[qqqqqq666]

Hi all!

I've had this problem for a while now. I have an Ascona 16 and its original differential was damage a while ago, so I installed one from an Ascona 12. The thing is that now I have greater acceleration but lower top speed. What bothers me though, is that the faster I go the bigger the error of the speedometer is. (eg. I go 80 km/h and it shows 120 (figures are just for the example)) What can I do? A thing that might be helpful is that the speedometer installed is W=655 and in my parents' basement I have a couple with W=743. Will they do any good?

Thanks!!

 

[GTJIM (R.I.P.)]

W-number

I think the "W" number on a speedo refers to the number of times the speedo cable rotates for each kilometre travelled. So a W-743 Speedo will help your problem as with the lower diff ratio your cable is doing more revs per kilometre. Try and find an Ascona with a 1.2 litre engine and see what "W" number is on its speedo face - if it is not 743 then you may need to change the speedo drive gear in the gearbox tailshaft. It is worth trying the W-743 speedo you have to see if that does move things in the correct direction.

 

[tekenaar]

Rear axle ratio and transmission speedo driven gear

I think the "W" number on a speedo refers to the number of times the speedo cable rotates for each kilometre travelled. So a W-743 Speedo will help your problem as with the lower diff ratio your cable is doing more revs per kilometre. Try and find an Ascona with a 1.2 litre engine and see what "W" number is on its speedo face - if it is not 743 then you may need to change the speedo drive gear in the gearbox tailshaft. It is worth trying the W-743 speedo you have to see if that does move things in the correct direction.

Don't believe that just changing speedometer will help anything. The "W" markings are just to let you know what "Wegdrehzahl" number they used to reflect one KM/MI driven (which GTJIM said), which is determined by axle ratio, tire size and driven gear on the transmission output shaft.

If you change the rear axle ratio, you must change the transmission output shaft driven gear (plastic, changeable) to arrive at the correct speedo reading again.

 

[GTJIM (R.I.P.)]

Why?

Otto, Why do some speedos have different "W" numbers then - and what is the effect of using one with a different W number without changing the plastic gear, diff ratio or anything else? This is one of the Opel mysteries that I would like to come to grips with due to my non-standard diff ratio of 3.9:1

 

[baz]

did they do a 1200 ascona jim? if so it must be a real rare beast (pun intended)
but qqqqqq 666 (and the number of the beast shall be 666) you may find a chevette or viva or kadett to get the drive gear otto is talking about ,the 1.1 , 1.2 and 1256 will be quite close and i think the same size to go in

 

[GTJIM (R.I.P.)]

As I Understand It

I have a sneaking suspicion that Opel made an Ascona with a Cam-In-Head 1.2 litre as I have seen several mentions of such a beast made by Euro members on Opel Tuners Forums. I may be completely out in left field here but that is the impression that I have.

 

[kwilford]

"W" in Speedo

Read this thread:

http://www.opelgt.com/forums/showthread.php?t=2919

HTH

 

[qqqqqq666]

So, correct me if I am wrong (it's rather early in the morning here!) changing the speedo by itself won't do a thing as the cable would have the same gear on the other end. What kind of gear should i find then? Oh, and I have a second Ascona for its parts. It is a 1200. So it will have the gear I need, right?

(FYI: there are lots of 1200 cc Asconas here in Greece mainly, I believe, because they were cheaper at the time. In fact I havent seen a 1600 Ascona for a long time (besides mine ) and in my whole life I have just seen 2 Ascona 19!!!)