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You've entered the realm of DIY add-ons... Grill covers are not available commercially, but rather from some forum members who have fabrication facilities and skills. In addition to reduced engine warm-up time, grill covers may be providing real aerodynamic benefit from reduced air infiltration and a smoother front end. One can eliminate air infiltration and gain most of the aero benefits from duct tape, albeit in a short-term solution. On a related note are air dams, which extend the front bodywork closer to the ground, are in their infancy here, but I bet we see more by Spring! I'm still waiting for someone esle to try side skirts... or Spring to arrive. GasPods are vortex generators that claim fuel economy benefits due to reduced wake drag. The problem in my mind, is that they are placed at the rear of the roof, and on the C-Max, there's nothing to improve about airflow above the beltline, based on aerodymanic testing. The problems start at tail light level and below... Then there's side mirror removal, Siriuis antenna removal/upgrade(?), aero wheel covers, etc. If you're interested in mods that reduce fuel use, here's the master list. HAve fun, Frank

With snow tires, pressure and traction go hand in hand. For added traction, increase your tire pressures. I look at it this way: higher pressure presses the tread deeper into the snow resulting in a better bite. Modern snow tire treads are designed with many narrow grooves called "sipes" across tread blocks. When the tread block is compressed, these grooves open, gripping the snow. Reduce tire pressure and you reduce forces opening these sipes. Then there's geometry; narrower contact patch is better two ways. It reduces the amount of snow that the tire pushes to the side, and it increases the amount of longitudinal force (accel/braking) available from the tire. Lower your tire pressure and the tire grows wider at ground level - not advantageous at all. By the way, I'm running X-ice 3's at 51 psi, and in highway driving, I see no change in mileage from the OEM Energy Saver/AS at 51 psi. Michelin did a good RR job here! HAve fun, Frank

C-Max only comes in 2 versions, Hybrid and Energy. The thing that sets this hybrid drivetrain apart on the EPA lists is they are the only CVTs in Ford's lineup (along with Fusion and MKZ). You'll note the listings are in pairs, (hwy and city) and that the C-Max has two pairs; the Energy gets different tests. HAve fun, Frank

AP is a news service. Subscribers choose which stories they pick up. Huffington picks up these kind of stories. Their choice... I failed to make any assumptions, preferring to read the piece and judge for myself. Please don't confuse conclusions with assumptions. If you think this article presents a balanced view of the topic, we will have to disagree. If you expect to find logic and reason in articles of dispute, sadly not in the internet era. When billions of dollars are at stake; the truth takes a back seat to influence and profit. I'm a member of the local Academy of Science (sounds better than it is) and as a result, get to speak with lots of technical people. That's the only place I see a complete picture, as most of the factual data is long buried in rhetoric. Talking with folks who do complex activities professionally gives you a different perspective. Finding such folks on the internet is highly unlikely; who needs critical thinking when you have a blog? Finally, in all fairness to the authors... (opening paragraph, ed.) The hills of southern Iowa bear the scars of America's push for green energy: The brown gashes where rain has washed away the soil. The polluted streams that dump fertilizer into the water supply. ... how far do you think I had to read to see signs of bias? As the old rule-of-thumb goes, "If it reads like a novel, it probably is." Have fun, Frank

I was trying to say the opposite - your surface changes may result in a greater reduction in Cd than reduced air infiltration, per se. The idea is that the air velocity will be much higher on either side of the car's axis as you part the air. I've seen V^4 dependency, V^2 for normal drag, and another V^2 due to increased air velocity at skin level, compared with the vehicle moving in an air mass. As you reduce infiltration, you just add air to this effect. It would explain the benefit from the fog light treatment, for example. Of course, I'm thinking Cd while you're thinking FE. Engine efficiency gains from thermal isolation are a secondary benefit of reduced air infiltration in winter, but they may well swamp out any aero gains. As these last couple sub-30F mornings have shown, it's darn hard to EV when the ICE won't turn off!! Have fun, Frank

I miss the avatar-of-the-week... you always knew if an Aussie won!

doc, if you only understood that you come across just like the guy who plugged his car in without asking...peas in a pod. You can change that; so can he. Have fun, Frank

Nicely done; your craft is excellent! While the CMax is not a Fiat Uno, the basic tendencies apply. On the Uno, there's a minima in Cd reduction at 2-3" airdam depth, with additional benefits as one moves the airdam further forward. It would be interesting to know what the curve shape might be for the C-Max. By way of mods, I got tired of choosing between being cold and being efficient, so I tried something new - an inflatable grill block. It's a 20x2" bicycle inner tube, folded in half with the valve at one end, slid between the grill slats and inflated. About 10psi filled the ~4" gap, and it seems the car warms up a bit faster. I'm considering something similar for the lower grill as well. What an inner tube does not do is affect anything beyond air entry to the engine compartment, and that's a big difference in our approaches. The external panels you've installed are providing aero-benefits two ways, I believe, reduced air infiltration and reduced surface drag, while I'm only addressing air infiltration. The trick with front surface drag is that air flow velocity is very high on either side of the meridian line down the middle of the car, and near the stagnation point, it's virtually all lateral, trying to get out of the car's way by going to the side. You've removed many of the surface details that disturb lateral airflow as you've blocked air infiltration. We'll see if just blocking air infiltration, as I am doing (and Ford supposedly did with the shutters) has much affect on fuel consumption. I'm just not looking forward to the snow tire baseline if these gril blocks really do improve engine warm-up, because I'll have to take them out... HAve fun, Frank

This is one where we agree 100%, Doc, and kudos to Jus for picking the only link I've seen with all the information. I first saw this on Ecomodder, a USAToday link that focused on Kamooneh's soundbites, not his long-standing misbehavior. Even ABC's is slanted toward the sensational, just as Kamooneh was hoping. Bottom line; courtesy costs nothing, but it pays dividends... or in this case, bail money, lawyers' fees, fines, and more! HAve fun, Frank

We, the members, have a right to police this forum whenever posters fail to meet basic standards of conduct. salman hit the nail on the head, and I've tried to do the same, both privately and in prior posts. We're having a hard time getting through to you. We can get moderators involved if you'd like, but the message is simple: boorish behavior is not tolerated by the members of this forum. You are welcomed to participate, contribute, express your opinions, but only if you do so gracioiusly, extending to others the same courtesy shown to you. Have fun, Frank

While that article does imply long term drain on the cars for actual power use during peak demans, the real value of this sort of thing is in power grid regulation. Simply put, electric generating stations cannot respond to short-term changes in load on the grid. Added load causes a reduction in line frequency, used for many functions, so untility companies need large power reserves available to satisfy new loads and restore line frequency. Think in terms of everyone's clock running slow during hot days with high AC usage. The link discusses the advantages of "fast" power leveling assets vs. generating stations. One source of fast power leveling assets is a plug-in hybrid's battery. In this case, net drain is minimal; lots of short discharges that are made up immediately. Li-ion batteries are good at this sort of application, and if you get paid (perhaps a free charge?), what's the harm? HAve fun, Frank

Well my highway testing continues to confound and amaze me! This time, it's snow tires all around and aero wheel covers on the back. (Lost a front, but that's another post). All the prior data is still shown, but with open markers and dotted trend lines to make the new data more evident. Once again, no effect given the noise. The snow tire data falls right on top of the prior data, with the trendline nearly coinciding with the prior test! Time to get off the highway... of course, that will confound VGs with the snows, as time precluded testing VGs on back roads. In theory, rolling resistance is a greater hit at lower speeds as rolling time lengthens, so given parity at highway speeds, perhaps I'll see a difference... Not complaining, mind you!!! Given what some others have reported for other brands of snow tires, this makes me very happy choosing X-Ice 3's. Have fun, Frank

The manufacturer is likely DuPont, as R134a is their naming convention... but R134a is Freon, regardless who makes it. Frank

Paul, That's a false statement. "Freon" is a DuPont trade name for halogenated hydrocarbons, and trade names mean whatever the owner wants them to mean. In Freon's case, it's a line of chemical refrigerants. For fire suppressant products, it's Halon. R-12 is the bad stuff banned at Montreal in 1987. R-134a is the ozone-friendly replacement for R-12. The key difference is chlorine; R12 is a chlorofluorocarbon while R134a has no ozone-eating chlorine. At the same time, R134a is a super-greenhouse gas. Watch for similar restrictions as we get serious about GHGs. HAve fun, Frank

I have issues will being logged out while browsing the forum... sounds like what you saw. I'll select several posts to view in new tabs, from "content I have not read" so I'm certain to be logged in, go to respond to one and it comes back "not authorized" because it's forgotten who I was. Reading subsequent tabs, reply options disappear at the one that logged me out. Simple fix (log in) but annoying. HAve fun, Frnak

Bump (because a good write-up deserves it) HAve fun, Frank

See Post #6

Not as much as the horn...

Glad you're back; it hasn't been the same here without you - you are missed!!

No, but yes. Yes, I plan to continue through the snow season into Spring. No guarantee I'll retain this configuration, but no reason not to... No, the data are sufficient to reach some conclusions. The inability to detect a difference is a very common result in experiments. The conclusion is that low-speed testing for fuel consumption is a lot more sensitive to changes in C-Max configuration; PCM and tire pressures showed positive benefit driving 35-45 mph speed limit roads while no difference was seen driging expressways, 55-65mph. HAve fun, Frank

Good move keeping threads consolidated. I think you'll be fine, but you be the judge. Once upon a time, cars came with "break-in" oil that was changed after 1500 miles. Some still do (Honda?). Next you needed to run natural petroleum oil "until the engine was broken in" before you switched to synthetic oil. Your C-Max comes with synthetic oil from the factory, and an engine oil monitor to tell when it needs changing. The bottom line is to follow manufacturer's recommendations. For more... http://www.edmunds.com/car-care/top-7-urban-legends-about-motor-oil.html http://www.popularmechanics.com/cars/how-to/saturday-mechanic-blog/how-to-break-in-a-new-car Have fun, Frank

http://ecomodder.com/forum/showthread.php/dam-works-air-dam-smart-fortwo-3-4-a-26046.html Just saw this on Ecomodder...

Have you all seen this? http://www.grandmarq.net/blaze/Blaze_Pics/AE%20507%20lect%207%20Aero%20Drag%20of%20Autos.pdf Pages 14-19 cover front end effects. - The key metric for front end shape optimization is pressure along the vehicle axis, page 14. - Extending the air dam can increase drag due to elevation of the stagnation point, page 15 - the subtleties of nose contour, pages 16-17 - air dams, pages 18-19. One of my next tests will be a pressure contour from windshield to air dam (page 14). I've got the parts, just need the time and the motivation... here's the equipment/methodology. The trick is to place the tubing perpendicular to the air flow, so there's no direct pressure into the tube, just what results from the air flow across the mouth of the tubing. No promises when, mind you. The tuft test was an abberation in some ways... In terms of expectations, Barnard's data on stagnation point, above, indicates you want it below 10% of body depth. Here's an idea where the 10% point is on a C-Max: Most of the discussion regarding effectiveness of grill blocks has focused on mechanisms using lateral flow perpendicular to the vehicle axis. Perhaps there's a component due to a lowering of the stagnation point... HAve fun, Frank

Well the high-speed results are in... and there is no joy to be found on the expressway side of my C-Max testing. The chart shows 3 data sets: - Baseline is roughly Labor Day through Columbus Day - TP_UG is a combination of the PCM Update plus tire pressures increased from 34-51 psi plus upper grill block - VG is AirTab vortex generators mounted on the rear quarter panels. The one caveat is the latter two data sets are taken over the last couple weeks - November - so there's very little overlap in temperature ranges. This data is for my expressway commute, taken in morning/evening pairs most days, mostly with ECO-cruise (didn't today). I did cull some data points from the baseline data as there could still have been some learning going on. That results in a non-zero correlation and a realistic curve fit, but... Without the trend lines, this looks like one population of data with a strong temperature sensitivity. In contrast, my lower-speed commute showed real improvements from the PCM update (5%) and increased tire pressures (1-2%). One might argue there was a reduciton in temperature sensitivity, but one does so based on very little data. Note that this data supports no conclusions regarding the efficacy of vortex generators. The PCM update has been widely praised for a positive result. Reduced rolling resistance from increased tire pressures can't go wrong. Given those changes show no affect, one cannot reach any conclusions regarding the slightly improved mileage seen in this data. And I'm starting a new test tomorrow - snow tires. Temps are dropping, the lake effect snow machine will start up tomorrow night and we're going to Vermont for the Holiday! This is one test that I don't expect to show an improvement... Have fun, Frank

Matt, two things: if you want to dispute anything I say, please do so with backup. Many disagreements can be eliminated if the disagreeing party does the research and finds out, before sticking foot in mouth, that they're the one in error. My numbers for drag are aleady adjusted from EPA estimates to account for hybrid drivetrain, and the guys who are halving their fuel consumption are doing a whole lot more than aero mods. Get your facts straight; I was agreeing with you. It would also be helpful if you organized your data when you think you have a point to make. What you're doing is known as "cherry picking" in data analysis. It's a common practice among non-techncial people (and lawyers) as it allows one to prove anything one wants, which also makes the results meaningless. Take a look at Paul's write-up on his grill blocks for an example of a well-documented improvement. Paul, Stop telling me to block off my front grills, you've graduated into obnoxious. This feels like about the fifth time you've quoted my posts to do so, and this time, it appears you didn't read a word I said. Can you not understand English? How much more plainly must I say it? Is rudeness a requirement for getting through to you? Courtesy isn't working... BTW, I had downloaded your write-up weeks before you forwarded it to me; it's nice work. What modifications I choose, especially in an experimental setting, says nothing about my regard for your work. For my part, I'll be posting my expressway results with the AirTab VGs on the tuft test thread; I want to keep things together. Suffice it to say, I don't see anything moving my expressway mileage, just one big trend line in several parts; no change with the PCM update, increased tire pressures or VGs. It'll be Spring before I get to test VGs on back roads, where the other two showed a difference, because... This weekend marks the end of aero testing for a while, as the temps are dropping, turning on the lake effect snow machine. Snow tires go on tomorrow morning, which will be a test of it's own, but with a negative impact... Have fun, Frank