My last run I did pulled these numbers (listed below). I've got a '94 Z-28 with 2.73 in the rear end. Next week I'm putting in some Motive 3.73 Gears. Just wanted to know if anyone knew how I could estimate how these new gears will change how my car runs other than kill'n my gas mileage.

R/T - 0.684
60' - 2.366
330' - 6.269
1/8 - 9.464
MPH - 77.33
1000' - 12.190
1/4 - 14.490
MPH - 97.84

 

That's easy... just run it at the track again.

 

You gotta work on that 60' Time FIRST! You get that down around 2.0X or better and then you'll really benefit from the gears! But, you should knock another .2 - .3 off your time with the gears if you can keep the wheels from spinning too much. Keep us posted if you go back to the track.
Mike

 

Yeah, you're 60' is a little sluggish. You need to work on better traction off the line. Once you install those 3.73's...your traction is gonna get worse. With a slightly modded like yours, you should be netting 1.9 or 2.0 60 footers. It'll really help your times.

But to answer your question...once those gears are in, you'll have to get used to driving your car all over again. It's gonna feel like a raped ape. Your gas mileage will suffer too if you have an automatic. You'll be running higher RPM's all the time....whether its on the highway or the street.

 

So how do I go about lowering my 60' time? I've tried before but I don't know the finer points of pulling better numbers. Pretty much still learning...

 

This doesn't work for everyone, but it does work for me, and helped me cut down my 60' times a little. When you're at the track...don't go through the water box...drive around it, unless of course you have drag radials...then by all means, light 'em up. But I'm guessing you have regular street tires, in which case, just clean the tires off a little. No need to smoke the tires or anything crazy. When you get up to the line before the lights come down, 'pre-load' the car. In other words, put one foot on the brake, and one on the gas, and give it enough gas to where the car wants to move...but doesn't. Once the lights come down, hit the gas, but not 100% full throttle. Maybe 3/4. Once you get traction...go 100%. This should help your 60' times. (If you have an automatic.) If you have a 6-speed...that's a different ball game.

 

60ft with the 2.73 are not impressive (without a good converter). With a high stall then you can be at the limits of traction due to using the STR of the converter to make up for the lack of RGR.

That said (and assuming street tires), I bet your first time out with the 3.73 you will have a very similar or worse 60ft. It is hard for most to cut much better than a 2.00 with street tires anyhow, so you will probably had a little bit of frustration trying to figure out the correct launch.

If you pull off a 2.0, Id be expecting anywhere around a 13.9-14.1. I need to run through the calc though ...