Wow, never realized this

Discussion in 'Gen 2 Prius Fuel Economy' started by Rxmxsh, Nov 3, 2008.

  1. Rxmxsh

    Rxmxsh Member

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    So - I'm using a SGII right now. I realized something for the first time tonight. I have an EBH that I've been using for about a year. I've always started my car, and kicked it into EV mode until I hit the downhill on the way to the freeway, thinking the EBH would keep the engine warm until then.

    Tonight it was "chilly" here, about 54 degrees. By the time I got from the garage to the point of leaving the condo complex (about 30 seconds, if that) the water temp had gone from 157 to 120! I never realized how fast the heat was lost!

    So I guess it's better to not force EV when using the EBH. I should just let it go from 157 to the 180's by itself, and do that right away....

    Does that make sense to anyone else?
     
  2. rpg51

    rpg51 Member

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  3. efusco

    efusco Moderator Emeritus
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    Yup +1...
    By far your best bet is to take advantage of that EBH pre-heated ICE, let the car start as normal. It will still cool down around 20 degrees or so then slowly warm back up. Hopefully you'll be back above 155F by the time you hit your stop at the bottom of the hill. If so be sure to let the car go into S4 before you start driving again. I'm betting you'll see a nice boost to your 2nd 5min MPG bar.
     
  4. qbee42

    qbee42 My other car is a boat

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    Remember that a block heater does just that: heat the block, not the entire cooling system. As soon as coolant starts to flow, it come into contact with the unheated portions of the system and cools rapidly.

    Tom
     
  5. Rxmxsh

    Rxmxsh Member

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    Did that this morning. Kept my first 5 minute bar at over 50, and my next 5 at about 75. I averaged 66.something on the way to work today, but that's mostly downhill. Let's see how it does on the way home today.
     
  6. nerfer

    nerfer A young senior member

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    Right. It's not that you're losing heat that fast to the air, but that the heated and unheated portions of the engine/pump/coolant/radiator are now all part of the same system.

    I've seen something similar without the block heater in cold weather - the engine is cold on start up, warms up immediately when the stored coolant is put back into the engine, but then cools off as the coolant absorbs the engine block temperature, all in less than 30 seconds. After about a minute it starts to warm up again.
     
  7. bubbacs

    bubbacs New Member

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    Warning...Hi JAcking in progress! :eek:

    After reading this "If so be sure to let the car go into S4 before you start driving again."
    I am sure that I am totally lost.
    I have a thread in the "Mods" section about the scan gauge II.
    Now that I have that part working correctly, I see this S4 and havent a clue!?!?

    Havent got the EBH installed yet, "will need help", but do have the grille block in place.
    As I leave the garage in the am, I get right up to 145 before ever leaving the sub-division. Maybe 30 to 45 seconds out time wise.
    At what point does the ICE stop running? Is there a temp range?
    I saw it get to 193 today and then drop back to 186 right away.
    This must be the themostate opening and closing I would guess.
    So it isnt over heating.....that's good news!

    The ICE does shut off at stops and such, but shouldnt it NOT start up say if I run into a coffe shop came out 3 minutes later and press start?
    The scan gauge says temps are 177.
    So why the ICE is kicking in and running again.
    I wanted to use the batts for the parking lot run and to exit onto the road again, but the ICE kept running for about 90 seconds!?!?

    I might add, I have had the '08 for 4 months now.
    Low tank was 54.7 and High tank was 65.3
    Over all it's 58.7 right now.
    I see several 75 and 100 bars but I get those pesky 50 ones during this ICE running to temp? Is that normal or maybe I am still missing something?

    Thanks,
    Bubba.
     
  8. rpg51

    rpg51 Member

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    Well, your doing something right with those stats. I usually end up just over 50 for each tank. I want to see what the others say on the issue of getting into S4. My guess - and it is just a guess - is that you have to come to a stop after a certain temp and let the ICE stop to get into S4 but I could be dead wrong. I think I remember reading about the various stages and how the system behaves in each stage somewhere in the forum - or maybe it was a link from the forum. Its out there somewhere.
     
  9. Rokeby

    Rokeby Member

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  10. efusco

    efusco Moderator Emeritus
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    This is dead right! I think the Japanese numbers are a little different, but for my Prius when I get over 154F, come to a complete stop and hold the brake for about 7 seconds the ICE will shut off and that's S4.

    While in S4 the ICE will shut off at any speed below 42mph when you lift your foot off the gas pedal. In S3 (the standard warmed up condition before S4) you have to be b/w 35mph and 42mph for it to shut off. Below 35mph the ICE will continue to run...obviously not as efficient.
     
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  11. JimN

    JimN Let the games begin!

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    Bubba, 3 minutes is a long time. The engine & cat will cool down. I park the car and manually lock the doors for quick trips up to 10 minutes.
     
  12. bubbacs

    bubbacs New Member

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    rpg51, thanks for the words.
    If I'm doing something right, I wish I could fully understand it! :eek:

    Rokeby, thanks for the links, they helped greatly.
    The top one din't pan out, but I got the info I was looking for. :)

    JimN, I must say I am fully puzzeled now.
    And this is not something hard to do.
    With all the help here the past three days, I now have had 3 days of 67.9, 72.7 and today 78.9.
    But like all kids at heart, I think I can get better.
    SO......about this manual door lock????
    I left the car running, and got out.....the peeps started right away.
    I pushed the black button on the door, but it didn't lock (manual?)
    I then tried to use the "FOB".....nope.
    So then I reached in and MANUALLY pushed the lock to close...POP, it opened right back up...hummmm.
    So tell me please, how can I lock this great auto and leave it running.
    Today I went in for coffee and the temp was 188, came out and it was 176....but the ICE still came on and did so for 45 seconds before I could use elec or glide.

    Thanks,
    Bubba.
     
  13. Rxmxsh

    Rxmxsh Member

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    Sorry to get back on track a little ;) but...

    Now that I know that I shouldn't force into EV on a warm start, I achieved my first 50mpg tank from regular driving (everyday city driving, not a road trip). I'm anxious to see if I practice this for a full tank how it will affect my mpg's.
     
  14. bubbacs

    bubbacs New Member

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    Hope it's ok to stay with this thread!?!?
    Sorry Rxmxsh, I wastrying to stay close to subject. :cool:

    Got the EBH installed fine. Thanks to Wayne from ChicagoPriusGroup. :rockon:
    Also got the grille blocked and then redid the upper last night, too many holes.
    As I was driving to work this afternoon, I looked down and saw the temp @ 202f.
    Got worried as I thought it said some where here that @ 204 the fans kick in.
    Well it reached 204 and then did a slow drop to 196 and then a slow climb to 204 again.
    Did this several times and I was listening for the fans to kick in, but didn't hear a thing.
    The driving was 35 to 50mph, several lights, and it never got above 194 before.....looks like I did a good job blocking thatupper grille.:eek:

    Anyone help with the correct temps to be watching for?
    Several threads mention several ranges, and I would like to get a firm figure maybe.
    And those fans I hear about kicking in, should I be able to hear them?
    Oh, outside temps were 37f during this trip.

    Thanks,
    Bubba.
     
  15. FireEngineer

    FireEngineer Active Member

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    The grill block helped somewhat to get those higher temps. Another thing is if your driving in the "Super Highway Mode". That produces a leaner condition that increases the engine temp a bit, I've seen that many a time. The slower your speed, or especially if your pulse and gliding, the engine temp stays high.

    You should have noticed a steadier temp at 50MPH than 37MPH. If you get uncomfortable just turn the heat on a lower fan speed to a comfortable temp. 194F is about the temp the engine thermostat fully opens, fans kick on between 202F-212F.

    I'd love to see your grill block, I know you were going to make it a "little" custom on the bottom.

    Wayne
     
  16. Danny Hamilton

    Danny Hamilton Active Member

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    There is a metal key hidden inside the fob. There is a small release latch on one edge of the fob. You slide the release latch on the fob, and pull out the metal key (it slides out where the keyring attaches). Then put the metal key in the keyhole on the driver's door near the handle. Rotate the key counter-clockwise to lock the door.

    If you do this, you will not be able to unlock the doors with the buttons on the fob or with the Smart Key feature. When you return to the vehicle you will again need to remove the key from the fob, and insert it into the keyhole. Rotate the key clockwise to unlock the door.
     
  17. Rxmxsh

    Rxmxsh Member

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    Out of context, this is hilarious. You're walking someone through *using a key*. :D

    Not trying to be a jerk, but again, there is humor to be found here. :D
     
  18. bubbacs

    bubbacs New Member

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    Yeah, imagine me.....MOROON. :eek:
    I knew about the metal key.....like in the OLD DAYS! ;)

    But the manual discription threw me.
    As I was reading it, I was sliding under the desk so no one would see me.

    At least I was able to bring a little humor to the table today.

    Wayne, I will get some pics of the grille block this weekend maybe.
    I did however go with the straight FOAM material you showed me Saturday.
    Put that in the upper grille.
    Still have the solid piece in the lower covering the whole screen.
    Last question about the temps......will I be able to hear the fans kick in?
    I was up to 208 today (55f outside) and driving Rt 59 @ 50mph.
    But it always went back to 196 soon after, never heard any fans.
    But it did heat up nicely this am with only a 1 mile distance.

    Thanks Again,
    Bubba.
     
  19. Rxmxsh

    Rxmxsh Member

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    You'll definitely hear the fans. I've only had mine turn on twice. I had no idea what it was at first, freaking me out. The first time I pulled over to check it out. The second time I cranked my air temp down. You'll hear it, trust me.
     
  20. JimN

    JimN Let the games begin!

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    ...then unlock the doors with the switch on the armrest to re-enable the SKS.
     
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