A discussion on EGT and Exhaust back pressure on an OM606
A discussion on EGT and Exhaust back pressure on an OM606
Yes, we need intake manifold pressure, intake manifold temperature, volumetric efficiency and engine displacement to figure out airmass in the cylinder.
For a 606 that's 499cc per cylinder. Volumetric efficiency is a bit of a guesswork, I would say 90% since it's a 4 valve head. So it's 449 cc of air.
1.5 bar boost gauge pressure (2.5 bar absolute), and assuming 40*C intake temperature (~100*F) intake density is 2.78kg/m3.
That works out to 1251mg of air in the cylinder. If you are maxed out on the 6mm pump that's around 90mm3/stroke, x0.832kg/liter diesel fuel density = ~75mg of fuel. 1251/75=16.7:1 AFR. IMO too rich for sustained running, aim for about 18:1 for a safe tune for sustained full power.
Raising the boost to ~1.7 bar, if the turbo can handle it, assuming charge air temp's don't go up will get you to 18:1 AFR. You could also reduce fueling to ~84cc.
Note that this is a bit of guesswork since we don't know exact volumetric efficiency nor the intake temperature. For best accuracy we need a wideband AFR. But tuning for safe EGT's works too. Note that since you have a 6mm pump at those fueling rates the injection time is long -> end of injection time is late -> high EGT for a given AFR.