Help from late model S2 owners please.

[JM1962]

I am embarking on a conversion on my early 944 and have aquired an S2 engine, clutch and most of the parts needed. The conversion is straight forward apart from the electrics. S2s are fitted with 2 types of ECU, before and after 1990. My question is a simple one, does the later model, say 91 onwards use an ignition amplifier (968 for example doesn't). If it uses one it will be positioned on the inner wing behind the headlight (passenger side I think). This would make a difference to me as the ignitor feed from the ecu is a screened wire and would be extra hassle to install. If someone could have a look I would be grateful.

I have electrical drawings for most models including 968 but don't seem to be able to find one for a late S2.

 

[eddieedmo]

yes my 1991 S2 has one fitted.

Nick []

 

[timfield]

I like your plan! Would love the extra oomph in my early car, I do love the front of the early car and the simplicity of no ac, no electric seats, etc... But more go would be nice!

 

[Tam Lin]

Sounds like a nice project ;-)
Have you planned a rev counter and heater actuation solution?
Good luck!

 

[JM1962]

Thanks Nick. That means theres no advantage to a later ECU.

Tam, not too worried about the rev counter at this stage and must admit hadn't even thought about the heater, maybe the old cable actuated heater valve will fit.

It is a long term project, its taken me 5 years to get this far. This week I am fitting Bilstein B6 shock absorbers all round and so far have fitted new front wishbones, complete rebush of the front end plus 968 anti roll bars front and back. The car is taxed to the end of September when it will be taken off the road for the winter and the engine exchange plus back end rebush.

 

[bluedexter]

The late S2's have different injectors and the ecu has a choice of maps. I had a problem last year with fuel delivery and made some comments on a previous post (see below).

I've done a little digging and discovered that the injectors fitted to my S2 are part no. 280 155 003, the correct part no. for the S2 is 280 150 811.
Both have approx. the same delivery but the correct injector has an impedance of 2.4 ohms whereas the ones fitted (brown) have an impedance of 15.4 ohms. The effect of this is explained in this extract:

High impedance injectors require relatively low drive current. Less heat is therefore generated in the drive circuits of the ECU, but the penalty is slow injector opening times.

Low imedance injectors require much more drive current. Faster injector opening times, but more heat generated in ECU.

Connecting low-impedance injectors to an ECU designed for high-impedance injectors would cause that ECU to switch greater injector drive currents than intended, and this can cause excessive junction temperatures in the driver transistors which equals smoke.

Connecting high-impedance injectors to an ECU that expects low-impedance injectors can't do any damage electrically to the ECU or injectors. But how well it would work is another matter as the injectors are opening far slower than the ECU expects and so presumably your fuel delivery would be up the creek.

More info here: http://www.witchhunter.com/injectorimpedance1.php4

I wonder how many other 944s there [/color]are around fitted with the wrong injectors?

 

[JM1962]

The early injectors (upto 1990) require a resistor pack to be fitted. The potential problem would be fitting low impedance injectors to an ECU that expects high impedance.