Contact the user but it's been 10-11 years so good luck trying to get a link that old to work ever again.
Tuning the VE and MAF the best you can will get you the best results, slightly adjusting the o2 switching voltage could help or heck you could go straight open loop forever and command a leaner AFR everywhere outside of PE. Not sure I'd want to do that though.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
same here. I'd like to see it too. Read all 14 pages with out seeing itOriginally Posted by gnnova
Here's the essence of the attachment:
fuel economy tweak.jpg
Best regards,
Bill
Silver 2003 C5 roadster, M6, Euro red/amber tails, Z06 Ti mufflers, Z06 2 cat H-pipe, Z06 airbox, and HPTuners s/w - available to any Corvette or other GM vehicle in Calgary, and also for Ford and Dodge products, including Cummins
Here is the original as I had copied it for reference.
hi bro how r u could u tell me step by step in which tables we can go and make changes to make good fuel mileage and which which table we can make changes to get horsepower of all gmc cars
how come i cant view/modify half of the things people show? my pcm is from a 2005 silverado 4.8l. cant view.PNG
Because you are in basic view.
Switch to advanced view under the edit tab.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Thanks 5FDP, thats what i was trying view
hello guys
do u have any tuned fuel economy file for gen3 or 4 GM
attach it pls
thans
i would expect tuning to be unique to each ecm/engine, unless 2 tuners had identical stock engines
play with deceleration fuel cut off(DFCO), upshift/downshift tables, & torque converter lockup tables for minor improvements
& lean cruise mode if you happen to have an aussie ecm
Last edited by shanekennedy; 08-19-2021 at 02:27 PM.
If you post your current tune and a highway log, I and others will jump in and make some suggestions.
Best regards,
Bill
Silver 2003 C5 roadster, M6, Euro red/amber tails, Z06 Ti mufflers, Z06 2 cat H-pipe, Z06 airbox, and HPTuners s/w - available to any Corvette or other GM vehicle in Calgary, and also for Ford and Dodge products, including Cummins
Sami 2008 Tahoo.hpt
Has anyone tried the MPG paid that Scott came up with early on in the thread? Or is there a better alternative to logging MPG? The numbers I'm seeing aren't close to my actual MPG when I hand calculate it. I've probably got one of the units wrong in the user math but I'm not sure what each one should be?
I do have an Aussie ECM but no lean cruise for me
I have lean cruise in my US controllers. Tuned and enabled lean cruise on several P01s and P59s now. Trade secret. My Express van runs open loop idle, closed loop off-idle and in lean cruise at highway speeds. That one is actually a mexican based GMT800 L31 350 tune though.
Gonna try this out tomorrow.
Will report back
DFCO seemed to work really well. Picked up some mileage. I live in a very hilly area. Haven't run a full tank of gas yet but there is a noticeable difference in the 2 100 mile trips we've.
The richer reading at idle seemed to help with the Cam too. AFR was better at idle.
I did not notice a large dip in the AFR while cruzing with the mode reading changes. I may not have hit the right zone in the tune. I do have a supercharger so I didnt go very far. Under low boost I dont command a Rich mixture.
Last edited by HellKnightHicks; 02-03-2022 at 11:49 PM.
2003 Yukon SLT 5.3l with 3.73 gears and 4x4 w/air
Averaging 24 mpg highway and 21-22 city depending on traffic, lots of stop and go drops it appreciativley with no help for that unless it is to use a wind sail or be towed.
Going to catch a whole bunch of "aint so!" and " you cant do that" and even "liar liar"
I know the moon will fall on my head and I will rot for ever in the depths of hell
but ok
I got mine and have had it for 90,000 plus miles with no oh my gods what have I done.
1) take the low octane timing table and bump it up by at least 5 across the board
2) smooth out said timing table in the 1200 to 3000 ish rpm ranges
3) really take the time to smooth out the VE table, get rid of the bumps and dips
4) bump up the VE table across the board by at least 3
5) make sure that afr is around 14.2 or so
6) back down knock retard by 2 degrees but do not delete it
That will be a good starting point and tweak as needed by very small amounts
having said that each vehicle is a different character and needs to be treated as such
just for S A G I did the same for a workmates 2002 suburban with a 5.3 and he was more than happy driving across the state with no problems
I drove 130 miles a day for work for several years and it is my daily driver now that I am retired and go where I want.
It does run better in open loop only though.
Been building and tuning everything from daily drivers to 1/4 mile draggers, even a few fuelers for over 40+ years
yes lambda is perfection on paper and engineering formulas and all the experts will have a hard time with this epistle
I dont look at fuel trims and so dont ask
I like control of my machine and let the computer handle minor stuff since I own it and I rely on it it is mine to use.
trained by an Air Force Staff SGT who took care of WW2 bombers in the last world war, great guy with a whole lot of insite on IC engines and how to make them run.
nough said,,do what you will, say what you want.
This is how I run all my cars since 1998. Open loop is superior in all ways for wideband tuned engines without closed wideband operation.
Narrowband closed loop will drag it back to some unwanted 14.7:1 target which is never a desirable a/f ratio.
Narrowband closed works as a handicap for mediocre tuning, lack of maintenance, like when you hand the car to a customer and they don't properly maintain the engine, of course the a/f will wander over time. Or maybe they drive to a new location up higher altitudes and you never tuned for that. Or maybe a MAP sensor is wandering due to poor quality.
The narrowband can serve a function for those situations, but notice none of those situations apply to us as individual engine tuning experts.
i.e., tuning experts:
1. Fully tune the engine
2. maintain the engine properly
3. Re-tune as needed for new situations and parts changes
4. Use high quality sensors and would never stand for that type of behavior
Keep in mind: Modern EFI for serious cars/racer will use a stand-alone with closed loop wideband operation. The feature is worth it's weight generally speaking even if only for safety purposes.
The discussion of narrowband specific closed loop falls under a very limited scope of extremely rare situations where performance is demanded from an OEM ecu without wideband closed a/f, in which cases I recommend you disable it completely and learn how to fully tune the engine by wideband open loop, which is how the first stand-alone computers (from say 1998 to 2007~) always forced you to tune since closed loop wideband didn't appear until later years.
General ranges gasoline a/f
General range for economy: 14.9 to 16.5:1
General range for power: 10.8 to 12.8:1
Example situations
Transitional into power 80-90KPA: 13.2 to 14.0
Gently accelerating up a hill on the highway 65-70KPA: 14.1 to 14.4
Boost threshold 95-115KPA: 12.65 to 13.25
Cruising along at 65MPH, 43-53KPA: 15.2 to 16.2
You basically avoid 14.7 completely no matter what the situation or demand from the engine is. 14.7 is an unwanted setting in every case.
Running at least 14.9 to 15.5:1 will cut down on HC emissions, which will reduce carbon coating of the combustion chamber, keep plugs cleaner, reduce carbon buildup rate. Plugs start coming out looking 'new white' after 50k miles instead of tanned and browned up like 14.7 will do.
Running leaner won't save much fuel but it cleans up the engine internals and maintain the spark plugs well.
No matter what you must run a full PCV system to keep the crankcase clear of combustion byproducts if you wish to keep the engine for a long time healthy and clean.
Now, the real question is how to save fuel.
Fuel use for a cruise is mostly related to vehicle weight and the rotating/rolling friction necessary to keep that weight moving on Earth.
There are myriad sources of friction, I can not list them all but I will some: wind resistance, tire friction with ground (tire pressure AND compound matters), differential gears, piston rings, transmission internals as planetaries and shafts through bushings, every snap ring and baulk ring riding up against a rotating internal series of shafts, Oil pump resistance, alternator resistance, water pump etc... accessories and internal pumps, cam lobe to lifter interface, valve spring force to overcome(heavier springs = harder to turn the engine = more fuel use), Crankcase pressure (exerts force on the bottom of every piston causing energy loss and reduced economy), axles and CV joints, every snap ring and baulk ring riding up against a rotating internal series of shafts, vehicle alignment, wheel bearings,
Alright you see there are enough sources here. And so begins your journey to becoming an economy master, this is what we do: Go through every single one of these items and ask yourself "how can I reduce the friction of ________?" and then start doing it.
For example to start off simple, check tire pressure and alignment. This is very basic but it can also be very challenging, getting the alignment perfect can be very difficult if the vehicle is old, tweaked, wrecked, or it's suspension has been changed or aged, severely used, etc... and still it must be done to drive the car like a normal car everyday. Since we are discussing economy I automatically infer that the discussion topic is daily drivers, or long distance drivers, since those are the main economical concessionaires.
Now, what tire pressure did you use? There is some specific number for every tire which can relief max economy. You probably need to test different pressures to find it.
How do you test economy:
Fill tank -> Drive X miles -> Fill Tank back to the top and divide miles out to get MPG.
Example
Fill tank -> Drive 200 miles -> Fill Tank (10.1 Gallons) so 200miles / 10.1gallons = 19.801 miles per gallon.
Do not use in-dash MPG reports or other computer calculated details.
Remember gas station 'gallons pumped' can also be wrong, and tire size changes constantly (you are losing rubber so engine rpm is always gradually increasing at the same speed) , And other details change (type of surface driving on matters, cement causes more or less friction than say asphalt, sand, etc...) and water content also alters friction.
Therefore, you can never rely on just 1 measurement. You must repeat the MPG test many times, collect as many data points as you can and then average them or even toss the outliers assuming you can logic why the condition caused the reduced or excess economy.
Couple more examples before I leave you to it
Going through a transmission there are many placses you may be able to reduce friction,
for example in the 4l80e at the tail shaft there is a flat shim the output shaft rides on, it can be changed out for a roller bearing which will reduce friction of the output shaft rotation. Similarly just by replacing bushings and sanding races for sprags and carefully file the tangs on certain drums, by setting some clearances 'more tightly', some parts get special coatings or treatments, all these little changes add up to reduced energy lost. You might think a tighter bearing or bushing would create more friction but it seems that by holding the shaft and seals more tightly there is less wasted energy from the shaft or seal moving around or leaking due to vibration or subtle changes in surface tension between two parts holding a lubricative film.
I know the inside of a trans could be scary so lets do some more general approaches. You can
1. reduce the weight of wheels (lowers overall vehicle mass AND rotating mass) This is where I point out that a $3400 set of forged aluminum wheels can save you 0.7mpg
2. reduce rotor weight and brake weight somehow (on some cars there are better brakes which also weigh less, or use smaller rotors ex. aluminum vs iron calipers, 26mm vs 30mm rotors)
3. Reduce interior/exterior weight (lighter hoods & throw out the back seat? I saw a guy cut holes in his door once) use imagination
4. Light weight driveshaft: I actually do not recommend this if you have a decent steel shaft already and it doesn't vibrate or cause noise, stick with it
5. High performance clutch/converter: This one is overlooked ALOT. There are some very efficient, 9.5" torque converters and similarly some very high quality, well balanced suitable clutch kits for performance engines which will dramatically improve the character and to some extent the economy of any vehicle. A factory converter at least is much extra heavy weight unwanted.
6. Wheel bearings and front/rear end stuff that moves or rotates: Whether it rotates or not, any suspension component not properly lubricated, set or damped to do it's job will cost energy and add friction.
Rotating weight discussion:
Part1: Rotating absorption and release
Objects that have to increase in rotational speed must absorb energy. Therefore, higher mass objects which absorb more energy tend to reduce economy.
It is true that once the energy is stored, some of it can be returned back to the drivetrain and recovered. For example, engine braking, or vehicle coasting (you can shut the engine off and coast for a bit on stored energy). The thing is, in a real world situation, very few people coast around from stoplight to stoplight, shutting their engines or just coasting 5mph up to a redlight for 1/4 mile like is necessary to fully recover all the energy from the rotating objects on the vehicle.
Usually, a person will accelerate quickly and then use their brakes to dissipate the rotating energy rapidly instead of coasting to a stop naturally.
-> Anytime vehicle brakes it is throwing away that rotating or kinetic energy that was initially invested into the vehicle.
Therefore, the heavier rotating objects, even though in theory you can recover alot of energy by coasting, it is rarely done in practice. thus it is best to minimize those rotating weights (wheels, driveshafts, axles, gears, etc... )
Part2: rotating RPM
The speed these rotating objects move is also very important. For example, a 5.3L Engine may cruise comfortably at 80MPH, 2200rpm, 3000lbs vehicle weight, 65KPA, 25MPG
But if we adjust the vehicle gearing so that now it is: 80MPH, 2700rpm, 3000lbs vehicle weight, 58KPA, 20MPG
With less engine load, same weight, same speed, it may lose 5 miles per gallon because a 5.3L engine uses that much more energy to rotate at 2700rpm instead of 2200rpm.
If we do the same thing with a modern 3L Engine or 2L Engine we would find that they are much more comfortable cruising at 2700rpm or even 3000rpm due to their smaller sizes and reduced friction at those rotating frequencies, mileage isn't as affected.
Therefore you must examine your own engine and friction situation, determine what the optimal cruise rpm would be some some vehicle speed generally below 90MPH or 80MPH because after 80+MPH Usually the wind resistance becomes a significant factor and pushes the vehicle outside of an 'economical state' unless it is very light or very well designed for high speeds or something like that.
5.3/4l80e/turbo playthrough
https://www.corvetteforum.com/forums...ge-budget.html
cancer research
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