Patrick:
Use the road speed calculator at the Buckeye site to figure out the real
speed vs. measured.
http://www.buckeyetriumphs.org/technical/Calculator/road_speed_vs_engine_speed_calcu.htm
This will at least tell you if the error you are seeing corresponds to the
ratio given by 1000/1120. If so then perhaps this is the right thing. Two
things strike me about your data.
1 - the ratio of 1000/1120 is nothing like 30/50 kph.
2 - I changed from a standard transmission to an A-type O/D unit without
changing the speedometer at all and my reading is perfectly fine.
Are you absolutely sure that your overdrive came from a Triumph? The Laycock
units were fitted to many different cars. Perhaps yours came from a
different machine where the speedometer gearing was setup for a different
differential or tire height.
Cheers,
Mark Hooper
72 TR6
-----Original Message-----
From: Patrick Bitton
To: 6pack; Triumph
Sent: 03/10/02 12:26 AM
Subject: TR-6 Speedometer for OD Tranny
Someone on Ebay is selling a speedometer that claims it's for OD
transmissions. I asked him the difference and he told me that
"Revolutions
are different for the OD compared to the non OD. One is 1000 and the
other
is 1120." Is this true? Do I need to replace my speedometer to get a
right
reading? It seems that when I feel that I am going 50km/h, the reading
is
about 30km/h. Has anyone experienced this while doing this conversion?
Thanks,
Patrick
|