Average MPG Duration
 

I found on another thread that Bill said the Gryphon uses 100,000 samples at 1 second apart to determine average miles per gallon. That is supposed to equal about 4 tanks of gas. I do not think that is the case with my Gryphon.

The reason I think this is because it will usually drop a good 3 to 4 tenths sitting at a light for a minute or so. With 100,000 samples you shouldn't see that kind of drop for that duration.

My questions are:

How many samples does the gryphon actually use and how far apart are they?

How can I increase the ammount of samples it uses?

Thanks

The gryphon will keep recording until the alotted memory is filled up. Unfortunately the only way for it to increase the number of samples is to run longer. Otherwise it would be just as accurate as the instant mpg. It will keep taking one reading every second. (But I'm not sure since the data log will take 5 per second)
Instead of looking at it as 4 tanks which can run out quicker depending on where/how you drive consider the memory full after 28 hours of driving. If you have a 30 minute commute to work, after a month you'll have your average.

If you accidentally cleared the average mpg then you lose all those samples the programmer uses for refrence. There are a few ways for that to happen. One is to hit the enter button twice, but the most common is to have the programmer get unplugged or have the power taken away some how.

Thanks for the reply Longshot.

What you are telling me is the same that I heard before. About 28 hours of driving will compute the average. I am just questioning the accuracy of this. I don't see how a couple minutes of idling can effect the AVG MPG to the extent it does with 28 hours of samples.

I know what you are thinking. "He must have reset the AVG MPG or something." I can assure you this is not the case.

Hasn't anybody else noticed how it will drop quickly while idling? Is it just mine? The other day I was picking up my kids and idled for about 6 minutes and the AVG dropped over 2 mpg. Just doesn't add up to me.

My honest opinion is the Average MPG and Instand MPG is BS.

I did a 660 mile trip to Cali for a F150 meet few months back. It showed I averaged 14.7 mpg, filled up and hand calculated it. 14.3 mpg. It always shows high.

My truck showed I averaged 14.8 mpg my last tank. I hand calculatd it, it came out to 13.4 mpg. :shrug:

I filled up, went offroading.. mashing the gas, having fun. Showed me 13.4 mpg, got on the interstate (75mph speed limit) it jumped to 15.9 - 16.0 average mpg. It's never been over 15.8 mpg average except GOING to Cali it showed like 16.6 mpg and dropped constantly to 14.7 - 14.8 mpg doing the same speed for atleast 200 - 250 miles at a time to each gas station.

The slower I go, the worse my average mpg shows. Harder I drive it, the better it shows.. :smiley_roll1: My tires are stock size, stock gearing. So it shouldn't be off.

Sitting at a light it will drop from like 14.8 mpg to 14.4 mpg just idling. Or cruise control doing 70 mph and I gun it to pass someone it drops like 3 tenths..

I keep forgetting to change it to another parameter. Watching it is silly.

I don't really know what to say to you guys. Bill Cohron is responsible for much of the software/firmware in the Edge/Gryphon and when he states the Avg Econ uses 100,000 samples, I have to believe him. I know when I used to monitor it, the Gryphon's value would stay more constant than my dashboard message center's readout, which tells me the dash readout DOES use a smaller sample size.

And, in my case, sometimes the dash readout would be exactly what I would "hand calculate", at other times it would be a bit high. The Gryphon was always higher.

I HAVE determined that when my "low level warning" comes on, I have about 60 miles of gas remaining, assuming normal fuel usage rates (and how much I was able to put into the tank when this happened).

I really don't monitor Avg or Inst Econ anymore. I just use the trip odometer feature in the dash and the gas gauge itself.

- Jack

Well you dont necissarily need to reset it for it to move. I figured you were talking about sitting at a light for 30 seconds. Lets say you have 1200 readings(20 minutes) of 17 mpg. Average in 360 readings (6 minutes) of 0 mpg or idle and you end up with about 13 mpg. If you had an hour (3600 reading) of 17 mpg driving you would still get dropped to 15.5 avg mpg.

And this was using an average of 17 mpg because I've heard of better and worse averages (and its pretty much what mine gets), if you went up a hill and had to give it some gas, that could lower the sample for those few seconds. Averaging that with a zero will make an even bigger impact.

My readings are continuously high also.
The same thing happens when sitting at a light the read out drops only about .1-.2mpg.
On the other hand when I get into it my average goes up by 3-5mpgs then after about 10 miles of hwy driving it levels back out.
I'll stick with the hand calculations over the digital readouts any day.

There is alot of people saying it reads high and it drops alot when idling at stoplights or what not.

And, if we're at the "stabilized" 100,000 sample calculation, all we're doing is multiplying by 100,000, adding zero and then dividing by 100,001 each second. Doesn't look to me like much would change.

After 30 seconds of zero mpg at a stoplight, and assuming a "stabilized" Avg Econ reading of 15.5, the equation is: 15.5 x 100000 / 100030 = 15.49535, which "rounded" is still 15.5. And I still get 15.49071 after 60 seconds. After 2 minutes, it's 15.48142, which is still "15.5". At this rate, looks to me like we could sit for at least 5 minutes, before we'd see 15.4.

Maybe the Mad Doctor will enlighten us when he returns.

- Jack

So if a person typically resets after every tank they are not getting the full effect of the AVG MPG. They should wait and reset after 4 tanks? Or don't reset at all?
The only reason I bring this up is if a person does reset it at every fill up then there would be less samples to draw from thus sitting at an idle would have a bigger drop? Am I applying the right reasoning?

i always reset mine when i get on the highway for more then about 50 miles. but where i live there is alot of hills so i get horrible MPG until i get about 35 miles west of where i live

the average MPG that comes on the truck not gryphon.

Yep, but as I said earlier 4 tanks is not always the 28 hours. I could burn through 4 tanks about 16 hours depending on how much I drive. I would only reset it after maybe you make a large change. As in when they change from winter to summer gas or if you put on new tires. Once you start getting past 50K readings the mileage isn't going to change much.

Haha, its a shame the gryphon cant record run time like some of those bike odometers. Mine will show how many minutes/hours I've have been riding the bike for. I wonder if Bill could add a feature like that to the gryphon. It probably wouldn't be hard if he can because the gryphon records engine run time for the average mileage anyways, 1 reading per second. Take the readings and divide them by 3600 and you have runtime hours. But I dont know much about the development capabilities on his side. As far as I know he could make the gryphon shoot out fire and sparks if he wanted. :hehe:

Okay I feel better now. Thought it was just my unit.

The only thing that makes sense is that it does not use 100,000 samples at 1 second apart. Either it uses less samples or many more than 1 per second.

We will have to wait for Bill to give us some accurate numbers on this matter and possibly increase the duration the average mpg uses.

I drove around all day today after a full tank of gas and it reading 14.0mpg. City and highway, then once I headed home which was like 10 miles, it went from 14.0 to 14.3mpg.. lol.

I've seen where it will show say, 15mpg and I hit a red light, sit there for a few seconds, light turns green, hit the gas and it drops to like .1 a few times for like 10 seconds. Then I'm showing 14.6mpg when it was showing 15mpg for like 30 mins doing the same driving style.

Or maybe I have no idea what I'm seeing. I don't reset my Average MPG, I didn't know we could. Either way I can see if I'm getting good gas mileage if I see 100 miles at 1/4 tank, if I see 60 at 1/4, I'm getting HORRIBLE mpg lol.

Haha wow. I've gotten over 430 miles on one tank without any lights or warnings coming on and I was just about to touch E...and that was before the programmer. :cheesy smile: I get even better mileage now.

I have also noticed the same thing, The idea that it resets too much to be too accurate im not sure if i agree with, it makes sense, but i have never purposely reset the grypon, I have unplugged it 2-3 times since i have had it, but i drove to Utah (8-9 hours), drove around there quite a bit (2-3 hours) drove to Wyoming (3-4 hours),drove back to Utah(another 3-4 hours), drove around a lot there(2-3 hours), and drove back to Colorado(another 8-9 hours), drove around here for at least 2 tanks now and I haven't reset it since, but it still seems to drop rather quickly, quicker than it should after 100,000 readings.
I also agree with the statement that they are just going to be inaccurate no matter how you do them.