No, cars run lean at closed loop with headers and the positive long term fuel trends cause it to dump more fuel at WOT making the PE run richer. My car went from 11.8:1 factory to 11.2:1 with headers untuned.

Your car didnt baseline what other C6's baseline at. The avaerage being 355rwhp unless your car is an auto.

The interesting thing is that on LG's website most of the early Z06 headers installs didnt have atune since the Z06 tuning software didnt appear untill 1/2 way through the production year. Most of those 485+rwhp cars were untuned.

 

When the corsa sports came out in 2005 they indeed claimed a 14rwhp gain for the base and Z51 cars.

 

What?

The first post i made had a dyno sheet on it. It showed a gain of 30+rwhp which you deny is able to be had on a Z06 since the existing manifolds give 80% of the gain by your own words. Adding the headers should have been only 6 HP if the headers only gain 20% over the manifolds comming off the car.

The very dyno sheet there was with no tune since HPT didnt have tuning out for the Z06 at that time.

It was headers only.

Here is some more proof so I dontget accused of being without evidence and being only sujective opinion. Keep in mind ALL of these cars had Z06 exhaust manifolds as the baseline and they were swapped out for headers:



Give it up already. The only posts you have had are guys with changes of corsa exhausts (the 3" butterfly system and a tune with a car that baselined less than any other C6. My car baselined at 355 like 90% of the cars out there. The dyno's were done on the same day either fro you controlled tests.

YOU said 80% of the gains of headers.

Taking away ther tunes and corsa exhausts you guys include on the header-only swaps, the gains of 40rwtq far outway the few HP the manifolds got without the tune and aftermarket exhaust. The peak HP non-sense doesnt tell the story for midband TQ and that is what moves a car. Even if you did get 10rwhp/10rwtq which is 25-30% of the headers and not 80% all it proves is you go slower for less money. Z06's that ditch the stock exhaust gain 34+ in every dyno I have seen. I posted enough sheets fro you. THEY ARENT HEADER DYNO SHEETS, THEY ARE DYNO'S OF THE Z06 MANIOFLDS AS A BASELINE AND THEN THE HEADERS STOMPING THEM.

Since non-Z06's make the same exact gains from the same headers it can only be assumed that the manifolds werent within 30+ hp of what the headers did when they replaced them. Thats not subjective....these dyno sheets show the manifolds vs the headers.

 

The dyno I've used put my former LS2 GTO at 336rwhp, my vette at 340rwhp, and a few other LS2 cars in the 330's. Could be a low reading dynojet but the results have always been similar for LS2's.

 

You have a thin skin if that is bashing them.

This is bashing them: They dont give you but a few HP if that and then only if you put the discarded garbage on your car because you cant afford real parts then maybe with a 1400dollar exhaust and a 500 dollar tune you will get 18hp over the normal baseline 90% of C6 owners get.

Z06 manifolds are a joke and people who cant afford real mods with documented gains should leave it stock and stock whinning when someone posts up a dyno sheet that has Z06 manifolds vs headers and it looks like this:

BOTTOM LINE: Z06 MANIFOLDS/TOP LINE: HEADERS



does that hurt your feelings?

After enough silliness about this and seeing that the only people that got gains also had a 1400 dollar exahaust and a 500 dollar tune, it seems to me that the 1800 dollar LG headers or any header would be a less costly path leaving the exhaust stock and just getting the tune. I do thnk they gain 5-8hp which isnt 80% of the gains from headers. Maybe if the guy that said 80% of the headers performance should acknowledge that the TQ gains from headers whcih are 40+rwtq are part of the reason to get headers and that 8hp isnt 80% of 32rwhp/40rwtq.

 

Fair enough, do you think the manifolds are 80% of the gains of headers?

this dyno is the manifolds bottom line and the headers top line:



How are th headers bettering the manifolds by 30+hp and 40+tq if the manifolds are 80% of the headers performance.

If someone would admit it is a gross exaggeration and the gains other have seen are from the expensive parts like a 1400 dollar exhaust and a low base line brought up with a tune, I will be satisfied.

 

No they only win the pole in World Challenge races and then get to charge 1.3 million bucks for each advertisment sticker on thier car. Keep in mind that when time came to design the Z06 head for the C5, GM didnt use the supercomputers you think exist, they went to Lingenfelter who designed the 243 heads your C6 has on it now; same guys who swap out Z06 manifolds for LG headers from time to time.

 

No I don't think someone would see 80%, 50% maybe. If they along with a tune produce 20-25whp it's a good gain for the cost if bought used off the forums. Just by looking at them you would assume there is something to be gained, GM decided the iron cast LS2 manifolds would not be good enough on the LS7 and restrict the motor, same thing with the intake design....GM improved those parts to bump up the HP.

Noone is saying Z06 manifolds are better performing then LT's because they in no way are. This is more a case of a stealthy oem upgrade that gives a bump in hp/tq, a great alternative if you can't run LT's.

BTW when I reference Z06 manifolds I'm talking the whole system mufflers/h-pipe/manifolds/cats.

Put the LS2 full exhaust on a Z06 and I'd be willing to bet you would see a drop in hp/tq, so if the Z06 system is just as good as the LS2 system you wouldn't see a drop correct? (this is like the opposite of LT headers vs stock on a Z06 dyno sheet that was posted)

 

Comment on the dyno sheet you keep ingnoring. The Z06 manifolds are the bottom number and the 495 is the header line. How is that 50%? The dyno is a direct comparrison between the Z06 stock manifolds and the headers.



It seems to me that when you take the Z06 manifolds off the car, the gains should be less than what a C6 gains from the headers. If the manifolds are so good then why is the gain so staggering with headers on a Z06.

I keep saying the same things over and over. The thread is here for people to se the evidence for themselves. i dont think anyone looking at the gain on a Z06 ditching these manifolds is going to be thinking the manifolds are so good that headers make little more difference. If I looked at the above dyno I would think that the headser make a massive gain over the manifolds and they arent even close. Its not 50%.

 

I should have stayed up later last night. This is getting really interesting. The good news is that I always learn something from these types of threads.

 

Anything that makes a pump inhale and exhale more effectively is going to work. How much is more is really dependant on cubic dollars than cubic inches.

The old age ' Speed cost money, how fast do you wanna go?' is still relavent.

Bottom line is that a manifold, whether cast or tubular, are not going to beat a long tube header, but they are a cheap and effective mod if you are not looking for the absolute.

They are quiter, cost effective, have an OEM appearance, fit and finish and most people wouldn't know you changed a thing.

 

Finally, a good post in this increasingly-argumentative thread.

It's interesting that nobody has yet addressed the difference in "port shape," LS2 vs. LS7.

 

I have seen many threads here showing an average baseline Dynojet of 325-335 rwhp for the C6 A6 and 335-345 for the C6 MN6.

 

Comment on the dyno sheet you keep ingnoring. The Z06 manifolds are the bottom number and the 495 is the header line. How is that 50%? The dyno is a direct comparrison between the Z06 stock manifolds and the headers.

The problem is that dyno is stock Vs headers and a tune. The tune gave the majority of the gains, not those headers. We dyno'd two Z's, both with CAI's and a tune, then added headers and retuned. Both gained some mid range torque and very little top end HP. Without a retune the LG headers lost top end HP compared to stock manifolds. GM did a very good job on the Z's manifolds. Having the requirement to light off the cats quickly required them to make them shortie headers, which compromises mid-range torque, but that's pretty much it. They're good enough to put on a supercharged ZR1 @ 620 +/- horsepower, and I believe they will produce most of the gains of long tubes on a LS2.

 

Quote:
Originally Posted by saber
Just a note, GM has Supercomputers running CATIA based Computational Fluid Dynamics Analysis tools for designing these hydroformed manifolds.
I don't think one of these weld shops making headers has that!



Sorry, yes they do exist and they do use CFD on these systems and yes they do some outside contract work and get opinions.

 

That's one of the most retarded posts I've read on this forum.
1. You're saying buy the best or don't bother modding?? Good thing I didn't listen to you w/my first car! ('83 Trans Am). That car went from a 170 hp "wonder", to a 320 hp car that would match LS1 'Vettes at the strip. I spent $1500 on everything I did to that car, and I guarantee you, YOU would turn your nose up at most of the things I did to that car. Fact is, what I did to it was effective; it worked, and for cheap. A REAL "Hot Rodder" isn't affraid to try new things, experiment and measure the changes. Anyone can go buy big dollar parts. That takes no brains at all.
2. So you use even more retardedly expensive cars and part, to make the over price 'Vette headers seem "reasonable"?? I laugh at you! Headers are headers. They are bent pipes, welded together at a collector and a flange. They aren't worth over $1k, no matter WHAT car you bolt them to. Crazy logic, we have going on here.

 

Good answers. I didn't know people bought used stuff and then brought it to an installer. That's crazy (IMO). If I could afford and installer, I'd buy all the best parts, hands down!

Also good point about the cost of the parts. I would definitely not pay $1k for take-off exhaust. You're right that at that point, you're better off going a little farther and buying a header that's on sale or used.

 

I know my cai/tuned z06 with factory exhaust (manifolds, cats, everything factory) made over 480rwhp and 450rwtq. I consider that "pretty salty" for a factory offering. I'm sure a set of aftermarket high flow catted headers would probably net more, but then I'd have to analyze how much the aftermarket cats make over the factory ls7 cats to even distinguish what amounts the headers themselves make.

good discussion, now lets play nice and not get ugly

 

Well, apparently you only know one way to mod. Of course, there is more than one way to reach a goal. What YOU might call "cutting corners", others might call "resourceful". If it achieves the desired result....

 

No. I'm not talking about a Z06 ENGINE, mani's vs. Headers. I'm talking about a smaller displacement motor, w/a lower state of tune, with Z06 mani's vs. headers, peak hp. Of course the Z06 mani's on a Z06 won't give 80% of what headers (on a Z06) will give! On that engine, the Mani's are the base line. Unless I'm just not getting what you're trying to say.