[mcsoul]

Won't the stock tune compensate for the less restricted exhaust after a few days and erase the gains, or is that a myth?

[hawk02]

Originally Posted by Mr. Wyndham

Seems like the stock exhaust system is pretty darn good!!

I was thinking the same thing. Given a cost of about $3K for headers and exhaust, the 14 hp gain isn't much bang for the buck.

[MA2010SS]

From the video looks like the system was cat-less also...probably see similar gains or better by just removing the cats and a tune

[Ron_Robinson1]

The best news out of this to me after contacting ATI was the weight.

"97 lbs for complete exhaust system top to tail. 12 lbs each for DS and PS Manifold. 121 lbs complete Factory system"

[Mr. Wyndham]

Originally Posted by hawk02

I was thinking the same thing. Given a cost of about $3K for headers and exhaust, the 14 hp gain isn't much bang for the buck.

I tend to agree. I am interested in, and curious what the weight/cost benefit is for removing the secondary cats, alone...

Originally Posted by Ron_Robinson1

The best news out of this to me after contacting ATI was the weight.

"97 lbs for complete exhaust system top to tail. 12 lbs each for DS and PS Manifold. 121 lbs complete Factory system"

24 lbs is 24 lbs.

That'll put the ZL1 1LE into the 3700 lbs club...

[Bigwhyte]

For me the headers are just a supporting mod for additional power. If wasn't going with a larger supercharger I would not change the stock manifold. I personally would just do a cat back with CA pipes

[big dave]

Originally Posted by Bigwhyte

For me the headers are just a supporting mod for additional power. If wasn't going with a larger supercharger I would not change the stock manifold. I personally would just do a cat back with CA pipes

I agree, maybe after a pulley change or a few more significant mods, the exhaust may become a little more needed...until then, that seems like a lot of money for very little gain.

[Ian SS]

Originally Posted by newmoon

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I understand but these are huge power losses from advertised to actual. Take for example many of the 2016/17 SS automatics which seem to dyno 410-420 hp, and 420-430 tq, which is very little loss as compared to advertised.

It's 17%....really not that big of a deal if it is a low reading dyno. Some dynos have stock c7z06 reading low 500's.

Some SS dyno at 410-420 and some dyno 385-395....different dynos....different weather. Mine dyno'd at 408 with 2nd cat delete, CAI, and MSD manifold......

[Michigan1LTRS]

Originally Posted by newmoon

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I understand but these are huge power losses from advertised to actual.

I think you may be confusing crank hp with wheel hp. GM advertises 650 crank hp. They never say what wheel hp is. But assuming you are not confusing the two, the dyno GM uses and what was used here could have totally different parameters. Still though, the numbers fall in line with an auto drivetrain loss. Unless you are testing two cars on same dyno, results between the two are not good for comparison. Dynos are tuning tools.

[Michigan1LTRS]

Originally Posted by Ian SS

It's 17%....really not that big of a deal if it is a low reading dyno. Some dynos have stock c7z06 reading low 500's.

Some SS dyno at 410-420 and some dyno 385-395....different dynos....different weather. Mine dyno'd at 408 with 2nd cat delete, CAI, and MSD manifold......

[BMWM.D.]

Originally Posted by newmoon

540/548 stock, wow that is huge drivetrain loss compared to the advertised 650/650.

It's not much different than what the C6 ZR1s were putting down through a manual transmission. 540 rwhp seemed to be a normal or even slightly above normal dyno reading for the LS9, which was rated at 638 crank Hp. That said, all dynos read differently. Great to show performance gains, but not so great for trying to calculate crank hp.

[NicD]

If you run the A10 in the correct 1:1 gear ratio (7th gear) on the dyno you would hit 185 on the dyno and that is a bit fast but is doable. Most people are going to end up using 6th gear on the dyno to limit tire speed with a 1.28 ratio so you would only hit 145 but that also typically results in a slightly lower number produced on the dyno.

Either way it's not as bad as the A8 Z06 where if you were to use 6th gear (1:1) with it's 2.41 rear gear you would hit well over 200 mph. All of the A8 Z06 guys use 5th gear (1.27) so it goes up to 165 or so but that cuts a solid 20 horsepower out of the numbers doing that.

Either way it's just a tuning tool and with the variances between all of the different types of dynos there really isn't much there for consistency.