Al,
That's probably good advice.  Do you know what other 20B guys are doing?  I only know of Tom Parkes that has actually flown.  I think I have his e-mail address and can ask him about his pulley arrangement. 

Thanks,
Mark


At 07:55 AM 5/7/2004 -0700, you wrote:

 

Subject: [FlyRotary] Re: E-shaft pulley diameters

 

Now this is beginning to make sense to me.  The stock 20B e-shaft pulley is

5.5", and the wp pulley is 4".  I guess Mazda did this in the Cosmo since

it was a luxury car (with an automatic trans) and not subject to as high of

rpms as the RX-7's.  Another probability is that the Cosmo's electrical

demands were greater, and therefore required the alternators to be spun

faster.  I need to find (or build) a 4" multi-V e-shaft pulley, or change

everything to a dual V-type so I can use undersize after-market pulleys.

 

Mark S.

 

I my opinion, using a speed reduction pulley on the alternator may make some sense, because you can get plenty of charging at a lower speed; but I wouldn t slow down the water pump unless I knew I had excess cooling capacity in the system. 

 

Al