[Vwdiesel] Add just turbo to NA?

[pmdolan at sasktel.net]

There is more to it when considering EGTs and turbocharging:  The 
increased mass of air entering the combustion chamber COOLS the whole 
process, whereas adding fuel INCREASES temps.  Not easy to see in a 
car, but if you have a truck handy, run it up a big hill heavily loaded 
and watch the EGT at a constant speed in the highest gear you can use 
to sustain speed.  Then, drop one gear and watch the EGT drop like a 
brick as you maintain the same speed (i.e., use the same amount of 
energy & fuel).  It is both the engine RPM and turbo working in a more 
efficient part of its map that throw a LOT more air into the same fuel, 
resulting in dramatically LOWER EGTs for a "leaner" mixture. 

Maybe that will help some of us to appreciate while a dedicated diesel 
head is disgusted in so many ways by seeing black smoke coming out of a 
stack. 

Further comment:: the valves, pistons and heads on an NA really are NOT 
very robust.  That is why we have cracked cylinder heads, and why you 
really need oil cooling jets to prevent the pistons from melting down 
when the power gets much over 70HP or so. 

On Sun, 1 Apr 2012 08:43:17 -0700, "Andrew .Libby" 
<libbybapa at gmail.com> wrote:
A "leaner" burn on a diesel does not increase EGTs.  That is gasser
> thinking.  Increasing the fuel for a given amount of air increases EGTs in
> the functional range of fueling for these engines.  Decreasing the fuel to
> air decreases the temps (this includes increasing the air side of the
> ratio). 
>
>
> On Sun, Apr 1, 2012 at 8:11 AM, Val Christian <val at mongo.mongobird.com>wrote:
>
> >
> > A "leaner" burn will raise the temps, but is unlikely to cause a problem,
> > as the valves, cylinderhead and pistons tend to be fairly robust, and
> > they are far from marginal in the NA engine. 
> >
> >
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