it has a 951 lsd transaxle and a 2.5 na now.

 

no wonder you feel slow, the gearing is tall in that one. The s2 motor will be as much work as the 968 engine swap wise, but if the s2 motor is cheap go for it. If you want to run on the stock electronics you need the engine harness and S2 DME, the 16v DME and the 8v/turbo DME are different and you can not just swap chips. You also need the S/S2 flywheel for the combined speed/ref sensor pick up on the back. Do not notch the bellhousing, if you have make sure you use the new sleeve/bracket porsche offers or the car will kick back when starting due to interference from the starter.

I'd probably Microsquirt that S2 motor you found since you've got it. You'll need a front mount trigger wheel and to build a harness. Find an S2 intake and port match before you bolt in on. Grab an S/S2 exhaust header or roll your own. S2 injectors are different than the NA so make sure your replacements are sized properly.

You'll love the motor. Part of me wants another 924S to stuff my 968 engine in. It would be glorious, that said its right at home in my S2 right now

 

With the S/S2 you technically don't need the front mount trigger wheel... it's a 60-2 IIRC flywheel which MS can natively use. However getting the 8v 132-tooth "trigger wheel" (which is really the starter ring gear on the pressure plate plus a stud for TDC reference) is a complete waste of time.

The S/S2 wheel actually gives an ok signal. On the 8v it's subject to noise, the teeth are not ideally spaced or shaped for a VR sensor (because it's designed first and foremost for mechanical use with the starter). Plus the S/S2 has a missing tooth section so you only need one sensor to run the car. The hall effect sensor on the cam is only needed for sequential fuel and/or spark (i.e. true COP).

 

I'd be worried about the magnetic interference when starting the car, but if the micro can handle it, great. The OP listed that he doesn't have a 16v flywheel for that motor, so in that case he would need the trigger wheel.

Man, I kinda want to MS the 968 motor, full sequential and proper COP spark sounds baller as hell.

 

Right - it would need to be properly shielded, the VR sensors are only creating a ~1v potential during cranking (and 50v+ at high revs!) which is why it needs to be conditioned to a digital signal. MS supports that onboard but it has to be configured. That's the main reason I went with a hall sensor on mine... digital from the moment the sensor reads a tooth, and provides a binary (on or off) 12v square wave to MS. Doesn't need to be shielded.

I'm running the 6" wheel from: http://www.goingsuperfast.com/Trigger-wheels.html

It is bolt-on to an 8v, it gets sandwiched right behind the crank pulley. It is 3mm thick, so 16mm length bolts are needed (M6x1.00mm), reusing the washers.







Pardon the oil all over the pan.

To the OP: can you compare the 8v to the 16v crank pulley? Not sure if the one I used will bolt up but perhaps it is something that can be worked around.

 

The damper section of the 944S/S2 sticks out a bit but a 6" diameter trigger wheel should be OK still.
The bolt holes and such are all in the same place.

 

There are also SC kits from various vendors for the 968 motor, for more beastly behavior.

MN