Attention: TDR Forum Junkies 
Yes again.....
There are a number of differences and some of those are as follows;
Lets reference the earlier trucks as "early models" and "later models for ease of identification...
1)The early trucks had no intercooler which is used to cool the boost air coming from the turbo and going to the intake plenum, were as the later models had an intercooler. (you can tell by looking to see if there is a large tube/piping connection that goes over the top of the head and connects to the intake manifold... if there is, it's a NON-INTERCOOLED truck.
2) The early trucks had different injection pump timing settings which ranged between 1. 35mm 1. 40mm spill port timing. The later models used 1. 25mm spill port setting.
3) There is some crossover here regarding turbo's exhaust housing component ... . from 89'-91. 5 they came with an 18. 5cm housing, then from 91. 5-92 they used a 21cm housing and finally during the 93 model year run they went back to the 18. 5cm exhaust housing.
**NOTE** the smaller the exhaust housing the quicker the turbo will spool up and start to produce boost. In addition the total boost will usually increase roughly 2-3 psi for each size DOWN you go in housing size.
Pastor Bob.
There are a number of differences and some of those are as follows;
Lets reference the earlier trucks as "early models" and "later models for ease of identification...
1)The early trucks had no intercooler which is used to cool the boost air coming from the turbo and going to the intake plenum, were as the later models had an intercooler. (you can tell by looking to see if there is a large tube/piping connection that goes over the top of the head and connects to the intake manifold... if there is, it's a NON-INTERCOOLED truck.
2) The early trucks had different injection pump timing settings which ranged between 1. 35mm 1. 40mm spill port timing. The later models used 1. 25mm spill port setting.
3) There is some crossover here regarding turbo's exhaust housing component ... . from 89'-91. 5 they came with an 18. 5cm housing, then from 91. 5-92 they used a 21cm housing and finally during the 93 model year run they went back to the 18. 5cm exhaust housing.
**NOTE** the smaller the exhaust housing the quicker the turbo will spool up and start to produce boost. In addition the total boost will usually increase roughly 2-3 psi for each size DOWN you go in housing size.
Pastor Bob.
