Perhaps the following will explain why an MGA Twin Cam can
sometimes beat a Jaguar on the track.
Blake
The following quote is from "MGA 1500, 1600, Twin Cam" by F.
Wilson McComb, copy right 1983 by Osprey Publishing Limited. If
you have the book it can be found on pages 73-76.
"Let us park and MGA Twin CAm side-by-side with a Jaguar XK120 on
an empty road. Both are production two-seater sports cars. The
MG weighs about 26 percent less than the Jaguar, but the Jag is
powered by a 3442 cc six-clyinder engine-well over twice the
capacity of the MG's 1588 cc four-cylinder. Now stand back, drop
and imaginary starting flag, and see what happens.
"Up to 30 mph the MG will be almost a second ahead, and, as you
might expect, because of its lighter weight, it is still leading
at 40. At 50 mph, the MG is momentarily checked by a change into
third gear while the Jaguar is still accelerating hard in second,
but at 60 mph it's the Jaguar's turn to change up. Notice with
some surprise that at this stage the MG is still almost
half-a-second ahead.
Now both cars are in third gear, the Jaguar driver (beginning to
go a little pink in the face, perhaps?) is still unable to catch
the MG at 70. He is even more embarrassed to find the Abingdon
product STILL holding him off at 80 mph. But then, as the MG man
changes into top while the Jaguar has another 7 mph to go in
third gear, the big six at last gets past the four-cylinder car
to open out a 1.1 second gap between them at 90. After 40.3 sec,
the MG is travelling at exactly 100 mph, whereas the Jaguar is
just getting close to 110.
"Finally, with both cars travelling flat out, the Jaguar is just
about touching the the 120 mph which gave the car its type
number. The MG (for which some folk claim the same top speed) is
dropping back, some 3 or 4 mph slower at the top end. If,
however, conditions change and repeated brake applications are
called for because of corners or slower cars in the way, the
Jaguar man is very soon in trouble with his notoriously
inadequate drum brakes. The MG driver smiles with quiet
satisfaction, unconcerned by thoughts of overheating and sudden
lining fade as he uses his all-round disc brakes to the full.
"Substitute an ASton Martin DB2 (2580 cc, six cylinders, dohc)
for the Jaguar and the result will be quite similar. The Aston
will remain behind the MG for almost a quarter mile, then pull
ahead to reach 100 mph some 5 sec before its rival-but whit the
interesting difference that in THIS imaginary contest the Aston
Martin runs out of steam at 110 mph, so the MG edges past it
again to draw gradually ahead, with just sufficient advantage in
top speed to keep it there. And the ASton like the Jaguar, has
drum brakes..."
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