[Supras] Speedometer, AFM

[Dan Gyoba]

On 11 Mar 2008 at 19:06, dgalyardt at cox.net wrote:

> Here are a couple of mundane questions for the group.  1st; I replaced
> my 89s existing speedo with a broken trip-meter with one from an 87,
> swapped out the face plates and needles and installed it.  It now has
> a major non-linearity in it.  (reads slow at low speeds and reads very
> fast at highway speeds; on the order of 7-8 mph fast at 70; crosses
> over about 40).  Both speedo's had the same number of revs/mile at the
> bottom at the bottom of the faceplate.  Any thoughts?

Hey Dave.

Interestingly enough, while I was getting my tach working with the turbo ignition, I found 
that I had the same problem.  The tach works differently from the speedo in main operation, 
however the actual needle itself is the same.

Note that the needles themselves are different for the '87/'88 models than they are in the 
'89+ models.  I think this may have something to do with the problem.  See, the first thing 
that I did for my car was to swap in the whole tach from my '87T donor car into my '89NA 
instrument cluster, but of course, for aesthetics, I put the '89 needle on the face.  By ear, 
I'd gauge redline to have been an indicated 7,500 RPM on my tach, and it'd get there with no 
hint whatsoever of hitting the rev limiter, but it showed idle as being a bit low.

When I put the '89 instrument back in, but with the turbo driver board, the tach is more 
consistent, though it now reads somewhat low.  I hit the rev limiter at an indicated 6,000 
RPM, now.  It seems that the driver board needs some tweaking to work with this tach.

Dan Gyoba
'89 NA 460,208 kms, Turbo swap COMPLETE
http://www.abstractconsulting.com/~dan