Recumpence

Frank, Here is a picture I took of my car today. We had powder snow last night and, after driving for a while, I noticed a few aerodynamic details that were worth noting. The clearest one was this shot I took. You can see by the snow line the exact point of air detachment on the upper portion of the rear fender before the rear window. I hope this information is useful to you Frank (and anyone else who is curious). Matt

Well we are in the single digits with snow and slush on the roads and my day finished with an average just shy of 44mpg. I agree about the air infiltration. I believe that has a greater impact on FE than the surface aero affect. Both contribute, but the faster warmup time is one major aid in this. Oh, I am absolutely LOVING the sealed hood and nose! Even in single digits, the engine stays warm, my heat works great, and my intake air temp is staying 30 to 60 degrees above ambient. The guys on Ecomodder insist that 80 degrees is the ideal intake temperature. I was able to stay around 60 degrees intake temp through the day today with the nose all sealed up. :) Matt

When is your car going to be done? Matt

I am happy with the results so far. Today I drove for 90 minutes at 24 degrees and snowing and I averaged 49.1mpg (50% highway 50% 35mph streets). I cannot wait to get the rear diffuser and Kammback done. Matt

ABA testing would be something like this; Group of runs labeled group "A" (without modification) Run #1 48.1mpg Run #2 47.6mpg Run #3 48.3mpg Group of runs labeled group "B" (this would be with a specific modification done that we are testing) Run #1 48.9mpg Run #2 51.2mpg Run #3 49.8mpg Last group of runs labeled group "A" once again because the modification was removed Run #1 47.6mpg Run #2 48.7mpg Run #3 47.9mpg (This is just an example. I did not actually do testing with those results.) So, "A" is without a specific mod and "B" is with the mod. Some guys do AB testing, some do ABA, some do ABAB. The more cycles you do of a given test, the more accurate and reliable the test. Matt

The short answer is yes. I did it this way for a number of reasons; #1 Simplicity. #2 Asthectics. A nose mounted chin spoiler would be huge work to make look correct. #3 Clearance. A nose mounted chin spoiler would hit everything, not just parking curbs, but inclines. In fact, I had one gas station that this dam rubbed a bit when I exited due to a deep dip at the road curb/junction. Actually, the best design from an aero perspective would be chin mounted, with a flat pan under it to reduce turbulence from the dam rearward. That is what I originally has envisioned. However, all of the previous issues came into play and one other thing; Oil changes! I did not want to make it too hard for the poor oil change guy to access what he needs to access. This dam is held on with 4 bolts in factory locations. He would have to remove them to do an oil change anyway. So, no additional time would be wasted to change oil. Lastly, the difference between this and the perfect chin spoiler would be relatively small. I bet there is maybe another 1/4mpg available doing it that way versus this simple dam. Matt

Here are the pictures. :)

Here are pictures of my new air dam. This was made from a 3/4 inch box aluminum tube (14 gauge) bent into the shape shown. Once bent, I rivetted lawn edging along the aluminum every 3 inches or so. It is screwed to the car with four screws untilizing stock holes that would normally attach the plastic belly pan to the fiber pan around 12 inches in from the nose. It took about 2 hours to complete. This was amazing time considering it was 6 degrees F when I started and I did all the work outside. I had to stop repeatedly to warm my hands and warm the lawn edging at my heater. The whole dam weighs very little. If I had to guess, I would say it is about 3 pounds or less. I have not done any ABA testing. However, here is what I did for the few minutes of time I had; I took my average mileage from yesterday (a full day of driving without the air dam), and compared it to a drive today around my area with the dam installed. Yesterday was 18 degrees and I averaged 47.1mpg. In 10 miles of driving today (after I warmed the car up), I averaged 49.3mpg. Now, bear in mind, yesterday's mileage was total mileage including the terrible MPG encountered with warm up. While todays mileage was recorded after the car was warmed up. Yesterday I drove 120 miles. So, the warm up MPG would have averaged in pretty well over those long miles. However, I would assume that I could have had maybe .5 to 1mpg better if I had warmed the car up yesterday before I reset the mileage trip odometer. So, realistically, the dam is probably giving me 1 to 1.5mpg increase (conservatively). This is right in line with what most people get on Ecomodder when they install an air dam (actually most report around 2mpg or more). I will do some ABA testing sometime soon and report back. :) Matt

Well, that is a good question (what you may be doing wrong). Honestly, I am totally open to getting together at some point for a C-Max mini gathering. I am an hour northwest of Chicago. :) First, let me tell you, I am not lying or exadurating what-so-ever. In fact, my mileage would have been better but for a few things. For one, I did virtually no drafting other than coming closer to the rear of various large vehicles before passing them and gaining a tiny boost at that point. But, I purposely did not draft through this trip so I could make sure my numbers were not skewed. I would say about 5mpg of my mileage was from the aero mods. Beyond that, there are a few things I do specifically to increase my mileage on the highway. First, I allow the car to speed up going down hills, then I let it slow down a bit climbing the next hill. Going through Wisconsin there are alot of rolling hills to achieve this. Second, I drive by sort of feeling what the car is doing. I watch my acceleration to not achieve more than 2 bars if at all possible. This gives acceleration and regen (battery charging) at the same time. Sometimes this is not possible with a huge load trying to get up to 70mph. But, I do it whenever possible. Third, and I do not have a clue how thise works, I watch my mpg screen and I slightly speed up and slightly slow down (very gradually so it is not noticeable to anyone in the car) and I watch the screen to see when it reads over 40mpg at the speed I want and I hit Eco-Cruise at that point. There is something about these Atkinson cycle engines that the valve timing does something special at a given rpm and load that makes it additionally efficient. However, it does not just kick in when you are crusing. I am not sure what is going on with it. But, I can be driving 70mph on a given road that is relatively level and see 34mpg for miles, then all of a sudden I see 42 to 44mpg without anything changing in the state of charge, terrain, or speed. I have learned that must have something to do with the Atkinson cycle kicking in because my engine rpm does not change much (maybe 10%) at that point. I just look for that and use it to my advantage. These things are not hugely time consuming to do while driving. But, they seem to increase mileage around 2mpg or so on the highway. Beyond that, I have learned how to run the AC in an efficient way. In the winter, AC is not run. So, that did not contribute to this trip at all. Oh, one other thing, defrost runs the AC. Watch your power consumption. You will see it is HUGE when running the defrost. So, I do not run defrost if at all possible. I will turn it on for a few minutes, then turn it off. I also do not start the car until everyone is in the car and buckled up, ready to go. Then I hit the start button and start driving. This prevents the engine from running while the car is stationary because that wastes alot of gas. Of course, over the 400+ miles of each trip, that would make very little difference. Matt

Hah, I will have at least another thousand miles on my car by then. :P Matt

Well, let's add it up; Me 175 pounds My wife 150 pounds My daughter 110 pounds My teenage son 150 pounds My youngest son 75 pounds Luggage (guessing) 250 pounds at least. So, yes, I was over it just a touch. :) Oh, remember, the weather was 25 degrees average for the whole trip. Also, I have 42,500 miles on my car at this point and my lifetime mpg is 49.3. Matt

I am back home. My return mileage was 44.7MPG. So, my round trip mpg average was 43.1mpg. I could not be happier. Again, this with five people and an overload of luggage. The trip each way is roughly 40 miles of 45mph driving and 370 miles of expressway averaging 70 to 75mph the whole way. I cannot wait to add the air dam and kammback. :) Matt

It is far easier to heat the air without drawing it into a ram system. My under hood temp averages 30 degrees above ambient by sealing things up as I have. I Have also found removing the snorkel from the intake increases temp another 20 Degrees with the nose sealed up. Matt

Thanks for the information, Frank. I am always pleased with whatever data can be gleaned by ABA testing. Matt

The biggest gains are found in two areas for cold weather; First, do not let the engine warm up in the driveway. Turn on the car and start driving to get the most use out of the running engine. Second, do not use the heater until the engine is warmed up. This keeps the EV driving more useable. These two things make a world of difference. So, where are you located? I am Mchenry. Matt

We are in Lichfield right now. My wife's family lives in Dassel. There is a huge difference in mileage between 60mph and 70mph. I mean HUGE. The added drag is very pronounced. The weight makes a big difference, too. Our luggage and 3 kids combined weigh about 500 pound minimum, plus my wife and I. I would say with one person and no luggage, the mpg would improve by around 2mpg or so. So, With five people at 41.5mpg, we averaged 207mpg per person. :) Matt

We arrived at 41.5mpg. the elevation is higher here than back home. So, I expect to see higher mileage on the return trip. Matt

We are going to Minnesota. 300 Miles so far at 40.1mpg driving 70 to 75mph. Matt

Sweet! I will keep you posted. Matt

Anyone know if you can run two scan gauges on our cmax? I know there are two OBD ports. Matt

The car is loaded. It is 17 degrees out......... BBBRRRRR!!!! Matt

Hey Guys, My family is going on a road trip for Thanksgiving today. We are driving 400+ miles on the expressway. We are leaving today and coming home Sunday. The entire trip will be over 900 miles. This will be the worse case scinerio for our beloved Max. The car will have 5 people and a FULL compliment of luggage. And, when I say full, I mean totally Maxed out (pun intended)! :) The entire cargo area will be loaded to the headliner. On top of the 70mph speed and fully loaded car, the temperature is in the 20s. So, this will be the untimate mileage killer for the car. I am hoping for 40mpg on this trip at 70mph. I think the cold weather, high speed, and high load of the car will make this difficult. But, the aero mods I have done should make it a bit more doable. I will post pictures and updates as I have them. Wish me luck! Matt

Lowering the latch is easy with a Dremel. You just need to oval out the 4 holes. It literally takes 20 minutes, tops. At this point, I am looking at a Kammback, and lower air dam (extended chin spoiler). Honestly, I have assumed my MPG was up around 7mpg. However, I have been doing a bit more testing and it looks like I have gained around 5mpg tops. That is nothing to complain about. But, I have to tell you, it is not easy increasing mpg. I bet sealing off the hood and lowering it with the slight aero increase and temp increase in the engine compartment is only good for 1/10 mpg. That is so hard to measure that it is purely conjecture. But, it is universally agreed by all the engineers and tinkerers at Ecomodder that everything I have done will net a gain. The quesiton is, how much? The engine runs at 175 to 180 degrees right now pretty much all the time. The fan does not kick on at all. I can still do a couple things to seal up the engine compartment further such as the lower vents in the belly pan. But, I think this is good enough at least for now. I am hoping to gain 1mpg more with the air dam and kammback (1mpg with the two combined). At that point, I would need to go to some pretty extreme measures to gain any more efficiency without making it look hideous. Matt

Hello All, I have been doing alot of FE reading and one thing that the guys at Ecomodder continue mentioning is that gas engines are more fuel efficient when run at their upper temperature. They go to great lengths to make sure their engines run nice and hot in the winter. Well, with our hybrids, we suffer from the fact that our engines do not run much of the time. Consequently, the temp drops quickly once the engine cycles off. This has been discussed in relation to grille covers. However, I found that, though my grilles are blocked (upper and center grilles are completely blocked and the lower has just a small opening in it), I still was seeing engine heat shedding rapidly when running in EV mode. So, I picked up some weather stripping and sealed up the border of my hood, around my headlights, and various little nooks and cranys I found. What a difference! It turns out, the gap round the edge of the hood allows cold in and heat out. So, does the gap around the headlight lenses. Once I sealed those up, I found my engine stayed hot all the time. In fact, letting the car sit does not drop engine heat nearly as much as before. This has, not only helped my heater, but it is good for FE. One side benefit is, my intake temperature went from 3 degrees over ambient, to 40 degrees over ambient! This increase in intake temperature is supposedly helpful for better MPG (when the engine is running). This may be a very small FE increase. But, hey if my heater works better, warmup time is faster and I get a tiny bump in MPG, it is a win-win. :) Matt

Today I removed my center grille and shimmed it forward flush with the fascia. It looks much better. That also gets rid of the ridge there to smooth airflow better in that area. I doubt any gain found there would be measurable. But, I wanted the look to be consistant with the rest of the nose of the car. Also, any gain (.05mpg?) is better than no gain especially when it is free. :) I have many very tiny things like that I plan on doing. All together they do add up. Of course, our wonderful little C-Max is already quite aerodynamic in many ways. There are a few areas Ford dropped the ball, however. Those are the "Low hanging fruit" items that I really want to tackle. Matt