What makes an Economy tune?

[soutthpaw]

Originally Posted by Power Hungry

DJ...

The thing to remember about the ICP/PW relationship is that the pulsewidth is already based partly off of ICP. So technically, if you raised the ICP then the pulsewidth should drop automatically. You shouldn't have to go in and make any further changes. Unless I change the injectors, the main pulsewidth table doesn't get touched. It's all handled elsewhere.

Cody...

Cow farts. That's funny right there, I don't care who ya are!

Oh, ok ya mean something that actually makes sense.... I was just messing with the 80HP trying to make it more economical on the freeway. I pulled down the Low boost fuel in the cruising RPMs progressively about 10-15% at less than 10PSI down to zero. haven't tried it yet... would I need to change anything else to compensate for the lower amount of fuel with that amount of change... maybe it won't run at all.. who knows but I'm on vacation so I got time to play around a bit Plus I'm at sea level for a change

[Power Hungry]

It'll run, but the biggest thing you'll notice is that the truck will seem a little slugish on acceleration. We've been there and done that and that's why we don't offer Fuel Sipper anymore. To many complaints that it just didn't pull well off the line at light to moderate throttle. Of course, heavy throttle worked nicely but then what's the point of the program?

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.

[soutthpaw]

Originally Posted by Power Hungry

It'll run, but the biggest thing you'll notice is that the truck will seem a little slugish on acceleration. We've been there and done that and that's why we don't offer Fuel Sipper anymore. To many complaints that it just didn't pull well off the line at light to moderate throttle. Of course, heavy throttle worked nicely but then what's the point of the program?

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.

Great, thanks,
I am looking for a really economical freeway program 1100 miles one way, shifting doesn't really become an issue. Ill bump the SOI and ICP up a little and see what happens
Actually 90% of the time I am very light on the throttle, but if I need it to, putting my foot into it I want it to move.. so that actually would work well for me....

[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]

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?