Sittingmongoose

iTrader: (1)

For the people that did install the headers, does anyone have dyno numbers?

AlabamaGuy

iTrader: (5)

I do.

91LT16SpeedFormula

iTrader: (60)

Inquiring minds want to know.....

AlabamaGuy

iTrader: (5)

Well I'm not sending everyone a PM lol. There's just lurkers on this board that don't need to know. lol

ImpSS07

iTrader: (3)

Does it really matter that much?

AlabamaGuy

iTrader: (5)

I'm not sure my numbers are accurate because the dyno was worked on since the last time I was on it. But I gained 13 peak hp and lost 10 lb-ft peak.

Sittingmongoose

iTrader: (1)

I am afraid to install mine. Between the whistling issue, it not fitting with my ls6 intake and the shear cost of doing it. If i don't gain at least 20hp, i will cry.

Sittingmongoose

iTrader: (1)

loss of torque is wierd

hexxLS4

iTrader: (1)

those are pretty unimpressive numbers for the entry cost. You get more from an intake alone. I'm sure it has synergistic effects with other mods, but still.

707chance

iTrader: (2)

That was my thoughts too; cost per horsepower is low and now the mystery whistle. I’m thinking about spending a little more and go for the rocker setup.

06 SS

It is exactly what was expected. Opening up the exhaust near the engine moves the torque curve to the right, the stock cam makes it's peak torque lower than the new natural torque peak RPM of the exhaust. A cam change with another 10-15 degrees duration and a tighter LSA would get it back and then some.

gulfstreamcpt

Hey Goose,
So you are saying that an LS6 intake won't fit with the new headers at all?? Or is it gonna be one of those things where it will work, just gonna take a sh*t ton of modification?? Care to elaborate?? I've been contemplating one of my next mods to be the intake and know there is gonna be some modification to make it work.... But if it's gonna be just a real b*tch to get one to work with the headers (or not able to work at all), would like to know about it before I get too deep into wanting to do that intake mod.

What issues have you seen with fitment so far???

Mgpeagle

iTrader: (6)

Do you guys think rockers and a ported intake would help with the torque loss? I am hoping that's the case.

-Mike

CenTexSS

iTrader: (2)

I wouldn't worry about the dyno numbers, you got on the dyno for a tune - and ya got it.

13.7 to a 13.4 is the best testament to the gains from the headers.

DavidGXP

iTrader: (14)

Those numbers were with the addition of a CAI, 3" custom exhaust and headers. Right?

And sittingmongoose, is right. The whistle is a pain in the *** and the LS6 intake will cause the tb and intake ducting to smash right into the crossover pipe.
I do believe that with his mods, headers will be a definite power adder though. Then again, he has the 02 LS6 cam and its got a very wide LSA and a lot of exhaust duration so the headers might not help at all.
I would install them sittingmongoose and if you don't like them then I'm sure you could sell them, just save your old stuff. Plus, they are not that hard to install. Your only issue might be the crossover pipe. but it wouldn't be to hard to get it sectioned.
Just try it and find out man. You've already got this far!!

JDMC5

iTrader: (3)

how much clearance is lost with the LS6 intake? You could try using an oval crossover pipe, that should give you the clearance you need. Honestly I wouldn't trust dyno numbers on a dyno that was recalibrated between runs. Depending on how well those headers were designed you shouldn't loose any torque at all. A typical LS engine gains between 15-20hp and 10-15lbs at the wheels with headers. They are ALWAYS a worthwhile mod.

Sittingmongoose - install them, your car is begging you!

DavidGXP

iTrader: (14)

Also, most LS4's put down about 260-280 ft/lbs at the wheels stock. AlabamaGuy's car put down 310 ft/lbs before, which seemed kind of high considering our engines put out 335 ft/lbs at the flexplate. When I got dyno'd, I put down 275 ft/lbs after tuning with just a downpipe.
The headers do add power. I can tell from my butt dyno and my 0-60 mph runs. The stock front manifold, has a 2" outlet with a 2" crossover pipe. And the rear manifold outlet is only 2 1/2". A lot of us are/were running 3" downpipes which honestly are useless IMHO, do to our rear manifolds outlet. Also, all 8 cyls were flowing through that outlet. The biggest restriction of all is our intake manifold. Porting yields big gains and the LS6 over the ported LS4 intake was even greater. We are basically running a 4bbl carb with a 2bbl intake. Our intake ducting is rather small too. Almost all LS motors have a 4" tb opening (not butter fly) and have MAF housings that are around 3 3/4-roughly 4". Our engines have a 3.5" tb opening with 3.25" maf inlet and outlets. Pretty much V6 stuff guy's.

CenTexSS

iTrader: (2)

I'd highly disagree that the 3" catless downpipe is useless. I went from 14.2 @ 98 to 13.9 @ 100 from stock DP to catted DP. Then 13.9 @ 100 to 13.5 @ 102 from a catted DP to a catless DP - two weeks apart and very similar condidions. I'd argue it's the best bang for the buck mod for our cars.

And I wouldn't ponder over dyno numbers really, every dyno is differnet. Timeslips tell the true story.

DavidGXP

iTrader: (14)

So you shaved off .4 tenths and gained 2 mph with going ONLY cattless. Sounds like the cat is a big time restriction. what were your 60 ft times. similar? I gained 1mph from the
3" downpipe but I also had very little gas and maxed my rear tire pressure out.

CenTexSS

iTrader: (2)

60 foots are close, the 14.2 times were in a little warmer weather.

But yes, I went from 13.9 to 13.5 with only swapping the catted downpipe to the catless - two weeks apart with nearly identical weather. And the times are consistent also, last time out I ran a couple 13.5's, and the slowest run was 13.7, trapping 101-103.