E38 Economy techniques

[macca_779]

One idea I had with this Steve is to go OLSD and fudge the Virtual VE to force it leaner. Its something I'd do on my own car if I owned an E38 but haven't had the chance to try it on one yet. Or even SD for that matter. Idealy I don't like this approach but alas we have no alternate as yet that I know of

[oztracktuning]

I had the E38 yesterday in open loop. The problem is balancing any drift with weather condition variations in open loop. If it was my own car i could get enough logging to rely on it. Maybe if the owner had a wideband installed permanently it would be OK.

[ringram]

well I have found that they like 2 or 3 degrees more timing than the typical LS1 engine at all rpm points during a full load run, infact at 6200rpm I run 26 to 27 degrees and the engine loves it. With an LS1 22 or 23 degrees is the limit on our fuel at 6200rpm.
Mike

On this topic I understand the combustion chambers have been designed to require more timing so that emissions are reduced. I guess more time for completing burn.

[ringram]

Hey Oz, if you check out a NB graph you will see it sticks near stoich until almost 0 volts or 1v when it swings right away.

Maybe you need to aim even lower?
Also what about adjusting the O2 trim rates so that if its over it swings faster to the lean side and when its lean it moves only really slowly towards the rich side of the switchpoint?

Also are you guys saying there is no longer a lean cruise mode?
If so I suspect this is because leaner mixtures produce larger amounts of NOx emissions and given the VE has worse economy than the earlier models I wouldnt be surprised if they did remove lean cruise altogether.

Ross do you know if this is the case?

[macca_779]

Ringram Holden hasn't used lean cruise since the VZ LS1. It was still available in the cal though and enabled easily. Unfortunentely with the new ECM's there is no provision for lean cruise.

[ringram]

Ok makes sense. I bet its NOx emissions.
So fuel economy is unimportant. Which reinforces my personal view that nobody should care about CO2, just the toxic polutants..
Im sure open loop can come to the rescue.

[Highlander]

any prgress??

[swingtan]

Hi Steve,
I mentioned the O2 switch points in another thread a fair while back. I can't make that table work no matter how much I change the switch points. I gave up on it in the end .

To get a "pseudo" lean cruise, I've tried running OL and found it works pretty well. You can command a leaner mixture in the light cruising cells and richen up again where it's needed. I'm going to try a long trip later this week to see how it goes.

Simon.

[The Alchemist]

Hey Swingtan, how did that work out for you ?
Mike

[gmh308]

Hey Swingtan, how did that work out for you ?
Mike

Ditto ^^^