1993-94 Ford 7.3L IDI Turbo V8
The ’93-94 7.3L IDI turbo is one of Ford dieseldom’s forgotten and unsung heroes. It appeared for less than two years and coexisted briefly with the first generation Powerstroke in 1994. It was factory rated for a modest 190 hp and 388 lbs-ft , but sources indicate it was deliberately “tuned down” so as not to out-power the Powerstroke, which was close on the horizon at the time it appeared. With very few mods (pump adjustments, getting rid of the crushed turbo outlet pipe and wastegate adjustments), this engine can make a very easy 225 hp and 440 lbs-ft for almost no money. Internal differences between the turbo and non-turbo 7.3 consist mainly of stouter anodized pistons with larger wrist pins, improved piston rings and Iconel exhaust valves.
Typical SpecificationsDisplacement:
7.3L (444ci)
Bore & Stroke:
4.11x4.18 inches
HP @ RPM:
190 @ 3000
Torque @ RPM:
388 @ 1400
Compression Ratio:
21.5:1

2003-up 6.0L Powerstroke V8, Generation 3
The 6.0L Powerstroke is the new kid on the Ford diesel block. The bore is almost 3/8-inch reduced (3.74 vs 4.11 inches) and it has a fractionally shorter 4.13-inch stroke. You can see many design hints from the old Powerstroke engine, but with only a handful of carryover parts, you have to call it a new engine rather than an evolution. The block is heavily revised and strengthened.

The biggest news mechanically is the 32 valve head configuration, four valves per cylinder with the injector centered in the cylinder, which greatly enhances breathing ability and combustion efficiency. It uses the same basic type of HEUI injection system, but at a much higher fuel pressure (26,000 vs 21,000 psi). It also features a new variable turbo, called EVRT (Electronic Variable Response Turbocharging). Boost rate is controlled by a unisyn ring, which is a movable trim ring around the compressor blades that controls boost. This is a much more elegant way of adjusting boost to suit engine speed than a wastegated turbo, and offers lower EGTs as well. Essentially, the engine can optimize boost at any rpm range without the restriction of a wastegate. The 6.0L also features “Pilot Injection,” a.k.a. Split Shot injectors, which inject the fuel in a couple of stages during the idle compression stroke rather than all at once. This is said to decrease idle noise and emission. These injectors were introduced at the end of the 7.3L Powerstroke era but weren’t used in all engines.

Typical Specifications
Displacement:
6.0L (363ci)
Bore & Stroke:
3.74x4.13 inches
HP @ RPM:
325 @ 3300
Torque @ RPM:
560 @ 2000
Compression Ratio:
18:1
Injection:
Direct, HEUI
Aspiration:
Turbo, variable geometry
Max EGT:
1250 max/1000 sustained*

Note that EGTs are monitored and limited by the computer.
1983-88 Ford 6.9L and 1988-92 7.3L

1983-88 Ford 6.9L and 1988-92 7.3L NA V8
Ford’s first entrant into the diesel wars came in 1983 with the 6.9L V8. Developed by Navistar/International, it cranked out 170 hp and 315 lbs-ft and out powered the GMs by a good margin but, in the 4x4 lines, was available only in the F250HD and F-350. It’s a very stout engine that’s capable of about 275 hp with the stock injection pump (a DB-2) and add-on turbocharging. The engine could probably handle over 300 hp with a high capacity pump.

The 6.9L lasted until 1988, when it was replaced by the similar 7.3L. Externally they looked almost identical, but inside, the 7.3L had a larger bore for the increased displacement, larger head bolts and (supposedly) improved valve stem seals. Overall, the early 7.3L isn’t considered quite as reliable as the 6.9L, though the 180 hp and 345 lbs-ft were improvements owners liked. Some spec sheets show the last year of 7.3L NA, 1992, with 185 hp and 360 lbs-ft.

The 7.3L NA probably has about the same power potential as the 6.9L because it’s limited by essentially the same injection pump. Again, it needs an add-on turbo kit to bring it up to good power levels. Bear in mind that, like many older diesels, the 6.9 is more or less designed to use small amounts of oil. My own has, even when it had only a few thousand miles. The new valve stem seals on the 7.3L were designed to solve that but had the unexpected bad side effect of causing early valve guide failure.
Typical Specifications
Displacement:
6.9L (420ci)
7.3L (444ci)
Bore & Stroke:
4.00x4.18 inches
4.11x4.18 inches
HP @ RPM:
170 @ 3300
180 @ 3300
Torque @ RPM:
315 @ 1400
345 @ 1400
Compression Ratio:
21.5:1
Injection:
Indirect, Mechanical,
Stanadyne Rotary DB-2
Aspiration:
Natural
Max EGT:
1250max/950 sustained degrees*