What is the differences in a 1991-1993 12v and a 1994 12v?? I think the pumps are but what else?? Can you make the older (91-93) 12v's run like the newer ones?? Thanks-Chris

 

From what I have been able to figure out by reading a lot of threads here. The "P" pump is a lot different, requiring different injectors, plumbing, linkage and timing gear housing. The turbo is also different than the 1993 and older. I think it is an HX35W with a 12cm wastegated exhaust housing instead of the H1C with a larger non wastegated housing. After that the auto transmissions and torque converters on the '94's are also different. As far as PCM's, and such, I don't know, but would be willing to bet they are also not interchangable without some creative thinking.
The older engines are limited by the VE pump. It seems the "P" pump is capable of more horsepower and torque, BUT there are those who swear by the VE and are capable of some impressive numbers on just #2 diesel. I haven't found all the secrets yet and would like to know how they are getting them myself. There seems to be some mention of 14mm heads on the pumps off a KTA motor, or something like that.

 

I thinking of using the earlier engines in "offroading" Can i get some pretty good hp out of them, just to turn big tires?? No sled pulling or anything like that. Just power and alittle smoke!!

 

Sure. You can get 'em up to 300hp no problem (500 if you want to throw money at it) if you stay with the manual transmission (you have to help the auto trans if you boost it up very far).

 

I'll second that on the automatic. A manual tranny is the best way to go if you only want to play. The auto of this vintage does not have lockup torque converter and the stock torque converter is too high a stall to have a lotta fun. Of course you can hold down the brake pedal until your boost reaches the high numbers and then smoke the tires.