Date:         Wed, 14 Oct 1998 08:42:55 -0400
Reply-To:     Bulley-Hewlett & Associates <gmbulley@BULLEY-HEWLETT.COM>
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Bulley-Hewlett & Associates <gmbulley@BULLEY-HEWLETT.COM>
Subject:      Jake brakes, Engine overrun fuel consumtion, was: Wankels
Comments: To: Michael Harrnacker <harrnack@IN-TCH.COM>,
          "vanagon@VANAGON.COM" <vanagon@VANAGON.COM>

>   In the Vanagon It makes sense to use the engine as a brake. <snip>
saves
more fuel then idling.
How?  When your foot is off the gas, the throttle is at idle regardless of
RPM.  Right?
>>>>>>>>>>>>>>>>>>>>>>>>>
I'm too busy to look it up to be positive, but I think what Eric from PA
was alluding to is that certain Bosch Fuel management systems completely
halt ALL injection during motor overrun, to reduce emissions. Right Eric?
 However, I thought that Bosch stopped using this method (no fuel during
overrun) after their MPC injection. So it may or may not be a fuel savings
to use your motor to slow you down when descending mountains. Someone
confirm?
As far as cooling the motor a lot, motor-braking does do that, which can be
handy if she got hot going up the front of the mountain. If you REALLY want
to slow down using the motor, shut off the ignition (leave the key in), and
open the throttle completely. Each Cylinder then takes a mighty gulp of
air, and then has to compress that air quickly (The theory behind the
"Jacobs Brake" on trucks). Do this at your own risk, all disclaimers apply,
you are responsible for your own life, not me, yadda-yadda-yadda.

G. Matthew Bulley
Principal
Bulley-Hewlett & Associates
Communications for Organizational Development
www.bulley-hewlett.com
(888) 468-4880 toll free