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CMAX Grill Cover Testing, 2-5 MPG Gain


ptjones
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Way to go Paul !!!   Is that 894.6 I see?  I could not do that 'even if I was paid a million bucks' (but I might try ;) )

 

Seriously, That is exceptional.  (I would never have the patience to even try - Mr. ECO Cruise here)

 

Now we have to work on your camera work, maybe just a little straighter and a scosh larger :)

 

Wish I could go to your tech sessions on scan gauges .......... down in Athens, you folks will have a great time.

 

Nick

Edited by C-MaxSea
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I had to take my wheel covers off on the last day of my San Diego trip because of high temps and speeds (65-75mph) the foam rubber seals at the edge of wheel cover kept coming off. When I got home it gave me a chance to clean my wheels and covers off and install new foam rubber seals. I didn't put them back on until I got my oil changed at FORD  Friday.  I noticed my MPG's haven't been as good as before I left on my trip, but with Wheel Covers on I've gained back at least 1MPG, probably 2. :)

 

Paul 

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Paul,

 

Why is your lifetime mpg so low when you are able to achieve such high mileage tanks? My lifetime mpg is 49.8 at 63,000 miles, yet my best tank was 766 miles....

 

Matt

If you go to my Fuelly Icon and click it you will see I do 81% HWY traveling all over the country in all kinds of bad weather making for low MPG's which takes a lot of High MPG's to over come it.. My Smart Gauge LifeTime average is 46.7MPG with 74K miles. :)

 

Paul

Edited by ptjones
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  • 3 weeks later...
  • 3 weeks later...
  • 4 weeks later...

grill blocks  Step 1.

 

Well I cut some aluminum to place behind the upper grille.  basically 4.25"x11" with a corner cut out  it dropped in behind the upper grill after removing the clips.  up close its visible  but from the street  can't tell.  One on each side.

 

Next step will be two work on middle and lower grill...  curious as whether or not I can come from under the bumper by removing the lower aeroshields....  so I don't have to remove the entire front bumper..

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post-2136-0-84167200-1416254424_thumb.jpg

Edited by Marc Smith
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Been awhile.  I'm following along with you guys and hope to install the foam inserts in my C-Max, Carly, today or tomorrow.

 

Question, though.  Regarding the oil pan heater, this is a plug in device for when the car is off, yes?  For the sake of honesty and accuracy, does the electric cost of running the heater need to be factored into the total fuel cost of running the C-Max since we're basically trading off cold oil needing to heat up for warm oil that was heated by an outside source?  It seems it would be similar to the whole e-mpg equation for plug-in hybrids like the Energi.

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Been awhile.  I'm following along with you guys and hope to install the foam inserts in my C-Max, Carly, today or tomorrow.

 

Question, though.  Regarding the oil pan heater, this is a plug in device for when the car is off, yes?  For the sake of honesty and accuracy, does the electric cost of running the heater need to be factored into the total fuel cost of running the C-Max since we're basically trading off cold oil needing to heat up for warm oil that was heated by an outside source?  It seems it would be similar to the whole e-mpg equation for plug-in hybrids like the Energi.[/quotes

 

Oil pan heater only uses 125 W like a lightbulb no real cost involved.

 

Paul

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grill blocks  Step 1.

 

Well I cut some aluminum to place behind the upper grille.  basically 4.25"x11" with a corner cut out  it dropped in behind the upper grill after removing the clips.  up close its visible  but from the street  can't tell.  One on each side.

 

Next step will be two work on middle and lower grill...  curious as whether or not I can come from under the bumper by removing the lower aeroshields....  so I don't have to remove the entire front bumper..

.

 

I don't think that is going to be easy to do. I think it would be easier to come from the front and fasten it to the grill.

 

Paul

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I don't do  "easy"  :)    When getting from point A to B.  I Usually go  A, Z, Y, X.....

 

I just really want to have something from the back side...    We'll I never said it would easy...

Aerodynamically the front end needs to be nice and smooth to create the least amont of drag, the best MPG's. Do you think it looks better to cover up openings from behind the Grill?

 

Paul

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Did you install a Grill Cover? Oil pan heater will improve short trips mpg's Tire psi 50? :)

 

Paul

No I haven't Paul to all you mentioned.  How is an pan heater installed?  Does it require cutting or drill to install?  Where do you get one?  I've really never heard of one before this thread started.

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Paul 

 

yeah the front end if its smoother is better.  but I live in the area of sand/salt and perpetual road construction and I think over time the lexan will become pitted and scratched.

 

So I'm  thinking about one of two ways.  either a large one piece sheet of aluminum that fits behind the opening and is painted flat black so its just behind the grill opening.  This is  most difficult to do and not easily reversible, IE if I'm on a trip and notice overheating,  I'd need tools. But from a manufacturing standpoint is the easiest

 

the other option woudl to be cut three pieces of aluminum to fit in the opening so they rest on top of the recessed vertical bars and paint them to match the surrounding black plastic.   with right angles bent into the ends so that can be attached with something a clip, a snap, ect.  so removal would be easy, like your grill blocker. and the look woudl be similar to the foam blockers just three pieces in stead of a dozen...

 

So either method would retain the "bumpiness" of the front fascia

 

the lower grille would be a similar process.

 

from all of my  research,  the grilles are just clipped in.  On my Prius with a little bit of elbow grease  I was able to pop the lower grill out once I removed the lower air dam.  Hopefully the ford is similar...

 

 

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post-2136-0-73574900-1416497664_thumb.jpg

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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...

Edited by fbov
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no real mountains here in Va  near DC so I'm not worried about overheating as I think there has been enough evidence on the site to show that  its not as big of a problem as fold think.  that being said.  having any mod that blocks the grille

 

Heck  today in the drive to work  the temp gauge barely got of the proverbial peg.

 

Also my mods are not strictly for aero purposes per se.  they are more to help isolate the engine compartment from cold air.  Ie  speed up the warm up time.   That being said,   doing the blocking I'm doing should not hurt the aero.

 

so I may realize a slight  aero benefit.

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From the testing I did the Grill Covers are worth 2 mpg HWY driving.

 

I made a trip to AZ last week through the bad snow storm and back. I was driving by myself so I was able to use heater speed to control WT using ScanGauge. This was with both Grill Covers on going up long uphill grades. It worked great and I didn't have to freeze.

 

Paul

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Paul 

 

yeah the front end if its smoother is better.  but I live in the area of sand/salt and perpetual road construction and I think over time the lexan will become pitted and scratched.

 

So I'm  thinking about one of two ways.  either a large one piece sheet of aluminum that fits behind the opening and is painted flat black so its just behind the grill opening.  This is  most difficult to do and not easily reversible, IE if I'm on a trip and notice overheating,  I'd need tools. But from a manufacturing standpoint is the easiest

 

the other option woudl to be cut three pieces of aluminum to fit in the opening so they rest on top of the recessed vertical bars and paint them to match the surrounding black plastic.   with right angles bent into the ends so that can be attached with something a clip, a snap, ect.  so removal would be easy, like your grill blocker. and the look woudl be similar to the foam blockers just three pieces in stead of a dozen...

 

So either method would retain the "bumpiness" of the front fascia

 

the lower grille would be a similar process.

 

from all of my  research,  the grilles are just clipped in.  On my Prius with a little bit of elbow grease  I was able to pop the lower grill out once I removed the lower air dam.  Hopefully the ford is similar...

Why not just use foam? It's the cheapest method, foam costs under $2 here for a package of pipe insulation. It's also very simple since all you need are scissors. And you can reuse the same foam pieces year after year so there's no on-going work or cost. If you push the foam in all the way it hides very well.

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Why not just use foam? It's the cheapest method, foam costs under $2 here for a package of pipe insulation. It's also very simple since all you need are scissors. And you can reuse the same foam pieces year after year so there's no on-going work or cost. If you push the foam in all the way it hides very well.

What about the 2mpg HWY? MPG's are everything! LOL

 

id rather only deal with 3-4 pieces  as opposed to over a dozen...

Grill Covers are only 2 things and only take seconds to put on and off.

 

Paul

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