Both Judson and Schorrocks superchargers
worked well on 948cc Sprites when leaded
100RON gasolines were available.
With the exception of racing fuels, the above-mentioned octanes are no longer
available. Thus, a water or water/meth.
delivery system would have to be made
available to get these vane-type blowers
(major heat producers, especially the Judson with it's interference-fit vanes)
to work as well on today's garbage octane unleadeds, without extensive
modification
to the blowers themselves in terms of
upgraded (fabrics) vanes, thermal coatings, etc.
The Judson must be overdriven to nearly
7700 rpm to produce the required 6psi boost curve to the 1275 motor. It's stock
design will not permit this without major premature wear and tear and it's drive
must be modified if the blower is to attain
such rpm's reliably over time, anyway.
The Shorrocks with it's "clearanced" vanes
(less heat - no friction between blade/bore)
can exceed 7000 rpm for short periods and
so is a better bet but even so, on today's
lower unleaded octanes, you can't run a
static compression ratio exceeding 8.0-1
with reasonable ignition timing without
courting detonation unless you're
running an aluminum head/radiator....in
which case you might be able to get away
with it using Citgo 93 or Sunoco 94 prem.
unleadeds.
I have run an overdriven Judson producing the intended 6psi boost curve to a
stock 1275 for a short period using NGK "8" plugs and a Cooper S dizzy set to
give us 28 degrees of total advance at 6,000rpm, using 100% Sunoco CAM2
"purple" (110RON as I recall).
While it didn't last (single belt drive very quickly begins slipping on
smaller-sized blower drive pulley used to overdrive the blower to get the 6 psi
boost curve to the larger 1275 motor) the car went like a
raped ape. Felt like a 2 litre engine under
the bonnet. Tremendous increase in useable torque.
No doubt in my mind the Moss kit will do
the same on today's unleaded premiums
with no detonation/overheating problems
(and no external oil delivery system to screw around with or required, etc.)
Big bucks but it's a better design blower to
begin with (much cooler running design)
and the kit contains everything
you need to simply bolt it on and turn the
key. As long as the motor will give the
required 6psi boost curve....it'll give you the
promised 40% increase in torque...BTDT!! :)
Cap'n Bob
Basic Frog
Cap'n. Bob '60 :{)
|