Hi Guys,
This is a case of comparing apples and oranges. The rolling radius of the
tires have to be taken into account.
A 4.40x19 tire is MUCH larger than the 5.50x15 tire. Hence a lower
numerical rearend ratio will give more MPH per 1000 RPM. Taller tires with
a common ratio will give the same effect.
To wit:
A TA with the standard rear end ratio gives 16.67 mph per 1000 rpm with a
top speed of 80 (approx) mph
The TD with the standard rear ratio gives 14.4 mph per 1000 rpm and a top of
77-83 mph (88 for the Mk 2). The enhanced top speed is because of the rev
capability of the XPAG versus the old 1292 engine.
The MGA ratio will make the TD tolerable on the highway, with the cost of
slightly less acceleration. This can be offset by a little special tuning.
Enjoy!
Safety Fast!!
Ray
PS- Anyone going to Abingdon for the 75th MG Birthday Party next month??
----- Original Message -----
From: <TATERRY@aol.com>
To: <JVK52TD@aol.com>; <lpalmer@vanstar.com>; <BobMGT@aol.com>;
<mg-t@autox.team.net>
Cc: <mgs@autox.team.net>
Sent: Sunday, August 22, 1999 11:29 PM
Subject: Re: Changing Rear End Ratio in a TD
> In a message dated 8/22/99 7:06:08 PM Pacific Daylight Time,
JVK52TD@aol.com
> writes:
>
> <<
> I have been following the thread on the changing of the "T" rear end.
How
> fast are you driving with this change ?? I have had trouble with the
engine
> not standing up to 65-70 mph speeds with the 4.3, even though it will go
> much
> faster than that !!! I am at 5000 when I am @ 65 & 5500 @ 70.. Do not
know
> how accurate my tach is.... >>
>
> With my 4.55/1 diff ratio, I turn 3500 rpm at 60mph.....but that is a TA
with
> 19" wheels....
> Terry
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