My 1330cc S/C Mini runs around 9.0:1 compression. And maxes at around 7psi (although usually doesn't see that, usually around 5psi on hard take offs. So much torque theres no need to ring it out beyond 6000 rpm)

I use an SC12 'charger from a Corolla. It runs around 1200ccs per revolution as oppoised to a tiny 300 or 500.

It's fun to drive, very grunty, great up and around hills (I live in a hilly area) with all that bottom end power. But can be a bit unreliable. I've broken an idler gear, and taken a lot of my gearbox with it. The car can easily overheat if the cooling system is not 100%. Burns a fair bit of oil these days, only done about 12,000kms supercharged. Also crankcase breatheing is a big issue, the motor just cant seem to get enough breathing.

And I think I'll need to move to better valves and valve guides sooner or later.

But that's no big deal, I've got a more powerful and much smoother Mini on the build.

_________________
1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

my 1360cc s/c Mini runs around 8.0:1 compression, it spikes to about 6psi currently.

like slinkey i am using an SC-12 from a toyota MR2, a bloke in SA makes kits to fit them to minis, "92" on here.

there are many threads about this kit on ausmini if you do a little digging.

you should ask ben "92" about it, otherwise LINK in victoria also sell a supercharger kit.

Having said all of that... I guess there lies the answer! Fit an intercooled turbo setup instead

Pete.

_________________

Click here for the Turbo Conversion Thread!

There's always water/methanol injection etc.

But if it's pinging and detonating on 98 octane fuel, try adjusting your ignition timing, reduce the advance a bit. Ok you'll probably lose some power, but the boost will more than make up for it. And the bottom end torque, due to the instant boost from the supercharger will make it a lot of fun to drive anyways, shouldn't ping or detonated under low boost anyways.

_________________
1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

9.5:1 might not be too high a comp. ratio due to the higher octane rating of the LPG.
Cam would be the thing I would worry about more, as mentioned previously.

I say give it a go. get a SC12 and a kit from 92 and have a play with it. If it doesn't run well take it off and sell it. you will be no worse off than you are now.

_________________
-James.

Toyota 4EFTE Powered Minivan.
102 Kw @ The Front Wheels....Oh What a Feeling!