Why Discrepancy in EPA MPG Between Milan and Mariner Hybrids?

[Transpower]

I recently had the powertrain computer controller recalibrated on my 2008 Mercury Mariner Hybrid and am now getting 30 mpg in city/suburban driving, instead of 26-27. The vehicle is staying much longer in electric mode. But I'm still not convinced that the controller has been optimized.

 

The new Mercury Milan Hybrid has EPA ratings of 41 mpg city and 36 mpg highway; Consumer Reports reports real world mileage of 34 mpg (versus 26 for the Mercury Mariner Hybrid). Why is there such a discrepancy in mileage between the Milan and the Mariner?

 

I understand that the Mariner has a higher drag coefficient (Cd) and that the AWD system will reduce mileage, but to this extent? (And the difference in engine sizes, 2.3 L vs. 2.5 L in the 2009 Mariner or 2010 Milan does not appear to matter at all.) I therefore think there must be some change in the design or operation of the powertrain controller. The batteries don't appear to be all that different.

 

So the question is: can Milan's new powertrain controller be retrofitted to a Mariner? I suppose the answer would be: certainly not, there are too many other changes and it wouldn't work. Regardless, can someone clarify this?

[akirby]

Escape is still the gen I system while Milan gets the gen II. The gen II is more efficient. Software is only part of it. At least that's what I remember.

[Green Lantern]

Escape is still the gen I system while Milan gets the gen II. The gen II is more efficient. Software is only part of it. At least that's what I remember.

 

I would also add that the OP is comparing what he/she is really getting off a Mariner H to what the EPA ratings are on the Milan H. I think he/she should first compare his/her real mileage to the EPA stated mileage on the vehicle sticker of his/her Mariner H. Then compare the EPA sticker mpg for both vehicles. I am betting the discrepancy between the two vehicles EPA rated mileage is not as severe as what was stated in comparing real driving vs EPA mpg on two different vehicles.

 

For example, in my 2009 FEH the sticker mpg is 34/31 for city/highway driving. I can easily see the body dynamics differences of the two vehicles making up the largest portion of the discrepancy between these values and those of a Milan H if they both had the same engine/powertrain and were operated in a wind tunnel.

 

I would be more concerned why the OP is not achieving what his/her vehicle was rated at on the vehicle sticker (assuming it is reasonably close to what is on my 2009 model).

[Transpower]

The EPA ratings of my 2008 Mercury Mariner AWD Hybrid are 29 city/ 27 highway. I'm now easily beating both. That's NOT the point. The point is: why is there a huge discrepancy between the EPA ratings of the Mercury Milan Hybrid and the Mercury Mariner Hybrid? The difference in shape and slight difference in engines and batteries would account for some, but certainly not all, of the discrepancy. Therefore I think the powertrain controller must be different. If so, is it possible to retrofit this new controller to the 2008 or 2009 Mercury Mariner Hybrids or recalibrate--again--the existing powertrain controller? I think the current system is not completely optimized.

[YT90SC]

The EPA ratings of my 2008 Mercury Mariner AWD Hybrid are 29 city/ 27 highway. I'm now easily beating both. That's NOT the point. The point is: why is there a huge discrepancy between the EPA ratings of the Mercury Milan Hybrid and the Mercury Mariner Hybrid? The difference in shape and slight difference in engines and batteries would account for some, but certainly not all, of the discrepancy. Therefore I think the powertrain controller must be different. If so, is it possible to retrofit this new controller to the 2008 or 2009 Mercury Mariner Hybrids or recalibrate--again--the existing powertrain controller? I think the current system is not completely optimized.

Mariner weighs more, has a lot worse coeiffcient of drag, is AWD, has larger, heavier tires and the differences between 'Generations' and you should probably actually see MORE loss.

 

Of these, AWD is probably the greatest loss.

 

PCM's are NOT interchangeable. Want more? I am sure that there is someone out there tinkering with programming.

[wptski]

I recently had the powertrain computer controller recalibrated on my 2008 Mercury Mariner Hybrid and am now getting 30 mpg in city/suburban driving, instead of 26-27. The vehicle is staying much longer in electric mode. But I'm still not convinced that the controller has been optimized.

 

The new Mercury Milan Hybrid has EPA ratings of 41 mpg city and 36 mpg highway; Consumer Reports reports real world mileage of 34 mpg (versus 26 for the Mercury Mariner Hybrid). Why is there such a discrepancy in mileage between the Milan and the Mariner?

 

I understand that the Mariner has a higher drag coefficient (Cd) and that the AWD system will reduce mileage, but to this extent? (And the difference in engine sizes, 2.3 L vs. 2.5 L in the 2009 Mariner or 2010 Milan does not appear to matter at all.) I therefore think there must be some change in the design or operation of the powertrain controller. The batteries don't appear to be all that different.

 

So the question is: can Milan's new powertrain controller be retrofitted to a Mariner? I suppose the answer would be: certainly not, there are too many other changes and it wouldn't work. Regardless, can someone clarify this?

The EPA rating for a '08 MMH is 34MPG/city, 32MPG/combined and 30MPG/hwy. The EPA rating for a '08 4WD MMH is 29MPG/city, 28MPG/combined and 27MPG/hwy. 4WD costs you 4-5MPG. You take a bigger hit in city driving because the 4WD kicks in "every" time you take off from a stop or slow down and turn a corner.

[Green Lantern]

The EPA ratings of my 2008 Mercury Mariner AWD Hybrid are 29 city/ 27 highway. I'm now easily beating both. That's NOT the point. The point is: why is there a huge discrepancy between the EPA ratings of the Mercury Milan Hybrid and the Mercury Mariner Hybrid? The difference in shape and slight difference in engines and batteries would account for some, but certainly not all, of the discrepancy. Therefore I think the powertrain controller must be different. If so, is it possible to retrofit this new controller to the 2008 or 2009 Mercury Mariner Hybrids or recalibrate--again--the existing powertrain controller? I think the current system is not completely optimized.

 

Sorry but I did not read your original post that way. It appeared you were trying to compare your driving of the mariner with the epa rating of the milan.

 

For the 2010 Mariner Hybrid the 2WD is rated as 34/31 and the AWD is rated as 30/27. Therefore the AWD factor alone on the same vehicle is accounting for 4 less miles per gallon.

 

The 2010 Milan Hybrid is 2WD and rated as 41/36 so the true difference between the two similar drivetrains would be 7/5 in favor of the Milan. I still contend that the majority of this difference is due to the drag difference between the two structures. I do not know if weight plays as much on this. The Mercury website does not list a weight for the hybrid Milan yet but the 2WD I4 is listed as 3308. On leftlanenews the curb weight for the Mariner 2WD I4 is listed as 3385 so only a difference of 82 pounds. I did not look for hybrid weight since that was not available for the Milan.

[GaryG]

The PCM has to be programmed for each vehicle and their options at the time they were built. Your vehicle's PCM programming is tied to your VIN number that Ford has a copy but most of the time the programming is retrieved from your PCM storage to reprogrammed the operating programming in your existing PCM or a new one if needed. The Ford techs have to use the "As Built" programming according to your VIN. You can turn certain things in your "As Built" programming On and Off (I don't) with certain Scan Tools but you may void your warranty. You can't compare the programming in the Fusion/Milan Hybrid to the Escape/Mariner Hybrid because their totally different vehicles and have their own "As Built" programming. The '08 FEH/MMH has a completely different engine (2.3L) than the Milan Hybrid (2.5L) and the gearing is completely different.

 

I was told by the Ford tech that worked on my '05 FEH that Ford wanted him to take pictures and check out if I had changed the programming in my FEH. He e-mailed the pictures to Ford and checked out my PCM and even my SGII. I really didn't care because I was clean and wasn't modifying anything to get the mileage I was getting. The problem was, it turned out to be 3 $12 relays that were not covered under warranty which cost me $1,200 for the Tech's time and labor and towing 3 times to the dealership.

 

If you want to get the mileage of a Milan Hybrid in your '08 AWD MMH your just going to have to learn to drive it much better. If Ford could simply reprogram the newer '10 FEH/MMH to get the mileage rating of the FFH, they would and sell the crap out of them.

[Transpower]

All of this brings up another point: why so much discrepancy between the fuel economy of the FWD and the AWD Mariner? In the case of the Milan, even with a change in engines from 4 to 6 cylinders, the loss in going to AWD is only 1 mpg. Ditto for the Infinity G37 vs. G37x (which has AWD). So, I don't see why there would be the huge drop from 34 mpg of the FWD Mariner to the 29 mpg of the AWD Mariner. This is 5 mpg! Seems to me it should only be 1 or 2.

 

As far as changing my driving habits: I live in an Eastern metropolitan area; if, from a standing start, you go very slow to try to stay in electric mode, the drivers behind you will run over you ....

[wptski]

All of this brings up another point: why so much discrepancy between the fuel economy of the FWD and the AWD Mariner? In the case of the Milan, even with a change in engines from 4 to 6 cylinders, the loss in going to AWD is only 1 mpg. Ditto for the Infinity G37 vs. G37x (which has AWD). So, I don't see why there would be the huge drop from 34 mpg of the FWD Mariner to the 29 mpg of the AWD Mariner. This is 5 mpg! Seems to me it should only be 1 or 2.

 

As far as changing my driving habits: I live in an Eastern metropolitan area; if, from a standing start, you go very slow to try to stay in electric mode, the drivers behind you will run over you ....

All 4WD, so called AWDs aren't equal. Ford's system is a gas sucker! Where's the need for 4WD/AWD to kick in dry hard pavement every time you leave from a stop? It's almost like full time 4WD.

 

I didn't learn how it "really" worked till months after my '09 4WD FE purchase! They call it "Intelligent 4WD". It doesn't sound too Intelligent to me at all!!

[GaryG]

As far as changing my driving habits: I live in an Eastern metropolitan area; if, from a standing start, you go very slow to try to stay in electric mode, the drivers behind you will run over you ....

 

The 2.3L Atkinson is way under powered when using E10 and if you accelerate with normal traffic you will more than likely reach maximum engine load (100%). The electric motors begin "ASSIST" at 100% engine load which can be as little as 2,000 RPM. At that acceleration rate the engine is no longer charging the battery and the motors are draining the battery and the engine is burning the most gas. This is the point the worst MPG can be found in the FEH/MMH because the engine has to make up the Assist battery drain after you reach a steady state speed. The AWD is even worst because it requires more energy during acceleration.

 

The SGII has engine load (LOD) as a standard gauge and you can also tell you are at 99% engine load when the Charge needle moves over to the Assist area. I've learned how to accelerate below 99% load without motor Assist and still keep the engine charging the battery with MG1. Of course, this is in no way a jack rabbit start but it's the best I can do to keep people behind me from running me over. I don't accelerate in EV when cars are behind me from a dead stop or before I get to the speed limit. If you keep the engine charging the battery during acceleration you can use that charge for efficient EV driving after getting up to city speeds.

 

The '09 2.5L Atkinson has just the right amount of efficient power on E10 that is needed for acceleration from a stop. My '09 FWD even has power to spare if I need a harder acceleration rate without using Assist. Now that I've owned both the '05 and '09 FWD FEH, I'm going to sell the '05 and get the '10 FEH for my wife if it has the electric A/C.

[Transpower]

The 2.3L Atkinson is way under powered when using E10 and if you accelerate with normal traffic you will more than likely reach maximum engine load (100%). The electric motors begin "ASSIST" at 100% engine load which can be as little as 2,000 RPM. At that acceleration rate the engine is no longer charging the battery and the motors are draining the battery and the engine is burning the most gas. This is the point the worst MPG can be found in the FEH/MMH because the engine has to make up the Assist battery drain after you reach a steady state speed. The AWD is even worst because it requires more energy during acceleration.

 

The SGII has engine load (LOD) as a standard gauge and you can also tell you are at 99% engine load when the Charge needle moves over to the Assist area. I've learned how to accelerate below 99% load without motor Assist and still keep the engine charging the battery with MG1. Of course, this is in no way a jack rabbit start but it's the best I can do to keep people behind me from running me over. I don't accelerate in EV when cars are behind me from a dead stop or before I get to the speed limit. If you keep the engine charging the battery during acceleration you can use that charge for efficient EV driving after getting up to city speeds.

 

The '09 2.5L Atkinson has just the right amount of efficient power on E10 that is needed for acceleration from a stop. My '09 FWD even has power to spare if I need a harder acceleration rate without using Assist. Now that I've owned both the '05 and '09 FWD FEH, I'm going to sell the '05 and get the '10 FEH for my wife if it has the electric A/C.

 

Thanks, Gary, for bringing a lot of clarity to this discussion!