Lean Cruise Setup for Australia & New Zealand

[neil]

I would like to start a thread on setting up Lean Cruise for the Australian and New Zealand PCM's.
Also any other information pertaining to tuning for fuel economy.
I would like to see a resource that is located in one area rather than a collection of threads so everyone could have easy access to it.
Maybe Paul could setup a new section on the forum.

Regards,

Neil.

[The Alchemist]

Hi there Niel, I have played around with lean cruise on the last few Holdens I have tuned and found how it works with trial and error really. I initially thought that lean cruise used the STFT to "remove" a set amount from the E Ratio via the O2 sensor trims etc as per outlined in the Lean cruise map. I quickly realised that when lean cruise conditions are met that the STFT turns off and flat lines and the mixture starts altering as per the lean cruise map if you are in the right MAP and RPM points at the time.
The thing is, the amount removed from the EQ Ratio needs to be set up for best results with a wide band of course and I guess your VE table needs to be spot on to get predictable results from lean cruise effects. It took a lot of reflashing and mucking around but I got the idea and decided just to turn it off, like the later 2005 calibrations did, and let the STFT's keep working instead. Using the Road runner would make setting up lean cruise a piece of cake but I haven't got one of those yet :(
The cars with lean cruise turned off still returned excellent MPG figures so I don't see what all the fuss is about with "lean cruise"......
comments.........

[ringram]

I kick mine in faster and sooner and tell it to go to 15.4:1
Its a lot leaner stock, but a few recon too lean hence Ive richened it up a tad.

[Tordne]

I think (looking at the stock table) that it tries to run as lean as 17:1 :D

[neil]

Hi,
There's an interesting article at the following address on Autospeed magazine
Tuning Air/Fuel Ratios

http://autospeed.drive.com.au/cms/A_1595/article.html

Regards,

Neil.

[traumadog]

Anyone feel up to posting what their LC settings are?

[Garry]

I went up to 15.4 in Table B3647 (COS5) for low MAP/RPM ...

[neil]

Hi,
Can you use the bi-directional controls to setup Lean Cruise?
If so what procedure would you use?

Regards,

Neil.

[Tordne]

Hi,
Can you use the bi-directional controls to setup Lean Cruise?
If so what procedure would you use?

Regards,

Neil.


Not really, you are wanting a RoadRunner already and you haven't even been allowed to open the V2 that's under the tree :muahaha:

[neil]

It's getting a bit much.
There might be an empty box under the tree at Christmas.

:bash:

Neil.

[Tordne]

Are have a stronger will than me thats for sure!! Or stricter penalties for your sins ;)

[traumadog]

Stupid question - is there anything in EFILive that will tell you whether or not this is activated? I've got my "Commanded AFR" graph up on my dashboard, but it only seems to go down (presumably due to PE), rather than vary from 14.68 @ cruise.

[Tordne]

I don't think there is a PID or anything - that I've seen anyway (didn't look real hard).

You can have a look at all the enables in the tune file and see when it might become active...

You're right though. The Commanded AFR will richen when PE mode is active, or you are in Open Loop with the B3647 table of a Custom OS.

[neil]

I noticed in the lean cruise section that you can set the speed at which it occurs.
Seems it would be good to drop the point of operation down to 30 or 40kms to improve economy around town

Regards.

Neil

[The Alchemist]

Well I've got a customer coming back this week for some more economy tweaks ( likes the extra grunt but "feels like he needs something else" lol ) so I will be spending my time on lean cruise setup. Will post my results or findings this week.

Mike

[neil]

That would be great Mike.

Neil

[traumadog]

Same here - as for whatever reason, the "Commanded AFR" hasn't changed on mine, even though I've dropped the enable speed to almost 25 km/h. I don't want it that low, but I'm trying to see if it will indicate when it comes on in a log file.

[Tordne]

Check all the enablers and multipliers.

The are timers for run time, and off idle, as well as the speed enablers and disablers.

Then there is the table that defines the amount to lean out the mixture when the enablers are meet.

But also check the Coolant Temp Multiplier table to make sure that the multiplier is a value of NOT 0 in the areas you're expecting, otherwise it will all just do nothing ;)

For example in the stock setup Lean Cruise does nothing below around 80*C ECT temp, so if your logging at around 50*C ECT then don't be surprised if Lean Cruise isn't working :)

I've never bothered running or testing Lean Cruise before but it seems to be a hot topic right now with all the new members - I'm almost temped to have a look at it just so I can help you all out.

Cheers,

[The Alchemist]

Alright guys and gals ( being "PC" ) heres the scoop on lean cruise from todays efforts on an auto 2003 SS Holden 5.7
Did a machine effort tuning the thing to start with, VE table averaged around 14.3 to 14.6 on the wideband from the dyno up to around 75kpa and up to 3600rpm. I have this hooked up via my Flashscan Ver2 onto my laptop which is a fantastic help for tuning etc etc.
Anyhoo, first of all I experimented with the O2 switch point map as my AFR always sits on about 14.4:1 with the O2 STFT on when doing holdens. Other factory cars always sit bang on 14.7:1.
Since we are on the subject of economy I adjusted the O2 switch point down from 540 to about 400 and achieved a steady 14.6:1. Quite chuffed!
And an easy way to tweak your cruise AFR.
Next I adjusted the lean cruise Km activation to 55km to make the learning process quicker. Now, here's the interesting bit......
Up to 55km the STFT is working nicely giving me a 14.6:1 steady, commanded 14.63:1, over 55km the STFT turns off ie: no feedback, and the commanded afr dropped to about 15.9:1 and actual afr to about 15.2.
The lean cruise map points I set the same at 0.08 to make the changes easier to track as you pass thru them.
Now when you pass through to a point on the Lean Cruise map (to the right) that has a "0" on it the commanded AFR goes back to 14.63:1 on the actual AFR goes back to whatever the AFR was your VE/MAF runs when the STFT is turned off...in my case 14.4:1 as I had spent time getting a good base tune.
Of course if you activate PE mode based on TPS all this goes out the door as you would expect.
So to have lean cruise actually work properly from a technical aspect you would have to have your VE table SD tuned perfectly to 14.63:1 and your MAF table calibrated to match so when you pass out of lean cruise into a "0" at higher load areas you would still acheive 14.63:1.
Interesting eh?
Tomorrow I will experiment with the lean cruise map settings at different rpms and loads to see if the amount of EQ ratio reduction alters the actual AFR by similar amounts at each point. A bit of mucking around but I think its worth doing.
phew
Also a point worth noting for you SD tuners out there is the when you are SD tuning, lean cruise will effect your AFR actual causing the VE table to have some funny skews at certain points ( I found this out the hard way ) so when you are SD tuning make sure you lock out lean cruise at 400km/hr. Also don't make the re-enable the same as enable as this also causes problems, make it say 10km/hr difference.

Cheers,

Mike

[The Alchemist]

feedback from customer after setting up lean cruise was good except for a "vtec" like effect under load in 3rd or 4th gear. This is of course when you pass in to a "0" point in the lean cruise map and the AFR goes to the base VE setting, so the car picks up a bit with the richer mixture. Have decided that the load point of 0.4 grm/cyl is to far for the lean cruise to be active and will set this back to "0" and see if that improves things for him. Set the other areas between 0.09 and 0.07, this pulled the AFR down to 15:1 to 15.3:1. Will keep you posted on mileage readings.
Mike

[JohnL]

Can you increase the timing with the leaner AFR on the lean cruise tune?

The leaner mixture will want more advance. My wife's VS Ecotech V6 used to have a factor lean cruise AFR of about 17.6 IIRC and a heap of timing.

John

[The Alchemist]

One of my good customers has come back to report on an extra 100km per tank on a trip (550km PER TANK) from what he used to get and figures in the mid 10's per 100km on the fuel trip meter which is pretty good as he used to get mid 12's before the tuning.
Very happy :rockon:

[Tordne]

Shit! I'm lucky to get 400 km per tank around town :eek:

[GMPX]

That much :bawl:

[The Alchemist]

Well that was on a trip on the open road though......I'll ask him whats the go around town but its hard to get a good estimate as he travels a lot in his job you see. He is very happy with the mileage though, what do you guys get on the open road....apart from tickets :) ?

[macca_779]

Thought I would post up what settings I use for lean cruise on the cars I tune. I have worked up to these settings so its by no means a stab in the dark. I was running as lean as 16.1:1 in my car for 15000k's, I pulled out the plugs and they were in good condition, so now I'm running as lean as 16.3:1 I use b3647 in my car but here is a screen shot of a customers car utilising b3639. I've also attached an excel spreadsheet that I use to convert EQ to AFR for calculating these kind of things.

http://i68.photobucket.com/albums/i39/macca_779/leancruise.jpg

[The Alchemist]

Hey Macca, thats great.....very similar figures here. I use around 0.07 to 0.09 depending on the car and how good I've tuned the VE table :) Small changes makes a big difference to the AFR eh?
I run around 15.5 to 15.2 for lean cruise but I creep it up to 2400 rpm though. Cheers for that.

Mike

[macca_779]

yeah as you can see i don't bother with it above 2000. The way I see it, if your up there you aren't cruising anymore. Thats for an M6 anyway. You can go heaps leaner mate. Try 16:1 and add about 6 deg to the apporpriate segments in the upper timing table.

[The Alchemist]

will do, haven't played around with higher timing figures during lean cruise yet I run the usual 38 to 40 degrees. I see the newer E38's run up to 44 degrees at light cruise. \
With the more timing does this allow you to lean it out further without lean surge happening?

Mike

[macca_779]

will do, haven't played around with higher timing figures during lean cruise yet I run the usual 38 to 40 degrees. I see the newer E38's run up to 44 degrees at light cruise. \
With the more timing does this allow you to lean it out further without lean surge happening?

Mike

i havent suffered any surging from running this lean. But yes with a leaner mixture you can run more timing

[Sikhabib]

when in lean cruise how much spark are you guys adding on top of the main table? and roughly what does this make your total timing?

[macca_779]

when in lean cruise how much spark are you guys adding on top of the main table? and roughly what does this make your total timing?

Hard and fast numbers are too hard to quote for each individual mate.. What I do though is set the AFR you want.. Say 16:1 then find a nice flat road. Open the Bi-Di's and play with Delta spark while logging MAP, move the timing up and down till you hit the lowest MAP. Once you've done that confirm the data on the log and transpose it to your tune. For a stocker around 30degrees is where you will find the sweet spot. But like I said its different for everyone but this method works a treat. :cheers: