Speedo constant (w=?) question

[Guest Anonymous]

I have a '74 tii that has been modified with the E21 overdrive 5-speed and a 3.91 LSD.

Shouldn't my speedo be more accurate if it was the one from a 1976 (which CAME with a 3.91, vs. the 3.64 in the '74)?

Walloth u. Nesch having these on sale has me thinking.

What is "w" for 3.64 vs. 3.91?

TIA,

John in VA

[Guest Anonymous]

maybe it's "dWiveshaft Wevolutions" (hee hee)

but yeah, the '76 speedo should make your speedo just about right. Depending on your tires and wheels, of course...

hth,

t

[Guest Anonymous]

3.64 will be W=1.29 or so. The 3.91 needs ~W=1.38.

Just tell Albrecht u. Alexander you want a speedo for the 3.90-

3.91 diff and they will fix you up. Watch for that shipping charge,

though.

Chris B.

'73 ex-Malaga

[Guest Anonymous]

when Bill Arnold built my A4, he did the math and put in a 4.10 speedo from a 1600 for the, Getrag 245 5 speed OD, 3.90 diff and the 15 inch wheels with 50 sidewall height. My actual read-out speed is very accurate from this modification. Of course, a 3.90 speedo would be great- but, in my experience,they are very hard to find:harder to find than an old 1600 speedo- and you dont have the confusion factor going for you when someone looks at your cluster and shakes his head and tells you that you blew it and put the wrong speedo in your dash, lol. It is fun to tell them the reasoning, etc. Plus: i like the retro look of that gauge. Just thought this might help the growing crowd of 5 speed OD conversion running 3.90 diffs( my favotite combo- 3.64 was not "peppy" enough off the line). I do miss the long leg of that final gear though- if you have enough engine to pull it up, you can really go fast in 5th. But, Now I have 3.90 in both 02s and will stay with them. The 4.10 in the M3(325ic) is really fun in the city. That is a nice diff.

[Guest Anonymous]

but S/H is more than the speedo cost!!

Anyone making a purchase and care to consolidate orders?

[Guest Anonymous]

(nt)