RSflared72e

I'm getting ready to install a SPEC brand aluminum flywheel on my 91 S2. It's a good-looking unit with what appears to be solid construction, such as for the riveted steel face panel. The flywheel has a single Hall sensor stud screwed into it. Otherwise it has a completely smooth perimeter edge. While I would want to assume this thing is set up for the sensor on the car, I am concerned about putting it on and having a no-start situation I'll then need to troubleshoot in a vacuum of information. Anybody used one of these?

rihaa

One thing that I have heard about using the aluminum flywheels on the 3L engines is that the DME cannot keep up with the rapid decrease in fuel delivery when you put the clutch in and it can sometimes stall. I have been told that you pretty much have to have a chip installed if you want the aluminum flywheel to work. This is coming from guys with the 968, so I'm not sure if that has something to do with the variocam or not, but that is somethingto look into.

RSflared72e

I've mainly heard of that problem on 911 series cars, particularly the 3.6L air cooled type. Haven't heard of it on 944s, the feedback I'm getting has been positive.

However - the technical problem I am concerned about is the fact that the stock flywheel has teeth all around the rim, and this one is smooth except for one Hall pickup stud. Not sure the aftermarket one will work with the sensor array, although it is supposed to be intended specifically for the S2.

L8 APEKS

91S2...


Are you just talking about the ring gear? Doesn't that just swap over to the new flywheel?

944_S_TYPE

Yea..The starter ring gear? Or do you mean those little squares around the "stock" flywheel...I think they are under the 1 position sensor?

SoCal Driver

There is only one sensor. The large "teeth" cast into the 'S' flywheel function as both the reference and speed inputs.

I would find it interesting that an 'S' or 968 can be chiped to compensate for the speed input.

Tom M'Guinn

As for flooding it when you put the clutch in because of the flywheel spinning down too fast, the DME cuts fuel above 1600 rpms when you take your foot off the gas (at least on the 951 it does). So, I can't see how that could be an issue.

RSflared72e

I am referring to a lack of the large teeth that are part of the stock flywheel itself (NOT the ring gear on the pressure plate, of course).

So, as SoCal Driver has mentioned, if they serve a sensory function for speed reference, how can the aluminum unit do without them? I called the folks at Spec Clutch, the vendor, and they say that it is indeed the correct unit. Unfortunately, David, the guy who knows the technical aspects of this, was not in...