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First Morning with a Blocked Grill

Discussion in 'Gen 2 Prius Accessories & Modifications' started by TonyPSchaefer, Dec 19, 2006.

  1. JimboK

    JimboK One owner, low mileage

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    <div class='quotetop'>QUOTE(efusco @ Dec 19 2006, 03:26 PM) [snapback]364278[/snapback]</div>
    Maybe it's just the way it appears in the photos, but your insulation material appears different too. Tony appears to have foam insulation (nearly identical to mine in appearance and installation technique), whereas yours appears to be sort of a rubberized material. Am I interpreting your pics correctly? If so, it would seem that that insulation might be more flexible and therefore lend itself a little better to your technique, which I like if it will work without zip ties. It seems simpler and quicker, and looks a little cleaner.
     
  2. donee

    donee New Member

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    Hi All,

    I have been using 3/4 in pipe insulation on the lower grill. Cut into about 9 inch lengths, the lengths fit onto the grill horizontal bars, between the verticals. So, one can leave open the left side slits to allow for keep flow on the inverter, and cut it off over the engine.

    The 3/4 in size fits perfectly into the grill slits and the 9 inch lengths can be installed, and removed and stored in the glove box in seconds.
     
  3. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(JimboK @ Dec 19 2006, 09:44 PM) [snapback]364426[/snapback]</div>
    Yea, there were two types, the one I got cost a bit more but seemed more durable and flexible. The kind Tony has was there and I was afraid it was going to be too brittle.
     
  4. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    Also please note that I got mine from Wayne. He gave it to me claiming that I owe him $2.00. In post number 10 he said that it was on sale for $0.99. I think I was ripped off!

    Also, the technique I pictured above is compliments of Wayne. I can not in good conscious even try to take credit for it. But I can learn to live with a guilty conscious!
     
  5. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    Thanks for the pics. I would like to give this a try but I think I will wait until I get a can-view so I can monitor the temps. Maybe next year.
     
  6. donee

    donee New Member

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    <div class='quotetop'>QUOTE(Display Name @ Dec 20 2006, 12:40 AM) [snapback]364423[/snapback]</div>
    Hi Display,

    Evan answers the bulk of your question above. But one comment about your last question. The engine is designed to be very good at turning heat into shaft power. As such its not as good as an Otto cycle engine at turning gasoline combustion energy into heat. This is the same situation with turbo-diesels (even more so), as more of the diesel fuel combustion energy is turned into shaft power. This is why over-the-road diesel trucks use winter-fronts.

    Still, climbing a mountain in the desert, the engine is at full power, and needs all that cooling area openings, as the car is at slow speed and full torque.

    But driving around in the city/suburban situation in sub freezing weather, with the battery doing allot of slow speed and shallow down hill motivation, the engine cools down. With the heater on, the computer will keep the engine running to make up the heat, even when the car is not moving.

    What is probably needed is a computer controlled door in front of the radiator openings. It would close the door at startup, and slow speed driving, and open the door a calibrated amount based on engine load running average, speed and temp, with full openings occuring at any engine, inverter coolant or transaxle temp or outdoor temp limits. This complicated a thing would also need an manometer across the door to be sure the door is opening when its commanded to.
     
  7. Cheap!

    Cheap! New Member

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    So if you use these and have a bra, would you call these padded bras? :lol:
     
  8. dreichla

    dreichla New Member

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    <div class='quotetop'>QUOTE(efusco @ Dec 19 2006, 09:34 AM) [snapback]364119[/snapback]</div>
    Evan,

    1. Could you take a picture of your insulation around the ICE as well? What are you using - standard fiberglass batt insulation one uses in house framing?

    2. What is the 2nd cord coming out of your lower grill? I assume one is for the block heater?

    Thanks
     
  9. Rick Grahn

    Rick Grahn New Member

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    <div class='quotetop'>QUOTE(donee @ Dec 19 2006, 11:28 PM) [snapback]364439[/snapback]</div>
    I appreciate this description. I've been contemplating this mod but 90% of my driving is at highway (65-75MPH) speeds and I drive several hours at a time. Based on this description, is it a safe assumption that it may not benefit my mileage that much?
     
  10. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(dreichla @ Dec 20 2006, 05:33 AM) [snapback]364507[/snapback]</div>
    I'll try to do that later, but it won't tell you much. If you open your hood you'll see the small gap in front of the ICE and b/w the ICE and the Inverter/MG2. Essentially I stuffed some standard fiberglass insulaton in there...they sold some stuff about 2" thick on a 6' roll at Home Depot designed to stuff in various gaps in you house to stop small drafts. That's what I used. The trickies and probably most effective spot that I put the insulation was from the underside of the car on the back side of the ICE just below the manifold...no way I can get a photo of that without putting the car up on ramps...and that ain't gonna happen just for a photo.

    *Disclaimer--Shoving the insulation in there may have little or no benefitial effects. It could block something important. It could catch fire. I don't recommend it at all unless you can monitor ICE temps closely with CAN-View or similar.


    <div class='quotetop'>QUOTE(Rick Grahn @ Dec 20 2006, 05:38 AM) [snapback]364508[/snapback]</div>
    Yea, probably little benefit. If/when it's really cold you might wanna do it, but it's unlikely to have a big impact.
     
  11. donee

    donee New Member

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    <div class='quotetop'>QUOTE(Rick Grahn @ Dec 20 2006, 08:38 AM) [snapback]364508[/snapback]</div>
    Hi Rick,


    The other part of the answer that Evan gives above addresses the highway mileage aspects. There is an advantage for highway driving, but tuning the amount of closure, when the temps could be over 25 F, is probably going to need some kinda instrumentation (based on comments on here). The air blast at highway speed through the radiator still cools the engine, and coolant. Just not as much as the coolant is not flowing. But, the coolant can still conduct heat out of the engine, by thermal conduction rather than movement. And the airflow over the engine will cool the block as well. Nobody has invented a zero thermal conductivty fluid yet.

    Transaxle temp apparently has a significant effect on mileage, but you also have the inverter sitting on top of it, and the inverter radiator in front of it. The inverter needs the cooling. The transaxle is only cooled by airflow over the casting. This is a non-synergistic situation. If you get under the the car, you will notice an opening in the aeodynamic faring to the rear and below the transaxle. So the car is setup to that air gets sucked out past the the transaxle, after coming through the radiators and bouncing off the front of the engine/transaxle assembly, primarily.

    Blocking off only the engine side is pretty safe below freezing. As if the engine gets hot, the thermostat goes open and in extreme cases the fan comes on, and pulls air over from the unblocked inverter side. I have not heard the fan come on yet this winter. Of course its been as cold as 2 degrees F when I leave for work so far.

    My commute is 23 miles with 5 miles on the outgoing leg on a 40 mph secondary road, and 2 miles at the end of the outgoing leg on a 45 mph secondary road (which is usually traffic impeded). The middle portion is on highway. Its common that the highway will drop below 40 mph in three traffic merging locations, and even lower. In those locations, one can stealth, and the engine goes off, and cools down. Sustained 65 mph speed is rarely more than 10 minutes. So, I have a situation that can be helped with the radiator blocking.

    So, its like I could drive 75, but, what would be the benefit? I would just run into the back of a traffic jam, and people doing 65 would just catch up. And this is at 6:30 in the morning.

    Now if that is your situation, you can just slow down with uninstrumented radiator blocking, like me. But if not, you might want to get some instrumentation and try the radiator blocking.
     
  12. FireEngineer

    FireEngineer Active Member

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    Rick,

    Go ahead and block the upper 2 grill slits and at least 3 of the lower grill slits. It will help you on the highway, modest but helpful. This past weekend when I went to the Milwaukee Hybrid Group meet-up I had the entire grill blocked. Coming home from the meet-up on I-94/I-294 to the southwest side no problems even though my outside air temp showed 52 degrees.

    Tony,

    Darn, I must have quoted you the MSRP, not my "wholesale" price. Looks good on the block. If you want to get fancy spray paint the bottom ones flat black (off the car). And finish the job and BLOCK THE WHOLE THING.

    Wayne
     
  13. efusco

    efusco Moderator Emeritus
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    Photos of my ICE insulation, as requested.
    [​IMG][​IMG][​IMG]
     
  14. Danny

    Danny Admin/Founder
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    So after reading through all of these posts and Rick's post and subsequent responses to his post, can I summarize that in South Carolina I wouldn't see much benefit from doing this during the winter?

    There are maybe 2-3 weeks that we see temps with highs only in the 30s, and then other weeks like this one with highs in the upper 70s.
     
  15. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(Danny @ Dec 20 2006, 10:18 AM) [snapback]364603[/snapback]</div>
    Probably not much utility. The pipe insulation is very cheap and once cut to length (if you install like I do) can be removed in seconds and reinstalled in about 5 minutes. So, if you wanted to leave it off the majority of the time then stick it on if you're going to have a spell of colder weather you might keep those MPGs from dropping so precipitously and killing your lifetime MPG. Likewise the block heater...it's cost/benefit ratio is very good.
     
  16. Rick Grahn

    Rick Grahn New Member

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    Thanks to everyone for your thoughts.
     
  17. Frank Hudon

    Frank Hudon Senior Member

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    <div class='quotetop'>QUOTE(Danny @ Dec 20 2006, 08:18 AM) [snapback]364603[/snapback]</div>
    like Evan said probably not much benifit with the grill blocker, but use a block heater on a timer for a couple of hours in the AM or before you normally leave for work. Huge benifit. I use mine year round now. It costs me about a half a gallon of gas, equivelent , per month. Don't forget our gas costs about $4.50 US a gallon. $2.76 per month for my current useage. One of the best investments you can make in increasing your life time milage.
     
  18. c4

    c4 Active Member

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    Evan-

    That big slab of insulation seems like a bit of overkill.. As I mentioned before, I just use a sheet of that foil/bubble wrap insulation (they sell it at Home Depot- you can get it as just a big roll or as a kit for insulating hot water tanks) with a few bits of stick-on velcro to make a hood liner for the inside of the hood, plus it's easy to remove for engine maintenance/inspection and for the summer..

    I cover the entire inside surface of the hood, so both the engine side and the converter are covered (but due to the nature of my version of radiator block on the Classic Prius, only the ICE radiator is blocked, and the hybrid radiator is still allowed airflow). The foil reflects heat back into the engine compartment and the bubbles form an effective air gap for insulation- you can get single or double layer varieties, but I'm just using single layer stuff and after long drives with the engine at temperature (thanks to the radiator block), the hood does not even get warm, but when you open the hood, it's nice and toasty inside..
     
  19. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    i did individual pieces for the grill as well. i took 3' 3/4" foam split in half for the top and 4' 3/8" whole on the bottom. i covered all the slots.

    this is the first year i have done this and despite a less favorable commute, significantly more passengers (and consequently more weight), i am consistently averaging 1½ to 2 mpg higher.

    last two years, i drove solo 80% of the time, 10 % with one passenger, and 10% with 4 or more.

    this year its 25% solo, 65% with two and 10 % with 4 or more (includes 165 miles in one day on one of the coldest days of the year)
     
  20. Bill Lumbergh

    Bill Lumbergh USAF Aircraft Maintainer

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    You guys are great....for less than $3 I blocked mine off sufficiently and hopefully it will improve my heater's performance and the mielage. Last tank was barely 29 MPG.

    I had to do mine fairly quickly because it's COLD outside, hence the less-pretty-than your's appearance. It's going to be covered in icicles tomorrow anyways.

    [​IMG]