Odometer inaccuracy

[g59tester]

Hi Guys, i recently replace the notoriously faulty gearwheel in my odometer. I gave my chassis number to a "reliable supplier" . Basically its a MY 1987 220 Turbo . He supplied a 20x23 pink gearwheel

The odometer now works but gives readings 15-20 % to high..
Clearly thats unacceptable . Were there different diff ratios available? Speedo goes up to 180 MPH . Tyres are standard sizes
Any ideas where to go from here

Eddie
2007 Cayman S

 

[944Turbo]

Hi Eddie,
Head to Germany and film some youtube videos of you maxing it on the autobahn!

Or ask the seller? if its the one I think they have several options as it is not always clear bit of a faff to swap it out again though. (I thought the 220's only had a 160mph speedo, but maybe its year related)
Tony

 

[bmnelsc]

This page might help. It doesn't say why there are different ones but apparently there are several to choose from. Diff ratios would be a good reason as would "using up what ever stock of gears they had available". The key tip is to count the teeth on the old wheel before ordering an new one. You already have some clues as a result of the difference you report so you know which one it is NOT.
Oh - just looked a Clark's Garage page for diff ratios and it shows ALL turbo transmissions had a final drive ratio of 3.375 so that shouldn't be a factor...sounds more like the whatever gears are left over argument

https://www.odometergears...+82-91+%28Non-US%29/83

 

[scam75]

Hi Eddie

I may be wrong, but I think the 220 turbo came with 160MPH clocks and it was the turbo s, and 250 turbo cars that came with the 180MPH clocks. It may be the case that you have got the right cog for your car, which should have a 160MPH clock, but someone at some point has fitted the 180MPH one. It would make sense but as I say, I think, not certain!

Stuart

 

[g59tester]

Hi Guys, thanks for your response. I thought I had sent a mail yesterday but it seems to have disappeared into the ether

From watching a You tube video which involved a walk round a220 turbo the guy made the point that this particular car was a very late 220 with a 180 MPH speedo. My car was first registered 8/10/87.
This presumably means its a88 MY??? My car is a dark colour Marron colour so maybe sat in a pound for some time. "Maraschino Red Metallic " Where would I find the build date? when were the 250's available?

 

[944Turbo]

Not sure they stuck to a particular changeover with some parts - could be if the 160s were running out they swapped to the new batch of 180s,

From woolies workshop
"The number of teeth in the instrument drives also varies within a model depending on engine and transmission type as well as differential ratio and country code."

They also say while they have sold lot and can make a good guess they may send you the wrong one and can change it with quick turnaround,

Tony

 

[g59tester]

Tony, Woolies was the supplier.... they may have a quick turnaround but there's a significant work in changing the gear wheel dismantling the dash and putting it back together

BTW the car passed its MOT the other day... first time and no advisories! There is some work to do on the wing bottoms and that is hopefully going to be done around Xmas.... and get rid of some of the excessive stone chip .
Eddie

2007 Cayman S
1988? 220 944 Turbo

 

[944Turbo]

Hi Eddie, easier the second time though, did the old one have enough teeth left to count? do the senders change for the different speedometers? that would be an option if so but possibly an expensive one.
Congrats on the MOT.
Tony

 

[g59tester]

Tony the old one had disintegrated. But the teeth that were left seemed to only be about 8-12 it was a brown gear that seemed to be made of wax!, nothing like20 odd teeth

 

[g59tester]

I've just done an accurate measure of how far out my odometer is. Firstly the speedo seems to read correctly. As far as the Odometer is concerned it reads 25 miles on a 17 mile journey measured from google maps and another car. That's a 47% error. I've also had a look at on image I took of the speedo head when I removed it and although I can only see half the gears it does appear to have 18 teeth on it. I've also checked that my car was first registered on 8/10/87 which presumably is a pretty late 220 and making it an 88MY...with 180MPH speedo

Where could i get the build date and the date of the last 220 built?

PS I'm enjoying the 50 mpg!11

Eddie
2007 Cayman S
1988 ? 944 220Turbo?

 

[graham.webb]

50mpg? Well done for saving the planet!
My build date is on the PCGB Certificate of Authenticity...was free to members, but I think they may have changed the system?
Often interesting...my S2 was built Sept 1990 but not registered until January 1992!! I think they were building for stock prior to moving the line from Neckarsulm to Stuttgart, and of course the banking crash was about then...

 

[g59tester]

I'm still struggling to solve the issue with my wildly inaccurate Odometer.. [47% inaccurate] i've replace the gear with a pink one 20/23 as recommended by Woolies/ Porsche Spares UK. I've checked against a photo of the old gear in place and that seems to be the correct number of teeth. Is been suggested that the issue may be problems with electronics/electrics in the speedo head or at the gearbox. if that were the case surely it would affect the speedo reading which appears to be correct an reads steadily.
Its an early car to have a 180 MPH speedo, i think, or is that a red herring?

Any further thoughts?


Eddie
2007 Cayman S
1987 944 Turbo

 

[944Turbo]

Could it be displaying Kilometres? I do not know where the difference is for a KM odometer - in the speedo itself or the sender. (or how it displays mph and KMs driven)
Tony

 

[Eldavo]

I had a spare 160mph cluster once with 180mph white dial stickers placed over the top.

 

[g59tester]

Guys, I've now come to the conclusion that my 'repaired' odometer has the correct gear wheel fitted but the electronics feeding the Odometer motor are at fault. i've found 2 companies who are familiar with this problem. One in Holland and one in UK. the Dutch one may be fraught with custom difficulties? also I'm awaiting their lead time but they've said they are busy. The other one in UK is on a 12/14 week turn-round time and wont let me book in the speedo head. It must be on their premises to get in the queue. Potentially that means the car off the road for that time ...... I'm keen to stick to the existing speedo reading on the 180MPH version
Anybody got a surplus speedo kicking about.... working or not

Eddie
1987 944 Turbo
2007 Cayman S

 

[944Turbo]

The drive cog on my cab has also failed I have a pink gear wheel to fit - hope mine is less grief! sorry, no spares though.
Tony

 

[g59tester]

Tony, i guess the age of the car is more important than the mileage when it comes to these items. 3 or 4 people in the know have indicated that circuit boards are becoming an issue. As an Electrical Engineer who used to be involved in power capacitors I know these items degrade over time which is a bit of a worry. Power capacitor's life was about 5-7 years!
My car 's gear was just like cork 94 K miles
Eddie