengths will hold you back. Sure you made 800 rwhp on a supercharged setup with 1 7/8ths headers.... But you would of made more with 2". It all depends on how much you want to leave on the table

Personally, I would just get 2" and be done with it. Just like 20 years ago, people would always argue 1 3/4 vs 1 7/8 on an LS1..... 10+ years later, it's finally widely accepted that 1 7/8 is the standard.

Learn from the past.

If you have the option yeah I'd go with 2" too, they sound better. But if you buy a set of 7/8th's you won't actually notice the difference. Not for most people.

We're talking percentage hp here. Less than 10whp on a car that dynos 400+ factory. And most of that hp is within the noise.

I'll put it this way, the guys who will have real gains going to a 2" (the big power FI guys), are not going to be using the forum to tell them what parts to use.

Some cars gain 10whp some cars gain 4whp. Dyno numbers are always a wash. If the cost and install is the same go with whatever you want.

Because nobody knows if some shop cooled the car off but kept the oil warm, or some little setting or some little change in ambient temp. If you're talking max difference of 10whp, it's negligible. Even trap speed of like 1mph or 2mph 3mph is negligible. Engines are pumps. Sure you want flow to be high but 7/8ths really isn't undersized or not enough, or that far from 2". Like when people convince each other 2.5" dual exhaust isn't enough for their sub 500whp setup.

I just want this info to be realistic and truthful. 2" is marginally better. If you can get a better deal on smaller 7/8th's, save your money and spend it elsewhere. If the cost is the same, then go for it. That's what this thread is about. Not what makes more power.

[Fraxum]

The deal on my car was JRE would send me home with 1 7/8 or 2 inch ARH LTs whichever was the better fit and the 2" was on last (I think) as I guess Ted thought that might be the best for me with my all out bolton goal. I went home with 1 7/8.

EST 6 STOCK vs ARH 1 7/8 LT W CATS TO STOCK MUFFLER, MSD ATOMIC AND ROTOFAB DRY. 460 RWHP 446 RWTQ
Peak to Peak gains 31 RWHP 11 RWTQ
Delta gains +46 RWHP +31 RWTQ

Final test 7 STOCK VS ARH 2 INCH LT W CATS TO STOCK MUFFLER, MSD ATOMIC, ROTOFAB DRY. 459 RWHP 444 RWTQ
Peak to Peak gains +30 RWHP + 9 RWTQ.
Delta Gains +45 RWHP + 29 RWTQ.

Ted's comments:

"All though the 2 inch headers did not match the 1 7/8 LT from 2200 to 6000 RPM the 2 inch headers did make more power from 6000 to Rev limit.

I can see the 2 inch Headers having the advantage with Cam and Forced induction."

http://www.camaro6.com/forums/showthread.php?t=472259

All in LTs were worth only 15 RW on my build. I was and am disappointed with the HP and the sound for the cost and the PIA of taking my car back to stock. and if I had it it to do all over again I would go Ported TB, Ported IM, a CAI (for the looks and the sound and getting rid of the horrible sound tube), and E85 and my car would still easily be in the 11s which really was my goal.

[cem]

Originally Posted by 62nalide

We have been making 8whp 3wtq more vs the 1 7/8s......these LT1s like the bigger headers. We will not sell nor install any 1 7/8s at our place.

Just curious, only have an upgraded air filter, flex fuel, and looking to get headers before my tune but should I go for 1 7/8 or 2 inch if this is all I’m going to be doing? I daily the car as well. Thanks for the help.

[oldman]

I think for a Max FI build 2" for sure. For NA cam I'd lean to 2", for FBO I'd be on the fence as fit and heat seem to be "better" with a 1 and 7/8, for sock and something short of FBO I'd go for 1 and 7/8... heck I'd go for stock headers and primary cat deletes (or modified for flow).


Right now my final build has: stock headers, section and ported front cats, stock rear cats, Borla 60608, stock x, stock squash pipes and stock suitcase. I'm COMPLETELY happy with the performance and sound. (stock+ ported front cats + 60608) And yes I have tried all combinations from 2" no cats to bone stock on my final setup. It is quiet and maybe even quieter than stock. But WOT at 7200 RPM OMG that engine is LOUD, like screaming LOUD.

[enzia35]

Necro post but I plan on going 1-7/8".

[6spdhyperblue]

If 62nalide is correct(mirrors prays advise), that’s about 30% increased gains with 2” over 1- 7/8