just a simple question that I would like to ask (which I know has been asked before, but I can't find the answer after half an hour of searching.) Doesnt' the M60 produce more boost than the M90? If so, why does it produce less horsepower than the M90. Somebody asked me this question, but I couldn't answer it for them because I don't know for sure either. I would have sworn that the M90 produced less boost than the M60 though..

The M90 produces more boost PER STROKE than the M62. More flow if you prefer. But the M62 is pulley'd to spin faster and keep up with the boost, while lacking in the flow and creating heat. Not as efficient.

The blower difference isn't the only, or primary indicator in the difference between generations. The rest of the engine is quite different, as well.

Yes it does produce more preasure but less volume so less hp.
I belive the overall volumetric efficiency is less too.
I think the m60 puts out 600cfm and m90 puts out 800cfm?

Just for clarity, it'* an M62 and not an M60. Eaton'* naming convention for their superchargers is based on the displacement of the rotors per revolution. In this case the two compare as follows;

M62 = 62 cubic inches/revolution or 1 litre/revolution

M90 = 90 cubic inches/revolution or 1.5 litres/revolution

You can find more details on Eaton'* web site;

http://www.automotive.eaton.com/prod...argers/M62.asp

http://www.automotive.eaton.com/prod...argers/M90.asp

It'* not necessarily an indication of efficiency when looking at boost in PSI terms. If you have a small supercharger pulley on a car with a restrictive exhaust you will get boost stack. This occurs because the volumetric efficiency of the engine is not sufficient to injest the output of the supercharger and therefore the pressure builds.

The opposite of the above occurs when headers are installed. Since the flow will be improved, therefore achieving better volumetric efficiency, then the boost will drop in pressure.

Hope this helps.

Cheers,

Some specs in Techinfo, Specifications on this.