Portofino
Well-Known Member
I'm afraid it's not that simple, P.
IIRC one of the lessons that the esteemed professor LS1 (aka diesel engine bible) teached to all of us, is that it's indeed possible to overload an engine also below its rated rpm.
In fact, by putting the throttles at say 75%, what you are doing is demanding the engines to reach a certain RPM, regardless of the load necessary to reach it.
So, in case of abnormal conditions (fouled hull/props, overloaded boat, too long props, you name it), the engine might actually run at 100% load also below its max rpm, because it takes a higher than normal load to reach the RPM which you are demanding with the throttle position.
In the worst case, when the engine can't reach the RPM you are demanding (even if the throttles are not yet at WOT), it actually keeps trying, hence running in a constantly overloaded condition, with the EGT skyrocketing and all the nasty consequences that this implies. :ambivalence:
That said, back to your first statement:
I sympathize with your view, since I also don't have EGT on my mechanical engines.
The very simple reason why EGT only became popular with the advent of electronically controlled engines is that, together with several other parameters, it became an input for the ECU, which in turn feeds the engine accordingly.
So, showing also those parameters on a display came with the territory, so to speak.
But one thing I found out which is worth considering, is that the very same engines that I've got on my boat were also installed in some fast patrol boats. And in those installations, EGT probes and gauges were indeed fitted.
Now, it's obvious that in military applications the risk of overstressing the engines is higher than in pleasure boats.
Otoh, that puts in perspective the view that EGT couldn't be so relevant just because it wasn't fitted, I reckon...
We are on the same page :encouragement:
Additionally a lot of American truckers seem to fit them and watch them dragging heavy loads uphill , stuff like Mack , White et al with base CAT and Cummins engines .
Your EU trucks n busses are lighter , smaller and esp buses work the Rev range via the gearbox a lot of tick over etc .
This boat thing is like running up hill in top gear all day long , with a weight or fouled props .
Also perhaps of VP conquest sales are really a bit naughty in the sense they know there hardly any headroom HP wise like the FL GTO 63 as a prime example so VP will err on the side of treating the punter (s) like a mushroom to clinch the deal .
Yo see strikes me VP can fart about ( electronically ) with IPS and joysticks etc but hold back on EGT role out ? why ??
So they have made a conscious decision it’s not like it’s all beyond them tech wise .
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