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grills blocked by insulating material

Discussion in 'Gen 2 Prius Accessories & Modifications' started by jarhtmd, May 12, 2007.

  1. jarhtmd

    jarhtmd Junior Member

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    “This forum's members don't represent the average Prius owner and that's no hit to anyone. I've seen dozens and dozens of Prius cars here in Baltimore, but not a single one had the grills blocked by insulating material. Mine will be the first . “

    I saw the above in another thread. I’ve never heard of “grills blocked by insulating materialâ€. Is that a good thing . . . done intentionally . . . or a problem? Please excuse my ignorance, but would someone please explain what it is & its advantages/disadvantages.

    I thought it best to start a new thread, rather than divert the direction of the other.
     
  2. efusco

    efusco Moderator Emeritus
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    I suspect the answer was within the thread you saw this. You could also search 'grill blocker'.

    But, we block the grill, in winter, to reduce air flow through the engine compartment thereby conserving the ICE's heat and improving fuel economy.
     
  3. ystasino

    ystasino Active Member

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    In short people here have used advanced instrumentation to show that blocking outside air intake through the grills in very cold weather keeps the engine within the most efficient operating temperature increasing mpg when it's colder than 40-50F.

    Use the search engine you ll see some very instructive photos and one very long thread about it.
     
  4. JimN

    JimN Let the games begin!

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    <div class='quotetop'>QUOTE(jarhtmd @ May 12 2007, 02:35 PM) [snapback]440671[/snapback]</div>
    There is a wealth of information (and pictures) on this thread http://priuschat.com/index.php?showtopic=2...l=blocked+grill (found by searching on "blocked grill"). [Search lesson included at no charge.] A member from NY made a video.

    In the opinion of those who did it, yes it is a good thing. It kept my winter mpg in line with the lifetime average. Keeping the ICE warmer causes it to run less when stopped. A blocked grill can be unnoticed until you get real close--it all depends on technique and materials.
     
  5. Old Marine

    Old Marine Junior Member

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    It also helps in hot weather. One blocked inlet crossbar reduces the inital mpg loss usually experienced when first taking off.
     
  6. gazz

    gazz Member

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    <div class='quotetop'>QUOTE(Old Marine @ May 13 2007, 12:15 AM) [snapback]440914[/snapback]</div>
    Has anybody else grill blocked in warmer weather, and if so how much.

    Other than the foam pipe insulation pushed in the crossbars are there any other methods such as blocking the radiator directly or is that a bad idear (that is what we used to do years past).
     
  7. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(gazz @ May 13 2007, 04:57 AM) [snapback]440987[/snapback]</div>
    I've been keeping mine blocked in the 80degree weather...but I can monitor ICE temps and wouldn't recommend that to someone without instrumentation such as Scan Guage or CAN-View do the same as driving conditions vary and we haven't been doing this long enough to know if there may be situations where doing so could be detrimental. I'd say up to 60 is definately safe to block just the upper grill. I'd take off the bottom one at 50 as I started seeing somewhat higher MG2 Inverter temps at that point (not critical, but enough to let me know it was having an impact.



    You could block the radiator directly, but it's harder to access and control.
     
  8. gazz

    gazz Member

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    <div class='quotetop'>QUOTE(efusco @ May 13 2007, 05:15 AM) [snapback]440988[/snapback]</div>
    I have a scangaugeII and monitor the ICE temp. Never seems to above 185F. If I block the uppers will this change of wil it just not cools so fast. Also is monitoring the ICE on its own OK, does this give you an idear of what the MG is doing, as I cannot monitor this?

    Thanks
     
  9. efusco

    efusco Moderator Emeritus
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    It won't give you any idea of what the inverters or MGs are doing. But if you unblock the bottom at 50F I think you'll be fine there.
     
  10. JimboK

    JimboK One owner, low mileage

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    I took mine off a couple of weeks ago when I did the full Zaino treatment, expecting to leave it off for the season. Last weekend, with overnight lows in the upper 30s, I put it back on. I forgot about it until it hit me, in a flash, on the way home Friday afternoon in near 90-degree temperatures ... Hey, I still have the grill block on! Not to fret -- I checked the ScanGauge and the maximum temperature for the run was only 202F.

    Two things to mention here. First, I keep one slit in the bottom grill open to provide a little air flow, especially to the inverter cooling system, except during the winter. Second, Friday's drive included a lot of ICE-off time (as most do these days) -- a lot of pulse and glide and sitting at idle in traffic. Continuous running of the ICE (e.g., highway driving) would, of course, cause more heat buildup.
     
  11. JimN

    JimN Let the games begin!

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    It's been almost 80F in the mornings. The car sits outside all day and it is in the 90s going home. The upper grill is blocked, the climate control set around 78F (I move it up & down a few degrees to keep it comfortable) and the fan hasn't come on. MFD indicates mpg between 55-57.5 for the tank. Commute is 35 highway miles. Today's traffic jam knocked almost 2mpg off the average at half a tank. If the numbers hold, this is a 10% increase over my lifetime average. I am losing at least 1mpg on the way home every day but make it up (and sometimes more) in the morning. I can confirm that just running the ac does not cause the ICE to start or run.
     
  12. Tyrin

    Tyrin New Member

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    <div class='quotetop'>QUOTE(JimN @ Jun 27 2007, 07:36 PM) [snapback]469130[/snapback]</div>
    Wow, so we're looking at possibly year-round upper grill block for the cooler climes?
     
  13. JimN

    JimN Let the games begin!

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    <div class='quotetop'>QUOTE(Tyrin @ Jun 27 2007, 11:08 PM) [snapback]469192[/snapback]</div>
    Yes, as recommended by Fire Engineer. IMO it is safe to block the upper grill until the fan turns on. Once that happens I'd remove one piece at a time until the fan no longer activates. Beats carrying the stuff in the small cargo compartment.
     
  14. gazz

    gazz Member

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    <div class='quotetop'>QUOTE(JimN @ Jun 28 2007, 08:15 PM) [snapback]469760[/snapback]</div>
    Is it obvious when the fan comes on? I have blocked mine for the past 3 months although the summer this year in the UK does not seem to be happening yet.
     
  15. JimN

    JimN Let the games begin!

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    <div class='quotetop'>QUOTE(gazz @ Jun 29 2007, 06:11 AM) [snapback]469913[/snapback]</div>
    I've never heard it. One of our pilot members said it sounds like a jet engine.