Your pos must be slow mine runs a 15 on the 1/4 with just an intake and servo
A stock Cobalt SS supercharged runs a low 15 second 1/4 at 4200 feet above sea level on Pirelli PZero Rosso tires with very little slip off the line. Want to see the time slip? A drop to 200 feet above by sea level didn't net much of a difference. A stock Cobalt Sport 5-speed runs the 1/4 in high 16s on Pirelli P6 All Seasons at the same track on the same day at 4200 feet above sea level. I haven't run it since moving to Virginia so I can't compare what a drop in elevation would net. I spent a couple years racing both cars. I use to own the 1st and still own the 2nd. I just happened to line up with my wife the other day while she was in the Cobalt and I was in the Tahoe. She killed me off the line with her 170-ish bhp and kept walking. This was done from a complete stop to the freeway speed limit of 60mph on a 2 lane on ramp. She has some experience, and trophies, with drag racing. So do I, plus land speed racing at Bonneville. Considering the model year differences between mine and your trucks I'm willing to state that even though mine makes more power from the factory, and I have a CAI too, no way you're running a 15 second 1/4. I'm definitely not. And, I'm fairly confident I'd beat you in a legitimate race. My little sis has a 2005 Yukon with the 5.3 and I beat her when we were playing around in Elmyra, New York last October. I edged her out. Quit magazine racing.
Also, street racing is just
