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Update to Grill Blocking Please

Discussion in 'Gen 2 Prius Accessories & Modifications' started by morpheusx, Sep 14, 2007.

  1. morpheusx

    morpheusx Professor Chaos

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    Here in Ohio the temps are now dipping into the 40's and peaking in the mid 70's meaning that Fall is right around the corner. I am planning on doing some grill blocking for the fall, winter, and spring. I've done some searches and I seem to see lots of conflicting information. Some have said its best to just block the upper grill until it really gets cold and I've seen threads that say to block the lower part first.

    My main questions
    1) when temps range from the 40's to 70's what part should be blocked (it seems I have also read some saying they leave their upper blocked all year round even in the 90's in the summer.)
    2) what temps should I wait for full blockage.
    3) How beneficial would it be to leave approx. 50% lower and 50 % upper blocked.
     
  2. FireEngineer

    FireEngineer Active Member

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    Our temps in Chicago are about 55F morning and peak at 75F. Blocking the upper fully is no problem. The lower you can block fully in the 40's, remove one or two slots of block when you go home. Right now I'm running upper full block and lower 3 out of 5 slots blocked, ScanGage shows I'm gaining about 10-12F in the morning commute, up to 15F afternoon.

    Unless the outside temp is 50F or less do not block the lower fully unless you have an instrument to monitor engine/MG temps.

    If you have an engine block heater, blocking will help retain the heat. At 55F in the morning without the block the EBH will get up to 125-130F, with the block the temps gain 5-10F.

    Wayne
     
  3. Allannde

    Allannde Just a Senior

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    I do have a Can-View and I do monitor engine temperature. I also block the radiator.

    I unblocked the upper grill last spring. I finally unblocked the lower grill in July when it got really hot here in Washington State.

    I have never seen engine temperatures above 200 degrees except crossing mountain passes. Then it was never above 209 degrees and only for a few minutes. Please note that with a pressurized system, 230 degrees is safe.

    I also monitor the MG1 temperature and have never seen it over 150 degrees.

    Having said that, I totally agree with FireEngineer's advice that one should not block the grill above 50 degrees unless you are monitoring the engine temperature. There is just too much to be lost by overheating if that occurs.
     
  4. Prius 07

    Prius 07 Member

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    <div class='quotetop'>QUOTE(FireEngineer @ Sep 14 2007, 09:32 AM) [snapback]512456[/snapback]</div>
    I understand this works well for short commutes. Are there any issues / risk with taking a long drive with blocked grills? Would the temperatures get to hot / need to be monitored? I do not currently have ScanGauge.

    Thanks,
    Gabe
     
  5. FireEngineer

    FireEngineer Active Member

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    <div class='quotetop'>QUOTE(Allannde @ Sep 14 2007, 09:03 AM) [snapback]512471[/snapback]</div>
    You might want to try to unblock the lower grill first since the inverter coolant is the lower 1/3 of the radiator. Engine runs real cool, inverter can get hotter faster.

    <div class='quotetop'>QUOTE(Prius 07 @ Sep 14 2007, 09:07 AM) [snapback]512475[/snapback]</div>
    When I went on my western EBH road trip I had the block I described earlier all the way to Amarillo, TX. Temp outside was about 100F, had the AC on 75F medium fan when I decided to take out all the block since I knew I would be encountering higher elevations/mountains/climbing later in the evening and I can't monitor the inverter/MG's with the ScanGauge. But all through IL, MO, OK and TX-temps 80-95F-rolling terrain in MO-engine never went above 197F. Upper should be very safe, lower on flat terrain should be OK if outside is under 60F. Remember, these grill blocks are not air tight, some air gets through, especially on the highway.

    Wayne
     
  6. Prius 07

    Prius 07 Member

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    <div class='quotetop'>QUOTE(FireEngineer @ Sep 14 2007, 01:09 PM) [snapback]512581[/snapback]</div>
    Thank you Wayne! This morning the temp here was 57F but now at noon it shows 82F (really???) The last two cool mornings my MPG was much worse for my short commute to work and made me think about blocking the grill at least partially.

    Gabe
     
  7. Neicy

    Neicy Member

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    Think it's about time to do in New England too. Was 61 this AM.
     
  8. hobbit

    hobbit Senior Member

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    The lower grill opening is where the vast majority of the air comes
    in. The piece of coroplast is still in my upper one since I
    put it in and is probably going to stay indefinitely; people often
    ask about the "yellow smiley" and it's a good explanation-conversation
    starter. The lower one leaves a little open space at the ends, and
    I'm thinking maybe I should do the full wazoo for this winter.
    Taking the nose off the car would probably make it easier and give
    another opportunity for some disassembly pix, not to mention a bit
    o' cleanout...
    .
    _H*
     
  9. JimN

    JimN Let the games begin!

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    My upper grill stays blocked. No problems cross country to Indiana in the 90's. The lower grill will get blocked when it stays "cold".
     
  10. morpheusx

    morpheusx Professor Chaos

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    Thanks I decided to do full upper and plan to make that pretty much permanent. As far as lower I just slid in a 3foot tube over the lower 2 slots and will just leave in place unless we have another hot spell, I am going to wait to block the other 3 slots on the bottom for when the temps stay below 45.
     
  11. bruceha_2000

    bruceha_2000 Senior Member

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    How does blocking the grill compare to blocking the radiator?
    Obviously it is easier to incrementally block/unblock the grill with 1/2" foam pipe insulation. On the other hand, blocking the radiator should keep less air drafting through it.
     
  12. Frank Hudon

    Frank Hudon Senior Member

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    <div class='quotetop'>QUOTE(Prius 07 @ Sep 14 2007, 10:35 AM) [snapback]512602[/snapback]</div>
    if your only doing short commutes your safe to go with full blocking if the day time hi is below 20C if above upper for sure and most of the lower is safe as well. The inverter is fan cooled and will draw air from the lower under body panel if needed. If you get down and look at the belly pan you will see several oblong holes in it in front of the rad that will be used by the cooling fan if needed. The inverter section of the rad has a temp sender in it that will turn on the RH fan to cool the inverter portion of the rad. Just put the full blocker in my Classic this morning and will do the wifes this afternoon when she gets home.
     
  13. gazz

    gazz Member

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    <div class='quotetop'>QUOTE(FireEngineer @ Sep 14 2007, 08:32 AM) [snapback]512456[/snapback]</div>
    Wayne,

    What do you mean by gaining 10-12F? does your engine in the cold not get up to temp. Mine reaches max temp assuming I am running the ICE and not using to heater much. Yes the EBH gats it there faster, thanks for you advice on the EBH.
     
  14. Allannde

    Allannde Just a Senior

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    Frank

    What is your take on the temperature at which there should be concern for the inverter?

    I asked Norm twice and I thought he said 180 degrees C. I still wonder if I misunderstood the response.

    I have never seen over 150 degrees F and usually around 120 degrees F. with a blocked grill.

    Allan
     
  15. FireEngineer

    FireEngineer Active Member

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    <div class='quotetop'>QUOTE(gazz @ Sep 18 2007, 12:19 PM) [snapback]514357[/snapback]</div>
    The engine temp in 65F weather likes to camp at 184F. With all the gliding I do in the city traffic it will go down to 174F. The grill blocks let me maintain engine temps of 185-190F with all the gliding. With more engine use, like highway travel, my engine temp will go up to 190-193F from 184F.

    Wayne
     
  16. gazz

    gazz Member

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    <div class='quotetop'>QUOTE(FireEngineer @ Sep 18 2007, 12:44 PM) [snapback]514376[/snapback]</div>
    Thanks for that as well, I have blocked the uppers but will look at the lowers as soon as the afternoon temperature cool a bit more.
     
  17. Frank Hudon

    Frank Hudon Senior Member

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    <div class='quotetop'>QUOTE(Allannde @ Sep 18 2007, 10:24 AM) [snapback]514360[/snapback]</div>
    Sorry for the late reply, I've seen mine at 87C which is about 183F and there is some where in the documentation from Arogon labs that says the upper limit for the IGBT's is about 220F which should give us a good saftey margin. Just finish a trip of over 11 hours of driving on the G2 and never saw over 87C which is thermostat opening temp. That was with out grill blocking but the OAT was as high as 80F but 9 mountain passes and I wasn't babying it. I've watched the temps on it with blocking and I firmly believe block the lower first then the upper and it perfectly safe as long as the OAT is below 70F 20C Both of ours are now blocked.
     
  18. Allannde

    Allannde Just a Senior

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    <div class='quotetop'>QUOTE(Frank Hudon @ Sep 19 2007, 07:11 PM) [snapback]515094[/snapback]</div>
    Thank you! By chance, I am doing as you say. I feel much better with your insight.