Lean cruise
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Lean cruise alright- new questions on actually tuning lean cruise.
the tab under COT, Lean cruise > EQ Ratio Subtractor > vs. RPM vs Cyl Air
I need clarification- hp tuners description here states this value is how much fuel is subtracted from the closed loop fuel/air ratio to lean the mixture. EG. if the value is 0.1 and the current F/A Ratio is 1.0 then the resulting Fuel / Air multiplier is 0.9 or 14.7/0.9 - 16.33 AFR
Can someone explain that a little clearer to me? I am not sure what it means if the current F/A ratio is 1? what is that 1?
For PE you take the enrichment factor and divide it by stoich (the 14.7) and you get your new commanded value...but for this it appears there is two numbers for calculations? 0.1 and 1 in the example?
I'm confused.
the tab under COT, Lean cruise > EQ Ratio Subtractor > vs. RPM vs Cyl Air
I need clarification- hp tuners description here states this value is how much fuel is subtracted from the closed loop fuel/air ratio to lean the mixture. EG. if the value is 0.1 and the current F/A Ratio is 1.0 then the resulting Fuel / Air multiplier is 0.9 or 14.7/0.9 - 16.33 AFR
Can someone explain that a little clearer to me? I am not sure what it means if the current F/A ratio is 1? what is that 1?
For PE you take the enrichment factor and divide it by stoich (the 14.7) and you get your new commanded value...but for this it appears there is two numbers for calculations? 0.1 and 1 in the example?
I'm confused.
( EQR 1 is the stoich AFR, there is a setting in your tune file, probably either 14.63 or 14.68 )
so the LC multiplier (what is left after subtracting the 0.1) and the PE factor are EQR's... there is a pid EQIVRATIO that reports the commanded EQR (i.e. the final divisor).
In other contexts, FAR is 1/AFR.
Last edited by joecar; Aug 13, 2015 at 12:20 AM.
alright- new questions on actually tuning lean cruise.
the tab under COT, Lean cruise > EQ Ratio Subtractor > vs. RPM vs Cyl Air
I need clarification- hp tuners description here states this value is how much fuel is subtracted from the closed loop fuel/air ratio to lean the mixture. EG. if the value is 0.1 and the current F/A Ratio is 1.0 then the resulting Fuel / Air multiplier is 0.9 or 14.7/0.9 - 16.33 AFR
Can someone explain that a little clearer to me? I am not sure what it means if the current F/A ratio is 1? what is that 1?
For PE you take the enrichment factor and divide it by stoich (the 14.7) and you get your new commanded value...but for this it appears there is two numbers for calculations? 0.1 and 1 in the example?
I'm confused.
the tab under COT, Lean cruise > EQ Ratio Subtractor > vs. RPM vs Cyl Air
I need clarification- hp tuners description here states this value is how much fuel is subtracted from the closed loop fuel/air ratio to lean the mixture. EG. if the value is 0.1 and the current F/A Ratio is 1.0 then the resulting Fuel / Air multiplier is 0.9 or 14.7/0.9 - 16.33 AFR
Can someone explain that a little clearer to me? I am not sure what it means if the current F/A ratio is 1? what is that 1?
For PE you take the enrichment factor and divide it by stoich (the 14.7) and you get your new commanded value...but for this it appears there is two numbers for calculations? 0.1 and 1 in the example?
I'm confused.
In the context of what you said, FA ratio is EQR (equivalence ratio) which is simply defined to be 1/Lambda... i.e. it divides into AFR (whereas Lambda multiplies into AFR) to achieve commanded AFR...
( EQR 1 is the stoich AFR, there is a setting in your tune file, probably either 14.63 or 14.68 )
so the LC multiplier (what is left after subtracting the 0.1) and the PE factor are EQR's... there is a pid EQIVRATIO that reports the commanded EQR (i.e. the final divisor).
In other contexts, FAR is 1/AFR.
( EQR 1 is the stoich AFR, there is a setting in your tune file, probably either 14.63 or 14.68 )
so the LC multiplier (what is left after subtracting the 0.1) and the PE factor are EQR's... there is a pid EQIVRATIO that reports the commanded EQR (i.e. the final divisor).
In other contexts, FAR is 1/AFR.
So is the EQR always 1? when would the EQR ever change? only while in PE mode correct? I am hoping at cruise this isn't a moving target because that just makes things really really really complicated.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Lean cruise I have found a way (well not me, someone else) to have lean cruise work - or theoretically should work anyways.
So is the EQR always 1? when would the EQR ever change? only while in PE mode correct? I am hoping at cruise this isn't a moving target because that just makes things really really really complicated.
So is the EQR always 1? when would the EQR ever change? only while in PE mode correct? I am hoping at cruise this isn't a moving target because that just makes things really really really complicated.
CL EQR is 1 (this what CL triming does).
PE EQR is from PE table.
Also, EQR can be set by the various protection modes (COTP, PPM, EPM).
You can set up OLFA table to run leaner during cruise, but this is not the Lean Cruise mode refered to in this thread.
OL EQR is from OLFA table.
CL EQR is 1 (this what CL triming does).
PE EQR is from PE table.
Also, EQR can be set by the various protection modes (COTP, PPM, EPM).
You can set up OLFA table to run leaner during cruise, but this is not the Lean Cruise mode refered to in this thread.
CL EQR is 1 (this what CL triming does).
PE EQR is from PE table.
Also, EQR can be set by the various protection modes (COTP, PPM, EPM).
You can set up OLFA table to run leaner during cruise, but this is not the Lean Cruise mode refered to in this thread.
Sorry my laptop isnt in front of me at the moment, maybe that is a dumb question
You guys are way overcomplicating it. On a drive by cable car like an F body, go into the system section (this works in HPTuners, I think EFILive can do it to though I haven't tried, I know Tuner Cat can). It does not require a CAX. The drive by cable vehicles need the CAX in EFILive or they lose cruise control.
Change the platform code to V. Now open the system options table, and copy your original platform data from F to V.
Congrats, your car now passed the platform check with no hack as V is Holden.
Now go setup the eq ratio table, on/off criteria, subtractor, and afr spark adder.
Change the platform code to V. Now open the system options table, and copy your original platform data from F to V.
Congrats, your car now passed the platform check with no hack as V is Holden.
Now go setup the eq ratio table, on/off criteria, subtractor, and afr spark adder.
I think I've posted that before, but I'd I didn't I'm sorry. It works fine. No OS hack needed. I've been reluctant to post it everywhere because I don't want to see access to the platform code and system options table go away in those cars, but at this point I've got enough stock files setup correctly that I can write them into any vehicle that I want to enable it on, so I don't care anymore.
You guys are way overcomplicating it. On a drive by cable car like an F body, go into the system section (this works in HPTuners, I think EFILive can do it to though I haven't tried, I know Tuner Cat can). It does not require a CAX. The drive by cable vehicles need the CAX in EFILive or they lose cruise control.
Change the platform code to V. Now open the system options table, and copy your original platform data from F to V.
Congrats, your car now passed the platform check with no hack as V is Holden.
Now go setup the eq ratio table, on/off criteria, subtractor, and afr spark adder.
Change the platform code to V. Now open the system options table, and copy your original platform data from F to V.
Congrats, your car now passed the platform check with no hack as V is Holden.
Now go setup the eq ratio table, on/off criteria, subtractor, and afr spark adder.
My main concerns now are trying to understand each of the tables for lean cruise.
Like I said, I really wish hp tuners had a better glossary of settings setup so that I could better understand what is going on when I change functions. I still need/want to know if the lean cruise tables are only functioning during close loop operations?
I will likely start with the settings from a holden vehicle, but I also want to be a little less aggressive than those tables as well as I have heard the holdens see as high as 17afr on lean cruise. I'd like to see 15.5-16 kinda max. I don't have EGT's in either of the vehicles and cylinder temps is a bit of a concern- even though holden is set that way from factory...
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo It'll still work if you're in open loop or closed loop. It just needs to pass the mph and enable time values, I'm posting from my phone but I believe there's a engine run time requirement and a time above the turn on speed requirement. Once you hit that, the commanded AFR will lean out.
I usually keep the lean out rate slow so I don't feel it engage. Like in power enrichment, I set that high because when I want to go fast, I want the fuel instantly. With lean cruise I let it happen slower (over a few crank rotations) so you can't feel it happen in the seat of your pants.
Remember to add timing in the AFR adder table, otherwise you won't gain much if any MPG... Could potentially even lose MPG.
I usually keep the lean out rate slow so I don't feel it engage. Like in power enrichment, I set that high because when I want to go fast, I want the fuel instantly. With lean cruise I let it happen slower (over a few crank rotations) so you can't feel it happen in the seat of your pants.
Remember to add timing in the AFR adder table, otherwise you won't gain much if any MPG... Could potentially even lose MPG.
Not sure what is over complicated about clicking an apply button, saving the file and writing the entire file with TunerCat. And it leaves the platform type correct for the vehicle.
Should it be stated tunercat for obd2 has not been available for sale to the general public for several years and only a few relative to hpt customers own it. Not sure why you keep talking about it repeatedly if no one can buy it and those that have it charge to use it. Kind of like I have a secret and you never hear what it is. Is that bragging?
You can call it whatever you want. I'm just stating another way to enable LC. You don't have to own TC OBD2 to use it, you just have to know someone that has it. And I know several people in my little part of the world that have it. It's not that rare. And you can still buy it from Moates.
Should it be stated tunercat for obd2 has not been available for sale to the general public for several years and only a few relative to hpt customers own it. Not sure why you keep talking about it repeatedly if no one can buy it and those that have it charge to use it. Kind of like I have a secret and you never hear what it is. Is that bragging?
You guys are way overcomplicating it. On a drive by cable car like an F body, go into the system section (this works in HPTuners, I think EFILive can do it to though I haven't tried, I know Tuner Cat can). It does not require a CAX. The drive by cable vehicles need the CAX in EFILive or they lose cruise control.
Change the platform code to V. Now open the system options table, and copy your original platform data from F to V.
Congrats, your car now passed the platform check with no hack as V is Holden.
Now go setup the eq ratio table, on/off criteria, subtractor, and afr spark adder.
Change the platform code to V. Now open the system options table, and copy your original platform data from F to V.
Congrats, your car now passed the platform check with no hack as V is Holden.
Now go setup the eq ratio table, on/off criteria, subtractor, and afr spark adder.
My main concerns now are trying to understand each of the tables for lean cruise.
Like I said, I really wish hp tuners had a better glossary of settings setup so that I could better understand what is going on when I change functions. I still need/want to know if the lean cruise tables are only functioning during close loop operations?
I will likely start with the settings from a holden vehicle, but I also want to be a little less aggressive than those tables as well as I have heard the holdens see as high as 17afr on lean cruise. I'd like to see 15.5-16 kinda max. I don't have EGT's in either of the vehicles and cylinder temps is a bit of a concern- even though holden is set that way from factory...
You can still buy a version of tunercat OBDII from Craig Moates if you own a Roadrunner true real time tuning pcm or are willing to buy one. Its a bigger initial outlay of money then HP Tuners or even EFI Live but saving $100 a pop in licensing pcm's makes that differance disappear very quickly.
Oh brother, well isn't that special.....looks like I struck a nerve. :-)
I have had Tc for over 10 years and use it regularly and have tuned thousands of vehicles.
You can also use a hex editor and modify just about any P59 compatible os into a LC compatable file. So I guess it is really not complicated.............
Been there done that.
I have had Tc for over 10 years and use it regularly and have tuned thousands of vehicles.
You can also use a hex editor and modify just about any P59 compatible os into a LC compatable file. So I guess it is really not complicated.............
Been there done that.
Last edited by aknovaman; Aug 15, 2015 at 09:49 AM.
Oh brother, well isn't that special.....looks like I struck a nerve. :-)
I have had Tc for over 10 years and use it regularly and have tuned thousands of vehicles.
You can also use a hex editor and modify just about any P59 compatible os into a LC compatable file. So I guess it is really not complicated.............
Been there done that.
I have had Tc for over 10 years and use it regularly and have tuned thousands of vehicles.
You can also use a hex editor and modify just about any P59 compatible os into a LC compatable file. So I guess it is really not complicated.............
Been there done that.
I think the issue is, that "option" wasn't available when many were looking to do this...I also think most threads on LC get deleted or locked...which this one may soon to by the looks of it.
Then I also think the other option is the guys who know this "hack" have mainly just PM'd the info and not put it online fearing hp tuners may take away this function...