Lean Burn Tuning?

[Mechanic prepper]

that's cool, do you know if the c6 e38 has the option? I haven't heard if it.

I have 67a unlocked too, but it's already in a hybrid, so I doubt it and wouldn't want to do a full write on that thing lol.


Australia always seems ahead of us on the os mod side. I seem to remember a pcm hacking board back in the day that was always busy with aus stuff. they took a old OBD1 gm ecm and make it run map 3bar with all kinds of custom patches.. thing sounded like it was a stand alone by the time they were done.


I'd definitely watch a video you made about it. link it up when you're done.

I will have to open up an e38 file and see if it's there. You could do a speed density tlean burn tune for sure. As I generally tune boosted cars for speed density... But if it has the equivalence ratios for timing and fuel reduction per cylinder mass in the pcm already that's more desirable ... I will check and get back to you. I will link video when done. I did screen capture on laptop and I live 59 miles from town so no internet to upload. And don't want to burn up all my hotspot or satellite data to upload. Still waiting for starlink ...haha

 

[Marky Dissod]

P01 & P59 pcms have Lean Cruise 'subroutine'; it sort of parallels Wide Open Throttle Power Enrichment.

Over a certain coolant temp, but UNDER several airflow thresholds, the pcm MAY allow or activate Lean Cruise.
Referencing several previous data points of closed loop, the pcm aims at a leaner AFR, adds spark advance, and checks to make sure engine load remains low enough to stay in Lean Cruise.

Sloppy Mechanics Wiki - Lean Cruise

How-To add Lean Cruise to p01 ecu (haven't tried with p59...may also work??) By Grady Do this at your own risk...please don't blow shit up...and if you do, don't blame sloppy ;)

sites.google.com

Weight and drag area will never allow GMT800s to spend as much time Lean Cruising as, say, cars.
Even so, the more time spent in 3rd or 4th with the TCC locked, the better.

 

[Mechanic prepper]

P01 & P59 pcms have Lean Cruise 'subroutine'; it sort of parallels Wide Open Throttle Power Enrichment.

Over a certain coolant temp, but UNDER several airflow thresholds, the pcm MAY allow or activate Lean Cruise.
Referencing several previous data points of closed loop, the pcm aims at a leaner AFR, adds spark advance, and checks to make sure engine load remains low enough to stay in Lean Cruise.

Sloppy Mechanics Wiki - Lean Cruise

How-To add Lean Cruise to p01 ecu (haven't tried with p59...may also work??) By Grady Do this at your own risk...please don't blow shit up...and if you do, don't blame sloppy ;)

sites.google.com

Weight and drag area will never allow GMT800s to spend as much time Lean Cruising as, say, cars.
Even so, the more time spent in 3rd or 4th with the TCC locked, the better.

I'll post logs but I am in lean cruise up to 50% throttle which equates to being in lean cruise 99% of the time..even climbing grades. And yes transmission shift schedule tuning and lock up tuning is worth around 1 to 1.5 mpg. The nice thing about these pcm is the tow haul button gives you 2 separate schedules that can be adjusted independantly of each other. In normal mode under 20 % throttle my truck hits overdrive by 30mph..just kinda idles through town in 4th... The shift schedule is infinatley adjustable and uses tps vs mph.... So when I tow my trailer I use the tow haul mode and it holds gears longer and is more friendly to heavy loads...but in both modes I keep them in lockup 90 percent of time from 2nd on up ... I do unlock during shift as I have built my trans and have higher pressures both mechanically and electronically so definatley don't want converter locked during shift because it's flat violent.


But as far as only being able to use lean cruise in certain windows that's only true if you copy a Holden file... If you populate the tables by hand you can stay lean burn all the time if you really wanted to. Like I said in previous post..there is very few who went down this rabbit hole ..

 

[Mechanic prepper]

P01 & P59 pcms have Lean Cruise 'subroutine'; it sort of parallels Wide Open Throttle Power Enrichment.

Over a certain coolant temp, but UNDER several airflow thresholds, the pcm MAY allow or activate Lean Cruise.
Referencing several previous data points of closed loop, the pcm aims at a leaner AFR, adds spark advance, and checks to make sure engine load remains low enough to stay in Lean Cruise.

Sloppy Mechanics Wiki - Lean Cruise

How-To add Lean Cruise to p01 ecu (haven't tried with p59...may also work??) By Grady Do this at your own risk...please don't blow shit up...and if you do, don't blame sloppy ;)

sites.google.com

Weight and drag area will never allow GMT800s to spend as much time Lean Cruising as, say, cars.
Even so, the more time spent in 3rd or 4th with the TCC locked, the better.

Here is a quick pic of a log. Notice STFT basically all 0. That's one confirmation it's in lean cruise. Also look at 02 sensor bar in middle..they stay down low dead lean . Commanded afr reads 19.32 but actual reading is 18.3 to 18.5. I have an older innovate wideband that doesn't import well into hotuners ...will be getting newer innovate or AEM. However notice speed , tps percentage and calculated torque....I'm climbing a small grade right by my house. It's 45 percent throttle and indeed in lean cruise .... Now this log 2as right when I started populating own tables and targeting higher throttle blade openings to reduce pumping loss and trim afr like an airplane during lean of peak operation. It's tricky to accomplish smoothly because a plane is like a generator...fixed load. Driving on a road with grades and different speeds becomes a challenge. But In the 1.5 months I e been playing with this I am starting to get a handle on eq subtract ratios on a given Map reading and ramp in and out rates to make seamless transitions for various loads and keep afr in 16.9 to max of my wideband 19....the truck will indeed choke itself out when my commanded afr gets up to 22 to 1.... But I can't watch real time anymore than 19:1 or 1.25 lamda... And lean of peak actually results in much lower egt and cylinder head temperatures...in fact on day I was curious and was on a 20 mile run and right at end of run I popped hood with my inflated fleer in hand and radiator was 125 degrees....ect in engine was 190 but was totally bypassing radiator with closed thermostat at that point. Ambient was in 40s and only cooling came from heater core itself.... Lots of people concerned about melting pistons running lean...that's not the case at lean of peak ...melting pistons is too lean for conditions and power demand at time... Say wide open throttle max power your at 14:1. That's too lean for conditions and in peak egt range and will damage engine....but technically speaking 14:1 is richer than stoich ....but at wide open max power you need fuel to cool intake charge and max power is in 13:1 area....

 

[Mechanic prepper]

Here is a quick pic of a log. Notice STFT basically all 0. That's one confirmation it's in lean cruise. Also look at 02 sensor bar in middle..they stay down low dead lean . Commanded afr reads 19.32 but actual reading is 18.3 to 18.5. I have an older innovate wideband that doesn't import well into hotuners ...will be getting newer innovate or AEM. However notice speed , tps percentage and calculated torque....I'm climbing a small grade right by my house. It's 45 percent throttle and indeed in lean cruise .... Now this log 2as right when I started populating own tables and targeting higher throttle blade openings to reduce pumping loss and trim afr like an airplane during lean of peak operation. It's tricky to accomplish smoothly because a plane is like a generator...fixed load. Driving on a road with grades and different speeds becomes a challenge. But In the 1.5 months I e been playing with this I am starting to get a handle on eq subtract ratios on a given Map reading and ramp in and out rates to make seamless transitions for various loads and keep afr in 16.9 to max of my wideband 19....the truck will indeed choke itself out when my commanded afr gets up to 22 to 1.... But I can't watch real time anymore than 19:1 or 1.25 lamda... And lean of peak actually results in much lower egt and cylinder head temperatures...in fact on day I was curious and was on a 20 mile run and right at end of run I popped hood with my inflated fleer in hand and radiator was 125 degrees....ect in engine was 190 but was totally bypassing radiator with closed thermostat at that point. Ambient was in 40s and only cooling came from heater core itself.... Lots of people concerned about melting pistons running lean...that's not the case at lean of peak ...melting pistons is too lean for conditions and power demand at time... Say wide open throttle max power your at 14:1. That's too lean for conditions and in peak egt range and will damage engine....but technically speaking 14:1 is richer than stoich ....but at wide open max power you need fuel to cool intake charge and max power is in 13:1 area....

 

[Geotrash]

Very, very cool. Thanks for sharing!

 

[B-train]

Super cool. I remember hearing about holden and lean cruise years back and totally forgot about it. I've done plenty of diesel development, but not too much on gasoline. I know there are a lot of similarities, but diesels can be much easier because it's basically fuel injection timing and fuel rate.

Does anyone know if the 2007-2014 ecms are easy to tune, or if they have the lean cruise in them? 2008 Denali 6.2L for reference.

Thanks!

 

[Marky Dissod]

Does anyone know if the 2007-2014 ecms are easy to tune, or if they have the lean cruise in them?

Newer ecms don't get any easier to tune.
Though the principles are the same, the number of tables goes up a bit as does the complexity.

Instead of Lean Cruise, the Gen4 V8s get both variable cam phasing and V4 mode.
Both of those cooperating in tandem, are not quite as capable of improving MpG as Lean Cruise.
Nevermind that V4 mode can lead to increased oil consumption, and V4 mode lifters don't last as long as normal lifters.

 

[B-train]

Newer ecms don't get any easier to tune.
Though the principles are the same, the number of tables goes up a bit as does the complexity.

Instead of Lean Cruise, the Gen4 V8s get both variable cam phasing and V4 mode.
Both of those cooperating in tandem, are not quite as capable of improving MpG as Lean Cruise.
Nevermind that V4 mode can lead to increased oil consumption, and V4 mode lifters don't last as long as normal lifters.

True on the V4 mode. I purposely buy stuff w/o AFM. I just like good old fashioned V8 power. I'd be interested in meeting up with someone who does this within a reasonable distance just to learn and see the process.

Thanks in advance. This has been a thread I've wanted to expand on for quite a few years and now have like minded people to bounce things off. Good stuff!

 

[Mechanic prepper]

Been a minute since I been here but last week did fill up tank and make a run to wrecking yards local to me (75 miles one way) 2 days in a row. So roughly 250 miles at a steady 63 mph on cruise and rest of miles in Spokane which seems to have a light every half mile and never hit 2 greens in a row..lol. Traveled 511 miles and used 22 gallons. So average of that tank was a tick over 23mpg. Best prior to tuning was 15.9 on a tank and all hwy on long out of state trip. However it wasn't without complication. Sporadically truck would go dead lean and max out at 19.1 afr and loose all power. Instead of taking time to read log I just assumed I needed to richen up equivilance ratio due to warmer spring days with less air density. After fighting it on the drive the last 30 miles I just turned lean cruise off in file.... Right before I got home it went dead lean again.... So that night I went through data log...could see where truck went lean and looked at commanded afr and could see where power enrichment kicked on but actual was lean. So that night I changed fuel filter and installed my snap on digital fuel pressure gauge I can Bluetooth to my phone. Put lean cruise file back in and sure as hell my fuel pressure goes down to 8psi from 48 sporadically ....loosing a fuel pump and need to change... So even with all the reflashes the lean cruise does work and hopefully this week I will replace pump and .Ake same trips again to go pick up a few 4l80e cores I need to build for projects.

Frankly I'm very surprised at mileage but very pleased being gas is 4.48 per gallon here.