Now that I have my gears broken in, I have been doing launches from a dead stop. Even with the add'l 10 RWHP of the smaller s/c pulley and the lower gear, I am getting less wheel spin. Now, I can stomp it to the floor from a dead stop and get just enough wheel spin to get a good launch but not hit the rev limiter. Before, if I tried that I would bounce off the rev limiter and have to back off.

This is great but it's not what I expected. Need some theories from the physics people. My guess is that the lower gear is just making it easier to get that 3.5K pounds of metal moving forward, so the tires don't have to push as hard. I suppose it could have something to do with the new tune too.

 

To me that seems weird. I would thinkwith the smaller pulley, which adds some more power and gears, you would spin even more. I know gears help with the launch and lower ET's, but I'm shocked you got less wheel spin.

 

Did you use a tuner to tell the computer (ECM?) the change in the gears? I changed out the gears in my 97 V6 from something in the hi 2.xx to 3.73's. Iam able to do burn outs real easy now but I didnt do any tuning...just the gear swap.

 

Yes, Roush was aware of the new gears and recalibrated the speedometer for the new gears when they reflashed the ECM for the smaller pulley. I'm hoping that they made any other necessary adjustments. The car runs great, I just would not have expected better hookup.

 

I thought that having the smaller s/c pulley could have put more load on the engine at low rpm, and that could bog down the start alittle. But when the rpm increases, watch out!

 

The engine should bog less with the lower gear tho..more mechanical advantage and torque multiplication going on to combat the friction the tire has with the road. Plus, you should be making boost sooner with the smaller SC pulley. Something is not right...

You didn't change anything else but the SC pulley and the gears?