Tippy flywheel v manual flywheel.
03-17-2022, 07:27 PM
#1
Racer
Thread Starter
Tippy flywheel v manual flywheel.
So a question to the techo's
The trigger wheel around the flywheel (not the starter Ring Gear) that is used to detect crank speed with use of the crank sensor ( I thinks its a type of Hall Sensor) - can someone confirm that the number of teeth will dictate if it will affect the timing. I have been told that if the toothed gear isn't the same number of teeth that the car had as an auto it will not run - or it might but will be out of timing/misfire and a number of other no run conditions. So if this is true - that means that the crank sensor is different for auto to manual (as the auto has a smaller toothed wheel) ...this doesnt make sense. I thought it only sensed the speed of the teeth whizzing by the crank sensor. I am trying to convert from tippy auto to manual and with the 944 S2 wheel on the crank sensor doesnt come close to bolting to the mount b4 fouling on the toothed wheel used to sense. Or am I barking up the wrong tree and its all about the ECU and tooth count etc..
I am past returning on this conversion and it has not been straight forward as suggested believe me. Donor parts to convert to a manual are from an 89 S2 with the 3.0L so I would have thought sensors, flywheels, ECU etc...would have all been related. Having said that I was told that an auto ECU is "wound" back a bit so that they dont produce as much HP.
Oh boy I am lost
Peter
The trigger wheel around the flywheel (not the starter Ring Gear) that is used to detect crank speed with use of the crank sensor ( I thinks its a type of Hall Sensor) - can someone confirm that the number of teeth will dictate if it will affect the timing. I have been told that if the toothed gear isn't the same number of teeth that the car had as an auto it will not run - or it might but will be out of timing/misfire and a number of other no run conditions. So if this is true - that means that the crank sensor is different for auto to manual (as the auto has a smaller toothed wheel) ...this doesnt make sense. I thought it only sensed the speed of the teeth whizzing by the crank sensor. I am trying to convert from tippy auto to manual and with the 944 S2 wheel on the crank sensor doesnt come close to bolting to the mount b4 fouling on the toothed wheel used to sense. Or am I barking up the wrong tree and its all about the ECU and tooth count etc..
I am past returning on this conversion and it has not been straight forward as suggested believe me. Donor parts to convert to a manual are from an 89 S2 with the 3.0L so I would have thought sensors, flywheels, ECU etc...would have all been related. Having said that I was told that an auto ECU is "wound" back a bit so that they dont produce as much HP.
Oh boy I am lost
Peter
03-17-2022, 10:44 PM
#2
Rennlist Member
You need someone other than me to give you a real answer, but my understanding of the toothed wheel is the following: indeed, the Hall sensor on top of the bellhousing can sense every tooth but it's really important for timing that the ECU/DME see the missing tooth. That tooth tells the DME where the crank is for timing purposes. Of course, tooth count is related to this but that's where I start to get a little lost on things. From memory, the S2 has a 60-2 pattern and it's important to the DME that this stay the same. Modern aftermarket ECUs can handle lots of different types but, even then, the ECU has to know what to look for.
On the 944 S2, the M44.41 engine uses a starter ring with PN 94411623903 (per my version of PET, on the Clutch page). On the 968 the Tiptronic transmission has PN 94411623904 for the starter ring. I don't know what the difference is but maybe that helps to start digging into things a little more. For what it's worth, I have found that some vendors (Rose Passion, in particular) have way better descriptions for parts which can really help to narrow down differences.
Good luck
On the 944 S2, the M44.41 engine uses a starter ring with PN 94411623903 (per my version of PET, on the Clutch page). On the 968 the Tiptronic transmission has PN 94411623904 for the starter ring. I don't know what the difference is but maybe that helps to start digging into things a little more. For what it's worth, I have found that some vendors (Rose Passion, in particular) have way better descriptions for parts which can really help to narrow down differences.
Good luck
04-07-2022, 10:04 AM
#3
Three Wheelin'
The 944 2.5 16 valve engine flywheel the S2 3 liter engine flywheel, 968 auto and manual flywheels all have the same number of tooth count for DME sensor reference and can be all used across the board for engine function as long as the rest of the corresponding parts group is put together
04-07-2022, 08:17 PM
#4
Racer
Thread Starter
The 944 2.5 16 valve engine flywheel the S2 3 liter engine flywheel, 968 auto and manual flywheels all have the same number of tooth count for DME sensor reference and can be all used across the board for engine function as long as the rest of the corresponding parts group is put together
I am using the original 968 sensor with the S2 Flywheel. However the S2 flywheel trigger with the 58+2 teeth is about 8mm bigger in diameter than the 968 so i have had to get a CNC machined shim made at 3mm to get the adjustment back on the sensor as it was hitting the toothed sensor at fully backed off adjustment.
