Timing and fuel tables

[Manjot12dosanjh]

How would you figure out what to set you timing and fuel tables when de mandating isx 870

[Bengy88]

I think there has been tables posted on the forum in one place or another that may help you. I can’t seem to find them though

[Rawze]

(05-09-2023 )Manjot12dosanjh Wrote:  How would you figure out what to set you timing and fuel tables when de mandating isx 870

The bigger question is for what engine operating mode are you referring to?.

Engine overload operating mode>?.. engine cranking mode?.. engine warmup mode?. low altitude mode?... High altitude mode?.... extreme altitude operating mode?.. etc.etc..etc.

Each of these operating modes are uniquely separate engine mode control states, and require all their own adjustments individually.

There is no 'Off switch" for this kind of stuff. There is no simple or single/master settings for de-mandating one properly ... The engine computer is not nearly that smart.

It ls like someone handing you a road atlas after you ask them how to get to Portland from Miami ... and then you don't like the idea of having to individually figure out what exact roads to take .. so instead, you ask them ... so where is the teleporter again?... surely it can't be that complex .. there has to be a simpler way to drive in my car to Portland ..... right?,. Isn't there at least just one single highway that takes me right there?/... like an ignorant fool.


And then, there is the matter of ... if there is any EGR gas introduced into he intake (for each engine mode being used), and at what percentage of clean vs. dirty air, etc. - Then, even without EGR (you did say for a de-mandated engine), there is still the matter of what injection timing offsets vs. the set fuel-air-mix, oxygen fuel control, and intake boost pressure, at what RPM and what power being produced at any given point on each of those individual operating mode maps that might still be used.

- That is how you calculate fuel air mix... and for each active engine operating mode individually that is being used.

- So... simplified questions like these points heavily towards someone not likely knowing how the engine, or its programming even actually works as whole... and that is very dangerous. That engine is not some clunky dinosaur from the 1970's.. it is a delicate flower that needs very specialized care and handling .. otherwise its life-span gets shortened real fast.

It is designed with much higher than normal compression ratios + shortened connecting rods that, on their own, would mechanically eat the engine apart in a hurry. Mechanically, it has a lot of excessive internal friction, several horsepower worth, it is enough to distort the liners, and eat them right out of the engine block, fretting liners and blowing head gaskets. It is high enough to distort and crack pistons under high operating loads. etc.. and that engine computer IS THE ONLY THING keeping all of this otherwise self-destructive design at bay.

That engine computer is the only thing keeping all of it in check.

Sounds like a lot, but I am not trying to discourage anyone reading this. It is not any kind of 'secret sauce' and some people would claim. It is just the reality of how things are, as there is no simple solution or answers to questions like this.

Answers to questions like this takes at least a basic understanding of the engines internal design characteristics, and how it operates in some detail. Otherwise, there would not be so many of the 90%+ bad delete programs running around out there, internally destroying people's engines into an agonizing death.

- If someone wants to learn how the engine and its programming actually works as a whole ... then you need to join my mumble chat server where questions like this can be explained and are covered properly.

my mumble server: http://rawze.com/forums/showthread.php?t...63#pid2163