PC3 maps

[seespotweld]

I was wondering if a map made at sea level would be correct for an engine run at say 2000 ft. elevation . I guess my real question is can the temp/pressure systems compensate enough ?

[MultiDoc]

Don't have a solid answer for you. But my guess based on the fact that 2000ft is around 600m only then I'd say that the difference wouldn't be at all noticeable. Again not sure

[seespotweld]

seems to me I was reading some of Brad Black's stuff and him saying that there really wasn't that much compensation going on .I did notice last year on a trip that at higher levels a small stumble at 5000 turned into a much bigger deal the higher we went.

[748R_bb155]

some where between 2-3% les fuel
-2% at 600 feet
-3 at 2600 feet
according to the table found at
sigmaperformance

EO

[seespotweld]

thanks...this should mean if I adjust the map on the face plate by 2% I should be good to go.

[748R_bb155]

The power commander just add or substracts to the puls lenght that comes from the ecu. (it does not know the lenght of the pulses its getting in the first place),
On the 996 it uses the positive egde of injector opening for RPM measurement.

but it knows from dyno run / configuration/map that at a certain rpm and tps its adds or subtracts the opening time for the injector.

I Dont know the ecaxt logic, but it means it has to measure puls length, and on the next cycle/revolution do the adjustment.
Adjustment must be made on the revolution after the "measurement" is taken.

1000 rpm = ca 17 adjustments a sec
12000 rpm = ca 200 adjustments a sec

Someone correct me if I'm wrong !

If the bike was mapped at se level the it there should be no reason to add og substract when going to an other altitude, as the ECU compensates for this.

Higher altidue means lower oxygen in the air, the bike need less fuel to work 100%.

Power will always be down with lower oxygen in the air.

IF you add fuel, it will probably run to rich.
But it comes down to the trim values in the Ducati ECU if these are correct, and I azume they are(they have to done som reasearch one this)

EO

[seespotweld]

----- not necessarily, according to Brad Black the trim values could be off or so small that no change would be felt.This assumes I'm reading him correctly .

[vij]

Originally Posted by seespotweld

I was wondering if a map made at sea level would be correct for an engine run at say 2000 ft. elevation . I guess my real question is can the temp/pressure systems compensate enough ?

I would not worry to much if you only go up to 2000ft.

At zero ft the density is 0,07245lb/ft3. At 2000ft it is about 0,07lb/ft3. Thats about 3,5 % difference. If the ECU did not compensate for it at all the mixture would be close to 0,5 richer (13/1 would be 12,5/1) but the ECU is compeasating for it so it is no worries.

I spend a some time going up to 9000 ft or so and there it makes a difference but at 2000 ft would not worry at all.

Jocke...........

[vij]

Originally Posted by 748R_bb155

Higher altidue means lower oxygen in the air, the bike need less fuel to work 100%.

Power will always be down with lower oxygen in the air.

EO

Just a small correction. High altitude does not mean less oxygen. It is still about 21% oxygen at high altitude but the air has lower density and when we are talking A/F ratios we are talking about mass. Not volume. Lower density means less air. Not less oxygen.

Jocke......

[Old Baldy]

2000 ft would be compensated for with the altitude trim.

The issue with the post 851 bikes was that Ducati had some early issues with the reliability of the air pressure sensor, and rather than continue to risk a blown engine due to incorrect pressure trim, Ducati reduced the effective trim range of the pressure map, to allow SOME effective altitude trim, but not sufficient dwell reduction for greater elevations (which results in an overly rich mixture at high altitudes since they reduced the trim range)

This is easily corrected with something like TunerPro or other chip/ECU mapping systems, provided you are comfortable with the risk that a faulty pressure sensor could reduce the fuel by, say, 25% at sea level (incorrectly), and result in an overheated/blown motor.

I don't recall the effective altitude at whcih the mixture starts to become overly rich, but it's fairly easy to spot on the map.

Perhaps Brad/TomTom/Doug or someone else can chime in.

[748R_bb155]

from 8000 feet and up its a -8 % decrease in fuel.
(on the older models it was up to -32 %).

as alway with sensor faliure (generic), they tend to give either 0 or the max value when faulty, ducati case max value that wold render the bike go get very lean if the senor was damaged.

EO