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Here is test data for my two oil changes. The first change was not sampled as it was still my Father-in-law's car (c. 5,600 miles), so these represent 5K-15K and 15K to 25K engine operation intervals. The most recent was done early, as the car was already going in for failure of the restraints control module (TSB14S21). Given the 15K sample was short on TBN, I wish I'd run comparable mileage - 9,8K vs 10.2K the first time - to see if it continued down. Everything else improved, especially the wear components. Now running 0W20 full synthetic, but Auto Zone brand... dealer's choice, not mine. Next change will be out of warranty, so I'll select the oil. I have always run my Volvos on 10K intervals with full syntheitc oil with no engine issues out beyond 300K miles, so I have no reason to believe shorter change intervals benefit anyone but the oil manufacturers' sales figures. That said, hybrid operation, while low on relative mileage, is high on stress miles due to higher load, frequent starts, and longer time to operating temperature. I was curious, so I did the sampling, and will continue to do so. As to fuel economy 0W20 synth vs. 5W20 blend, the blend wins, 57.42 to 56.69 MPG, but with 2.2F higher temps, and such a high level of overlap in the range (blend: 52.2-63.2; synth: 52.9-61.3) that leds me to believe it's a wash. Regardless, the real test would be winter driving, when the engine never reaches operating temperature, so the 0W-side of viscosity will matter more. Sadly, that won't be a fair fight, as I'm getting ~15% better mileage this summer than last, due to improved driving technique, which I expect will continue this winter. Again, the driver is the biggest variable. Do what your understanding leads you to expect will be an improvement, then drive like you want to confirm the improvement, and you will! HAve fun, Frank

PORTER-080114.pdf I would have sworn I'd posted the second oil change sample... but I can't find it, so here it is. Note that both changes used FoMoCo 2W20 synth blend, so the Jan 31 report (corrected below) was in error. Filled with Auto Zone-branded 0W20 full synthetic, which the dealer purchased at Auto Zone. Not what I'd have expected... Frank PORTER-013114.pdf

I did a tuft test of the C-Max rear airflow. Where most folks put their gas pods, the air flow is close to ideal from the factory. That makes it very unlikely that any change would achieve any beneficial result. In a quick test of a competetive product ("Airtabs," developed by NASA Dryden in the early 70's), placement across the rear lip of the roof gave a negative result, and they were removed. In an ideal application, such as the rear edge of a tractor pulling a similar-sized trailer, the proved very effective reducing turbulence caused by the gap between tractor and trailer. Lots of testimonials from truckers and RV owners, none of which applies to the C-Max. That said, since I had a bunch of these things, now with adhesive removed, I did add them where I thought they might do some good, above and below the rear tail lights (which already have an aero feature molded into them). If there was improvement, I haven't been able to quantify it. There is no question, however, over the efficacy of front grill blocks, or increased tire pressures. However, the biggest factor in fuel economy remains the driver. Learning how to extract energy from gasoline is as much art as science, and the art is the "art of self control." Regardless the technical knowledge or skill of the driver, self-discipline is the biggest hurdle for most of us. HAve fun, Frank

Winter has arrived, so I've got several days at 20F now... and I've found a better way to trade off ICE run time against cabin heating - leave the climate control at minimum temperature; 60F. While I still get the ICE running well past it's warm-weather EV point, when it does flip to EV, I have full EV capability, limited only by SOC, which is always very high by this point. If you increase the temperature setting even a little, like to 64F, the ICE threshold in EV mode drops to ~1 bar, making it real easy to get into ICE when you'd rather not. You can still increase the cabin temperature once the engine warms up some, but so far, it's eliminated the annoyance of sitting at stop lights with the engine running. (Boy, that sounds funny... annoyed that your engine is running... hybirds lead you into a whole new world!) HAve fun, Frank

That's a good one!

Since no one's mentioned it, what were the wind directions? We did a trip from Rochester to Louisiana last February, and despite the well-known mileage temperature dependence and a large change in ambient temperature, my mileage using eco cruise at 70-75 mph was 33mpg going down and 36mpg coming back. My only good explanation was prevailing winds are from the SW, so I have a head-wind going down and a tail-wind coming back. Add some speed, remove the benefits of high tire pressure and the aero mods I've done to the car and you're right in the expected ballpark. HAve fun, Frank

Paul's got a point that a smoother nose is better aerodynamically than simply blocking the grill. It all has to do with aerodynamic assumptions regarding laminar/attached flow and turbulent/detached flow. It is well known that aerodynamic drag force for high Reynolds number objects (like cars) is proportional to the square of velocity. However, that's assuming ideal flow behavior, where flow remains attached across the front to the object, detaching at the rear. The question here is what happens if the front of the object generates turbulent flow at the front, effectively changing he dynamic pressure on the body, increasing the drag coefficient? This could occur due to the presence of surface features, like the grill aperture. Use of Paul's full-coverage grill would remove the vast majority of the surface feature effect, reducing the dynamic pressure at the point where air velocity is greatest (centerline of the body). This would improve the drag coefficient more than simply reducing air infiltration through the grill. That said, I've not gone Paul's route, preferring a simple bladder approach (bicycle inner tube) to block air flow here. My reasoning is based on the relatively benefit of reduced air infiltration (large) vs. additional smoothing of the front surface (small). In addition, I am coming to the conclusion that such drag reductions are a small part of what's necessary to minimize fuel consumption per mile. I'm working on a write up that points to ICE operating RPM and throttle control as having orders of magnitude greater effect. Simply put, aero drag is low enough that there's little incremental benefit to be gained, compared with the reducing the thermodynamic inefficiency of ICE operation. After all, we're only using 30-40% of the energy in our fuel to drive the car... lots more room for improvement there. HAve fun, Frank PS regarding your plan, above, I think you'll find the middle grill can be blocked without major concerns with overheating. The lower grill also lets in air to the shutters, and I've left that one easily removable due to the same overheating concerns you mention. It's not been an issue for me, but I also don't drive up mountians...

+1 to asking one of the Ford reps... dealers have cars in storage for long periods of time, so Ford must have a procedure to maintain the vehicles in those situations. Frank

I have an early SEL (10/2012 delivery) and lost the air bags, RSC and traction control after hitting a bump. A short circuit explains everything, including the wait... for a seat back as well. Frank

At least you're getting into this with your eyes open... it's like you're young again, when you had to drive on empty because you douldn't afford gas until payday. Frank

My technique is the opposite: When possible I try to charge up the HVB before I get to the top of a hill so I can get the maximum glide range on the way down. I know... spoken like a true flat-lander. I can accelerate up most hills with less than 2-bar throttle, so I'm still charging. You may not, and it may be one reason your mileage eclipses mine. Regarding fuel-off engine RPM, consider that, without fuel, the engine's using pumping losses to dissipate energy, and not experiencing a power stroke, so internal stresses are much, much less than if you were running under load at that RPM. It just sounds terrible compared with the relative silence of normal operation. HAve fun, Frank

http://www.etis.ford.com/ Select "Vehicle" in the top line menu, and enter your VIN. Look on the left under "Outstanding field service actions." Frank

Just to be clear, I'm not considering a circulating immersion heater, that is, one with a pump. The link shows all the options available. The lower radiator hose heaters specify installation in a stretch of hose that's inclined upward, toward the block, with no downward dips between there and the block. I take this to mean they only use convection within the hose to distribute the heat. With a 600W element, there should be a strong thermal gradient... and I once drove ~200 miles without a water pump, using only thermally driven circulation. It's plenty of flow for warming a small engine like this one. And I look forward to Paul's experiences this winter! Have fun, Frank

I've got it in the log book I keep in the car... but wait, I transferred it to my mileage spreadsheet! Well, some of it... 17x7 H2 +55mm and nothing more on the 16x6.5's than the size. I'll check the log book, and the wheels as I'll be doing the swap very soon... winter's arriving now! HAve fun, Frank

I suspect you either have an overly sensitive "kick" sensor, or are unaware of an action that triggers the sensor. It could be seeing your ankles or shins moving into the sensor's scan area. Do you hear a "beep" when it starts to close? I have installed a 2" trailer hitch and that would solve your problem... almost completely blocks the sensor; it took a while to find the remaining sweet spot, as I find "kick" to be a really neat feature now that I'm used to it. Have fun, Frank.

See my reply here... wheel specs are all in the snow tire thread. http://fordcmaxhybridforum.com/topic/3920-aftermarket-or-focus-wheels/?p=51707 Frank

Take a look at the snow tire thread... I posted the specs for both alloy 17-inchers and the 16 inch steel wheels I got with snow tires. rim diameter rim width offset center hole diameter bolt pattern Have fun, Frank

... or not. All depends if the heater still works. My experience with the seat heater: - at first, a setting of 1 was uncomfortably warm, a true roaster. - then it stopped working... perhaps burnt out? - now that I've had it replaced, a setting of 1 is comfortably warm, and the passenger side won't heat up... This in an early 2012 build... may have been fixed in later models, along with the seat back welds. Have fun, Frank

+1 to key life test data And that's expected, give the poorer performance in the key life test. Have fun, Frank

I'll add a quick thought to use a tape measure if you need to carry fixed-size items. Sometimes, it's not the "volume" but rather the size of the usable space. Not everything can be crammed into odd shapes... even my Volvo wagon had to tilt a 4x8 sheet of plywood as it didn't fit between the wheel wells, and with 2' hanging out the back! The C-Max is a tad over 36" (measured) between the rear strut tower intrusion, and about 65" from tailgate to seat back (specs) so I've been able to fit a dresser in the back with no issues. The dash is about 8' from the tail gate, if you have something long and skinny. I'm seeing on Prius Chat that there's more like 38" between wheel wells, with more like a 70" deck length, consistent with a longer car. Can't speak to height, save to say I've fit a drop-leaf dining table in upright, using the side door. It all depends on what you want to haul... I couldn't fit a second dresser inside, so it went outside (cargo platform). HAve fun, Frank

Looking at the datasheets you linked, I think you've actually found a good alternative to the oil pan heaters... low-wattage, open loop, but with mounting flexibility that allows them to be placed where they can be more effective than an oil pan heater pad. Regardless, you're still relying on a low-power heater so it can be safely used without a thermostat. I still like the commercial imersion heaters, as they are thermostat-protected as well as intended for the application. I got one for 1 3/4" from a co-worker, and I'm impressed with the build quality, even if it's won't fit a C-Max. I'll consider installing one next year, as my mileage has improved so much over last year that I need to re-baseline performance if I want to give an honest estimate of the improvement. Anyone out there have an immersion heater from the factory? Do you use it? What's it do? (Hoping for someone a ways north of you, Paul.) HAve fun, Frank

I see no reason to doubt the explanation provided. It's not a stretch to most audiophiles (or audiofools depending on your point of view); separate amp and pre-amp/source installations are especially common in car audio. . Amps can have more than one input, and newer Class-D amps have very low standby current draw, so there's no reason not to leave them on. You'd just be shutting off one of multiple sources to the amp when turning off the radio. Can you use the phone when the radio's off? From an engineering standpoint, doing otherwise is poor practice, as there's nothing critical in this feature that would warrant redundant amps, with associated weight and cost. HAve fun, Frank

I suspect the immersion heater will be far more effective when ambient air is actually cold... 72F is summer around here! Just the weather you want when crawling under a car, though! And it makes sense that the coolant temp initially drops, as coolant circulation hits the cold parts, and assuming the thermostat's open, the radiator is a reservoir of ambeint temperature coolant. It'll be interesting to see how you feel about the install after a few months... yesterday morning, my engine never reached operating temperature, and as a result, it wouldn't kick into EV+ when driving past the dealer (on my route, 4 miles from the start) or at my destination, 15.3 miles. No issues in the evening, even at the same ambient temp. It's the cold soak at the daily minimum temperature that really hurts... but only about a 10% hit to mileage, as I was able to follow my normal ICE/EV pattern with temps around 40F. HAve fun, Frank

Good man! Doing it the right way! Frank

FYI, CU sent out a questionaire yesterday and since I was indisposed when it came in, I completed the survey. The topic turned out to be Hyundai real-world mileage... we own an Elantra. my wife's car, which she chose based on EPA mileage ratings, orignally 29/40, now 28/38 city/highway. While I've been able to achieve the updated EPA highway ratings averaging 70 mph on a long roundtrip, I was driving solo... I kept defrost off (and so AC off as well) and shifted the tranny manually into 6th, so cruise control couldn't downshift going up hills. She gets ~25 mpg around town, and is disappointed... blames me because she wanted a hybrid, and I got one. (Thanks to her, of course; we inherited her father's car.) I gave CU contact information, so if one of their writers contacts me, we'll have an interesting conversation... I completed the survey because I suspected this would be the case. Have fun, Frank