Going through the traps

[James Vincent]

Hey guys. I'm new here. Looking for some info. I just recently supercharged my 12 gt. Ran it at the track the other day and noticed that now it shifts fourth gear before the traps I have 3.15 gears. It use to finish in third before the blower. My question is, what rpm would it have to be at to finish in third? My motor is stock and my mph was between 123.5-125. Car is shifting at 7k. Also what the safest rpm?

 

[Fastnature]

if you have 28" tire 7500 rpm will net you 130mph in 3rd

 

[James Vincent]

It's a 27.6

 

[James Vincent]

Is it safe to rev the car to 7500 with 9 psi on a stock motor?

 

[Blazer707@TBR]

A lot of people have revved to around 7500 to finish out in 3rd.

 

[2003mach1]

What supercharger you running?

 

[James Vincent]

Ok thanks

 

[James Vincent]

Vmp stage 1

 

[Dig Race]

Why not a little more gear so you'll use up 4th

 

[5lho]

Obviously you're shifting up bc you are going much faster but, honestly, if it were my motor and I hadn't budgeted for a new engine and/or wasn't willing to risk the stocker I would not raise the rev limit under 9 psig of pressure. The motor sees that as ~23 pounds of boost pressure (9 + atmo at ~14), plus the heat of the charge so, you decide if it's worth the risk. I'd probably tire up or live with the 4th gear shift; it probably isn't costing you that much anyway.

 

[The Beast 2014]

http://www.andysautosport.com/learning_center/calculators/

You can plug info in here to see the shift points. Mine doesn't shift out of third on a 28 inch tire but I cross the traps at 7300 rpm. If I add more power I will need to live with a shift.

 

[JohnRichard]

Have you had the car dynoed? Try a smaller tire or different gears... You want to be at the top of the HP peak in whatever gear you desire when you cross the strip. Taking it past the HP peak will slow down the rate of acceleration.

 

[POPPAJ]

Spinning those tires a lot and ending up in second gear before the 60ft?