What makes an Economy tune?

[907DAVE]

Originally Posted by Power Hungry

You'll find something that's going to work for you. Things that have always helped me with economy:

Shifting (lower the shift points)
ICP (up 5% to 15%)
SOI (up 2 to 6 degrees)

Hope this helps.

Would it be better to add the SOI using the SOI delay map, or SOI map?

How about for altitude?

And how many feet above sea level counts as high altitude?

[Power Hungry]

DJ,

Make sure you are not significantly modifying BOTH the SOI Main and SOI Offset tables. They compound each other and can easily result in SOI values well over 45º. For reference, stock is about 24º at full throttle at around 3000 RPM.

Dave,

Since the SOI is handled in degrees on the SOI Main table, this is easier to translate. The SOI Offset (Delay) is much more vague, but is also more useful in the respect that you can control the temperature at which timing is added. This prevents one from running too much timing when the engine is cold and possibly causing damage. You could also use the SOI Adder vs. ECT, but this lacks a bit of resolution as it is only 7x7 to start with and 3 cells are wasted below 800 RPM.

[soutthpaw]

Originally Posted by Power Hungry

DJ,

Make sure you are not significantly modifying BOTH the SOI Main and SOI Offset tables. They compound each other and can easily result in SOI values well over 45º. For reference, stock is about 24º at full throttle at around 3000 RPM.

Dave,

Since the SOI is handled in degrees on the SOI Main table, this is easier to translate. The SOI Offset (Delay) is much more vague, but is also more useful in the respect that you can control the temperature at which timing is added. This prevents one from running too much timing when the engine is cold and possibly causing damage. You could also use the SOI Adder vs. ECT, but this lacks a bit of resolution as it is only 7x7 to start with and 3 cells are wasted below 800 RPM.

I didn't touch the SOI offset as it seemed to vague cuz it would modify the whole map rather than specific areas, right? hadn't though about the SOI and ICP vs temp, Nice being in CA is that its easier to test out tunes due to the mild weather....

I was doing some figuring on milliseconds vs degrees and rpm... is this right
@600rpm= 10revs/second = 1rev/ 0.100 seconds or 100 milliseconds this 100/360 degrees = 3.6 degrees of rotation per millisecond at 600rpm or 7.2 degrees of rotation at 1200rpm ...10.8deg/millisecond at 1800 rpm and so on...
so for example at 1200 rpm an injector pulse width of 2ms would inject diesel through 21.6 degrees of rotation ???????

definitely doin' too much thinkin' 2nite...

Is there a constant for the burn rate of diesel... or I guess it would be on a slope variable to temp hence the reason for the offset for cold temps???

[Power Hungry]

See if this calculator helps...

Also, I think you boo-boo'd your calculation. I think you meant 21.6º of rotation at 1800 RPM and 2 ms. In any event, the rest of your math is correct.

[soutthpaw]

Originally Posted by Power Hungry

See if this calculator helps...

Also, I think you boo-boo'd your calculation. I think you meant 21.6º of rotation at 1800 RPM and 2 ms. In any event, the rest of your math is correct.

yep we will call that a typo... ok thanks for the chart too

[907DAVE]

I like the idea of using the SOI delay map to add timing, but what makes this map so complicated(ms instead of deg).? Can I get a Clif Note version?

[cleatus12r]

The reason the map is so complicated isn't because of the time value in the table but the fact that time is fixed and engine speed varies. That means that the actual SOI degree variance increases as the RPMs increase.

For example:

At 1500 RPM, the crankshaft will rotate 9 degrees per millisecond.
At 2600 RPM, the crankshaft will rotate 15.6 degrees per millisecond.

Using the same RPM values and a similar delay value will give you a difference in overall SOI advance difference of 6.6 degrees at 1ms and it goes up with more delay as long as all the other SOI adders and maps stay the same. For example, if the delay is doubled to 2ms, the actual SOI advance doubles as well to 13.2 degrees.

I hope this makes sense....

[907DAVE]

Ahh...I see..... does seem like things could get a little hairy.....quick!




Hmm....

[Power Hungry]

Especially when building files for high RPM racing/pulling applications. A small change in the SOI Offset could end up being a large timing change at 4000 RPM.

[soutthpaw]

But your fuel still burns at a constant rate.. haven't found the numerical constant for that but you can't get the fuel to burn faster so burn rate vs milliseconds should be a constant... (unless you add or remove something like NOS or elevation less O)
EDIT: Life should be so simple.. wrong again see next post