Engine temperature and knock retard

[4600cc]

While experimenting with my megajolt on my ford crown vic, R.I.P. I discovered that a map that works well under light throttle on the highway, does not neceserally works well under WOT on the highway or in stop and go in the city. The problem was the cooling system. Cooling system was ok for stock engine, but that was about the limit of it. After installing and tuning megajolt for 93 octane, improved thermal efficiency resulted in overheating at heavier than normal duty.

It be nice if megajolt would have a fail safe against situations like this. Same as ECC-IV does it. An advance value would be taken from the table, and retarded (or advanced) a number of degrees based on the engine temperature. A real life scalar for such a function from stock 93 cobra ECC-IV computer:

ECT Advance
-256 2
86 3
120 0
200 0
236 -2
246 -4
254 -4

ACT Advance
-256 0
-256 0
-256 0
150 0
240 -6
254 -6


First one is based on engine temp, second one is based on air temp.



Implementing these will probably take the tuning to the next level of complexity. However, it gives us the ability to use these if needed, just as an extra measure of safety.

It is somewhat true that if knock sensing is implemented, then this is not necessary. However, I'd like to see this implemented along with the knock sensing. A user would then be able to enable or disable all three of these features, knock sensing, retard based on air temp, and retard based on coolant temp. Though, when something like this is implemented (I'm hopping), one must consider that existing sensors are also used by another controller (ECC-V, or megasquirt II for example).



AL

[brentp]

That's a great suggestion. I'll have to consider that for a future version- might need to sacrifice some user defined outputs, or go to a bigger processor.

[4600cc]

I suggest a bigger processor. MS2 is perfect as far as price and availability goes.

[Paratime]

I am having a similar problem. Doing 80 or better up hill resulted in a pesky HOT light in about 5 minutes. I tried a new 17x24 4 core radiator, new thermostat, water pump and a 4600 cfm fan. Now it takes 10 minutes. sigh. But at least it cools down a bit faster. the engine holds about 200 degrees cruising, but a long mountain grade will top that up to 240. And the pinging, oh, don't get me started. I'm considering a second 4 core radiator, but will wait until after I fit the SMPFI on this spring. So, I look forward to a temperature related retarding as well. My thought has been programming in an adjustable number of degrees retard taken across the board on the map, for every so many degrees temperature above a programmable value.

[Oliver Sedlacek]

Pinking is related to inlet air temperature, so you should try and route the air intake so that it picks up cooler air. This will also give more power . As long as the oil temp stays within limits and the coolant doesn't boil, you don't really have a problem. Current race engines are running with 310 deg F coolant temperatures at full output.

[Paratime]

True, but they aren't running 310 degree engine temperatures with 10.25 compression on 87 octane gas. In this case, the pinging is a direct result of the head being so freaking hot.

[4600cc]

Something just hit me thought. What about spark plugs? I kept my heat range when I used the advanced map. Maybe I should have dropped a heat range or two, to remove all that extra heat. But in any case, Brent should consider ECT and ACT, as well as Knock Sensing for the up coming new megajolt.

[Ivan]

How soon do you see this happening for knock sensing
I sure can use this, because fine tuning it on the road would
be mutch safer for the engine.
One could program a lot of retard when knocking to get a better feeling on the road.
Am I right on this ?