Im new to this, just wanted to see if i could get some help. I have a 2002 dodge ram 1500 that i put a 1993 12v cummins with transmission in. The top speed is around 75mph. Thats not good enough for me. I believe it's getting horrible gas mileage going down highway because of it. I think it has the 46rh transmission not sure though. What could i do to increase top speed?

 

Welcome aboard i guess. Hope you have a great time up here at this community.



Tevida

 

Welcome to DF. Moving to the correct section.

 

If 75mph is not good enough for you then you need a car and not a truck...

I'm not sure to what extent you did your swap, but I'd assume that the limiter on the 93's was around 75mph...

 

replace/change governor.

change the final drive gear ratios. lower numbers
if you have 3:55 .. then replace to 3:00 or lower.

if 4 wheel drive .. both finals need changed.

better off with a car.. smaller size, less weight, better handling,

or get a Hemi Dodge truck. you got yours setup for Work, NOT SPEED.

my opinion.

 

I have 3 55 gears in the rear end. I know it's not going to be lighting fAst. I want to be able to go 70mph with ease not maxed out. Would I newer transmission help? Like out of a 1995 dodge ram 2500

 

You have to make sure you won't over rev the engine's RPM and/or Load Rating.... The Higher the speed the more load you are putting on the engine.

You will likely need to change the rear end gearing as well as the transmission to see any decent gain without losing a whole lot of torque....

Also make sure you keep an eye on the welded frame joints, with all that added weight from the engine as well as the increase in torque you might end up with some stress cracks...

 

Are you running a manual or automatic transmission by the way?

 

I am running a automatic transmission. Do I need to get higher gears? And doesn't the motor only weigh 400lbs more?

 

Yes but there is a lot more torque to worry about, so just keep an eye out for it.

Anyways... Your PCM is only going to handle the same transmission as you have currently, so you'll likely end up in the Aftermarket ECU/PCM world... You could go with a manual transmission but then you'll still need a different PCM to prevent CEL from coming up.