RE: Choke as an engine brake? (fwd)

["Stegmann, Steve" <Steve.Stegmann@domain.elided>]

Tom,

One problem is fuel shutoff. On a diesel with fuel injection, or a gas
engine with fuel injection (and access to the programming) it is no trick to
shut it completely off.  My Aerostar does this on long downgrades.  With a
carburetor I have no idea how you could shut off the fuel completely.
Shuttting the gas line and waiting for the carb to run dry takes too long.
Anything short of a 10 mile downgrade wouldn't work.

I sort of doubt if the heat riser shuts tight enough to develope enough
pressure to do any good.  It also isn't nearly strong enough.  That's a lot
of force on a 2 inch dia valve.  

Steve

> -----Original Message-----
> From:	Tom Mandera [SMTP:tsm1@domain.elided]
> Sent:	Monday, March 01, 1999 11:45 AM
> To:	Stegmann, Steve; ihc@domain.elided
> Subject:	Re: Choke as an engine brake? (fwd)
> 
> "Stegmann, Steve" wrote:
> > Now, if you shut off the exhaust with a pressure relief valve so you
> don't
> > blow anything up, you can get a bmep much higher than this and get much
> more
> > engine braking.  On a big truck this is called a "Jake Brake".  It is
> the
> > loud noise you sometimes hear big trucks making as they decelerate.  The
> 
> Hmmm... how well do Jacob's brakes work on a gas motor?  I wonder if
> those heat risers could be adapted... (LOL)
> 
> -Tom