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Date: Fri, 12 Nov 2004 06:12:30 -0600
From: msteitle@mail.utexas.edu
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: EWP
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No, the 20B pump and alternator both turn the same direction as the 13B.  I
measured the stock 20B pulleys today.  The eccentric pulley is 13.5cm, the wp
pulley is 9.5cm.  So, it appears that Mazda saw a need to fit the 20B with a
larger diameter water pump, and spin it faster than the 13B.  Maybe to get 1.5
times more flow?  Sounds logical. 

So, the question is, will the 3-rotor running wot for hour after hour cool
adequately with the slower turning 13B pump?  I guess we'll have to wait and
see. Anyone know which wp and pulley sizes Tom Parks is running on his turbo
3-rotor?  

Mark S.  

> Did you account for the fact that the 20B pump might be belted to run in
> the reverse direction than the 13Bs? I can't remember my 20B belt layout
> anymore..wonder if the alternator does too.
> Marc W.
>  
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
> Behalf Of Al Gietzen
> Sent: Wednesday, November 10, 2004 12:13 AM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: EWP
>  
> Subject: [FlyRotary] Re: EWP
>  
> Al, 
> Good data, but for clarification, aren't you running a 13B pump on your
> 20B?  Are you running stock main pulley or an undersized pulley?  The
> 20B pump should flow more gpm due to a slightly larger impeller.  Also,
> comparing a 20B eccentric pulley with a 13B from an 89 n/a engine, the
> 20B pulley is larger, which should also increase flow, up to the point
> of cavitation.
> 
> Mark S.
> Mark;
>  
> Yes, I have a 13B pump housing; I'm not sure what impeller.  All I know
> is Dave Atkins billed it as "high performance".  The pump pulley and the
> e-shaft pulley are the same size, which I believe is 11 - 12 cm.  I
> can't confirm right now because I'd have to take the cowl off to check.
>  
> Al
>  
>