Best Engine RPM for minimal FE loss.

[ptjones]

I live in a rural county and most of my driving is done on 50 mph or less highways.  The method described by John Sparks works well for me.

 

 I often drive 20.1 miles from my house to Costco/Trader Joe's.  Last summer, a good result there and back would have been in the low 50s mpg.  Last Wednesday, using this method I got 58.8 mpg from my house to Trader Joe's and an amazing 61.8 mpg coming home.  This route is up and down hills, and I sometimes used 2 bars on the Empower screen to maintain the speed limit.  The big difference for me is that I am much more likely to intentionally stay in ICE if running at 2000 rpm or lower.  Before reading Mr. Sparks post, I would try to be in EV mode as much as possible.  Now I am driving more aggressively (faster) and getting better mpg.

viennacoup, you are getting close to P&Ging(Pulse and Glide) where you speed up(TWO BARS, don't worry about RPM's) to 60mph (55mph speed limit road) then Glide(coast) down to 50mph and bring in the EV power to stabilize at 50mph. When you run out of HVB accelerate(TWO BARS) back to 60mph. You need to watch traffic so you don't become an annoyance. This is the method I used to get 65mpg on to tanks. :)  :shift: 

 

Paul

[ScubaDadMiami]

I have also been playing around with this. What I am finding that seems to be a good balance is: EV to 13 to 18 MPH (EV has good low end torque, so you get moving nicely), ICE at 1.75 to 2 bars, briefly, to gather some speed and momentum, and then reducing to 2,000 RPM while continuing to accelerate to speed, which corresponds to 1 to 1.125 bars. This allows decent pick up to keep along with traffic, but keeps fuel economy at a good number. ICE runs a bit longer than going with a 2 bar burn, but due to lower RPM, it seems to use the same or maybe even a little less fuel.

 

Last year, on a typical route of 12 miles that I routinely run, I was usually averaging about 50 MPG. Since starting with this new procedure, I haven't made this trip enough to verify with certainty, but is seems that I am now getting 52 MPG on the same trip. When I say last year, and to explain why it has been a while for running this route, up until about three weeks ago, I was running with no air conditioning during the winter. So, I didn't count trips made without the air conditioner in the 52 MPG; those would be more like 60+ MPG.

Edited May 6, 2014 by ScubaDadMiami

[John Sparks]

I live in a rural county and most of my driving is done on 50 mph or less highways.  The method described by John Sparks works well for me.

 

 I often drive 20.1 miles from my house to Costco/Trader Joe's.  Last summer, a good result there and back would have been in the low 50s mpg.  Last Wednesday, using this method I got 58.8 mpg from my house to Trader Joe's and an amazing 61.8 mpg coming home.  This route is up and down hills, and I sometimes used 2 bars on the Empower screen to maintain the speed limit.  The big difference for me is that I am much more likely to intentionally stay in ICE if running at 2000 rpm or lower.  Before reading Mr. Sparks post, I would try to be in EV mode as much as possible.  Now I am driving more aggressively (faster) and getting better mpg.

 

 

 

This is basically the exact same terrain I deal with. 55 mph or less highways, lots of hills. Everyone always says that a 2 bar burn gives better charging. I have to disagree. I find that going up a hill, big or small, at 2000 RPMs not only uses less fuel (though you will really slow down on big hills), I also find that I have accumulated more charge on the battery. Now this may simply be due to the fact that the engine is running longer, or could be the lower speed puts more load on the engine. Either way it's nice to reach the top of a hill with a higher charge.

 

 

 

I have also been playing around with this. What I am finding that seems to be a good balance is: EV to 13 to 18 MPH (EV has good low end torque, so you get moving nicely), ICE at 1.75 to 2 bars, briefly, to gather some speed and momentum, and then reducing to 2,000 RPM while continuing to accelerate to speed, which corresponds to 1 to 1.125 bars. This allows decent pick up to keep along with traffic, but keeps fuel economy at a good number. ICE runs a bit longer than going with a 2 bar burn, but due to lower RPM, it seems to use the same or maybe even a little less fuel.

 

Last year, on a typical route of 12 miles that I routinely run, I was usually averaging about 50 MPG. Since starting with this new procedure, I haven't made this trip enough to verify with certainty, but is seems that I am now getting 52 MPG on the same trip. When I say last year, and to explain why it has been a while for running this route, up until about three weeks ago, I was running with no air conditioning during the winter. So, I didn't count trips made without the air conditioner in the 52 MPG; those would be more like 60+ MPG.

SDM...I just started to have to use the A/C around here and it amazes me just how much of a difference it makes. Fortunately most days I leave early and get home late, after the temperature has dropped however, I suppose that wouldn't make much difference there in Miami

[ScubaDadMiami]

2000 RPMs not only uses less fuel (though you will really slow down on big hills), I also find that I have accumulated more charge on the battery. Now this may simply be due to the fact that the engine is running longer, or could be the lower speed puts more load on the engine. Either way it's nice to reach the top of a hill with a higher charge.

I agree. 2000 RPM for longer uses less fuel while allowing for more charge, overall. I use this for battery charging when State of Charge is low, such as after a long glide.

 

I've noticed that when stopped, ICE, when running, is at 1200 RPM (it could be 1500; just going by memory). So, that's all that is required to charge. Before, I just wasn't sure if higher RPM = faster charge. Even if it does, the amount of fuel used goes up, and starts to go up much faster after 2000 RPM. That's why I give a short burst to 2 bar, and then I back off to 2000 RPM once I am speeding up sufficiently. It seems to be a good balance between moving along and good numbers.

 

Yes, there is a bit of a difference between AC and no AC, as you see!

[ptjones]

 

 

 

This is basically the exact same terrain I deal with. 55 mph or less highways, lots of hills. Everyone always says that a 2 bar burn gives better charging. I have to disagree. I find that going up a hill, big or small, at 2000 RPMs not only uses less fuel (though you will really slow down on big hills), I also find that I have accumulated more charge on the battery. Now this may simply be due to the fact that the engine is running longer, or could be the lower speed puts more load on the engine. Either way it's nice to reach the top of a hill with a higher charge.

 

 

 

SDM...I just started to have to use the A/C around here and it amazes me just how much of a difference it makes. Fortunately most days I leave early and get home late, after the temperature has dropped however, I suppose that wouldn't make much difference there in Miami

 

I think what is going on here is you are trading speed for gas mileage. The slower your average speed, the better your gas mileage. If you wait longer with the two bar method before you start the Ice  so you end up with the same average speed as 2000rpm method I woulld guess you would have atlest as good of gas mileage. Two bar method is a lot easier to do too. IMO :) 

 

Paul 

 

 

[salsaguy]

So Ford sales reps aren't trained about the cars they are selling? You would think they would train you a lot especially on a very different car like the cmax so that you in turn could train/teach your would-be customer.... hnmmmmmm

A new car launch I thought would prompt major training of staff members as required...

 

Thank you for your reply. I did buy my C-max new. (I'm actually a Ford Sales Rep) I have about 3300 miles on it at this point. I do believe I have noticed some difference in it in the last 500-600 miles. One thing that is so very different about this car vs my Civic Hybrid is the way it works and charges the battery. My initial reaction to the Cmax was a bit negative. With my Civic, if the ICE was running I was able to easily keep the instant mpg around 50....so naturally was concerned at first when the engine would come on with the Cmax and my instant FE would drop to 20 or below.

Realizing that the Cmax is charging the battery and becoming more experienced with how it worked, I understand better, the Civic didn't charge the battery near as much and this is probably why the batteries in those cars fail so often. (I had 2 failures in mine). Anyway you can see why this was an adjustment.
 

[salsaguy]

If you can export the data to a csv file you can do all the factors / graphs u want in excel. Most data loggers will allow exporting of the data for more detailed analysis. Some charge you more for this feature built in or as an add-on.

I did manage to get Torque to create a line graph of fuel used, but it's pretty limited, i.e., x=time y=fuel used, but I can't get it to display more than one factor at a time, i.e., fuel used/load/rpms/degree of uphill-downhill, etc.,etc.,etc. so I could easily test and retest the same street using different acceleration curves to determine the most efficient one...

 

There is a "track recording plug in" that WILL display all that info and let you play it back, but then you'd have to create a line graph by hand... maybe I'll get around to that when I'm not in the middle of my busy season, say after march or so.

[salsaguy]

Get an app for your smart phone like "My Tracks" (Android Google Play store) which lets you save various trips/routes and you can record them and it will show the elevation vs speed graph so that you can know how much uphill or downhill you are driving on your most common routes so you know if  you can expect to get good or bad/worse mpg one way and the opposite mpg when going on the other way.

I think there is another thread here where we discuss the elevation aspect in detail. Search for it.

There are many free apps out there that so this. Any GPS logger, like used for hiking or cycling will do this. Some better than others.

Good luck

So I've been experimenting with incorporating a 2 bar burn into my daily driving.  I find it good for acceleration / pulse & glide but, I live in East Tennessee and we've got a lot of hills around here. (putting it mildly)

 

What I've found is while I get up a hill faster :shift: , my battery has no where close to the charge that it does with a 2000 RPM burn, and it definitely uses more fuel.  That being said, On "more" :airquote:  level ground my findings so far are that if I'm at a good speed, a 2000 RPM burn will generally keep my momentum, okay maybe 2100 RPM, while a 2 bar burn helps with accelerating.

 

All in all I agree with JUS, knowing your roads is a large factor in increasing fuel economy.  For the terrain I have around here I think that 2000 RPM with occasional 2 bar burn mixes up to the best fuel economy but, of course I've just reached 5600 miles on my Cmax so that may have something to do with it too and I'm still relatively new to driving it.  

 

This forum ROCKS :rockon: BTW.

 

(This is just my observation.  I have no app, or scan gauge for hard data)

[ScubaDadMiami]

If you wait longer with the two bar method before you start the Ice  so you end up with the same average speed as 2000rpm method I woulld guess you would have atlest as good of gas mileage. 

 

 

Surprisingly, that has not been what I am finding. What I have found is that doing a half bar versus 1 bar (which is just under 2000 RPM) burn does not make that much of a difference. On the other hand, a 1 bar burn versus 2 makes a big difference, saving more with a longer 1 bar burn than a 2 bar burn to get to the same speed, up to at least 45 MPH. (I haven't yet done enough 55+ MPH driving to comment on that.) I've tried this comparison from ranges of 10 to 20 MPH EV from a stop.

 

I've also played around with 1.75 bar burns, which are definitely better than 2 bars but not close enough to 1 to work the best. If I need to speed up to a higher speed--46  to 55 MPH--I often go EV, then a very brief 2 bar burn with an almost immediate reduction to 1.75, and then I back down to 1 bar as soon as I feel like I am either with traffic or getting up enough speed to relax and enjoy the ride.

 

Again, I was surprised, because, having had an 62+ MPG/800+ tank already, I figured that there wasn't much more to learn.

[John Sparks]

So Ford sales reps aren't trained about the cars they are selling? You would think they would train you a lot especially on a very different car like the cmax so that you in turn could train/teach your would-be customer.... hnmmmmmm

A new car launch I thought would prompt major training of staff members as required...

How familiar are you with computers and software? When a software company creates a new software, OS, etc., they go through an Alpha stage (smaller group of developers) and then Beta run which is released to sometime thousands of people. A software, or service's Beta period can last quite sometime before the bugs are worked out at which time it is released to the public.

 

I say that to say this. Yes they train us on our products! However, sadly, most people don't really care and are just in a hurry to get through training. Not me. I pride myself in knowing as much as I can about each and every vehicle we sell and have more product knowledge than any other salesman I work with. That being said, the 2013 was a first year release. So in reality, first year models are really the Final Beta Run. There are so many things that may not or cannot be discovered in quality testing. It's not until it goes out to the masses that the "bugs" are worked out. So while break in may be considered to be 1000 miles, ideal break in is 3000-6000 miles and I lean more towards 6000 miles.

 

Plus things are always different on paper than in the real world, and real world experience with a product is always better than any training a person can receive. If you need a more precise example, just look at the owner's manual revisions. Some vehicles have as many as 5 revisions in 1 year, recalls are much more common on first year vehicles too. If you compare the 13 Fusion, Escape, & Cmax, there are many more recalls on the 13 year models than the 14.

 

This forum is here for fellow Cmax owners to connect, learn, discuss, discover, & brag. Just because you are unwilling to try a technique that others have had success with doesn't mean you have to insult the intelligence of others.

 

I hope you are enjoying your Cmax and doing well! I'll get off my soap box now. :)

[ScubaDadMiami]

Unfortunately, as with other careers, there are those that know what they are doing, and there are those that are good at selling. It is rare to find people that are both, but there are a few of them out there.

Edited May 13, 2014 by ScubaDadMiami

[salsaguy]

John S, thanks for your response and input and insights on the training program. 

Yes as a Senior Quality Engineer (and certified QE) for various manufacturing companies for over 20 years, I know all too well about first year issues with any product. You will find many posts by me here stating that fact to others here about their issues tied to buying a "beta test/first gen/brand new development car", which is always a bad idea if you don't want to deal with minor(sometimes major) issues, tweaks, fixes, etc. I've been thru many recall of product from the field or had to have our field service folks fix things later due to issues with our products at initial launch.

In my second company I even worked for an OEM manufacture to one of "The Big Four" auto mcg companies (back then).

 

 

I completely agree about the initial quality issues, just was wondering about how much training you guys/gals received, as it's been posted here many times in the forums that the forum users know a lot (ALOT) more than their dealers/service managers knew about this car, which is kinda dad if you have to bring papers/printouts from an internet forum to your dealer top tell them how to diagnose/fix an issue they should be aware of and be trained on.

I knew that most companies spend way too little on trading people, sadly.

The "let the users/owners be the beta testers" model, so prevalent with Microsoft, needs to stop though. Yes there will always be defects and issues with anything new but it seems to many just "let it work itself out in time" which upsets customers.

As a quality engineer, I have to be the voice of the customer and look at it from there point of view as well as my own companies.

The Kano model (look it up when you have time) states that it's not just enough to MEET customers expectations, but to EXCEED them and be one step ahead of them and also to try and predict what they want, before they even knew they wanted/needed something....not an easy task.

 

I look forward to your "insiders" point of view on this forum.

Glad we have a rep from the company who can provide a different perspective since the car owners don't always see what it's like from the car complaints side of the world. They have a lot of things going on and with that many employees and moving parts/logistics, it's amazing just how fast things do get resolved sometimes, sms other times they take clever, like the "dead battery issue" which I've read recently is STILL affecting new owners....

 

BTW, if you check my signature or profile you'll see I'm a POTENTIAL  CMax buyer for my wife's new car, to replace her 1999 Toyota 4Runner SUV (gas eater). I have been "lurking" ;) top gain as much insight I can to learn (train myself) about this car and all the good and bad things, before spending $30k+ for it. This forum is like an @ngies-list for the CMax :)

 

We dont have the CMax.... ye,t but I have been on here for a long time and contributed a lot to the discussions and learning all about the CMax. We are getting very close to getting it finally though, I believe.

 

At last year's Ford Eco-boost challenge I came in second place for my designated hour (only got beat out at the last 5 mins) for obtaining the highest mpg of the group with 98+ average mpg around the test track, partly due to the info on these forums.

 

Looking forward to hearing more about your results/testing.

Cheers

[ScubaDadMiami]

The camera work is not the greatest, but here is pretty close to the actual technique. I could not both use the camera well and also make a textbook acceleration using the proposed method. Setting things up, I also didn't have my normal State of Charge on the HV Battery.  However, the video still gives a good idea of the technique basics.

 

For clarification, I'll break it down once again.

• EV to 13 - 18 MPH (in this case, 18 MPH);
• Quick ICE burn at 2 Bars, and then almost immediate back off to 1.75 Bars as soon as good pick up established. (Due to trying to do several things at once, I didn't really get to the 2 Bars, but that would normally be for perhaps 3 seconds before the reduction to 1.75 Bars)--you can see this in the video where there is a quick dash from between 20 to about 32 MPH;
• Left screen switch to My View, showing reduction to 2,000 RPM, which corresponds to about 1.2 Bars or just under;
• Slow pick up and battery charge from 30 to just under 40 MPH. (This is on a 35 MPH road.)

Note that I am at 53+ MPG with air conditioning, so far on this tank, which is mostly city driving.

Edited May 15, 2014 by ScubaDadMiami

[fbov]

...EV to 13 - 18 MPH (in this case, 18 MPH);...

So... what's your secret? How do you get the car to jump off the line like that? My car won't accelerate like this in EV unless I'm pointing downhill. From a stop, I rarely get across the interesection in EV, much less up to 10mph! Starting uphill, I need ICE to move.

 

Conversely, my mileage this Spring is up 12% @ 60F over my baseline period last September... at least on the back roads. Expressway data is limited, but shows no sign of the improvement seen in rural driving.  

 

I've previously documented that the PCM upgrade was good for 5% above baseline, but I saw no change due to aero aids, increased tire pressure, switching to snows or blocking off the top two grill openings. What's different now? 1.8-bar burns...

 

My baseline period was the second month of ownership, thinking the first month I was coming up a learning curve. I was using Jus's method, keeping ICE no higher than 2-bar to maintain charging while accelerating, but I was using the full 2 bars. This Spring, I'm targetting 1.8 bars so I get longer ICE runs coming up to speed, and hit EV with a higher SOC so I don't run out of battery as much. As temperatures finally warm to the point where I'm not wasting gas on "normal operation" it seems the car also glides farther. And it's not an artifact of undocumented side trips; three of the top four are consecutive commutes, averaging 60.4mpg at 65.7F.

 

One difference might be city vs. rural driving - I see a lot of corn fields, traffic is quite light, and speed limits are 35-40mph. This is neither city nor highway driving.

 

Have fun,

Frank

[ScubaDadMiami]

So... what's your secret? How do you get the car to jump off the line like that? My car won't accelerate like this in EV unless I'm pointing downhill. From a stop, I rarely get across the interesection in EV, much less up to 10mph! Starting uphill, I need ICE to move.

Don't be too hard on yourself. After all, I am mostly driving on level ground. So, I do have a bit less of a challenge on that front.

 

When in the right conditions, the trick to staying in EV is to "chase" the EV bar indicator as you get rolling. I explain below.

 

With great low end EV torque, rolling to about 5 to 7 MPH is easily done while a decent acceleration rate. Getting just above that speed requires easing up on the throttle, because the good low end torque of EV quickly goes away, and continued throttle pressure will trigger ICE. However, there is a bonus in all of this.

 

If you replay the video, you will see that the threshold from EV to ICE starts out low, but it actually moves up right after I get rolling at that 5 to 7 MPH speed zone (probably because it takes less strain for the battery to speed up a moving vehicle than it does to start one moving). The trick is to control the throttle as you approach the upper limit of that lowest end EV/ICE threshold, and then to regulate the throttle as you also follow the threshold as is moves upward to the point where you kick in ICE for brief 2 Bar burn, followed by backing off to 1.75, and then to 2,000 RPM/1.2 Bars as you head up to your speed target zone.

 

Following this procedure gets the battery topped back up, uses little fuel, and keeps you up with the traffic flow.

[John Sparks]

Don't be too hard on yourself. After all, I am mostly driving on level ground. So, I do have a bit less of a challenge on that front.

 

When in the right conditions, the trick to staying in EV is to "chase" the EV bar indicator as you get rolling. I explain below.

 

With great low end EV torque, rolling to about 5 to 7 MPH is easily done while a decent acceleration rate. Getting just above that speed requires easing up on the throttle, because the good low end torque of EV quickly goes away, and continued throttle pressure will trigger ICE. However, there is a bonus in all of this.

 

If you replay the video, you will see that the threshold from EV to ICE starts out low, but it actually moves up right after I get rolling at that 5 to 7 MPH speed zone (probably because it takes less strain for the battery to speed up a moving vehicle than it does to start one moving). The trick is to control the throttle as you approach the upper limit of that lowest end EV/ICE threshold, and then to regulate the throttle as you also follow the threshold as is moves upward to the point where you kick in ICE for brief 2 Bar burn, followed by backing off to 1.75, and then to 2,000 RPM/1.2 Bars as you head up to your speed target zone.

 

Following this procedure gets the battery topped back up, uses little fuel, and keeps you up with the traffic flow.

Nice explanation. Watching that threshold in Empower mode is key. What really amazes me about this hybrid Powertrain is the number of rather descent sized hills I am able to traverse in EV mode. Compared with Fords previous gen hybrids, this is truly phenomenal.

 

Sure I may slow to 25-30 mph but the EV threshold is what allows me to accomplish this. I simple back off of the accelerator as the threshold begins to back down.

 

Loving this car more and more every day. Think we're going to lease an Energi for my wife in the next year.

 

Hey SDM. When you are logging your fill-ups with Fuelly, do you go by the gallons you pumped or the gallons the car says it used?

Edited May 16, 2014 by John Sparks

[ScubaDadMiami]

Hey SDM. When you are logging your fill-ups with Fuelly, do you go by the gallons you pumped or the gallons the car says it used?

Other than when I am on road trips, I always fill at Costco (93 Octane), and mostly at the same pump. In winter, I noticed that the pump and the C-MAX meter are very close to agreement; when it's hot, there will be a bigger difference. So, I decided to just go with the C-MAX meter, not the pump.

 

I am not convinced about the theory that many have stated about the meter being way off. It could be, but I am chalking some of the reported differences up to factors like expansion and evaporation, poor pump maintenance, etc. My guess is that the C-MAX meter is measuring actual flow of fuel at a given moment, just as it reaches the engine. I just can't imagine Ford purposely chancing the risk that the public would find out about altering the code to make fuel economy look better. So, I am not buying into the conspiracy theory.

 

Also, there are people reporting that numbers are different (I believe the reports are actually that fuel economy comes out a little better in these cases) when checked against a GPS. So, there could be many factors to change the final number a bit.

 

In the end, I chose to go by the meter. If anybody doesn't like my numbers, feel free to knock a couple of tenths off of my average.

Edited May 17, 2014 by ScubaDadMiami

[salsaguy]

Its not just Ford that would be doing that, my VW Passat always reads better avg MPG for my trip than when I calculate with pump numbers. (anywhere from 1.5 to 2.5 mpg better mpg on the car's dash computer)

also the cars dash only has one number after the decimal point whereas the pump has 3 numbers after the decimal. does the car round up or down?

rounding ALWAYS causes inaccuracies especially when dealing with averages. when you average an average that is one of the biggest sins in statistics and data analysis they teach you in school.

 

the pumps are regulated and have to the calibrated and tested to get their stickers to operate so i would say its more risky for the pumps to cheat and be put out of business (only own 1 station usualy and that would really hurt them) compared to if a car mfg tweaked some code

not everyone compares or checks BOTH like we do

 

I think most car mfgs do this why would you want your owners to think they are getting less mpg?

but yes there are different ways of measuring and inaccuracies as some do the top off method of filling and some stop at 1st click

some wait 5 seconds before removing and some remove nozzle immediately

gas will evaporate more on a hot day vs a cold day

some fill up when tank is empty and some fill when 1/2 or 1/4 left

meter in car is different from flow meter in the pump

tank will get deposits over time and also parts will drift in calibration or wear out and become less accurate

 

im sure someone has done a white paper on this topic somewhere out there..

Edited May 17, 2014 by salsaguy

[Jus-A-CMax]

Mine is abut 0.3 gallons off, one time it was a wee off. I don't care...the MPGs I am getting certainly makes my Lemon CMax very, very sweet indeed. Been clocking up some :flirt: personal best MPGs lately that I have never seen till now. :love_shower: Temps have helped tremendously as we are having a heat wave...

[C-MaxSea]

The 'Tom & Ray' take - FWIW.

http://www.cartalk.com/blogs/tom-ray/counting-mileage-case-prius-syndrome
 
I don't trust either pump or gauge sometimes. ;)
 
('Rounding errors' insignificant when one shows 11.4x and the other shows 12.2x - What's a good OCD type to do - average the two? ;) ;) ;) )

 

(Our lemon got 54 mpgs on Thursday over 113 miles - or was that only 52 mpgs?)

 

No worries, at less than 8 cents/mile, we  :wub2:  our Full Featured Lemon !!!

 

:redcard:     :judge: Your out of order here :finger: , back to best RPMs please.

Edited May 17, 2014 by C-MaxSea

[kostby]

Back to the question posed in the title of this thread, "The best engine RPM for minimal Fuel Economy loss" is always ZERO RPM, isn't it???

 

If that gosh-darned, gasoline-sucking, air-polluting, environment-spoiling, global-climate-warming, efficiency-leaf-removing, INFERNAL Combustion Engine is at zero RPM (in other words "not running"), you are not losing any fuel.  ;)

[John Sparks]

Back to the question posed in the title of this thread, "The best engine RPM for minimal Fuel Economy loss" is always ZERO RPM, isn't it???

 

If that gosh-darned, gasoline-sucking, air-polluting, environment-spoiling, global-climate-warming, efficiency-leaf-removing, INFERNAL Combustion Engine is at zero RPM (in other words "not running"), you are not losing any fuel.  ;)

Snarky......I like it! Are you a car salesman? :D

[scottwood2]

Great post here guys.  I have been on the fence about buying the Cmax.  I get excited about all the techniques in driving the car to get the most MPG.  I just test drove one before I saw this post and I played around on my test drive to try to get best MPG.  Not really knowing what to do I was able to get 44 MPG over 7 miles.  Pretty short but found it fun trying to learn how to get the best MPG.  After this post I am really wanting to play with one again to see what I can do.  Thx for all the great posts here.  

[ScubaDadMiami]

Great post here guys.  I have been on the fence about buying the Cmax.  I get excited about all the techniques in driving the car to get the most MPG.  I just test drove one before I saw this post and I played around on my test drive to try to get best MPG.  Not really knowing what to do I was able to get 44 MPG over 7 miles.  Pretty short but found it fun trying to learn how to get the best MPG.  After this post I am really wanting to play with one again to see what I can do.  Thx for all the great posts here.  

Sounds like you will be joining the ranks soon enough.

[John Sparks]

Other than when I am on road trips, I always fill at Costco (93 Octane), and mostly at the same pump. In winter, I noticed that the pump and the C-MAX meter are very close to agreement; when it's hot, there will be a bigger difference. So, I decided to just go with the C-MAX meter, not the pump.

I am not convinced about the theory that many have stated about the meter being way off. It could be, but I am chalking some of the reported differences up to factors like expansion and evaporation, poor pump maintenance, etc. My guess is that the C-MAX meter is measuring actual flow of fuel at a given moment, just as it reaches the engine. I just can't imagine Ford purposely chancing the risk that the public would find out about altering the code to make fuel economy look better. So, I am not buying into the conspiracy theory.

Also, there are people reporting that numbers are different (I believe the reports are actually that fuel economy comes out a little better in these cases) when checked against a GPS. So, there could be many factors to change the final number a bit.

In the end, I chose to go by the meter. If anybody doesn't like my numbers, feel free to knock a couple of tenths off of my average.

 

Okay, so I saw a video about this at an Exxon station in Knoxville, TN and I wondered, do all gas stations do this, so I conducted a test. When I filled up my Cmax the other day I pumped a few dollars then stopped the pump. To my surprise, about every 2 to 3 seconds the pump would progress another cent. So now it all makes sense, the gas stations are ripping us all off, but it makes sense as to why the pump to gauge is usually off.

 

Anyone else came across this?