is lean cruise bad for the engine

[ExtTB]

would this affect the life of the engine even if i could do it in my LL8 I-6??

[Highlander]

its not bad for the engine. Only problem is if it pings...

[Boost]

I'll have to try to figure out how to enable that. I am getting tons of requests for ecomony tunes. Guess I better read up on custom OS...

[ScarabEpic22]

Well since the LL8s have never been able to do lean cruise like the Holden rides or 04 GTO, I dont know how you'd do it. As Highlander said, shouldnt have any effect unless it pings.

[2002_z28_six_speed]

Yes and No.

If you live in an emissions state they will nail you for the NoX emissions.

It can be a problem if you don't have it set up well.

I have tried running the engine at 17:1 for short periods of time. Basically what I have heard is as long as the load is low you will be ok.

[87gmc]

Been running lean cruise for a couple of years now. Just get ready for it to burn the cats up:beer:

[2002_z28_six_speed]

Not a problem here. No reason at all!

[Sid447]

I was under the impression,

lean-cruise raises cylinder head temps and thus raises ECT?

[Boost]

My initial thought is that I wouldn't worry about it damaging the engine. Most of the conditions where lean cruise is enabled are very low load anyway. Severe damage occurs at high RPM / load.

And I thought a rich mixture would cause hotter operating temps, or is that only on the rotary engine?

[GMPX]

On cars with reasonable camshafts you generally can't use it because the lean mixture causes misfiring. The jury is still out on the real world savings lean cruise actually makes, don't think it's going to turn a 6.0L in to a Honda Civic!

Cheers,
Ross

[Garry]

I was under the impression,

lean-cruise raises cylinder head temps and thus raises ECT?
Lean condition raises the burn temperature, so yes, anything will heat up more. Anyway, as someone else stated, under low load, this usually isn't a real problem. The only thing to watch out for is the cats, if you still have some ... IIRC, cat protection will add additional fuel when it kicks in to lower exhaust temperatures ...


lean cruise actually makes, don't think it's going to turn a 6.0L in to a Honda Civic!
Well, I sincerely hope not! :doh2::grin: J/K

[vzsv8]

I don't aggree that leaning the mixture ( from stoich ) will increase temp. If we are running lean at cruise than the load is clearly low, so if we go lean we are going lean from 14.7. Therefore less fuel than optimum, giving less temp.
This is not a guess, pilots regularly run 75% throttle at cruise and 50 degrees Celcius colder than stoich, for best safe economy.
On the other hand, if we start at 12.5 or so at full load and start to lean off temps will certainly increase, toward 14.7.
Does anyone have an EGT gauge and the ability to run lean cruise? There would be some interesting data to be gathered.
I think that PLX will be getting an order for Fathers' day:hihi:
Cheers, Steve

[Boost]

Thanks for the interesting info, vzs. Care to explain why you think that occurs? By the way I love the sig! :)

[kbracing96]

I have a log with Tech Edge WB installed and a pyro. This is all at highway speed. Load increases temp, but lean cruise doesen't let me know what you think.

[vzsv8]

I have a log with Tech Edge WB installed and a pyro. This is all at highway speed. Load increases temp, but lean cruise doesen't let me know what you think.
Your log is exactly what I have been looking for. I have mapped your EGT vs Throttle Position, filtering out transient throttle, low throttle, cold ECT and cell counts less that 10. It shows that as AFR leans off EGT drops. Not sharply, just a big, wide, fat curve.
My take is that 14.7:1 represents exactly the correct proportions of reactants (obviously), and so gives the hottest flame, if we vary from stoich then the flame cools and burns more slowly.
This means that a rich or lean mixture needs more timing, sort of explains B5908 (Fuel mixture spark correction) and its use for lean cruise.
More timing should compensate for the slower burn and lower temps even more.
The OEMs can't use this approach because a lean mixture gives good economy, controls CO and CH but fails NOx badly.
BTW your drive home from work is about 100Kph faster than mine:doh2:
Cheers, Steve

[kbracing96]

I'm glad you found it useful. :) I have had the EGT prob installed for quite some time, just have never really put it to good use.

Oh, and that was my drive home from the track this Sunday. My truck ran a best of 12.21@110.5mph, not bad for a 5300# pig at 4800' elv. (DA was 7000') :lol: And our interstate speed limits here are 75mph ;)

[GMPX]

All this talk of lean cruise reminds me. I was sent an Email a month or so back stating that on a Torrent download site there was some cax files posted that allowed lean cruise on all GenIII's from 2001+, US vehicles included.
If someone can find them please let us know what it's all about. I've had no luck in my searches.

Cheers,
Ross

[Chevy366]

Hmmm , does it really work ? : http://thepiratebay.org/torrent/4303296/Lean_Cruise_patches_for_all_ls1_engines
Tried DLing , nothing .

[GMPX]

Thanks for the link, from what I see yes that would do the trick. If you dig back far enough on our forum (or it was LS1Tech), there was some guys that figured out what needed to be done.

Cheers,
Ross

[Chevy366]

If someone can get it to download , would they post the file ?
I have tried several times and will not download .
Thanks

[kbracing96]

I got it to DL, but not quite sure what to do with it... Does it just go in the EFILive calibration folder, or in the tune it's self?? And will it only work on the Camaros and Vettes, or should it work on the trucks too?



Cax extentions for EFILive tuning software to allow you to activate lean cruise on US based camaros/corvettes.

Just dump these files into your calibrations folder in the lsb folder. Look for the new tables to show up and then do a full flash of the file after making the change, then all tables will be used.

Be warned. THESE ARE FOR TESTING ONLY. Do not damage my air. EDIT: It won't let me attach it's cuz it a TORRET file and I have not converted it... I can email it.

[kbracing96]

Does this work?

[Chevy366]

I think all you have there is the TORRENT start script , used to start the TORRENT file download , the file is 23.3kb in size , that file is 375b .
Still when I try to download it stalls or says "stalled" and just sits there , tried 2 different Torrent programs .

[Highlander]

someone please upload this to rapidshare.

[Highlander]

I got it to download but it doesn't work.. files are CAX Format.

[Chevy366]

I got it to download but it doesn't work.. files are CAX Format.

Can you post it here ?
It sucks , the EPA would force a gas saving setting to be restricted , especially now when gas is so high in cost . :mad:

[rpadams]

See if this link works:

http://rapidshare.com/files/139396339/EFILive_Lean_Cruise_Patch.zip

[joecar]

Ok, now what do I do with the .cax files...?

[vzsv8]

There is a readme file inside the zip, it says.
Extract this zip in to :\Program Files\EFILive\V7.5\Calibrations
When you next load a tune file you will see a option at the bottom of the engine segment, look for parameter B9000.
I never found B9000 but there is a new entry at the bottom of the engine segment, exactly as stated, called 'bad things inside'. This contains an option enable/disable lean cruise. It also states that all the maps and parameters also need to be set up as per the Holden calibrations and then you you do a full flash. Then if it works.:cucumber:
All the Holden info is available at Holdencrazy.
Good luck, Steve

[kbracing96]

There is a readme file inside the zip, it says.
Extract this zip in to :\Program Files\EFILive\V7.5\Calibrations
When you next load a tune file you will see a option at the bottom of the engine segment, look for parameter B9000.
I never found B9000 but there is a new entry at the bottom of the engine segment, exactly as stated, called 'bad things inside'. This contains an option enable/disable lean cruise. It also states that all the maps and parameters also need to be set up as per the Holden calibrations and then you you do a full flash. Then if it works.:cucumber:
All the Holden info is available at Holdencrazy.
Good luck, Steve

That seems to work as it shows up in the stock tunes I looked in, but it's not in the CO's like I am running, Will have to find some thing to try it on. :)

[Chevy366]

See if this link works:

http://rapidshare.com/files/139396339/EFILive_Lean_Cruise_Patch.zip

Guess I wasn't rapid enough , rapidshare seems to be off line now .

[kbracing96]

Try this :)

EDIT:
Sorry guys, we can't have these patches on our forum, try the torrent sites or pass them around via PM or Email.

[Chevy366]

Try this :)
Thanks kb got it . :cheers:

[kbracing96]

Has anyone tried this to see if it actually works? I want to, but my truck is COS3 and I broke the steering on my dads truck, so I haven't had a chance.

[Chevy366]

Thought you were gong to try it first . :gossip:
I run a COS3 as well , since you said it would not work with it I didn't try . :badidea:

[kbracing96]

Haha, I would if I could find a test vehicle around here I could put my WB in to verify it, but for whatever reason, the B9000 enable button doesn't appear in the COS's :( or I would test it on my truck since I have a permanit WB installed on it and the other tables are there.

[GMPX]

The Lean cruise routines won't work on a custom OS because the custom OS's run in open loop mode, Lean cruise is only activated once the PCM is in closed loop.
The whole idea behind the AFR table in the custom OS was to be able to create a pseudo Lean Cruise mode anyway.

Cheers,
Ross

[Chevy366]

The Lean cruise routines won't work on a custom OS because the custom OS's run in open loop mode, Lean cruise is only activated once the PCM is in closed loop.
The whole idea behind the AFR table in the custom OS was to be able to create a pseudo Lean Cruise mode anyway.

Cheers,
Ross
Thought that was the case for the COS .
So , in your opinion do you believe this patch will work ?
Have you seen or tried it yourself ? :cheers:

[Sid447]

My initial thought is that I wouldn't worry about it damaging the engine. Most of the conditions where lean cruise is enabled are very low load anyway. Severe damage occurs at high RPM / load.
And I thought a rich mixture would cause hotter operating temps, or is that only on the rotary engine?

Rich mixtures cause incomplete combustion, the residual unburnt fuel helps keep things cool and "safe," though obviously not good for economy and emissions.
Factory tunes for example run some PE tables in the mid 11:1 ratios for cooling purposes (cat protection, exhaust valve).

A lot of the Holden tunes (holdencrazy.com) have factory validated lean cruise parameters in them. If you want to play safe, download a few of the Holden Commodore tunes and copy the same parameters.

Though a read of this might be helpful.
http://www.americanaviationinc.com/effectsCessnas.html

I've seen quite a few engines with piston damage due to weak mixtures and considering no HSV or Corvette tune uses lean cruise, it's for a good reason and they (GM) have an awful lot more money to experiment with this kind of thing than I do. Though having no lean cruise is clearly for performance applications.
As mentioned in the above link, a couple of extra gallons of fuel used is cheaper than a new engine.

Whereas for daily drivers that aren't tuned for all out performance and enjoy cooler climates than the desert regions, the parameters in the Holden tunes mentioned would be a help.

p.s. Unsure why ppl say there's no closed-loop operation in the Custom OS tunes?
OS3 (SD) here with CL operation.

[Chevy366]

Rich mixtures cause incomplete combustion, the residual unburnt fuel helps keep things cool and "safe," though obviously not good for economy and emissions.

p.s. Unsure why ppl say there's no closed-loop operation in the Custom OS tunes?
OS3 (SD) here with CL operation.

You do realize that , Ross is a owner of EFILive and programmer for it ? COS3 has a "Semi Closed Loop" mode which if values are set to stoich it will use O2 sensors for fueling , but you still have full control over AFR mapping .
When in COS3 , I understand that the some tables have been moved to another part of the EPROM memory , does the Algorithm still look for those tables and if not found , look for alternate tables , ones that were added ?

[joecar]

I've seen quite a few engines with piston damage due to weak mixtures and considering no HSV or Corvette tune uses lean cruise, it's for a good reason and they (GM) have an awful lot more money to experiment with this kind of thing than I do. Though having no lean cruise is clearly for performance applications.
As mentioned in the above link, a couple of extra gallons of fuel used is cheaper than a new engine.One of the reasons [among various] why lean cruise is not allowed in the USA is because it elevates NOx emissions well above the limits set by the EPA.

[joecar]

I though I had run COS5 in CL at various times...:nixweiss:

[Sid447]

One of the reasons [among various] why lean cruise is not allowed in the USA is because it elevates NOx emissions well above the limits set by the EPA.

Hello Joecar,

HSV don't either, though Holden did until end of 2004 as far as I know.

Yet the Holdens that came to the Middle East (badged as Chevrolet Lumina SS's Caprices) which were LS1 powered from MY2000 through to end MY2006 didn't have LC parameters in them either.
These ME cars, had considerably different tunes to the domestic Holdens and were speed-limited to 249kph.

This is an untouched Middle East tune for an '02 Lumina SS A4 which is basically the Holden Commodore VX series 2.

[Chevy366]

I though I had run COS5 in CL at various times...:nixweiss:

Why would you ? :confused::nixweiss:

[GMPX]

Thought that was the case for the COS .
So , in your opinion do you believe this patch will work ?
I looked what it did on one OS and yes it will work.



I've seen quite a few engines with piston damage due to weak mixtures and considering no HSV or Corvette tune uses lean cruise, it's for a good reason and they (GM) have an awful lot more money to experiment with this kind of thing than I do. Though having no lean cruise is clearly for performance applications.
If you look at the range of operation lean cruise is active from factory it should be safe enough, if I recall anything more than about 5% - 10% throttle and it stops. But I do agree with you that trying to save a few bucks on a fuel with a $20K engine is like filling it with generic $5 oil to save a few bucks.


I though I had run COS5 in CL at various times...:nixweiss:
Where you have 14.63 in the AFR table it will be in 'semi closed loop', not the same as 'full' closed loop like the factory PCM does. I am sure from memory (it's been a few years!) the PCM bypasses the lean cruise routines unless it is in full closed loop.

Cheers,
Ross

[joecar]

Why would you ? :confused::nixweiss:At various times I experiment to try various permutations... (I'm an engineer... I have to do that). :hihi:

[joecar]

Ross, I'll go back and check my logs... you're probably right. ;)

[Sid447]

Where you have 14.63 in the AFR table it will be in 'semi closed loop', not the same as 'full' closed loop like the factory PCM does. I am sure from memory (it's been a few years!) the PCM bypasses the lean cruise routines unless it is in full closed loop.
Cheers,
Ross

Ross,

I had LC activated for a while during 2007, though it was much more moderate than the factory settings (i.e. only between ECT of 80 and 99c with the target AFR EQ set at a maximum of 0.1) and the car ran in LC mode at around 15.2:1 (verified with PLX WBO2) within the normal Holden speed parameters that were set.

[Chevy366]

Once I get my new cam , springs and push rods , I may go back to MAF tune and try this then , got to re-tune might as well play some .
I think the Super Charger will have to wait till next year now .
Dang Economy is killing everyone .

[rally1]

I worked for a research company for a few years looking into ways of reducing NOX while running lean, we found we could very safely run around 16-18:1 on light throttle and low load with no adverse affect on the engine, we had a few test vehicles that coved tens of thousands of miles on the road and dyno with no damage to the engines. however running any leaner than around 17.5:1 will drop the efficiency of the combustion so low it will negate any fuel savings,

we had one engine running at 19-20:1 for some time with no damage, it didn’t drive that great but it was running!! We only did it to find out how lean you can go..

With our testing we found lean cruise did not make a huge saving in fuel economy, to the extent the technology need to run lean with low NOX cost more than the savings made over an average vehicle life.



HSV don't either, in the GTS SD tunes, yet Holden domestic did until end 2004 as far as I know.

HSV may have just decided that the fuel savings where just not worth turning lean cruise on.. for the same reason they did not turn on displacement on demand with there engines even though “some” LS2 had the hardware, after testing they decided the fuel savings just weren’t enough, after all most customers who are paying to buy the HSV badge don’t really care about the price of fuel.

[2002_z28_six_speed]

This is true but the latest diesels coming out for the new 2010 emissions laws MUST HAVE these technologies in place to even go into production. Times are changing aren't they!!

[joecar]

In the USA, the EPA/CARB want to reduce NOx emissions (which are produced when gasoline engine runs lean),
so gasoline engines won't be having LC from the factory...

Diesel engines don't produce NOx so the EPA/CARB have no issues with this.

[rally1]

In the USA, the EPA/CARB want to reduce NOx emissions (which are produced when gasoline engine runs lean),
so gasoline engines won't be having LC from the factory...

That’s the reason why we where working on a system in decrees NOx to a level that was accepted by the EPA/CARB while running an engine very lean.
I spent two years in Seattle working on it, we developed a system that would reduce the NOx buy around 90% while running lean but that was still not good enough for the EPA.

[ScarabEpic22]

What, Seattle what? 90%, that sounds like a pretty good start to me...

[GMPX]

I spent two years in Seattle working on it, we developed a system that would reduce the NOx buy around 90% while running lean but that was still not good enough for the EPA.

Is the EPA run by engineers and realists, or politicians worried about votes?

[Cougar281]

Diesel engines don't produce NOx so the EPA/CARB have no issues with this.

Actually, Diesels do make NOx, which is why they added the EGR :Throwup:: to cool off combustion temps and reduce NOx.

[joecar]

Then I stand corrected...;)...I didn't know they added :Throwup:EGR :Throwup: to diesels.

[GMPX]

Then I stand corrected...;)...I didn't know they added :Throwup:EGR :Throwup: to diesels.
Yes, but it seems to become optional for some :).

Cheers,
Ross

[Cougar281]

Yes, but it seems to become optional for some :).

Cheers,
Ross

EGR on a diesel should never have been implemented... Whoever thought it was a good idea has A) never seen the intake of a EGR equipped Diesel vehicle (VW's have HORRIBLE EGR problems) and B) doesn't care about longevity (With the soot that ends up stuck in the intake, you might as well have a really fine sand feed in your intake). My EGR has been dead for some time, and since I cleaned part of the intake when I killed it, the intake has remained clean, surprise surprise :rolleyes:

[ssvolvo]

This is how I clean my TDI intake!
http://www.youtube.com/watch?v=oet4qWeZuYA

[vzsv8]

I read an interview with the/an tuner for HSV and the question of lean cruise came up, his answer was that they did not consider that it was a priority for their customers. He also mentioned tip in response.
Unfortunatly I can't find the article, I pinched the magazine from the huge pile in the son's room.
Corvette probably has a similar market position.
As for Diesels they produce huge levels of NOx, which has been why in Australia at least until very recently they did not bother to measure it.
As for the Cessna link these motors are at around 65% load and they are running turbos (mainly to compensate for altitude). When I cruise I am using 20% or less load, at around 2000rpm. Very hard to burn a piston or valve like this, if in doubt check the EGT map I posted up earlier in this thread.
If it was bad for the motor, Holden would not have used it for years.
But perhaps F**d would have:grin:
Cheers, Steve

[ssvolvo]

Almost certainly some of you remember the old days when leaning out a carbed engine eventually lead to burnt exhaust valves, cracked heads.


One has to love late model fuel injection. I goofed my VE early on and was riding around at 17-18/1 A/F. Never would have known it by the way it ran.

[Wolfie]

RE: Where you have 14.63 in the AFR table it will be in 'semi closed loop', not the same as 'full' closed loop like the factory PCM does. I am sure from memory (it's been a few years!) the PCM bypasses the lean cruise routines unless it is in full closed loop.

Cheers,
Ross
-------------------------

I'm playing with it now, and I believe in OLmaf...
It does work this way.
I was leery of trying it as I rely on my vehicle day to day in my business.
But always looking for gas milage. I was just running with a commanded
afr of 16.30 but with leancruise am playing with 15.4

[Extinct]

Can anyone one email me the CAX file that was downloaded ? I have a 2006 truck that there is no COS available for that we would like to use the LC on.

Thanks

Tim

[Extinct]

OK, I got the zip file downloaded from the bit torrent site, however my idiotic version of Vista won't allow me to open it. Anyone want to extract the files and remove the permissions for me ? I can email it to you and then you can email it back ?

[joecar]

OK, I got the zip file downloaded from the bit torrent site, however my idiotic version of Vista won't allow me to open it. Anyone want to extract the files and remove the permissions for me ? I can email it to you and then you can email it back ?You mean these ones (post #8): showthread.php?t=9143 (http://forum.efilive.com/showthread.php?t=9143)

[Extinct]

I think those are probably the ones, thanks.