Lower Grill Block 2005 Honda Civic

[Arminius]

I finally received my Scanguage yesterday, so I decided to run an experiment on a lower grill block. I drove 8-mile runs on Highway 16 from Hartland (H) to Oconomowoc (O), WI and then back.

Here are the results (average mpg) in the order in which they occurred:

With grill block (cruise set on 52 mph):
H to O: 46.2 mpg
O to H: 45.9 mpg

Without grill block (cruise set to 52 mph):
H to O: 44.9 mpg
O to H: 44.9 mpg

Without grill block (cruise set to 51 mph):
H to O: 45.0 mpg
O to H: 46.0 mpg (see notes on this stat below, underlined)

With grill block (cruise set to 51 mph):
H to O 46.2
O to H 46.2

A couple of notes:

The grill block consisted of layers of packing tape, so it was not flush with the bumper.

The stats on the Scanguage were reset at the same specific points (road signs) at the beginning of each run. Resulting stats were recorded at the same specific points (road signs) at the end of each run. The car was up to speed and set on cruise at least a quarter of a mile before the beginning of each run.

The road was slightly wet, but there was no rain or puddles. I did not use the wipers.

Weather:
Temp: 38 degrees F
UV Index: 0 Low
Wind: From WNW at 4 mph
Humidity: 96%
Pressure: 29.45 in.
Dew Point: 37°F
Visibility: 8.0 miles

This experiment took place between 2:00 AM and 4:00 AM CST. I stayed in the right lane at all times. I kept the radio and fan off, so the headlights were the only device I had on. I was passed by only one car on each run, going in each direction. The exception was the last run without a grill block (O to H: 46.0 mpg), when a semi passed in front of me for the last 60 seconds of the run, most likely providing improved stats due to drafting.

There were no other modifications to the exterior of the car, including the upper grill.

[boxchain]

Good stuff! So a LGB (new acronym) is worth 2.5%...at low temps and high humidity

2-4am...and you didn't get pulled over for driving erratically?

You: "I'm doing a fuel economy experiment"
Officer: Pulls you out of the car, drunk test, checks car for drugs, calls for backup

[Arminius]

That road has officers all over it at that time of night. I was followed a couple of times. I did intend to use that excuse, plus point out that my bumper was covered with several layers of tape.

Oh well, there's always next time.....

[fabrio.]

good test Arminius.
Could you post some pictures of your car and your aero mods?

[Arminius]

Originally Posted by fabrio.

good test Arminius.
Could you post some pictures of your car and your aero mods?

I'll try. I'm not very good on the computer, plus I took the tape off and am trying to make or buy something to replace it. Right now I've got a black garbage bag (hardly noticeable) covering the area. I'm continuing to test the block and I keep getting the same results, except I get better results at faster speeds. I'm not going to put anything permanent on until I study the engine temp for a while.

[fabrio.]

no problem.
You use the foam spray for fill the back bumper, I am interesting at your experience

[SVOboy]

It's always nice to see a little testing in action,

[Arminius]

Originally Posted by fabrio.

no problem.
You use the foam spray for fill the back bumper, I am interesting at your experience

Yeah, I will test that too. I don't expect the results of that to be as good as covering the entire back area, like some have done. I plan to test it, first, by filling it in with cardbaord. Frankly, I think that the air has lost a lot of energy by the time it reaches that area, so there will be some advantage. But whether or not it is so marginal that it is unmeasurable is anyone's guess. (Hope I'm not using too many English idioms for an Italian to understand!)

Like I said before, all the changes I make must be unnoticeable to my wife, since this will be her car in the future. If/when I do use the foam, it will be way in the back, only, so that she can't see it. I will also paint it the color of the car so that it doesn't stand out.

[Arminius]

Originally Posted by SVOboy

It's always nice to see a little testing in action,

I'll post any formal testing. I'm not using controls or attempting to isolate variables, as I did before. I'm just using the judgement of an experienced observer at this time.

[Arminius]

One more thing: I'm making a sign for my back window that says, "Efficiency Testing / Ecomodder.com" so the cops don't pull me over for going too slow.