OBS 7.3 and SD 7.3, what is the difference?

bill11012 · #1 (**permalink**) 10-30-2009, 11:50 PM

OBS 7.3 and SD 7.3, what is the difference?

I see they have different threads, but what did ford change?

rollerstud98 · #2 (**permalink**) 10-31-2009, 01:01 AM

I don't think they were intercooled in the obs were they? also completely different truck for one. different injectors, turbos likely, i don't know what else since i'm a 6.0 guy

bill11012 · #3 (**permalink**) 10-31-2009, 01:11 AM

I know the truck is different, I meant the motor its self.

I think you are right about the intercooler.

parkland · #4 (**permalink**) 11-02-2009, 09:43 PM

They are totally different. Nothing is interchangeable.

The OBS used 7.3 Indirect mechanical injected non-turbo engines.
The new are direct injected electronic hydraulic injected turbocharged engines.

The stroke & bore are identical I believe, but everything else is upgraded to handle more power and more advanced systems.

It's like comparing the newer 7.3's with the 6.4.

95_Dually · #5 (**permalink**) 11-03-2009, 01:21 AM

The 94.5 - 97 OBS PSD's are Direct Injection and have Turbos. The motors are very similar between 94.5 to 2003. Parts can be interchanged as long as specific parts are used as well. IE: the turbos can be interchanged as long as you use the pedestal and the spider intake.

bill11012 · #6 (**permalink**) 11-04-2009, 06:16 PM

Quote:

Originally Posted by parkland

They are totally different. Nothing is interchangeable.

The OBS used 7.3 Indirect mechanical injected non-turbo engines.
The new are direct injected electronic hydraulic injected turbocharged engines.

The stroke & bore are identical I believe, but everything else is upgraded to handle more power and more advanced systems.

It's like comparing the newer 7.3's with the 6.4.

I think you are thinking of the 83-94 IDI 6.9/7.3.

All the 95-03 7.3s were DI.

drivembig · #7 (**permalink**) 11-10-2009, 04:46 AM

I know that there are a lot more people to chim in on this that knows way more than I do, but the first generation (1994.5-1997) versus the second generation (1999-2003) I think are very similiar.

I know that the fuel pressures are different. The injectors are a little different, but I think can be interchanged. The HPOP (High Pressure Oil Pump) is different, but also can be interchanged. The turbo got an intercooler, which can also be put on the first generation. The waste gate on the second generation is also different. AS mentioned in a previous thread, you can put the second gen turbo onto a first gen if the pedestal and mounts are also used. I'm sure the IPR is different as the higher pressure HPOP. The IDM is of a higher voltage, which can also be used on the first gen.

Someone please chim in and take it from there. Correct me if I'm wrong or add to what I have missed.

ghunt · #8 (**permalink**) 11-10-2009, 10:03 AM

I don't know all the little differences- what I do know off the top of my head is that the 94-97 7.3 PSD was non intercooled, and had a non-wastegated turbo with a 1.10 AR turbine housing and a squished downpipe. '99-03 7.3 had an intercooler, the turbo was essentially the same except it had a .84 AR wastegated turbine housing and I was told it had a better compressor wheel. It also had a real downpipe.

One thing also of note was that as far as I know, the PSD in E-series vans was always non wastegated with the 1.10 housing, even when the SD trucks were wastegated.