John,
It is very interesting to hear of your differential. I have a 4.1 which seems
to have been more scarce (in the US) than I had been lead to expect. I
deduce this by the TOTAL unavailability of the proper speedometer for the 4.1!
What calibration number appears on your speedometer? (I assume that the
gearing inside is represented on the dial; a big assumption) And, is
your ODOMETER accurate? I had to get an MGB speedo guts to use in my
Jeager case. It is the closest I could find (1280). The one I really
need is a 1312 (to be correct for the original tires), but with my current
185/70's I really need a 1344 caibration. The calibration number appears on
the dial just above the "MPH" lettering. Common TR (pre-6)numbers are 1152,
1184,
1280, 1312. The TR6's had many different numbers, commonly LESS than the
earlier TRs. My guess is that you would need 1332 to 1370, and the closest
"standard" calibrations would be: 1344 to 1376.
The calibration theory is described in my Speedo repair manual on my web page.
http://ourworld.compuserve.com/homepages/arhodes
As for the lower gearing, I find it only annoying. I do have OD and
that helps significantly. I also have a very low first gear (racing gear set),
and I am out of first before I get the clutch all out! It is so low, that I
am SLOWER off the line since I do not rev the engine up to redline prior to the
next shift. Overall, I think that the designers of the original cars made
some very sensible gearing and cam choices (for my desires), and I really
don't value the changes. I do not like winding these engines out, the way I
do on my little honda engines (Like the new honda which comes on the cam
at about 6000 rpm! (which I don't have)).
-Tony
Message text written by INTERNET:triumphs-owner@autox.team.net
>Date: Thu, 04 Mar 1999 00:49:18 -0800
From: John Cowan <jfcowan@earthlink.net>
Subject: TR-4A - 4.28 rear end; what gives?
I measured the ratio of the differential on my '66 solid axle TR-4A
several times and it fell between 4.26 and 4.28 to 1. This result was
unexptected, but is borne out by the fact that the car revs up and tops out
especially quickly. I've heard rumor of a special 4.3 to 1 rear end, which
if accurate could explain what I have (the disrepancy being experimental
error, although I was pretty careful).
Is there a 4.27 or 4.3 to 1 differential available? If so, it would
seem suitable for Autocross. Would it also be suitable for road racing?
Thanks.
John Cowan
<
|