700R4 RPM 2500 @ 70/75MPH Normal?
09-17-2018, 09:05 AM
#1
Junior Member
Thread Starter
Join Date: Sep 2018
Location: Detroit
Posts: 4
Likes: 0
Received 1 Like
on
1 Post
Car: 1992 Firebird Formula
Engine: 5.7 TPI
Transmission: 700R4 4SPD Auto
Axle/Gears: 3.23
700R4 RPM 2500 @ 70/75MPH Normal?
Hello,
Asking if this is normal, my birds running at 2500 RPM around 70/75 MPH with 700R4. I just had the trans rebuilt it's got a 3.23 rear end. It ran like this before having rebuilt as well.
Asking if this is normal, my birds running at 2500 RPM around 70/75 MPH with 700R4. I just had the trans rebuilt it's got a 3.23 rear end. It ran like this before having rebuilt as well.
09-17-2018, 04:00 PM
#4
Re: 700R4 RPM 2500 @ 70/75MPH Normal?
FWIW, mine (700R4/3.23) turns about 2050 at 70mph on stock-size tires (245/50-16). I have verified the speed accurate to +/- 1.5 mph. I have not verified my tach, however, the gear ratio speed calculator (http://www.apexgarage.com/tech/gear_ratios.shtml) calculates this to be about right. Are you running different diameter wheels/tires than stock? According the speed calculator, 2,500 rpm with stock (25.6-inch diameter) tires and .70 overdrive/3.23 final drive ratio, you should be going 84 mph.
09-20-2018, 08:14 AM
#5
Supreme Member
Join Date: Mar 2003
Location: Florida
Posts: 4,771
Likes: 0
Received 14 Likes
on
10 Posts
Car: 1987 Black IROC-Z (SOLD)
Re: 700R4 RPM 2500 @ 70/75MPH Normal?
Easy check for correct RPM.s & speed with the 700R4. In OD the tach @ 1000 RPM.s and the speedo @ 40 MPH....at a steady speed.
09-21-2018, 10:59 AM
#6
Supreme Member
iTrader: (2)
Join Date: Mar 2014
Location: South Ms
Posts: 4,436
Received 724 Likes
on
493 Posts
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: 700R4 RPM 2500 @ 70/75MPH Normal?
Are you positive it's still got the stock 3.23 gear or maybe it has been swapped for 3.42s?
Thread
Thread Starter
Forum
Replies
Last Post
383firebirdokc
Transmissions and Drivetrain
3
06-16-2011 10:02 PM