Diesel de-rating for altitude ??

[VeggieDiesel]

Does anyone know how to de-rate a non-turbo diesel engine for altitude ?
In my case it's a Model 195 Changfa rated at 12.5 HP @ 2200 rpm (at sea level).

Actual operating altitude is 3300 ft.

Do I reduce the HP by  2% for every 1000 ft. above sea level.??

Thanks to anyone who can offer some assistance,
Veggie

[mobile_bob]

figure on a 3% reduction per 1000 ft of elevation
so you are looking at about 10% reduction at 3300 ft elevation.

give or take a bit

bob g

[dieseldave]

  Also,what about Pump Timing at higher altitudes. Should it not be advanced slightly?

[blacksea7]

Leave the timing alone. Injection timing is based on maximum combustion chamber turbulence... Regardless the altitude, max turbulence happens at the same place every time.... The same stands true with forced inductions...

Bill

[blacksea7]

I better add something to this... High speed diesels have an advanced timing mechanism built into the DPA or Jerk pump... Either way leave the timing alone... Slow speed engines could care less about advancing (the combustion chambers weren't exactly state of the art . Think of them as something along the lines of... yeah, this worked pretty good... let's leave it alone! Engineers knew what they had to accomplish but lacked the devices to meter the successes of their trials and errors. Accordingly, it took until the early sixties before technology actually made the words "variable speed" and "diesel" make sense in the same sentence. For what it's worth, Lister's parent had the first diesels onboard ships... the HMS Dreadnaught's electric and standby power was generated by Armstrong Siddeley.... at any rate, high speed engines have the timing advance built into them.

[sodbust]

Agree for the 3% for every 1000 feet.. I also factor the air temps.. Anything over 60f,, I kick off another 2% for every 10f gain in air temp.   IE,, a natural breathing diesel at 100F will have about 8% less power than at 60f.

Did allot of farming in the peak of the summer at night just for that reason.. I could pull a gear faster at dark,, then in the heat in the mid afternoon.  That and the tractor would not overheat!

sodbust