The Bosch LSU4.2 wide-band O2 sensor voltage

[Guest Nigelstephens]

Having fitted a Bosch LSU4.2 wide-band O2 sensor I was wondering what Lambda that folks have settled on to achieve best performance (power or fuel consumption)?

[Alex-Corsa]

Having fitted a Bosch LSU4.2 wide-band O2 sensor I was wondering what Lambda that folks have settled on to achieve best performance (power or fuel consumption)?

 

Which guys? concerning what kind of sensor?

Here are some voltages to AFR"s

http://www.techedge.com.au/vehicle/wbo2/wblambda.htm

[Paul Minnaert]

well you don't tell what the bosch is connected to, but I think lambda 0.9 is considerd best powerwise, going to lambda 1 will be better for fuel consumption

[luhbo]

Others say lambda as rich as 0.8 for max torque, lean up to 1.1 for best economy. My experience is also what Paul said already, 0.9 is fine. Lambda 1 is tricky, leaner is almost useless as you only very seldom run the engine steady at low load. That's for my single spark, 2-valve hemi-heads

A tuneable acceleration pump emulation in the efi software would be great for experiments with lean running big V-twins.

 

Hubert

[BrianG]

I have my data logger set to read in A/F ratio rather than lamda.

 

So, I have my A/F map set to 14.7:1 up to 1/2 TPS, and then fade rapidly to 12.5:1 for all of the upper 25% of TPS. This did noit result in any significant increase in max hp or max torque, but it did substantially smooth the midrange torque dip in the 2500-4000 rpm range. Still not progressively climbing as it does before and after this "spot", but at least not a dip any more.

 

Also, I did get some "very low TPS" stumbling. I just enrichened the lowest 3 rows in the lowest 2 columns (6 cells) by an arbitrary 20% and that drivability issue went away.

[Cliff]

Nigel, I would suggest a more hands on approach with the Optimiser and the ECU in OPEN loop.

 

With the bike on its centre stand use the fast idle to set 2000-3000RPM. Now go into the Optimiser Autotune mode. This will allow you to dial in a correction factor.

 

While doing this note the voltages the sensor is giving you. Also check that the voltage tracks the way you expect(clockwise is richer). You will easily hear the spots when going too lean or rich. Probably easiest to go too lean and then richen it till the motor smooths out. You'll only be running lean for a couple of seconds at low power levels so it is quite safe to the engine. Note this voltage and use that as your first target for all of the 7 targets.

[Guest Nigelstephens]

Its okay Cliff got my Guzzi quite nice on Lambda 0.9.

 

Thanks to everyone. I was interested to see what people were using as a fuel/air mixture. I found that to go to lean (less than 0.9) makes the engine lumpy and noisy. Much smoother when rich. However fuel consumption on mine is never beter than 42/gal. This is daily commute (20 mins) so only just gets to operating temperature. On longer runs it gets around 45 MPG (imp).

Quite happy to have smoothness over efficency.

 

Has anyone played about with ignition timing with MYECU (sorry to those who dont know what I'm talking about)? I get a very heavy sound about 4,4 to 6,6 in the grid when accelerating at low speeds. Will have to play around with settings but not had the time yet. My limited knowledge suggests too advanced as the sound is knocking. I am wondering if retarding the timing at these points will reduce heavy sound (increase comfort) at the expence of less power. I know that kocking can reduce power but if its is a fine line between knocking and less power (with less advance) I'm not sure which way to go.

 

I could just try loads of different variations of ignition map and decide what is best, but, I was wondering if anyone else has had this experiance and guide me a little as to what they have found to be the best settings.

[luhbo]

Here is my actual advanc map. I was running an ignition table based on the one Marelli/Guzzi is using, which has a lot more of advance, but I could see no advantage in power or efficiency so I went back to this one. This one is probably like the one Cliff is providing, also it looks quite similar to the standard points based ignition advance curves.

 

The engine now does not run remarkable smoother or more or less powerfull. It does not ping now as it didn't do so before (high loads not under 2500min-1, of course).

 

Hubert

 

[Alex-Corsa]

The engine now does not run remarkable smoother or more or less powerfull. It does not ping now as it didn't do so before (high loads not under 2500min-1, of course).

 

Hubert

 

 

I notice a too high Ignition advance at low RPM (up to 2500) and what is this vertical axis for (oo, 01, 02 ,ect.)

TP opening?

[luhbo]

It may look so, Alex, but it works fine.

 

The first row just is for naming the cells, the same does the upper most row (in combination of course).

 

Spark Advance 00 (flap closed resp. at idle) up to 14 (WOT)

 

Hubert

[Alex-Corsa]

It may look so, Alex, but it works fine.

 

The first row just is for naming the cells, the same does the upper most row (in combination of course).

 

Spark Advance 00 (flap closed) up to 14 (WOT)

 

Hubert

 

OK , I see , it is different than the maps I have to adjust.

[luhbo]

You're using Wayne Orwigs tool? This shows the maps in a very similar way, just angle instead of 00 for instance.

 

Hubert

[Alex-Corsa]

No I just do the map on a different Guzzi ECU

[Guest Nigelstephens]

Has no one tried different ignition timing maps with myECU on big Guzzis?

 

I think I'm going to have to try some variations of map over the weekend. I

plan to do a retard and an advance map on what I have and report back with my results.

[luhbo]

No I just do the map on a different Guzzi ECU

 

Ok, but what tool do you use for mapping, means read and interpret the eprom content, then modify and translate the figures back into bits and bites?