On my 94 S10 with a FB4001A motor, I am trying to figure out the max RPM’s without damaging the motor. The reason is to get the max MPH on Interstate grades and not irritating the guy/semi behind me.
So spent a few hours tying to figure out the ratios to avoid buying an rpm tach, plus heard some aren’t too great anyway. So I jacked up 1 tire and spun the motor. I know the figures I got are wrong (5.5 motor rev per 1 tire rev in first). Guess both tires must be moving to be accurate.
What I know:
1- 2800-4500 RPM is max efficiency per a performance chart. Previous owner said to run it at 3-4K. Agreement here.
2- Evconvert.com calculator says 60MPH @ 4211 in 2nd, 2586 in 3rd for a normal rear end. Mine was a factory special order 2.56 ratio. That is at least 10% fewer turns of the shaft, right? Safe to do 60 in 2nd since 3rd bogs down to much?
What speeds do you safely use?
1994 S10 120v US145 Batt
So spent a few hours tying to figure out the ratios to avoid buying an rpm tach, plus heard some aren’t too great anyway. So I jacked up 1 tire and spun the motor. I know the figures I got are wrong (5.5 motor rev per 1 tire rev in first). Guess both tires must be moving to be accurate.
What I know:
1- 2800-4500 RPM is max efficiency per a performance chart. Previous owner said to run it at 3-4K. Agreement here.
2- Evconvert.com calculator says 60MPH @ 4211 in 2nd, 2586 in 3rd for a normal rear end. Mine was a factory special order 2.56 ratio. That is at least 10% fewer turns of the shaft, right? Safe to do 60 in 2nd since 3rd bogs down to much?
What speeds do you safely use?
1994 S10 120v US145 Batt
