Consumer Reports MPG Result For 2013 Fusion & C-Max Hybrids!

I think it was CR that threw all hybrids under the bus. There article seemed like it was libelous, and Ford could have sued, but ... they are a reviewer, and suing a reviewer is always bad for PR. Instead they got the new piece that explained how CR wasn't even trying to replicate real world driving (IMHO) or the EPA test.

Car and Driver did the line that when they drive hybrids like hybrid drivers they can get good mileage, they can get close to epa, if they drive it like they drive them they get much less. 39 on the prius c, 30 on the Camry hybrid, 32 on the fusion hybrid.

I honestly believe Car and Driver is onto something. There are things about the prius that makes a driver go slower, accelerate slower, brake earlier - that improves their mpg. The c-max, fusion hybrid, camry hybrid don't act that way.

 

Many good points here, and I also believe the regen is too aggressive on the new ford hybrids. When I take my foot off the gas, and my wife behind me has to ride the brake in our 2010 FFH, well, that could be something. When I apply light braking to kick the regen circle on, there is no noticeable difference in braking. When I do it in the 2010, you can feel the car slowing.

I think this coupled with the Goodyear tires is why I am seeing at least a 5 MPG difference between what I get and what I should be getting, and what others are getting with the Michelins.

Today I had to drive to our Colo, and the trip there I got 45 in the new car, which I normally get in the 2010, return trip a little heavier traffic, 40 MPG. I should have seen more like 50 there and 45 back, just based on past driving experiences there in my other car. My drive in this morning should have netted at least 43, I got 39. I normally get that in my 2010.

Its in the shop now, so hopefully they will find something, they have been pretty good to me in the past, so I feel they can get this resolved.

 

Acdii, can you swap wheels with your 2010 to do some tests?

 

I did give it some thought, not sure if the wheels mate, and the calibration would be way off too, but its in the dealers hands now, so if it comes down to it, I may just do that to see what happens.

I would like nothing more than to prove it out one way or the other.

Would also show me if the more performance based tires improve teh handling of the older car.

Why the heck do I have such a hard time typing THE!

 

The tires sizes are close enough to not throw things off much. Your 2010 tires are 803 revs/mile and the 2013 are 793 revs/mile. Never mind. The bolt pattern is different. The 2010 is 5x114 and the 2013 is 5x108.

 

I had a feeling it would be something like that. darn.

Need to see if the tires are the same size between the two, I could always get a cheap set of rims and put the 2010 tires on them and get a new set for the 2010. It could use a new set soon.

Just checked, 225 vs 235, all the rest being the same, so it is doable as a test.

 

He said he had to set the cruise control to 60 mph to get 47 MPG.

 

yeah, right, been there, done that, didn't work! Try again! The Prius was SO much easier to get high MPG out of. Too bad it doesnt handle as well or be as comfortable for us.

 

Before that he said, he used the car eco-assist gauges in the city. So that combined with highway at 60 mph, he gets 47 mpg.

If I drive like that with a Prius, I can beat EPA estimates.

 

yeah, been there, done that too! 75 MPG on the highway doing 65 MPH in a Prius, been there, done that, *yawn*. 33 MPG in a Fusion Sport on the highway doing 65 MPH. 24 MPG in an F150 4X4 Supercrew with 3.73 gears. For some odd reason though, why the hell cant I get anywhere NEAR 40 doing 55-60 in the new Fusion?

Dealer SM called, Ford requested they fill the tank, and drive it for a while, so he is taking it home which is 45 miles one way, rural roads and interstate. I told him to check how quickly it slows down when he takes his foot off the gas and compare that to other cars he has driven. It will drop from 30 down to 25 in a few seconds instead of coasting like my other one does. Should be interesting to see his results tomorrow. He also did some of his own research and found that people are getting between 30 and 50 in the car.

 

Got the car back. They pretty much said, it gets what it gets. It's within our specs, so your on your own.

 

OWCH!

Over at Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com they have a protocol and spreadsheet that allows you to take a set of roll-down tests to calculate the rolling and aerodynamic drag. There is one Ford thread over there. I never bothered because the Prius characteristics are so well known thanks to Ken@Japan and the brilliant Japanese Prius owners. However, this methodology provides a way to find out what the f*ck is going on. It is what I would use to begin fault isolation of these hypothesis:

• rolling drag - based upon the nearly flat MPG at speeds under 70 mph.
• gas engine problem - almost as bad as an Otto engine, the efficiency would have be really fall off at partial power but we need live torque, rpm and mass-flow/injector timing.

Your highway benchmark data strongly suggests one or both of the above is going on.

The roll-down test means reaching a starting speed on a flat road and shifting into "N" and recording the vehicle speed as the car slows down. Starting at a high velocity, the aerodynamic drag causes the initial deceleration. But as the speed slows down, rolling drag becomes the primary force. The roll-down test fits the measured data points to the well known formulas to calculate the rolling and aerodynamic forces and constants for the vehicle. But then what?

As an Ecomodder member, I would being looking at modifications to minimize rolling and aerodynamic drag. BUT these are not going to be appreciated by the Ford dealer and probably not by the Ford engineers. You might still fault-isolate to a vehicle specific fault but this is how I would approach the problem.

There are alternatives . . . sell it or keep it for 'special' trips. Also, you might find a landshark who wants to start a class-action lawsuit but these are way above my pay-grade.

Bob Wilson

 

Thanks, for the tips, going to check the roll down for sure. I still feel its an over aggressive regen and tire combo. I may get a set of 17's and transfer my used Michelins from my 2010, since they are the same size as the stock 13, and could use a new set on my 10. If anything, it will keep the factory 18's clean during the winter. If it proves out to actually be the tires, I could probably get at least $400 each for the wheels and tires.

 

Ok,

I found the EPA table that has the roll-down tests from the manufactures. I used this to plot the effective horsepower needed at different speeds:

• rolling drag - higher than a Prius v, impacts City driving, not good
• aerodynamic drag - competitive with Prius v, should have close high-speed, highway performance

So lets look at the EPA ratings:

	Column 1
0	[th]model[th]City[th]Highway[tr][td]CMAX[td]47[td]47[tr][td]Prius v[td]44[td]40[tr][td]Prius hatchback[td]51[td]48

Source: Fuel Economy

The rolling drag is pretty sad and the EPA rating does not make a lick of sense. There would have to be a remarkable bit of magic in the engine-drivetrain efficiency . . . we're talking too good to be true wonderful.

Bob Wilson

ps. BTW, I used my 2010 Prius MPG vs mph chart to project the CMAX and 'Prius v' should at 18 hp at 67 mph should get ~33 MPG . . . the original poster reports 38 MPG @65 mph and 33 MPG @70 mph.

 

A little thread drift, I decided to take three sets of EPA roll-down data and plot the horsepower needed to overcome vehicle drag at 25-85 mph for:

• NHW11 Prius
• NHW20 Prius
• ZVW30 Prius

• 02-Prius (BYJ) - The 2002 Prius, column BYJ, is known to have higher rolling and aerodynamic drag. So it consistently takes more power across the board.
• 08-Prius and 13-Prius - These have lower rolling drag from improvements in transmission and aerodynamics. The smaller NHW20 Prius has lower aerodynamic drag above 50 mph while the ZVW30 Prius with a redesigned transmission has lower rolling drag.
• 52-55 MPG zone at 15 hp - there is a curious cluster in all three models of middle 50s MPG but there is a welcome, 5 mph spread.
• 39 MPG zone at 19 hp - there is another curious cluster at 39 MPG with a greater 7 mph spread.

Reducing rolling drag can be accomplished by:

• inflation - at some loss of ride softness, up to maximum sidewall pressure is OK. Given the loss of ~1-2 psi per month, use the pump every 2-3d fill-up is a good idea.
• four-wheel alignment - Firestone and possibly Goodyear offer life-time alignment, ~$150, but just for toe of the front wheels. In reality, toe and camber (the tilt), of both the front and rear wheels can be adjusted using camber bolt(s) on the front and shims on the rear. This lets the tires wear down uniformly so the $250-500 tires run for their rated miles and don't have to be replaced early. It also improves handling and reduces rolling drag.
• transaxle oil replacement - unfiltered, the oil accumulates wear particles and drag increases. Our best studies indicate an early change, 5k service miles, is needed to flush left-over manufacturing debris and early sealant bead loss. Due to carry forward from each change and the reduced particles from the gears as they 'wear in', the subsequent changes should be 15k, 45k and thereafter 90k service miles.
• larger diameter tires - a very advanced technique, it in effect adds a permanent, increase in gear ratio. This will throw off the odometer and speedometer calibration and lower the true 0-60 mph time. The indicated MPG will appear to be lower but if you measure and apply the calibration correction factor and drive 'true speed', there is a small reduction in rolling drag. It also reduces the rotational rate of the transaxle gears and the higher gyroscopic forces will tend to improve steering tracking.
• save weight - part of rolling drag comes from the vehicle weight but given vehicle weights of ~3,000 lbs, it would take 300 lbs to have a 1% effect.
• user expectations - rolling drag effects are only dominant at slow speeds, 50 mph or less. But these techniques help mitigate the gradual increases in rolling drag as bearings and parts wear.

Reducing aerodynamic drag:

• cooling drag - fully enclosing the engine compartment air inlets reduces the drag by minimizing how much air flows through and robs energy. Typically done in the winter where the cold air can easily carry away the engine heat, it remains an area of study at Ecomodder.com. Active air inlet vanes is an area of advanced study.
• wheel wheel drag - there are small air-dams in front the tires and they help. However, a lot of air is entrapped and spills out the wheel wells. Wheel well covers can reduce this significantly.
• wheel spoke drag - moon caps
• bottom panels - already built into the ZVW30 and partially in the NHW20, the NHW11 has none. An advanced technique (speculation) would be a 'shark jaw' air inlet, temperature controlled that lowers down to take under-car air just behind the front bumper and routes it up to the radiator(s). This allows complete coverage of the ordinary bumper and front air inlets.

Follow-up

The curious falloff of MPG, 50s->39 MPG, between 15 and 19 hp suggests something is going on in the engine and/or transmission. In theory, we can use the BSFC data along the operating line to build a model for MPG vs mph. This is an interesting area for Prius performance investigation.

I have uploaded a zip file with the excel workbook used for this chart. Feel free to download and play with it.

Bob Wilson

 

Had a thought, what if the transmission fluid was different in the test? Either in the formula or supplier.

 

My oil testing service performs two tests that gives three results:

• 40C viscosity
• 100C viscosity
• viscosity index

These pretty well define what happens in the transmission due to 'stirring losses.' So "Type WS" in the NHW20 replaced "Type T-IV" in the NHW11 and is cited in the SAE paper as one of several efficiency improvements.

Bob Wilson

 

bob, interesting graph, it shows that the gen III did not get that much worse in terms of hp need inspite of the increase in size and weight, but we knew that from other sources.

A quick search for bsfc, shows the charts, and why the gen III is more efficient
2010 Prius 2ZR-FXE engine efficiency map | PriusChat


We see the gen II is getting more efficient when hp is increased. The gen III is at its best efficiency in that range. Which means, something outside of these maps is a factor. Are the wind tunnel numbers accurate? Are there greater transmission losses? I don't know. Its also way off topic.