Tom, the AMR is a straight lobe design, which is good for long term durability, but has a couple issues. The useful operating range is narrower because it can get into reheating at lower pumping speeds. Toyota, and others, used electric clutching or electric intake cutoff to stay out of that, on production cars and vans.
Heres proof I can really mess this up! Long story, but food for thought.
That reheating issue was a problem for the M62 based blower on our 3.0 V6, 5-speed manual, Pace Cars...one day in March many years ago. It was Press Day for the Long Beach Grand Prix and we had our pro drivers giving Press rides with those two cars. This blower system ran the little "vacuum operated bypass closing system" I had developed. Its primary purpose was to momentarily pull back boost at wide-open-throttle upshifts on auto trans models.
In that application, it worked fine. Using a vacuum storage canister and a solenoid vacuum control valve, I pulled the boost back for about 800-850 milliseconds durng each upshift (to protect the clutch packs during engagement). On both M/t and A/T models, I also had "bypass shut off" engage just before the 6800rpm rev limit, because knock detection (in those years) stopped at 6200rpm on 6-cylinder engines. When the power sagged, the average driver would upshift as a matter of course.
I had experienced some broken knock sensors (which can occur at very high rpm detonation), but I didnt know what I was doing back then (still dont). Now....there were two knock sensors on the engine; one for each bank.
So, on with that day in March, 2000. We had Rocky Jr and Juan Paul driving the two fast pace cars, giving rides to press, politicians, and VIPs. Montoya was getting faster and faster. I was in the pit area, working on various little "typical stuff" that pops up when you have 20 or so amateur drivers bumping into each other on a track, while fast movers are passing them right and left.
Suddenly, here's Montoya in my stall...."Jeem! Jeem! I have this yellow light and no power until 6200 RPM, then BIG power!". It had broken a knock sensor on one cylinder bank. We decided (mistakenly) that I could splice the remaining knock sensor into both channels, so we could keep giving rides. Shortly after I got him back on the track, here came Rocky with the same problem.
So...now I'm ready. Plug in the scantool, see which sensor broke, dive under the dash, splice the wires, clear the code, send him back on the track in about 10 minutes. Man, I saved the day.
One lap later, they are towing in Montoyas car with oil and parts dribbling out the bottom of the block. We get the car tarped, I walk back to the pit straight, just in time to watch Rocky go by. I saw the blue smoke and orange flash under the front of the car before I heard the bang.
So, that is how you can go from "great" to "goat" with just a scantool, a pair of wire cutters, and your own wits!
So...that reheating issue, as you see, must be prevented. We were only running these things at 8-9 psi and they would drop to about 3 during bypass pull off. I think that problem might have been avoided if I would have understood why the declutch or blower intake "full cut" mechanisms were developed.
You'll also be heading into a difficult area with a near-matching displacement 2-lobe rotor against a single cylinder. The potential for very heavy pulsing in the intake tract worries me, at least in the low-midrange that you must pass through during various points of acceleration. Twisted rotors really help, in that respect.
That pulsing has me worried for my project, because it plays Hobb with MAP sensors and intercoolers. I saw broken up intercoolers during early development of a small V-8 supercharger kit (M90 blower rotor package). The intercooler was too close to the rotors. The engines ate a lot of aluminum bits and water a few times.
I plan to run the largest bypass I can, but the first few gears will be risky because of more time spent in that transition area where some recirculation might occur (like trying to control wheel spin).
I can certainly see the flow advantages of turbo type impellers, but the maps are pretty skinny when you mechanically drive them. Its also very difficult to run much turbo on a four-stroke single, from what I have seen. We both have a steep hill to climb, and we get a little winded at this age.
JimL
