Miata Mailing List: September 1994, Message #83
sponsored by



     


   From: BILL.ALLEN@metrokc.gov
Subject: Turbochargers/Superchargers
   Date: Tue, 6 Sep 1994 13:33:48 -0400

Al, I was wondering how you were going to respond to this request, with your
commercial interest.  As they say in some parts of East Texas, "good on you!" 
I really appreciate your being on the net, as you provide a lot of solid and
unique information!
I can't comment on the Bell Engineering turbocharger unit, as I have no
experience with it. But I and four others in the Puget Sound area have and
enjoy Downing/Atlanta/Eaton/Sebring supercharger units.  The drivability is as
advertized, very linear and transparant over its range.  You don't hear the
compressor whine 'till you get up to about 4-5 psi boost.  While I haven't done
any performance measurements, my observation is that it's very similar to that
described by Herb Samuels for the BBR unit.
Around 10% of the Sebring units have had problems with the fuel pressure
regulator, which is, ironically, manufactured by competitor, Bell Engineering. 
I have enjoyed this problem :-(  The symptoms are whistling or occasional 
surge on acceleration.  I'm on my second Bell FPR!  Norm Garrett is just
finishing up testing an alternate regulator made by an international
manufacturer.  He also should now be ready to ship superchargers for "94
Miatas, as he was observed testing one several months ago.  
The Sebring unit has also had random problems with the support bracket and
multi-groove belt drive - bolt and bracket breakage and belt-wander.  I have
the belt-wander situation.  Sebring is about to send out notice cards to all
their customers offering a redesigned support and drive configuration.  
We only have 92 octane fuel in the Northwest.  I've been running with an 8
degree BTDC setting (6 degrees is recommended with 92 octane), and have had no
detonation.  We'll see how I do going to Gold Rush, where altitude and
temperatures may be more trying.  
Would I do it again?  I'll tell you after I get the replacement pressure
regulator and drive configuration.  There's not a lot to tinker with on the
Miata, so it's kind of fun dinking around with this rig :-)
Bill Allen