I have a 93 z28 auto with factory 3.23 and i just bought a set of Motive 3.73's. In the 1/4 can you stay in Drive (3rd gear)?? I plan on getting headers really soon to but i dont know if i will run out of gear at the end of the track?? What are you 3.73 guys with like heads and cam swap doing at the track b/c i always heard that you dont want to shift into overdrive but some autos trap like 120mph how are you doing that?? Are you going into Overdrive?? thanks

 

Its about at 120 mph when 3rd gear runs out with 3.73s and a 26 inch tall tire.

Been doing it for years with the gearing of the 4L60s and Es never had to shift into overdrive in the 1/4.

 

No chance of hitting 4th.

I trap at 116+mph in the 1/4 mile at 5800rpm. My redline is at 7000 though.

 

Good point we both arent even at 6 crossing the finish line and both of our cars make power past that. As a matter of fact I'm shifting at 6500 on the first 2 gears.

 

Well my car is stock. With the stock steet tire what would be my rpms at like 100mph with 3.73's. Then what would be the top speed in 3rd with a factory tire? If someone could answer those two questions that would help me a TON!!!! thanks

 

Stock street tire (~26") at 100 mph in 3rd gear (1.00 to 1) with a 3.73 to 1 final drive would be at 4822 rpm's.

Top speed calculating 5800 rpm's in 3rd would be around 120 mph.

 

THANK YOU SOOOO MUCH!!!! that is the answer i have been looking for!!!!

 

3.73's in an auto are no problem at all. I had 3.73's and love them. Like the guys said above, even with heads/cam, you'll still have plenty of gear left at the end of the 1/4.

 

not to hijack the thread or anything but is part #g875373 the right part number for motive 3.73s that will be going into a 94 z28 that had 3.23's stock?

 

I trapped 119 before I pulled the motor and 3rd is about gone, but all you need is 3rd, unless you are trapping 125+, like I will soon be doing. Hoping to trap around 130.... hehe...

 

With the stock motor, I was trapping 106 MPH @ 12.82 with 4.10 gears...Going through in 3rd.

After heads and cam, I was trapping 112 MPH @ 12.05 with the 4.10s. I always saw "yellow" from the shift lite, set at 6200 RPMs, about 75-100 ft. before the line. I was shifting into 4th before going through.

I now have 3.73's which I had to do for the nitrous. I can run through at 112 MPH, now, @ 5900 RPM's.

Frank

 

Do you lock your converter? Because I'm trapping high 115's and best of 116.7(in crappy weather), and using a laptop it shows me crossing traps at 6,000rpms with my converter locked. Also I can watch my tach(which is off 200rpms compared to datamaster/tech 2/etc) and it will be right at 6200 when I cross traps, thus 6000rpms. This is with 275/50/15 et streets which are a little taller than a stock tires.

Either way, 3.73's will be fine for heads/cam. I'm hoping this fall to be cross traps around 6400-6500 on motor, and will have to run a 28" tire if I want some good spray times. Stock bottem end won't like anymore than 6500rpms, especially on spray.

 

Sorry to resurrect an old thread, but...

I noticed that my car shifts into overdrive at around 110mph. Could this be due to the Nitto's running smaller (275/50/15 on 15x8 Welds)?

(3.73s)

 

If its a shorter tire then it almost definately is the reason why.

 

Whats the average price for a install for gears?