2000 miles with grill blocking - Results

Discussion in 'Gen III 2010+ Prius Fuel Economy' started by Codyroo, Dec 13, 2011.

  1. Codyroo

    Codyroo Senior Member

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    I opted to block about 66% of my lower grill this November to see what impact it would have on my mileage. I've tracked my mileage on a spreadsheet and on Fuelly, so I can compare my unblocked mileage vs blocked mileage. The only variable favoring my current results are that my tires have ~35,000 on them rather than 15,000 miles.

    Updated with more mileage

    Total miles since November 15 = 4852 miles with Grill Blocking.

    All results below are calculated from the pump. Each fill up is around 550 miles.

    11/12/2010 vs 11/15/2011 = 61.4 mpg vs 60.8 mpg
    11/23/2010 vs 11/23/2011 = 56.1 mpg vs 60.2 mpg
    12/02/2010 vs 12/02/2011 = 56.3 mpg vs 60.5 mpg
    12/12/2010 vs 12/12/2011 = 55.6 mpg vs 59.5 mpg
    12/18/2010 vs 12/21/2011 = 56.1 mpg vs 60.9 mpg
    1/11/2011 vs 1/10/2012 = 51.8 mpg vs 60.2 mpg
    1/17/2011 vs 1/20/2012 = 56.7 mpg vs 57.3 mpg
    1/26/2011 vs 1/26/2012 = 55.5 mpg vs 58.9 mpg
    2/03/2011 vs 2/03/2012 = 58.2 mpg vs 60.7 mpg

    November 12, 2010, I had a note on fuelly that we still were having warm weather, which would explain the 61.4 mpg. My note for November 12, 2011 was that morning temps were in the 40s (much colder).

    The remainder, we've been having steadily cold mornings (below 40F, recent tank was pretty much 32F +/- 2F each morning). On average, I'm seeing a 4 MPG improvement due to grill blocking (and more worn tires, I'd guess 3 MPG due to blocking, 1 MPG due to tires).

    *Edit* Interestingly, on my 1/11/2011 fill up on Fuelly, I had a note saying morning temps were in the high 20's/low 30's and my mileage was 51.8 mpg (my worst tank ever). Grill blocking may be even more effective than I realized, as my last tank had morning temperatures in that range.

    **Edit** My tank for 1/20/2012 was for same conditions as the tank for 1/11/2011. Morning temps in the high 20's (27 - 28F) to low 30's (32F) and even a touch of wet weather last night. The grill blocked fill up was 57.3 mpg vs unblocked of 51.8 mpg.
     
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  2. Flaninacupboard

    Flaninacupboard Senior Member

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    Good data, thanks.
     
  3. alfon

    alfon Senior Member

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    OK looks like I'll will try it. Now, how do I block the grill???

    I know years ago people use to block the grill / radiator with cardboard, but that was 40 years ago.

    Al
     
  4. xs650

    xs650 Senior Member

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    Thanks for the data. Those are some real improvements considering our mild climate.:cool:

    What was the route like and was it morning only or an average of morning and evening commutes?

    It looks like grill shutters would be worthwhile in the real world, maybe Toyota will get around to it someday. If you get a 4 mpg improvement, someone in East Snowshoe, Minnesota would really benefit.:cheer2:
     
  5. Codyroo

    Codyroo Senior Member

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    The route has been my daily commute from Pleasanton to Foster City (and back). The only real variables are on the weekend, where I typically do shorter trips. (For example, my tank went down from an average of 64.4 mpg to 63.4 mpg for the ~7 miles I drove this last weekend.....3x short trips.....ugh and the tank had 300+ miles on it).

    I've maintained the block at all times, with one exception, which was a couple of weeks ago when we had that last burst of Indian Summer and the weather was up in the low 70's. I took it off for my drive home that day.

    Alfon - I went to our local hardware store and bought 2 lengths of 3/8" black pipe insulation (about 8 foot lengths, I think). Cost a whopping $2. I cut the lengths such that they would cover most of the width of the lower grill and just wedged them in there. That worked OK, but the ends would "pop" out. When I inspected more closely, the vertical support slats were preventing the foam from pushing in further. I just cut some matching slits into the foam insulation and tried to line it up the best I could. I put 3 pieces in the grill. They press against each other and keep themselves in place. No need for twist ties.

    At a minimum of 3 mpg for the 2188 miles I've put on since blocking, I've saved 2.6 gallons of gasoline (at $3.80/gallon) = $10 - $2 = $8.
     
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  6. xs650

    xs650 Senior Member

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    Having your warmer afternoon/evening return trip in there makes your 4 mpg even more impressive.:cool: Thanks for sharing your data, most Prius grill blockers are in cold enough climates that I haven't considered the effort worth while in our climate.

    It looks like your commute is in the 30+ miles range one way, so it looks like you benefiting from more much than just a quick warmup.
     
  7. dan2l

    dan2l 2014 Prius v wagon

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    After you get the ScanGauge so that you can see the ICE temp I expect you will find that you need just a little more GrillBlocking to be optimum. Also I put in a EBH and that really helps the first warm-up, even when it is not that cold out.

    Thanks,
    Dan
     
  8. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    It's much more advanced now. You buy some cheap foam insulation tubes and cut them the right size and shove them between the slats. :D
     
  9. Codyroo

    Codyroo Senior Member

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    I think I do benefit the whole journey. I'm even using the heater now to keep the cabin warm, mostly because I don't know how high the engine temperature is getting, thus I want to make sure I'm not overdoing it. Plus, I get to keep warmer and the battery benefits from the warmer air too. I just hope the inverter is happy.

    I purposely under blocked, because I didn't know the water temps, but wanted to do something to allow me to maintain my MPG's as well as have a more comfortable cabin temp. I just ordered my Scangauge from Amazon (I need to thank Cwerdna for posting updates on the prices) and am looking foward to seeing what the engine temp is running in the morning and afternoon.

    I've considered the Engine Block Heater, but currently (pun) I park in the street while my wife parks in the driveway. I imagine we could share the driveway and I could run an extension cord to the car. I think she'd say I was going overboard with the Scangauge II, I can't imagine what she'd say about an EBH.

    Still, we have solar panels, and although we generated an excess of 600 kwh beyond what we used, we received about $30 from PG&E for the excess. If I used and EBH for 250 days per year at 0.8 kwh/day (400W @ 2 hours), that would be 200 kwh. Hmmmm, we'd likely still have a net generation and it would be free (we have had a $300 credit at the end of the year for our electric bills).

    Back of envelope calculation for the first 2.5 miles of my warm up commute. 25 mpg for 2.5 miles vs 50 mpg for 2.5 miles = 0.1 gallons/day vs 0.05 gallons/day = 0.05 gallons/day * 250 days = 12.5 gallons = $50 savings + less pollution + bragging rights. :D
     
  10. tv4fish

    tv4fish Member

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    WELLL - I don't live in East Snowshoe, but I DO live in Minnesota and I think I'm going to give it a try. :)
     
  11. Codyroo

    Codyroo Senior Member

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    Got the scangauge this weekend and put it in yesterday. On my drive this morning, we had warmer temps (mid 40's) instead of low 30's coming in. The water temperature got as high as 195F, but typically was near to 190F when moving at freeway speeds. I drove without heating the cabin, because I wanted to see how high the water temperature would get, and I think 195F is pretty safe. It would go down if I stole that heat and put it into the cabin.

    What was also interesting was to see the temperature drop as I coasted downhill (upper 170's to low 180's). I'll get an idea of the "warmer" evening commute tonight. (Temps = low 50's).
     
  12. Codyroo

    Codyroo Senior Member

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    11/12/2010 vs 11/15/2011 = 61.4 mpg vs 60.8 mpg
    11/23/2010 vs 11/23/2011 = 56.1 mpg vs 60.2 mpg
    12/02/2010 vs 12/02/2011 = 56.3 mpg vs 60.5 mpg
    12/12/2010 vs 12/12/2011 = 55.6 mpg vs 59.5 mpg
    12/18/2010 vs 12/21/2011 = 56.1 mpg vs 60.9 mpg

    Updated with latest fill up.

    Temps in the morning have started around 32F +/- 2F with two days around mid 40's (one with light rain). The grill blocking definitely seems to be working. Max water temp ranges from 190F (outside temp low 30's) to 195F (outside temp low 50's).
     
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  13. Codyroo

    Codyroo Senior Member

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    This last fill up was 57.3 mpg. Morning temperatures have been in the upper 20's to low 30's. This compares to weather we had last year on 1/11/2011 and my average MPG's were 51.8 mpg.

    I don't have evening weather data, but it has been in the upper 40's to low 50's when driving home. I'd assume it was similar in 2011 at this time.

    So in colder weather (relatively speaking) the grill blocking is doing a helluva job!
     
  14. kneedraggin

    kneedraggin Junior Member

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    i've gotten fantastic results as well with 100% blocking of the lower grill here in LA. Temps 50-60's day and 40's at night. Avg 52-53mpg with it blocked vs 47-48 prior. Can't get in the mid 50's with all the hilly terrain out here but i'm happy with the 5-6mpg bump. Not sure at what point I should remove it as our temps now are warming up...daytime in the 70's now and night in the 50's. Any harm leaving just the lower blocked?
     
  15. F8L

    F8L Protecting Habitat & AG Lands

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    It could cause your car to get too hot once temps warm up and you start getting stuck in traffic. There is no benefit to grill blocking once temps are over a 60 degrees. I'd remove it at that point just to be safe.
     
  16. kneedraggin

    kneedraggin Junior Member

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    ok...thanks for the info
     
  17. Codyroo

    Codyroo Senior Member

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    Updated with an additional 1000 miles of data.

    To date - stats from November 15, 2011 to 2/3/2012

    4851.7 = miles driven
    81.1 = gallons used
    59.9 mpg

    In 2011 the numbers were
    5365.2 = miles driven
    95.5 = gallons used
    56.2 mpg
     
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