Not my car.
2011 GT. With Boss intake andv3.55 gears it ran 12.40s in 80 deg weather.
Now, with a bigger matching BBK T body, Kooks 1³/⁴ LTs with cattted Hpipe and $600 dyno tune it runs 12.80s at 111mph. Thats a full .4 loss in excellent air conditions.
Its an auto and dead hooks with ET Streets.
Dyno shows max-378 whp @ 6500rpm where they let off.
Max-334 wtq at 4725.
It ran consistant 12.40s with the Boss intake, stock throttle body and exh.
What did we miss?
Why slower?

Thanks for your time

 

You'll need a higher rpm stall torque converter to take advantage of the extra mid/high rpm torque.

 

Thank you Dino.

All agree that a higher stall would improve ET.
However, I would think that once the car is underway we should see some improvement in acceleration from the added power.
The car is significantly slower all the way down the 1/4 mile.
Perhaps the tuner was too conservative or didnt put in enough pulls?
Anyone?

 

Why the throttle body? The stock one is all you need unless you either add cams or go forced induction/nitrous.

You most likely increased volume of the intake air but reduced the velocity. That means you may see a bump in power at the high end of your rpm band but lost some under 4500 rpm.

you have before/after upgrade Dyno runs?

what was you 60 ft before and after the upgrade?

You didnt include your trap trap speed from before the upgrade.

 

x2 on what Derf00 said, and it IS possible though unlikely that the dyno tuner was too conservative.