ptjones

You lose approx. 2mpg for each 10deg drop in temp. So at that temp you have lose 12mpg. Paul

There is nothing wrong with the engine. Read 3mpg gain with grill covers thead and mileage theads in general. Should answer all your questions. Paul

Keep us posted. Great. What part of the country do you live in? Temps? Paul

Check out my 3mpg gain with grill covers thead. I can get 3mpg back for the same outside temp.

Go to my 3mpg gain with grill covers thead and I have a graph that shows MPG loss with temp drop. Paul

I should have some covers ready next week for shipping. They're $50 plus S&H shipping weight should be 3lbs.

The covers will make a big difference in WT, it should be in 202-215deg range for the best MPG. You should gain 3mpg with covers for the same outside temp. Should have covers ready next week. Paul

The cold weather is the reason I developed the covers. You should expect about 3mpg increase and your ICE will warmup faster. I don't block off top grill but you could when it is really cold. BTW the upper grill right side lower opening is for the ICE intake,so don't block that off. I hope to have some covers ready to ship next week. Let me know if you want a set. Paul

I only saw a 30deg+ difference between garage temp and WT with ScanGuage in the morning with heating pad on. But the ICE ran 15deg hotter on the fwy at 70mph with the pad I used. I pulled it off and temps came back to normal. In cold areas 30deg and below I think the Wollverine Model 9 is a good solution.

I had heard about other possiblities but hadn't looked into yet. Thanks, being semi transparent they might not showup as much. I have a set of prototype plexiglas covers I could send you to try out if your interested. Thanks Paul

I believe I can mount covers using Velcro in only in dark areas of grill and there is no reason not to have one or the other center covers on all the time. The grill is curved so corners need to be heald down so center mounting won't work. The goal I had for the covers was that they had to be funtional, inexpensive and easy to install without damaging the car. Any other solution would negatively impacted those goals. At $50 plus S&H and it would have short payback period. All test were done with no HVAC and the only varibles were outside temps and covers on or off. There maybe only difference of 2mpg at 35mph and 3mpg at 55mph. At slower speeds the covers allow engine to warmup quicker and stay warm which saves mpg. On testing Prius outside temps are important, 10degree could make 2mpg diffence in the results.

Here's my CMAX cover vs. no-cover improvement plot. As you can see I gained 4mpg for all temps between 37-65deg.F I did 6 runs with cover off and 11 runs with the cover on. A run was 14.2mi long with .5mi to start from my shop to fwy ECO-criuse to 70mph GPS and go 6mi to off ramp and back on ramp to return to my office. The average EV was 2.2mi and regen was .6mi with brake score of 98%. The ICE got up to temp twice as fast with cover on. At lower temps ICE never got up to temp with cover off.The graph points out dramatically the effect temps have on MPG's with a loss of 7mpg for 30deg.F drop in temps. Unfortunately your graph makes no mention of temps which could make big difference in results. As far as breakin goes I think 1-2mpg improvement is reasonable. You could get a 5mpg improvement from change in driving technique. I think there are a couple of post of MPG vs Speed in Mileage thread. BTW it was 16mi from Bell Ford to my daughter's in Suprise.

Here's my CMAX cover vs. no-cover improvement plot. As you can see I gained 4mpg for all temps between 37-65deg.F I did 6 runs with cover off and 11 runs with the cover on. A run was 14.2mi long with .5mi to start from my shop to fwy ECO-criuse to 70mph GPS and go 6mi to off ramp and back on ramp to return to my office. The average EV was 2.2mi and regen was .6mi with brake score of 98%. The ICE got up to temp twice as fast with cover on. At lower temps ICE never got up to temp with cover off.The graphpoints out dramatically the effect temps have on MPG's with a loss of 7mpg for 30deg.F drop in temps. As far as attaching the the cover on, I needed to make it as simple as possible, no hole drilling. With the Velcro it takes 10-15min to install and a second to remove and install again. I don't think I need to put Velcro on silver part of grill now. You would always have a center cover on with cut out or not. Bottom one would come off for Summer. I hope to have PolyCarbonate Plastic by the end of week and puting together cover sets for sale at $50 a set plus S&H, shouldn't be much, they don't weigh much. BTW I asked my Ford Service manager What is the normal operating temp of the engine at idle and while driving and when should the cooling fans come on? They replyed "The gasoline engine (depending on the vehicle and ambient conditions present at that time along with the HVAC settings) typlcally is not operating at idle. There are no published spdecifications due the many factors that have to be accounted for when deterniming the engine temperature and the cooling operating. The thermostat is fully open at 202 degrees, so normally the engine should be approximately 202-212 degrees (again depending on the conditions present and if the engine is operating at that time).;If there is an overheat concern present,recommend to check the PCM, TCM, SOBDM and the BECM modules for DTC's. When checking for DTC's on this hybrid vehicle it is slightly different than when checking for DTC's on a gasoline only vehicle. In order to accurately check for DTC's, the nodules listed above need to be individually self tested. Veryify if there are any signs of coolant expulsion and/or if the coolnt level is low. So there you have it from Ford, thermosat is fully open at 202deg and opperating approximatly 202-212degrees.They didn't say what temp the fans come on, but I have only heard the fans on twice at around 215deg. very rare ocurrance. On my trip I saw temps 213-215deg 90% of the time. When outside temps in 25-35deg WT of 207deg. I did have one time on a long uphill climb drafting at 70mph and outside temp of 63deg., I hit 233deg WT so I took bottom cover off and temps droped to 204deg. There is a direct correlation with speed and heat generated by the engine. If you are using the AC you will need to put center cover with cutout on and remove bottom cover for maxium AC efficiency. Anyone interested in ordering?

I used ECO-cruise about 25% of the time. Usually it is hard to draft and use eco-cruise. Only use P&G 65mph and below. It is best to keep your speed below 70mph to get better than 40mpg. It is also better to draft at 75mph than go it alone at 70mpg. The prefect hwy MPG for the CMAX is 65mph ,P&G,70deg.F, drafting with tail wind=55-60mpg.

Buy a ScanGuage and you will have that info all time.

I used that button a lot during my long trip , I think it only stayed on for 15-20min. I didn't find anything in the manual to get it to stay on.

I just got back from my trip to Phoenix and I can tell you Phoenix is a CMAX mileage paridise. I was easily getting 50mpg around town with the temps around 50deg.F. I filled up near Bell Ford and jumped on the 101 fwy to Suprise with traffic going 70+mph drafting and got 52.5mpg for the trip and temps in the 50's. I do have my grill covers on for a plus 3mpg and I had 5.5k miles on the CMAX at the time. I have a hard time believing that my car is that much better than yours. Have you checked your odometer with GPS? I gained .5mpg on mine. Drafting safely can improve your MPG by 3mpg. Some of us make a challenge to ourselves to do better each time we go out and then figure out what we could have done better. It's a work in progress.

I just got back from trip to Phoenix and back, 3880mi which gives me the dubious honor of being the highest mileage CMAX on fuelly with 7700mi. On my trip I averaged 40.8mpg with temps 26-60deg.F. My experience tells me at 70deg.F I have no problem getting 47mpg city but at 40deg.F It's very hard. BTW my CMAX wil stay in EV at 63mph actual, tested with GPS. I did have one tank that I averaged 45.6mpg with temps in 35-45deg.F and a little tail wind. When temps are 70-85deg.F averaging 65mph on fwys around Atlanta I can get 47mpg regularly. I was wondering if anyone has checked their odometer with GPS? Mine is off by 1.5% or about .5mpg to the plus. It is amazing that Hybridcars.com would state something without testing it.

I'm getting 50mpg in Phoenix with temps in 40-50deg. Haven't seen a single CMAX on my long trip. Maybe on the way back.

That was Cool!

The top air openings are for cooling the engine compartment.

I'm made it to Phoenix with 40mpg average, 37-65deg. temps some head winds. Hope to do better going home. I found I can cuise in EV at 63mph actual GPS Cool!

I checked three PlugIn battery suppliers and they said they only supply an additional battery plugin system. They don't mess with Ford's system mainly to keep from voiding warranty.

They are automatic and only partially effective.

I will be in Suprise, AZ XMAS week. Just leaving GA. Hoping to get some good MPG Numbers.