Headers on a Corvette
Melting Slicks
Joined: Mar 2007
Posts: 2,391
Likes: 23
From: Santa Barbara CA
Some of you guys might be surprised, but there have been claims by a reputable LSx engine shop that LS7/LS9 manifolds actually make more top-end power than a big set of headers. This is without cats, of course. They flow very well, but give up some torque due to the shorter primary tubes. This is on 427ci LS9 builds, for what it's worth.
http://www.gmhightechperformance.com.../photo_27.html
I don't have any dyno results yet, but I just switched from LG 1 3/4" headers, 3" x-pipe (no cats) and 2.5" B&B Fusions to a factory LS9 manifold and cat setup, Corsa X-pipe, and full 3" Z06 mufflers with the 'muffler mod' done. Yeah... it sounds a lot more mellow, but for guys with cams like me it's nice not having the exhaust smell or valvetrain noise. The setup is also basically smog legal (more or less), and I'm in California. I'm actually really happy with it at this point. I can get on it and not be heard 3 miles away
http://www.gmhightechperformance.com.../photo_27.html
I don't have any dyno results yet, but I just switched from LG 1 3/4" headers, 3" x-pipe (no cats) and 2.5" B&B Fusions to a factory LS9 manifold and cat setup, Corsa X-pipe, and full 3" Z06 mufflers with the 'muffler mod' done. Yeah... it sounds a lot more mellow, but for guys with cams like me it's nice not having the exhaust smell or valvetrain noise. The setup is also basically smog legal (more or less), and I'm in California. I'm actually really happy with it at this point. I can get on it and not be heard 3 miles away
Racer
Joined: Mar 2012
Posts: 388
Likes: 0
From: NC
Some of you guys might be surprised, but there have been claims by a reputable LSx engine shop that LS7/LS9 manifolds actually make more top-end power than a big set of headers. This is without cats, of course. They flow very well, but give up some torque due to the shorter primary tubes. This is on 427ci LS9 builds, for what it's worth.
http://www.gmhightechperformance.com.../photo_27.html
I don't have any dyno results yet, but I just switched from LG 1 3/4" headers, 3" x-pipe (no cats) and 2.5" B&B Fusions to a factory LS9 manifold and cat setup, Corsa X-pipe, and full 3" Z06 mufflers with the 'muffler mod' done. Yeah... it sounds a lot more mellow, but for guys with cams like me it's nice not having the exhaust smell or valvetrain noise. The setup is also basically smog legal (more or less), and I'm in California. I'm actually really happy with it at this point. I can get on it and not be heard 3 miles away
http://www.gmhightechperformance.com.../photo_27.html
I don't have any dyno results yet, but I just switched from LG 1 3/4" headers, 3" x-pipe (no cats) and 2.5" B&B Fusions to a factory LS9 manifold and cat setup, Corsa X-pipe, and full 3" Z06 mufflers with the 'muffler mod' done. Yeah... it sounds a lot more mellow, but for guys with cams like me it's nice not having the exhaust smell or valvetrain noise. The setup is also basically smog legal (more or less), and I'm in California. I'm actually really happy with it at this point. I can get on it and not be heard 3 miles away
Melting Slicks
Joined: Mar 2007
Posts: 2,391
Likes: 23
From: Santa Barbara CA
I mean, I didn't really mind it -- but I do mind going to jail and having my license revoked. Plus, not getting loaded off my exhaust fumes is a nice change.
Racer
Joined: Mar 2012
Posts: 388
Likes: 0
From: NC
Haha, well I guess that depends on your definition of "quiet" and "loud". When you have a cammed and blown LS3 making ~700 whp through long tubes (no cats) and open B&B Fusions, it CAN actually be too loud.
I mean, I didn't really mind it -- but I do mind going to jail and having my license revoked. Plus, not getting loaded off my exhaust fumes is a nice change.
I mean, I didn't really mind it -- but I do mind going to jail and having my license revoked. Plus, not getting loaded off my exhaust fumes is a nice change.
Burning Brakes
Joined: Apr 2011
Posts: 770
Likes: 2
From: Alexandria VA
i just finished doing this i put on LG 1 7/8 inch headers, had my throttle body ported, and custom tune by one of the best tuners in the country, also had 160 degree thermostat and Tr6 plugs, i put my fuse back in my NPP exhaust. you will love your car more than you ever have, my car drives like a "normal corvette" until you give it some gas and let me tell you the car is Z06 quick. i honestly can't believe how well these cars respond to headers and a tune, i was worried about the 1 7/8 inch headers being overkill but my tuner who knows these cars quit well said he has seen no power loss with going to the 1 7/8 inch over the 1 3/4 inch headers. trust me get the headers
Anyone else have any input?
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Pro
Joined: Sep 2005
Posts: 662
Likes: 1
From: hudson florida
I went with 1 7/8" headers and a used zo6 exhaust on my 11 Grandsport because I knew I was either going to cam and supercharge it or go with a larger ci short block and better heads. I ended up with a cam and the super charger is sitting on the shelf awaiting install. The sound is so much better (and I hate loud cars) and when you get into the throttle the LS sounds great. If you are going to stay stockish go with the smaller headers, think you'll run nitrous or a blower then the 1 7/8" might be the way to go. Oh Im 44 and my car had 2,000 miles on it when the work was done, 4,400 now and getting blown on E85.
Pro
Joined: Sep 2005
Posts: 662
Likes: 1
From: hudson florida
Is your car a Z06 or reg? I am about to do 1 3/4 headers, ported TB/manifold, vararam, stock exhaust and tune and i cant figure out which plugs to get. I have a read a ton of posts and people always talk about plugs for their blown and cammed cars but nothing about reg bolted/tuned cars. I know the TR6's are a different gap than the stock plugs... did you regap back to .04?
Anyone else have any input?
Anyone else have any input?
Last edited by besz28; Aug 8, 2012 at 10:17 AM.
Burning Brakes
Joined: Apr 2011
Posts: 770
Likes: 2
From: Alexandria VA
Pro
Joined: Sep 2005
Posts: 662
Likes: 1
From: hudson florida
article on header size
Which Header Size Should you Choose?
Most of the debates on header selection have centered around the LS2 engine found in the earlier variations of the C6 (’05-’07). For the LS2, the 1-3/4-inch headers are the better choice unless you are planning on a stroker engine, a serious set of heads and camshaft, or boost. The smaller cubic inch LS2 cannot take advantage of the larger 1-7/8 inch header and will loose torque and exhaust port velocity.
However, if you have an LS3 with the larger displacement engine, the 1-7/8-inch header is by far the better choice, even if only doing the basic intake/exhaust modifications. It will produce slightly more power than the 1-3/4-inch header, and give you room to grow if you decide to add a camshaft or ported cylinder heads to your engine combination.
Most of the debates on header selection have centered around the LS2 engine found in the earlier variations of the C6 (’05-’07). For the LS2, the 1-3/4-inch headers are the better choice unless you are planning on a stroker engine, a serious set of heads and camshaft, or boost. The smaller cubic inch LS2 cannot take advantage of the larger 1-7/8 inch header and will loose torque and exhaust port velocity.
However, if you have an LS3 with the larger displacement engine, the 1-7/8-inch header is by far the better choice, even if only doing the basic intake/exhaust modifications. It will produce slightly more power than the 1-3/4-inch header, and give you room to grow if you decide to add a camshaft or ported cylinder heads to your engine combination.
Pro
Joined: Sep 2005
Posts: 662
Likes: 1
From: hudson florida
Burning Brakes
Joined: Apr 2011
Posts: 770
Likes: 2
From: Alexandria VA
Which Header Size Should you Choose?
Most of the debates on header selection have centered around the LS2 engine found in the earlier variations of the C6 (’05-’07). For the LS2, the 1-3/4-inch headers are the better choice unless you are planning on a stroker engine, a serious set of heads and camshaft, or boost. The smaller cubic inch LS2 cannot take advantage of the larger 1-7/8 inch header and will loose torque and exhaust port velocity.
However, if you have an LS3 with the larger displacement engine, the 1-7/8-inch header is by far the better choice, even if only doing the basic intake/exhaust modifications. It will produce slightly more power than the 1-3/4-inch header, and give you room to grow if you decide to add a camshaft or ported cylinder heads to your engine combination.
Most of the debates on header selection have centered around the LS2 engine found in the earlier variations of the C6 (’05-’07). For the LS2, the 1-3/4-inch headers are the better choice unless you are planning on a stroker engine, a serious set of heads and camshaft, or boost. The smaller cubic inch LS2 cannot take advantage of the larger 1-7/8 inch header and will loose torque and exhaust port velocity.
However, if you have an LS3 with the larger displacement engine, the 1-7/8-inch header is by far the better choice, even if only doing the basic intake/exhaust modifications. It will produce slightly more power than the 1-3/4-inch header, and give you room to grow if you decide to add a camshaft or ported cylinder heads to your engine combination.
Sorry, yeah i am def doing ARH 1 3/4". The question is about the plugs... my car has 51k miles so i was thinking of putting new plugs anyways.
Pro
Joined: Sep 2005
Posts: 662
Likes: 1
From: hudson florida
on the LS3 dont go with 1 7/8...the 1 3/4 produce the best tq and hp. i live in NC as well...i have headers, no cats and npp exhaust with the mild to wild switch. but honestly...i leave the valves open 100% of the time. under normal driving its not very loud...under WOT it is but it sounds great. not raspy at all...just very mean and throaty sounding like it should be.
but my taste is different than some people...because i saw someone a few comments back on here say that they thought the headers were too loud and he even had high flow cats (which will quiet it down just a tad) and i wouldnt mind if mine was even louder lol its all personal preference.
but my taste is different than some people...because i saw someone a few comments back on here say that they thought the headers were too loud and he even had high flow cats (which will quiet it down just a tad) and i wouldnt mind if mine was even louder lol its all personal preference.
Most of the debates on header selection have centered around the LS2 engine found in the earlier variations of the C6 (’05-’07). For the LS2, the 1-3/4-inch headers are the better choice unless you are planning on a stroker engine, a serious set of heads and camshaft, or boost. The smaller cubic inch LS2 cannot take advantage of the larger 1-7/8 inch header and will loose torque and exhaust port velocity.
However, if you have an LS3 with the larger displacement engine, the 1-7/8-inch header is by far the better choice, even if only doing the basic intake/exhaust modifications. It will produce slightly more power than the 1-3/4-inch header, and give you room to grow if you decide to add a camshaft or ported cylinder heads to your engine combination.
Burning Brakes
Joined: Apr 2011
Posts: 770
Likes: 2
From: Alexandria VA
What is the "hole cut in the shroud" that i keep seeing. is it a fitment issue? i have an old vararam for the LS2...
Burning Brakes
Joined: Feb 2011
Posts: 833
Likes: 470
From: Goodyear AZ
I had Kooks 1 7/8", catted x pipe and a retune done a few weeks ago. Picked up 60 hp doing it! Was 396 rwhp for a baseline and 458 after install(I also have Corsa sports and a Blackwing intake that were already on for the baseline). I have not been able to take the smile off of my face, best money I think I ever spent and sounds AWESOME! DO IT!
Intermediate
Joined: Jun 2012
Posts: 46
Likes: 4
From: Tampa, FL
I had Kooks 1 7/8", catted x pipe and a retune done a few weeks ago. Picked up 60 hp doing it! Was 396 rwhp for a baseline and 458 after install(I also have Corsa sports and a Blackwing intake that were already on for the baseline). I have not been able to take the smile off of my face, best money I think I ever spent and sounds AWESOME! DO IT!
Shouldn't hear any valvetrain noise but you will be able to hear some "sucking" noises as the exhaust gases scavenge. This is usually just at low engine speeds or when you close the throttle and coast.
Burning Brakes
Joined: Apr 2011
Posts: 770
Likes: 2
From: Alexandria VA
I had Kooks 1 7/8", catted x pipe and a retune done a few weeks ago. Picked up 60 hp doing it! Was 396 rwhp for a baseline and 458 after install(I also have Corsa sports and a Blackwing intake that were already on for the baseline). I have not been able to take the smile off of my face, best money I think I ever spent and sounds AWESOME! DO IT!