Hey, I swapped an OM617A into my s10, used an ax15 trans and have 4.88 gears and 35" tires but my truck is super slow and cant make it past 55mph anyone know why the motor would be so slow or have ay problems with it being super slow?

 

If you are in 5th you must be turning around 2k rpm's. You should run it all the way to 75 in 4th, this motor is on torque at around 3200 rpm's. If you get it to 75 in 4th, you may be able to cruise in 5th. With 35 inch tires you may be geared too low in the axles for the AX15.

Have you turned up the pump? I have three of these cars and some are more powerful than others. I have read that there can be a variance of up to 10%. That seemed hard to believe since theses motors were built to such tight tolerances. However, real life experince seems to verify it.

Do you have a California emissions motor? Did you intercool the motor? This is an interesting thread I wish I could come tinker with you on this.

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I think to make 5th gear usable you may need to go to a ratio closer to 6 to 1. 33 inch tires ought to be better.

 

i started out with 3:50 gearing and the motor was slow due too it bogging down in 4th gear haha, now with 4.88's its reving threw gears quick until 4th but you cant get much faster than 50. I can use 5th gear it doesn't bog down my motor but it just will not go any faster in 5th than it will in 4th. my motor is not the cali emission motor, not intercooled. did turn up the injection pump a quarter turn. My throttle also sucks its either your 3/4 throttle or full throttle at all times there's not much and i cant figure that out either