QSC ECU remapping

[Luke Nelson]

Hi Guys,
I have had a few thoughts and I require some more grey matter.. So in regards to engine life and what could be possible. At present I am happy and I get to a maximum of 75% load at wot.

Looking at some of the other posts I noticed that the newer QSC rev out to 3000rpm and mine being older do 2600. Reading into it the higher rev model would have less engine load per rpm ? 2600- 540hp to 550 hp -3000rpm.

So could I change my engines to 3000rpm with a ecu remap? Or is there some mechanical changes as well. I haven’t even looked or thought about props and shafts..

Looking at the engine life charts and articles they all seem to run lower rpm. So what would be seen to be the longest life engine of the 2 above?

If you drove around at say 16 knots at present that gives 55% load. If it is possible and everything worked out and I drove the same rpm got the same speed but got 70% load but also got another 400rpm of wot. Would this be worse for the engine as it has more load?

I know its a bit out there but you have to ask some times.

Thanks Luke

Topic

[Tony Athens]

Luke,

You are looking at this totally wrong, besides making it more complex that it needs to be.

1) Think of the “insides” of your engine as the same as all of the QSC versions as to what REALLY matters.

2) Put the term “Load % ” out of your vocabulary for this discussion , as in the real scheme of things, and for what you are trying to sort out in your mind, it’s just about totally meaningless

3) Only think GPH at the various RPM’s if you want to think REAL ENGINE LOADING.. For every 1 GPH your engine burns, your pistons, rods, valves, and crankshaft are trying to deliver about about 19-20 HP to your prop.

4) Next, look at few of the various prop curves on the QSC’s, or any of the Cummins engines.. From that you can “see” where Cummins would like to have the engine at “GPH wise” as various RPM’s when cruising around. Notice how none one curve mentions “LOAD”.

5) Now put all that together and hopefully you will come up with an answer to your questions and what I want you to understand… But in a nut shell, the higher the RPM is in relation to the fuel your engine using in GPH, the lighter the LOAD is on all of those things INSIDE moving around in side the engine along the thermal stressing of all those components..

Or maybe this is easier—think more RPM is GOOD, vs “lugging the engine” to make the HP needed to meet your needs for speed. Why? Because you are pumping more oil to the bearings, wear surfaces, to thru the piston cooling nozzles, more thru the oil cooler, pumping more coolant, and your EGT will be noticeably cooler thru out the manifold & turbo……….

Tony

[Author]

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