But Ben,
  Wouldn't the compression release braking be more effective in a lower
gear?

Larry A.

On Sat, Sep 14, 2013 at 1:55 PM, Ben <syncro@gmail.com> wrote:

> On Sep 14, 2013, at 8:37 AM, Don Hanson <dhanson928@GMAIL.COM> wrote:
>
> > That is why we encounter very slow trucks on the downhills
> > as well as the climbs....They've shifted to a low enough to hold their
> > trucks from gaining speed...and thereby they can control the heat they
> > create with their brakes.....
>
>
> If this statement is about very large trucks such as diesel rigs, this
> would be less than an accurate statement. Excerpt taken for Wikipedia which
> is accurate enough for this discussion.
>
> "Diesel engines do not have engine braking in the above sense. Unlike
> petrol (gasoline) engines, diesel engines vary fuel flow to control power
> rather than throttling air intake and maintaining a constant fuel ratio as
> petrol engines do. As they do not maintain a throttle vacuum, they are not
> subjected to the same engine braking effects."
>
> So, NO. Those trucks are not downshifting to slow down. They are using
> alternative mechanisms such as jake brakes. Ever notice that the diesel in
> your Vanagon & other VW's have an auxiliary pump to create vacuum for your
> brake booster? Same deal.
>
>
>
> BenT
>