Boy this car likes the warmth I Blocked front grille to experiment

35 degrees outside when I left for work this morning, still managed to pull 58.1 MPG out of the 9.7 mile trip.

Later, at 56 degrees, pulled 88.8 MPG on the 7.4 mile trip to the post office, though the return leg only managed 62.3

 

I should really do this. Getting sub 40 mpg on my 3.4 mile commute in the morning. It's not even that cold here, but my car sits out overnight, and the trip is short. (I know, I know, I should bike. But I don't.)

 

My car sits out overnight as well, but if your commute is that short I'm not sure the blocking would help very much. My morning drive has two major legs, each about 4.5 miles... and I don't start to get MPG numbers above 40 until the second leg of the drive. In fact, it's the last two miles being almost entirely EV (not my choice, speed limit) that gives me the boost in my morning mileage.

 

here's another hypothesis behind why the grill-blocking might be helping improve MPG...

In addition to the additional "warm up" points it gives you...

It also probably improves aerodynamics quite a bit. Basically all of the front-impact air that used to get jammed into the engine block area is now directed more smoothly and turbulence-freely over the hood and over the car. All other things being equal (like engine temp issues), the improved aerodynamics/reduced wind resistance from blocking the front grill is likely a contributer to the improved MPG.

Thoughts?

 

That's kind of what I was thinking as well. I'll just suck up the low mpgs for the time, and be happy again in the summer. (Kinda worried about what it'll be like when it freezes overnight...still better than my old car!)

 

Mind you, Ashley7, the blocking certainly can't hurt. And for a couple of bucks, it might be worth experimenting. Also keep in mind that I did not do a full blocking, only partial. On the other other other hand, you might be one of those folks who really could use a block heater (if it was convenient and practical for you to do so).

You could block the whole front for under 3 bucks, probably, in about 15 minutes time. Wedge 'em in like I did, and then just pop them out again come warmer weather.

 

Worth a read: http://www.cleanmpg.com/forums/showthread.php?t=17560

 

As far as the blocking goes, that is exactly what I did... except that I used smaller bits fit into each space rather than one large piece.

 

This made me laugh pretty good. Thanks for that.

 

It was cold around 6 AM today at about 40 and will be colder tomorrow at high 30. Right now temp is dropping outside so I don't want to drive to Home Depot or Lowes to buy tubes to try block the grill. Found some box and cut and use paper clips to hold them and will report if they help tomorrow.

 

Alright, so I got the 3/4" pipe insulation and blocked off all of the top grill but the furthermost outside section on either side, and blocked the middle three of five rows of the lower grill entirely. Roughly 67% of the top grill, and roughly 60% of the lower grill. I did this just in time to drive a good 800-1000' mountainous incline tomorrow morning- but it should be damned cold. I always love the drive back down, too.

I'll let you guys know how it goes.

 

UPDATE: No improvement that I can see.

I guess cardboard didn't cover good, should I try the tube like everybody?

 

I suspect it's the insulation properties of the material that is the key - the cardboard will do next to nothing for that, compared to the foam pipe insulation.

 

Make sure it is still attached and that some homeless person didn't steal it. I could see someone using your cardboard as a roof support for the plastic crap the OP used on his car.

Seriously, a lot is going to depend on your commute temps and commute length. There are a lot of little variables to consider before making a determination of effectiveness of grille blocking. If it is lower than 60F for your commutes then I say go for it. The foam insulation is really cheap at Home Depot and it's kinda fun to install. Makes you feel handy.

 

Lots of variables here. I have mine blocked. Some days life is good and some days it ain't. Yesterday, 55 mpg. Today 35. No wind yesterday, 40 mph headwind today. Same road, same speed, 67 mph.
I have had mind blocked for about 5 weeks. Overall I do believe this does help with fuel milage during colder season.
Dan

 

<deleted> (didn't realize this was Prius C discussion)

 

I made a grill block out of the spare tire well cover from my old CRX. It's a piece of plastic constructed like cardboard. It's held on with a couple of toggle bolts. The little missing corners are where I put my fingers when I tighten the bolts.

I put the familiar piece of pipe insulation on the top vent. We'll see how it all works tomorrow.

 

I live in DFW, TX and will be driving to Chicago after Christmas. This will be my first road trip on the Prius C3. Most of the time the weather here isn't cold enough to bother blocking but going to Chicago it seems like I might benefit from doing this, especially since there might be snow through MO and IL. How much benefit would there be for longer drives? The few days I'm in Chicago I think the car would benefit but I'm not sure about the drive to and from DFW.

 

Looks good. It looks like it belongs there.

 

Takes 5 minutes to block it with the foam insulation. You can pull it off in 10 seconds. I would block it before leaving DFW. I live where I-55 and I57 come together. Snow and cold is predicted here, and south, for Wednesday.
Dan