KLR maps

[johnb]

There's been some interest in KLR maps lately, and I never really documented these before - I was always more interested in how the logic worked than the details of the maps. So here are the early and S boost maps, and the baseline CV map (which is the same for both).

Someone did post images like this years ago on rennlist, but as far as I know no one ever included the axis values and proper units, which is harder than it sounds! KLR maps are not as sophisticated as DME maps - they don't come with their own breakpoints. Instead the breakpoints are calculated as a standalone process elsewhere, and then just scaled for different maps.

klr_cycling_valve_map_1.png (168.32 KiB) Viewed 84 times

1987_target_boost_1.png (150.1 KiB) Viewed 84 times

1989_target_boost_1.png (151.04 KiB) Viewed 84 times

Speaking of breakpoints, you'll notice that the RPM breakpoints are not evenly spaced. I've double and triple checked my logic and I keep getting the same answer, so think this is really how they are.

Assuming I haven't made a mistake somewhere, here's one way of (possibly) making sense (though I am guessing now): if you were given the boost curve as shown below (the middle one) and told you have to approximate it as accurately as possible with 15 straight line segments, but you can space the breakpoints however you want, I think the spacing you'd want would be something close to what we see in the KLR maps. That is, they're bunched together where the curve is at its curviest, and spaced apart where it's straighter (for the most part). This spacing ends up being applied everywhere whether its needed or not. But I don't think it causes any problems anywhere else.

951_boost_curves.png (158.11 KiB) Viewed 84 times

Also, if my units are correct, the overboost threshold would be about 0.25 bar and the underboost about double that.

[whalenlg]

Thanks - very interesting. Have you decoded the map input voltage vs bar/psi so far? I have never seen this online…

[johnb]

Thanks - very interesting. Have you decoded the map input voltage vs bar/psi so far? I have never seen this online…

Yes, I think so - the path is confusing in places, partly because my 1989 KLR's MAP sensor reads a little lower than it should, so it's hard to get anything from it experimentally that I can rely on. But here's my best attempt to make sense of it: https://jhnbyrn.github.io/951-KLR-PAGES ... p.html#map (that's very much a work in progress document)

The upshot of it is

1 ADC unit = ~0.833kpa = ~0.20v

or

1kpa = 1.2 ADC units = 0.023mv.

It has an offset (discussed in the link) so that atmospheric pressure is about 120 ADC.

[Jeff84]

There's been some interest in KLR maps lately, and I never really documented these before - I was always more interested in how the logic worked than the details of the maps. So here are the early and S boost maps, and the baseline CV map (which is the same for both).

Someone did post images like this years ago on rennlist, but as far as I know no one ever included the axis values and proper units, which is harder than it sounds! KLR maps are not as sophisticated as DME maps - they don't come with their own breakpoints. Instead the breakpoints are calculated as a standalone process elsewhere, and then just scaled for different maps.

klr_cycling_valve_map_1.png

1987_target_boost_1.png

1989_target_boost_1.png

Speaking of breakpoints, you'll notice that the RPM breakpoints are not evenly spaced. I've double and triple checked my logic and I keep getting the same answer, so think this is really how they are.

Assuming I haven't made a mistake somewhere, here's one way of (possibly) making sense (though I am guessing now): if you were given the boost curve as shown below (the middle one) and told you have to approximate it as accurately as possible with 15 straight line segments, but you can space the breakpoints however you want, I think the spacing you'd want would be something close to what we see in the KLR maps. That is, they're bunched together where the curve is at its curviest, and spaced apart where it's straighter (for the most part). This spacing ends up being applied everywhere whether its needed or not. But I don't think it causes any problems anywhere else.

951_boost_curves.png





Also, if my units are correct, the overboost threshold would be about 0.25 bar and the underboost about double that.

Wonderfull!

About the underboost threshold I found the following note in the attached document at the blink code description 3-1 (charging pressure too low) :

"The "charging pressure too low" problem is only stored in memory when the difference in pressure from normal pressure is 0.45 bar; this problem can thus exist without setting off a blink code defect indication."

So it's pretty close to your calculation.

[johnb]

There's been some interest in KLR maps lately, and I never really documented these before - I was always more interested in how the logic worked than the details of the maps. So here are the early and S boost maps, and the baseline CV map (which is the same for both).

Someone did post images like this years ago on rennlist, but as far as I know no one ever included the axis values and proper units, which is harder than it sounds! KLR maps are not as sophisticated as DME maps - they don't come with their own breakpoints. Instead the breakpoints are calculated as a standalone process elsewhere, and then just scaled for different maps.

klr_cycling_valve_map_1.png

1987_target_boost_1.png

1989_target_boost_1.png

Speaking of breakpoints, you'll notice that the RPM breakpoints are not evenly spaced. I've double and triple checked my logic and I keep getting the same answer, so think this is really how they are.

Assuming I haven't made a mistake somewhere, here's one way of (possibly) making sense (though I am guessing now): if you were given the boost curve as shown below (the middle one) and told you have to approximate it as accurately as possible with 15 straight line segments, but you can space the breakpoints however you want, I think the spacing you'd want would be something close to what we see in the KLR maps. That is, they're bunched together where the curve is at its curviest, and spaced apart where it's straighter (for the most part). This spacing ends up being applied everywhere whether its needed or not. But I don't think it causes any problems anywhere else.

951_boost_curves.png





Also, if my units are correct, the overboost threshold would be about 0.25 bar and the underboost about double that.

Wonderfull!

About the underboost threshold I found the following note in the attached document at the blink code description 3-1 (charging pressure too low) :

"The "charging pressure too low" problem is only stored in memory when the difference in pressure from normal pressure is 0.45 bar; this problem can thus exist without setting off a blink code defect indication."

So it's pretty close to your calculation.

Interesting, thanks! Do you happen to have the rest of that document? It looks similar to but different from the "Test Plan" document that's been around for years. I wonder if it's a later version.

[Tom]

Interesting, thanks! Do you happen to have the rest of that document? It looks similar to but different from the "Test Plan" document that's been around for years. I wonder if it's a later version.

That doc appears to be the factory manual turbo supplement (the maroon binder). Although, interestingly, the version posted here seems to have typo's that mine doesn't -- so maybe an earlier edition or maybe non-US version. Substantively the same as far as I saw though...

[johnb]

Interesting, thanks! Do you happen to have the rest of that document? It looks similar to but different from the "Test Plan" document that's been around for years. I wonder if it's a later version.

That doc appears to be the factory manual turbo supplement (the maroon binder). Although, interestingly, the version posted here seems to have typo's that mine doesn't -- so maybe an earlier edition or maybe non-US version. Substantively the same as far as I saw though...

Yeah you're right, the version I have does have this info, I just never noticed it before.

[Jeff84]

Interesting, thanks! Do you happen to have the rest of that document? It looks similar to but different from the "Test Plan" document that's been around for years. I wonder if it's a later version.

That doc appears to be the factory manual turbo supplement (the maroon binder). Although, interestingly, the version posted here seems to have typo's that mine doesn't -- so maybe an earlier edition or maybe non-US version. Substantively the same as far as I saw though...

Yeah you're right, the version I have does have this info, I just never noticed it before.

Yes, you're both right!

Just in case, everything is downloadable via the link below:

http://p914-6info.net/944%20Manuals.html