MattSlay

I met a guy today who has a 1989 or 1990 S2 (I can't recall which), and he said he has installed an ECU from a 1991 S2 in his card, and claims that he feels noticeably more power out of the engine.
Says he pulled these parts from a 1991 944 Cabriolet that had a blown engine and he bought the whole car for next to nothing.

Says he swapped out the following parts:

• 1991 ECU
• 1991 Wiring harness (he says the 89/90 harness is different that 1991)
• 1991 fuel injectors
• and, he removed some resistors that were used on the 89/90 fuel injectors and this isn't needed for the 1991 ones)

So, has anyone ever done this, or heard of it, and can anyone confirm if there really could be better performance in a 89/90 by doing this???

Noahs944

Could it be chipped?

Dan Shea

If I remember correctly the early years of the 3.0L 16v had low impedance injectors, which had a resistor pack in the engine bay to simulate a high resistance injector the ECU could handle. This is the difference between the two harnesses, the 89-90 have the connector for the resistor pack, the later models go straight to the injectors.

With that said, the only improvement you'll see is possibly the improved design of the injector spray pattern, if there was even a change. But that doesn't gain hp/performance, it just maximizes the power you already have. You could achieve the same results with less invested by either cleaning your current injectors, or purchasing the correct impedance injectors with a newer spray pattern.

FWIW this is what I run on my car, but I am no longer using a stock ecu, so my options were wide open on what injector to pick.

38lb Bosch Blue Knights

Jfrahm

I think I have a 1991 S2 ECU laying around I should sell. I do not know if it obviates the need for the ignition module, which the 968 does not have but the S2 does, at least the 89/90.
I also have some S2 injectors but one of them is stuck. 0-280-150-811 ; 28.35 lb/hr ; EV1 ; Low impedence

-Joel.

Dan Shea

Still need the ICM for the S2 regardless of the year. I think even the S's ran them. 968 changed a lot of things.

Zirconocene

My '91 does not have the resistor that the '89/'90 seem to have, unless I am totally off about where it is located. I could be totally wrong, however, but everything that I have read and seen on my car indicates that it is running with the higher impedance injectors, without the additional module.

I'm happy to share pictures and learn something about my car, if that would be helpful.

Cheers

Arominus

Things changed in 91, running that ECU will likely lose the A/C system as the wiring changed, found that out when we swapped in the 93 968 motor into an 89S2. The changes in wiring carried over to the 968, so if you have a 91 thats something you don't have to deal with when swapping the 968 motor.