Off the line 0-35~

[Skulldragger]

In reading this forum and others I find that I should start off slowly and increase my speed to what is necessary for conditions to maintain the best FE. After getting my scangage and getting it all setup I find just the opposite to be true according to the readings it puts out.

First, the vehicle is a 2001 Chevy Z71, 4 door, 4x4, Mud Tires ( I use them way too often to be able to swap them out. ), 5.3L V8, 3+1 AT, BLACK (that makes it go faster? . The truck has 125k Miles on it and runs great. I keep the maintainance up on it as best as I can. EPA is 13-16mpg and I have normally averaged about 16-17mpg.

When I decided to look into driving habits to improve my fuel mileage I found that the normal recommendation was to start off slow and slowly speed up till I reach the required speed and then to maintain that speed as best I could. After getting and installing the ScanGauge I find that if I stomp the gas from a stoplight (setting the tps @ 50 from 0) which is just below squealing the tires, until i reach 35-40 mph then backing the throttle off till my mph reaches ~ 20-21 and keeping it there till I reach the desired speed (increasing the throttle to keep speed increasing and my mph about what my max will likely be) and I can maintain an average of ~20 mpg over the tank.

Am I doing it wrong? If I do the slow start I drop back to 17 maybe 18 if I am really careful.

[Krayzie]

you dont need to "stomp" on it but if you use the LOD setting. You should be in around the 70-80 mark for acceleration.

im sure someone with more knowledge can clarify

[Lokalazeros]

Hi,

ICE engine are more efficient when operating under a certain load, usually found between 65-85%. Try this for a week: Have the gauge ''LOD'' (Engine Load) on your SG display, and try to maintain this value between 65-85% when accelerating while shifting to the taller gear as soon as possible without bogging the engine (MT right ? oh nevermind, just saw you had an AT).
What would be better, would be if you found a BSFC graph for your specific engine. That graph would show you exactly at what load/rpm you should keep the engine. Beware, these graph are kinda rare, and may not even exist for a specific engine

Anyway, have fun with all those EPA and fuel efficiency related things

[Dr. Jerryrigger]

Edit: Lokalazeros, you posed wile i was writing this... so yeah, it's now rather redundant...

I have found the same thing (but it took much longer, as I still don't have a scan tool).
look at: Brake Specific Fuel Consumption (BSFC) Maps - EcoModder

Your engine is likely not on this list, but it shows with other engines, that you get more energy out of your fuel by running it a little bit harder (well hard to my standards). So you want to maximize this to get up to speed, and then drive as gently as you can.

[user removed]

With the automatic you want to use as much throttle as you can without delaying the upshifts.

regards
Mech

[comptiger5000]

In my Jeep, I find I get best mpg around 1/3 throttle on accel, which shifts around 2300 rpm. If I go too much slower, it takes forever to get up to speed, wasting a bunch of gas. Much faster, and it brings the RPMs up too high. By the time I get up to about 2500+ on acceleration, she's really hauling, so the only need for that is merging.

[Skulldragger]

Ok, thanks all. At least now I don't feel like I have something broken. I think after I get the driving habits fixed I will start working on mods, I think I need to learn the basics first.

I appreciate the help, and will look around for that graph. perhaps I will get lucky.

[Skulldragger]

By the way, has anyone else had problem with the ScanGauge2 causing the Radio clock to not keep time? Mine has just reset to seemingly random time every time I leave it for a few hours or more. Only happened since I have had the scangauge plugged in.

[Skulldragger]

Originally Posted by Krayzie

you dont need to "stomp" on it but if you use the LOD setting. You should be in around the 70-80 mark for acceleration.

im sure someone with more knowledge can clarify

Ok, I set the gauge as you suggested and tested it out. I am now wondering if there is a calibration that I need to do for this part of the gauge as well. I have calibrated the speed, engine size, tps, but even if I floor the silly thing I only bring the LOD to ~40 ( the mpg drops to 1.5-2, tps is 100, tires are squalling ) If not then i suspect I would have to be pulling or carrying a lot of weight to get the engine to preform at 60-80% capacity. It "seems" like the 20% range is where it shifts about right but still accelerates quick enough that the Police look at me and stare a bit... My "normal" acceleration would only pull about 8-10% but then my "normal" driving habits are what I am trying to fix.

[DonR]

Originally Posted by Skulldragger

By the way, has anyone else had problem with the ScanGauge2 causing the Radio clock to not keep time? Mine has just reset to seemingly random time every time I leave it for a few hours or more. Only happened since I have had the scangauge plugged in.

It never affected my Mitsubishi. I have recently switched it to my 97 Suburban, which I haven't driven for some time. I noticed that I need to reset the clock quite often now. I will unplug it for the ride home & see what happens this weekend. I just figured the bus was 13 years old & doing weird things.

Don