Headers only on LS3?
Thread Starter
Racer
Joined: May 2012
Posts: 293
Likes: 1
From: Pasadena CA
Headers only on LS3?
Hello all,
I have been searching but could not really find the answer to what I am looking for.
I have an 08 z51 6mt with just a Corsa catback.
I love the exhaust but I prefer a much quieter ride.
I've been thinking of just putting a stock exhaust back on and adding a pair of long tubes, cam, and tune.
Does anybody here know from experience what a stock catback LS3 with long tubes sound like? I'd imagine it would only be marginally louder than stock since the stock mufflers will mute it quite well? This would be perfect for me.
More importantly, how much power will I be leaving on the table with a stock catback with a cam/headers/tune set up on pump gas?
I know catback exhausts in general add sound more than anything, but this stops being true past a certain power level.
Happy holidays to all
I have been searching but could not really find the answer to what I am looking for.
I have an 08 z51 6mt with just a Corsa catback.
I love the exhaust but I prefer a much quieter ride.
I've been thinking of just putting a stock exhaust back on and adding a pair of long tubes, cam, and tune.
Does anybody here know from experience what a stock catback LS3 with long tubes sound like? I'd imagine it would only be marginally louder than stock since the stock mufflers will mute it quite well? This would be perfect for me.
More importantly, how much power will I be leaving on the table with a stock catback with a cam/headers/tune set up on pump gas?
I know catback exhausts in general add sound more than anything, but this stops being true past a certain power level.
Happy holidays to all
Le Mans Master
Joined: May 2011
Posts: 5,022
Likes: 18
From: Tampa FL (formerly Justinjor)
Tech Contributor
St. Jude Donor '11-'12-'13-'14
Catbacks are generally worth 0hp and only change the sound of the vehicle. You won't be leaving anything on the table.
I've seen claims from vendors on this site of their catback adding 10hp but never any proof to back it up.
I've seen claims from vendors on this site of their catback adding 10hp but never any proof to back it up.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
You can go back to the stock catback and the car will quiet down. However, when you add headers it will get a little louder and when you add a cam, believe it or not, it will get a little louder again. Heck, I'd go with the headers and cam and then put on the dual mode exhaust with a controller that allows you to open and close them. You get the best of both worlds. Loud when you want it and quiet when you want that.
Drifting
Joined: Jul 2012
Posts: 1,270
Likes: 254
From: Indiana
Headers
I had a 2008 Coupe,LS3 with a 6 spd and Z51 options. Also had a GM 'Hot Cam' installed. The factory exhaust was not much louder nor was there interior drone with that set up. You could feel the additional power. The headers were 1 7/8" long tubes from Billy Boat Exhaust. I added a Billy Boat X-pipe with cats and Bullet mufflers. All B&B products are top quality.
Racer
Joined: Aug 2010
Posts: 309
Likes: 1
From: Mendota IL
I'm sure you already understand but just in case. If you add long tube headers you will not be able to use the stock cats and H-pipe, only the stock overaxle exhaust will remain.
But LT headers, midpipes (especially catted), cam and tune with the stock overaxle exhaust will be more quiet then what you have now. The stock mufflers will not hold much power back at all, maybe a very minimal amount. What I assume what sounds like what you're looking for is; a cam of your liking, 1 7/8" long tube headers w/ catted 3" X-pipe and the stock overaxle exhaust. This will give a substantial power increase and it will be louder then stock but not by much. Also, you could add a pair of electric cut-outs to the aftermarket collection pipes right before the stock overaxle exhaust if you so desire.
But LT headers, midpipes (especially catted), cam and tune with the stock overaxle exhaust will be more quiet then what you have now. The stock mufflers will not hold much power back at all, maybe a very minimal amount. What I assume what sounds like what you're looking for is; a cam of your liking, 1 7/8" long tube headers w/ catted 3" X-pipe and the stock overaxle exhaust. This will give a substantial power increase and it will be louder then stock but not by much. Also, you could add a pair of electric cut-outs to the aftermarket collection pipes right before the stock overaxle exhaust if you so desire.
Drifting
Joined: Dec 2012
Posts: 1,717
Likes: 28
From: O'Fallon IL
To the OP. That's exactly what I plan to do, so thanks for creating this thread. Another thing I'll like to add is that unless you have the z06 oem over the axle muffler you won't be able to use 3" h or x pipe. I think that the base muffler connection would have to be modified since they're 2 1/2".
Racer
Joined: Aug 2010
Posts: 309
Likes: 1
From: Mendota IL
To the OP. That's exactly what I plan to do, so thanks for creating this thread. Another thing I'll like to add is that unless you have the z06 oem over the axle muffler you won't be able to use 3" h or x pipe. I think that the base muffler connection would have to be modified since they're 2 1/2".
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Racer
Joined: May 2012
Posts: 293
Likes: 1
From: Pasadena CA
Thanks for all the replies so far 
I saw your post here - http://forums.corvetteforum.com/1581759290-post10.html - were you running the OBX headers with the stock catback ?
I have been reading up on this for the past 2 hours instead of working 
- it seems like the Z06 full exhaust is giving up about 40% of power to a set of long tube headers?
Reference thread - http://forums.corvetteforum.com/c6-t...s-exhaust.html
I live in California so from a smog perspective the Z06 full exhaust route would be great, but not if it's leaving that much power on the table...
- it seems like the Z06 full exhaust is giving up about 40% of power to a set of long tube headers? Reference thread - http://forums.corvetteforum.com/c6-t...s-exhaust.html
I live in California so from a smog perspective the Z06 full exhaust route would be great, but not if it's leaving that much power on the table...
Racer
Joined: Aug 2010
Posts: 309
Likes: 1
From: Mendota IL
That's what I thought. Thanks.
OP, basically the route to take for the best power output and the quieter sound you want, that I know of, would be a set of long tubes and a 3" catted x-pipe (since they're mandatory in your case) to connect to the stock overaxle exhaust. Throw in some electric cut-outs before the stock mufflers if you think there will be moments where you want the car to be loud as sin. It'll sound sweet with a healthy cam and really wake up in the power department.
Good luck
OP, basically the route to take for the best power output and the quieter sound you want, that I know of, would be a set of long tubes and a 3" catted x-pipe (since they're mandatory in your case) to connect to the stock overaxle exhaust. Throw in some electric cut-outs before the stock mufflers if you think there will be moments where you want the car to be loud as sin. It'll sound sweet with a healthy cam and really wake up in the power department.
Good luck
Burning Brakes
Joined: Dec 2010
Posts: 886
Likes: 1
From: Orlando FL
St. Jude Donor '12-'13-14
I have the ARH 1 7/8" headers with 3 inch catted xpipe on my 011 GS that has the factory NPP on it. When the valves are closed its just a little bit louder than when it was stock. Still very quiet. If quiet is what you want then you'll be happy with the stock exhaust.
Melting Slicks
Joined: Nov 2003
Posts: 2,155
Likes: 56
From: Escondido CA
here is what i did mark..i live in SD area of so cal....
http://forums.corvetteforum.com/c6-c...-09-coupe.html
hope that helps..
http://forums.corvetteforum.com/c6-c...-09-coupe.html
hope that helps..
Last edited by bud miller; Dec 28, 2012 at 12:32 AM.
Burning Brakes
Joined: Nov 2011
Posts: 1,042
Likes: 283
From: West Dundee IL
2024 C5 of the Year Finalist - Modified
St. Jude Donor '12-'13
LS2.5 with headers and cam, stock axle back.
I had Corsa sport but couldn't take it with a stall. I'm switching to modded Z06 mufflers for next summer.
I had Corsa sport but couldn't take it with a stall. I'm switching to modded Z06 mufflers for next summer.
Melting Slicks
Joined: Mar 2001
Posts: 2,979
Likes: 281
From: Tulsa OK
I have the stock catback with LG headers and x-pipe (with hi-flow cats) on my '08. It is slightly louder than stock, but not that noticeable during normal driving. Under WOT, it is louder. It is quieter than an aftermarket cat-back with stock exhaust manifolds, with much better performance.
Burning Brakes
Joined: Nov 2012
Posts: 968
Likes: 8
I know of a few tuners who have done hundreds or more tunes on cars and bikes, and they have said that cats or no, make very little difference to almost unmeasurable in HP on a tune with almost any vehicle they have seen.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I run stock mufflers with heads and cam, and open my QTP cutouts when I want to sound mean.
I get 6 rwhp more with cutouts open vs closed when I was cam only (perhaps more now that I have heads) so I can confirm the stock mufflers aren't much of a restriction at all.
The stock mufflers are perfect for my daily drive. The car appears like stock until I open the cutouts, then it bellows.
Here is my thread with pics and sound clip if you are interested. I did this before the factory NPP came out. Cutouts sound much deeper than the NPP but sound is a personal preference.
http://forums.corvetteforum.com/c6-t...-on-my-c6.html
I get 6 rwhp more with cutouts open vs closed when I was cam only (perhaps more now that I have heads) so I can confirm the stock mufflers aren't much of a restriction at all.
The stock mufflers are perfect for my daily drive. The car appears like stock until I open the cutouts, then it bellows.
Here is my thread with pics and sound clip if you are interested. I did this before the factory NPP came out. Cutouts sound much deeper than the NPP but sound is a personal preference.
http://forums.corvetteforum.com/c6-t...-on-my-c6.html
Had QTP cutouts installed by Florida Performance in Fort Lauderdale. Overall very pleased with the job Rob, the shop owner, did. This was his first C6 and he found a great place to put them and made the custom mandrel bent Y-pipes to maximize flow from the cutouts. We found no way to put them right after the collectors but they fit well by the trans. I have the DTE brace too but it wasn't in the way.
Installed the wiring myself along the drivers side rocker panel, behind seat then out the wheel well under the carpet. Removed the rear inner fender and drilled a small hole in the wheel well then ran the wire down to the cutouts. Hardest part is finding a hot wire when the ignition is on on these C6's. I ended up tapping the seat heater fuse as others here have done.
They are loud and DEEP when open at idle. I've actually heard louder exhaust though, I was kind of surprised they are not louder. I think it is because of the turn downs and the fact that I have cats and the pipes are pretty long before the cutouts. On the track they have a nice race car sound - I'd say like Borla Stingers plus 25%. When you open them at a stoplight you will turn heads, that's for sure.
Overall happy with the mod, it gives me quiet during my morning drive but loud when I'm at the track which is what I wanted.
Here is a video of idle with cutouts open and closed. The gain on the mike makes the closed sound much louder than it is, it's really quiet with factory mufflers even with my cam.
Here are some pics:
Installed the wiring myself along the drivers side rocker panel, behind seat then out the wheel well under the carpet. Removed the rear inner fender and drilled a small hole in the wheel well then ran the wire down to the cutouts. Hardest part is finding a hot wire when the ignition is on on these C6's. I ended up tapping the seat heater fuse as others here have done.
They are loud and DEEP when open at idle. I've actually heard louder exhaust though, I was kind of surprised they are not louder. I think it is because of the turn downs and the fact that I have cats and the pipes are pretty long before the cutouts. On the track they have a nice race car sound - I'd say like Borla Stingers plus 25%. When you open them at a stoplight you will turn heads, that's for sure.
Overall happy with the mod, it gives me quiet during my morning drive but loud when I'm at the track which is what I wanted.
Here is a video of idle with cutouts open and closed. The gain on the mike makes the closed sound much louder than it is, it's really quiet with factory mufflers even with my cam.
Here are some pics:
Thread Starter
Racer
Joined: May 2012
Posts: 293
Likes: 1
From: Pasadena CA
Thank you all for the replies, and I hope everybody here had a great holiday season 
I think I will end up going with the stock catback or Z06 catback with aftermarket catted LTs for maximum gain while maintaining a quiet ride.
I will not install the LTs till I decide on the cam package for my car, then I will put everything on and get a custom tune, all at the same time.
Oh boy, that will be a great day
Hopefully I will gain around 80-100whp delta with the stock catback and on 91 pump gas.
I think I will end up going with the stock catback or Z06 catback with aftermarket catted LTs for maximum gain while maintaining a quiet ride.
I will not install the LTs till I decide on the cam package for my car, then I will put everything on and get a custom tune, all at the same time.
Oh boy, that will be a great day
Hopefully I will gain around 80-100whp delta with the stock catback and on 91 pump gas.
