I have been away for a little while and just cam across this thread....

Have you honestly done the calculations on these superchargers .?

The displacement and inefficiency's of the Amr 500 work against it on the A12,they require over 3hp to drive at the 6000 rpm ,Have you considered those forces will be working on your shear pin and also the pitch of the thread ,one backfire will sort that out quick smart at least a serpentine belt will allow some slip

At a ratio of 2:1 the Amr is spinning at 12,000 rpm ,at that rpm depending on the fuel you use You are on the cuff of flow Vs heat....making them work harder will cause the coating to fail on the rotor's and spinning them hard will lead to them exploding past there designed max rpm.

Then consider this they are a positive displacement supercharger like Turbo's they can be pushed Harder ,but it doesn't mean the gains are there to be had as heat will force reduced timing to avoid detonation to the point were output is lower than using lower levels of boost, Amr500 will produce higher intake temps than a Turbo at the same given boost level that's why they have efficiency maps !



At a ratio of 2:1 the Amr 500 displaces 1 ltr which is .035 CFM , so at .035x6,000 rpm the charger displaces 210 Cfm at motors peak rpm range ,A12 requires 123 Cfm (max) at 6,000 rpm that's just 87 cfm @6000 rpm above whats needed Na, 14.5 Cfm per 1000 rpm that has the potential to add 21.75hp to the out put over stock, a more efficient head like h89 will drop that figure considerably meaning the real life gains will change as you reach peak port choke velocity and other mechanical losses of different heads and inlets.


Assuming 7psi is used on 9:0 .1 compression that will give a dynamic compression of 10.93:1 that's around 4% gain... 4% nearly 3hp (2.70) at 6,000 rpm would be drained by the hp to turn the amr at it's ratio.....

The A series motor will never be the restriction in these setups and will handle any boost these chargers can throw at them but not the superheated air associated with it or there small displacement

Same can be done with sc12 or sc14 on A12 where there displacement has a more positive effect to hp

Cheers Anthony