Im hooking up in all gears but first

 

Sorry, I meant that 12.8 @ 100 mph seemed high for even a stock time. There was a good amount of difference between that stock time and what you ran, so there was an improvement on 0.6 s and 17 mph with the supercharger.

Considering the stock time and trap speed also weren't great, I don't think the issue is something with your cars, since two of you are seeing the same issue. I would think maybe it's driver inexperience, DA (which is based on weather conditions), and/or track prep/conditions.

What was the temperature like the days you guys ran? If it was pretty high, that's part of the problem there. How was the track preparation? Were other cars there running slower than expected? If the track prep was bad it could be another potential cause of the problems. All of these factors could add up to explain the bad times that you're getting.

As a disclaimer, I don't currently own a C7 but I am furiously researching them for a purchase in the next couple months. Do have some experience drag racing, which is why I'm trying to help. My 370Z ran a 12.9 @ 111 mph close to sea level and 50 deg F temps, with only 320 whp. Stock C7 should be able to beat that easily.

 

Right but if you have traction control on it would be pulling a lot of power to make you hook. Is traction control on or off?

 

That wasnt my car that posted stock times

 

it was with traction controll off

 

I also have an A&A V3Si setup /w TSP headers + meth (for protection). Plus some extra dead weight on sound deadening material. Depending on the dyno, it made 560rwhp (mustang dyno) to 625rwhp (dynojet).

Long story short, the car began at 12.4 @ 118 with all those mods. Ended up at 11.4 @ 129 on the stock run flats. Same mods, same boost, same rwhp, same track (****** prep btw), same everything. Now it is at 10.5 @ 131 by only adding drag radials (just stabbing the pedal from the get go with all the nannies. Cheat mode: ON! haha)

You would think driving an automatic wouldn't be that hard. Hell, my tuner always gets better times and MPH than me, even on back to back runs. The difference? He has a lot of experience drag racing and knows how to launch the car and when not to lift up. Me? I either launch slower than grandma on a walker (by trying to roll on the pedal to avoid wheelspin) or spin side ways to hell by stabbing the pedal. Of course, now I bought some drag radials, so now it feels like cheating

Things you could check:
Datalog IAT's to make sure they are not high, thus making the PCM retard timing to save the engine. This kills the MPH.
Datalog your RPM's to make sure you are not short shifting before it is time since you are on a M7. I would get a shift light, makes things a bit more consistent.
Got a friend with drag racing experience that you really trust? Let him have a go at the car, this might tell you if the problem is driver technique.
Datalog knock retard, this will also kill the MPH if the car senses knocking (real or false, it will retard timing).
Getting on & off the pedal on the run also kills the MPH.
Can you post the full time slip information? 60ft, 1/8 et / mph, 1/4 et / mph? It may help determine if the problem is at launch, first half, or last half.

 

I went 11.52@119.5 bone stock, something is wrong with your car.

 

we found a problem in the tune, been data logging things r looking good now, will b back at the track this weekend i will post tge results of the tune

 

As expected--data logging tells no lies...