[Matt TuneTime]

Originally Posted by irpq11

BTW all. For buying a BRAND NEW car, It sure is a pain in the ass to own right now.

If I go to another shop and the reading are not showing the car running right, then I'll need to go to ANOTHER shop.

You need to go to another dyno. Just one more to see if all things are equal ...Then well or I'll help you move on .

Originally Posted by 08z51c6

I'd seriously take your car to another shop and get it dynoed. Look at it this way, you already have this set of numbers so if you take it to another reputable shop and get the same results you have that much more in proof to take to your dealer and show them some thing is not right.

My guess is bad fuel pump or injectors.

Injectors are with in 5% so it's possible to have a 10% variation between 2 cycl's but highly unlikely

Originally Posted by Verio

So how many dynos does he need to do before the results are good? 5? 10? Does he need to take it to a track next?

Seriously, there's an issue and everyone can see it. Now he has cold hard data to show it.

Building a car or complaining or tuning based on wrong data sucks ... He needs to go to one more shop then we can help him move on ..

Originally Posted by Rockets

My L99 hop's around on the Tach,about 100 too 200rpm's and talked too the Mechanic and he said its a lean roll cause of the lean fuel mixture and injectors need a few thousand k too seat,driving the bag off your new hot rod is not the way too break it in and suspect some of the problems are compounded from the driver ripping the bag off the car before its time too do so

No he's way off here , The rpm hop is normal on almost any LS ...

Originally Posted by pcmforless

Honestly, this is how these cars are factory tuned. They are set up to run a high 10 to low 11 Air/fuel at WOT. Looking at the power enrichment table in the factory cal it is at 1.32 to 1.34 in most of the HP band which equates to a 10.97 air/fuel (14.7 divided by 1.34 = 10.97 WOT air fuel). I'm not sure why GM is commanding such a rich air/fuel on these cars, the LS3's are typical GM rich in the 11.5 to 12.0 range, but the high 10's to low 11's on the L99's reminds me of how bad they do on the stock tune on the trucks. The timing is also very weak on the L99 factory tunes and there looks to be a lot of gains to be had on these tunes. Once I get one on the dyno instead of just a street tune I will get some before and after numbers up.
The six speed auto is good for 20 to 22 % drive train loss at least based on Vettes and STS-V's I have dyno tuned. Only the M6 is going to give you a 15 to 17% loss. The A6 is pretty heavily built for strength and that eats up power to the tires.
Really there is nothing wrong with your car, that is just how it is programmed from the factory and the dealer has no way to fix that.
Something in the 320 to the tire range is what I would expect one of these to make to the tire stock. 400 X .8 (just a 20% drivetrain loss) is 320HP.

Not to argue here but the commanded PE vs accual is off you'll find Even if you comand 12.8 on a bone stock car you'll get 13.3-5 you have to take out of the maf up top to get commanded

Originally Posted by pcmforless

From a tuner who is always looking to get the best air/fuel mixture and peak timing, No, I would not say it is Satisfactory, BUT, it is putting down the exact Air/fuel that GM has it programmed for, so there is no defect in your car. Unfortunately the dealer has no ability to adjust this as they can only load stock GM cals. If GM comes out with a leaner cal due to multiple customer complaints of low power (they have done this in the past) then your dealer could load that updated tune, but otherwise it is what it is.
If you go to your dealer and tell them the guy from PCMFORLESS or the Camaro5 board for that matter says you are losing 25 to 30 HP because the factory tune is rich and the timing is weak they just aren't going to take you serious because they just don't understand the inner workings of the ECM themselves.
I think if enough of you guys go in with compaints of low power GM may consider tweaking the tune some to get the air fuels at least into the mid 11's and add a bit of timing. Back in the late 90's a bunch of Mustang Cobra guys compained of lack of power and Ford changed all of their intake manifolds and I think exhaust manifolds to raise the power. Changing the ECM cal is much easier and less expensive.

No it was the cylinder heads the cars where 40-50hp off and ford replaced the heads and Cal to get the car to the rated hp of 305hp ... IMO untill I get a few more L99 car's on they dyno and see them at the track I'll wait to comment on the L99 stock tune ...