Imported from years of club emails (sent round Graeme Oxley's Stag Forum email list). Names, dates and details may be incomplete or wrong. If you spot a mistake, please let us know and we'll fix it. Got old Stag emails, from before 2017 or on a subject that isn't here yet? Forward them to mail@triumphstag.info and we'll add them to the archive.
What I am putting to the Forum is the pros and cons of fitting a 3.45 diff to an auto Stag. We will look forward to your feed back.
I have a 3.45 diff ready to fit to our manual Stag when the time comes.
Look forward to your responses.
Chris S.:
Just a quick observation but if you drop the revs at cruising speed, the
torque curve is not really falling, if anything it will rise.
Lowering revs will give a more relaxed feel, and save fuel.
Just my 2c
Dave M.:
Roger, Graeme,
It depends what you're looking for.
The 3.7 ratio fitted to auto Stags puts your engine RPM at and near peak
torque when driving at 100 -120 kph (around 3000 rpm) This makes for a very
responsive car at highway cruise. The 3.42 will drop your revs by 7.5%, a
little over 200rpm at cruise. This won't make a lot of difference to the
sensation that the engine is spinning too fast.
However, dropping you down the torque curve, coupled with the taller
gearing, would, for me, make too much difference to the highway
responsiveness to contemplate doing.
It will also manifest as reduced responsiveness and acceleration around
town, one of the delights of the Stag.
Remember, the Stag V8 is designed to rev, not slug along.
I'm not against taller diffs per se - I used to drive a 5 litre V8
Commodore SL/E that ran a (factory fit) 2.60 diff, but that could handle
such a low ratio with ease, as peak torque for that motor was high, and at
a lower rpm.
