changing the switchpoints... does little to nothing on the E38s... can you show your differences by changing this?
changing the switchpoints... does little to nothing on the E38s... can you show your differences by changing this?
"All that is needed for the triumph of evil is that good men do nothing..."
Correct, we know it makes no difference, hence the mention of the "O2 switch point sanity check" pid that we are missing. If we can get access to the PID, then we may be able to make some changes for lean cruise CL operations.
Simon
I would probably try setting up like steve does. Raise OL tables and match them together and change stoich aswell increase these to something around 15.3:1 this is what the lean limitation is in the e38 its the OL tables then try reducing the switch point to around 100mv and see what happens then.
I know this has nothing to do with EFILive, but I've written all the embedded code to make a proper digital dash gauge for an LC1 and adding an adjustable narrow band out where you could set the switch point on the fly would be a rather trivial addition. Conceptually, that would allow lean cruise on any vehicle as it would let you change what the ECM sees as 14.7. The issue might be how it messes with trims, but other than that it ought to work. I offered to do it for some of the hydrogen generator increases mileage folks last year, but never heard back.
Ira
Bringing this up again...... because I have a new PB for economy. Last week I went as a parent helper on my daughters year 6 camp. So I thought I'd see what I could get on a bit of a drive. Starting from Yarragon and driving about 20km to just past Moe, I got the following.
After that I hit some road works and a couple of bigger towns so that figure rose to 8.7l/100km when averaged over 150km. But I'll still claim that 8.1 for my record
Back in town this week I've managed the following....
That's after 3/4 of a tank, driving 15km to and from work for 5 days and a trip across town to Thornbury last night. I'm pretty happy given I can still do 0-100kmh in under 5 seconds. All this with the MAF and CL still enabled.
Simon.
13.8 around town! Very impressive for commuter traffic.Originally Posted by swingtan
Bringing this up again...... because I have a new PB for economy. Last week I went as a parent helper on my daughters year 6 camp. So I thought I'd see what I could get on a bit of a drive. Starting from Yarragon and driving about 20km to just past Moe, I got the following.
After that I hit some road works and a couple of bigger towns so that figure rose to 8.7l/100km when averaged over 150km. But I'll still claim that 8.1 for my record
Back in town this week I've managed the following....
That's after 3/4 of a tank, driving 15km to and from work for 5 days and a trip across town to Thornbury last night. I'm pretty happy given I can still do 0-100kmh in under 5 seconds. All this with the MAF and CL still enabled.
Simon.
To be fair, I think the trip computer does some funny stuff. I get the feeling that....
- The average speed is calculated over the time since the last reset of the tirp computer.
- The average economy is a moving window that averages figures over something like the past 30min.
Before the trip across town, I was sitting on 14.7l/100km which was just the trips to / from work. The trip to Thornbury was done in 34'C heat though with the aircon running the whole way.
Still, I'm pretty happy with those figures.
Simon.
all just having a quick look at a tune on a friends cam'd car which is suffering from economy beyond what is expected from just the cam.
Without a wb fitted there is little to present log wise but noticed that the switch point for b1515 is set to 600mv rather than 450mv (which is what it was set to before cam). Now the tune shop that fitted the cam have been fiddling around as the car was stalling a lot but looking at a side by side tune before and after cam there is little difference (other than slight maf table, spark and kr burst adjustments). Not convinced the tune is anywhere near as optimum as could be. Tune is basically flashed, then feedback (no logs) given back to Aus, update tune sent etc and repeat.
Now having seen reports that adjusting the switch point has no effect, why would hsv themselves be adjusting b1515 to 600mv? It will surely be used elsewhere for calculating feedback from the o2's.
The tune was flashed with hp tuners but was based on the stock o/s, are there any issues in reading a tune from hp tuners like this?
HSV and/or HPT may have the switch point calibration access. Going from memory, the O2 switch point is comprised of...
- B1515 / B1516 : O2 Sensor Rich/Lean Threshold
- An "Airflow Mode" table that does not yet exist for the E38 (it would be something like B4107 in the LS1 controler).
- A hard limit setting for the minimum lean value in the tune (not available in the E38 calibrations that I have seen). Setting the stoich setting to say 15.5:1 seems to have no effect on the changing of the O2 switch points.
That being said, I've looked at some log data and my stock NB-O2's are generating
771mV @ 14.5:1
107mV @ 14.9:1
36mV @ 15.5:1
23mV at 16.3:1
So the "switch" is extremely fast on these O2's. Chances are that even setting the switch point at 36mV will do very little as the O2's themselves will be the limiting factor. Due to their switching characteristics, the average AFR they will end up returning is probably still very close to the 14.7:1 std.
the HSV's running switch points of around 600mV is probably an attempt to run marginally richer when cruising. This might be for power, exhaust note or even a smoother running motor. It's probably not goign to make a huge difference though.
Simon
I'd imagine its part of the cold stall issues he was having - the tune looks pretty stock with no changes other than to timing and knock burst. I'd have thought a more dialed in ve table of some sort but nothing. It even has an osram otrcai so there is more potential with a decent tune, car runs good but the fuel use seems excessive more than seen on other similar cam setups (with more customised tune).
Think the best bet for him is to look at borrowing my scanner and talking to the likes of oztrack etc. Thanks for the pointers too, I take it hp have a few more tables open to them than we do?
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