Guys - my apologies for sending this on Wednesday to mgs-owner@ rather
than to the list :=((
Charles:
Having two MGA Twin-Cams (one sorta not 'running') and a 2.8 litre V6
(ex-1500) MGA coupe, and having had both a running Twin-Cam and a
Judson-powered 1622 MGA 1600 Mk2 (and several 1500s and 1600s over the
years) I think that I can shed some light onto your question.
1. The 1500 was/is slow compared to the standard 1600 Mk2 (72.5 bhp
versus 86+ bhp). The 1600 was in-between.
2. The horsepower curve for the Twin-Cam is similar to that of the 1622
up to the 1622 power peak (max 86 bhp @ 5500 rpm), although 5 to 10 bhp
higher at any given rpm. The pushrod engines just lose power after that
point, while the Twin-Cam power curve keeps on rising to 6700 rpm (108
bhp). The torque curves are quite different though, since the pushrod
torque peak is at around 3800 rpm (97 lb-ft) while the Twin-Cam peak is
around 5000 rpm (104 lb-ft). And the torque curve shapes also differ,
with the Twin-Cam's being much flatter.
3. The Judson set-up claimed 20 to 25% power improvement (max around
100?? bhp from the 1500/1600 engine). My experience was that, on a 1622,
it probably matched the Twin-Cam power up to the pushrod power peak
around 5500 rpm, but then of course it just ran out of steam. The real
attraction of the Twin-Cam for me is not the extra power, but the large
rev range and the amazingly smooth and quick march up to and over the
redline. Others on the list can tell you how easily the Twin-Cam engine
can shoot past redline!!!
The intake set-up is totally different for the Twin-Ccam than for the
pushrod engines, so the pushrod Judson wouldn't work on the Twin-Cam.
And particularly not with the Twin-Cams 9.9:1 compression ratio!!
4. Vancouver ABFM in May/99: several Twin-Cams AND one or two
Judson-powered pushrod cars.
5. My Twin-Cam will be a road car once I obtain the moderate number of
missing bits which a series of DPOs managed to strip-off or lose. Most
of the remaining parts aren't broken, just worn. The other Twin-Cam
was/is a basket case, with most of the baskets missing!!
Dave Q.
Neuhorst, SK
> From Charles D. Sorkin:
> All this talk about substantial performance gains over the 1500 beg the
>question as to whether or not the intake manifold/carb assembly would have
>been hospitable to the installation of another MGA period accessory, the
>Judson supercharger. How many twin cams are still on the road? I don't recall
>seeing any at shows or for sale ever. <
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