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Thread: Coolant Temperature and Fan

  1. #11
    Quote Originally Posted by cyclopathic View Post
    Don't block grill in summer! The only advantage of blocking is quicker warm up in winter.
    Actually, one of the major (maybe even the major) efficiency advantage to grille blocking is reducing aerodynamic drag. Diverting excess air flow around the car's body instead of through the engine compartment has a measurable effect on MPG. That's why more and more new cars (especially efficiency focused ones) are coming with automated grille shutters. (Expect to see it on the next Prius.)

    But sizing a grille block is highly dependent on driving style, terrain, traffic and accessory use. So yes, that's the tricky part! You need proper instrumentation and you need to monitor it.

    I drive with my grille over 90% blocked, year round, and the cooling fan rarely comes on even in the summer. I also watch coolant temp and know what the e-fan threshold is.


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        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 63.2 mpg (US) ... 26.9 km/L ... 3.7 L/100 km ... 75.9 mpg (Imp)


  2. #12
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    Quote Originally Posted by MetroMPG View Post
    Actually, one of the major (maybe even the major) efficiency advantage to grille blocking is reducing aerodynamic drag. Diverting excess air flow around the car's body instead of through the engine compartment has a measurable effect on MPG. That's why more and more new cars (especially efficiency focused ones) are coming with automated grille shutters. (Expect to see it on the next Prius.)

    But sizing a grille block is highly dependent on driving style, terrain, traffic and accessory use. So yes, that's the tricky part! You need proper instrumentation and you need to monitor it.

    I drive with my grille over 90% blocked, year round, and the cooling fan rarely comes on even in the summer. I also watch coolant temp and know what the e-fan threshold is.
    Well I was camping on St Laurence river on 4th of July a couple years back, and I was freezing! everyone else acted like it was a heat wave and I think it got up to 80F in afternoon. This year has been cool but a few years back MD had 3 consequent weeks of temps exceeding 100F, big difference, esp if it doesn't go below 78-76 overnight.

    I doubt Gen4 Prius will have active shatters. Toyota tested and found aerodynamic improvements negligible, MPG improvements were something like 0.1MPG or so. Need to find an interview with Toyota engineer.

    Blocking does improve MPG in cold weather as it shortens warm up cycle. If it gets too cold it would also keep Prius from restarting engine just to keep it warm.

    But aerodrag improvements are minor, you probably get more by removing wipers or installing plastic shielding under engine compartment.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  3. #13
    No arguing the warm-up benefit.

    aerodrag improvements are minor
    Lots of automakers would disagree, including Mitsubishi, which varies the size of the Mirage's fixed grille opening for aero efficiency, depending on the drivetrain.

    Everything I've read on the subject and my own experience with testing grille blocks on all my cars says that cooling system drag is one of biggies. We'll be be seeing more and more examples of active aero in grilles as CAFE rules continue to tighten.

    I measured a ~3% improvement in fuel economy at just 80 km/h (50 mph) steady speed cruising with a grille block vs. none in my Firefly (Metro). That's in line with results others have seen in steady speed testing.

    YMMV, of course -- the potential gains will vary from vehicle to vehicle. The Mirage's grille opening is already more optimized than my Firefly's was, so smaller gains to be found there.

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 63.2 mpg (US) ... 26.9 km/L ... 3.7 L/100 km ... 75.9 mpg (Imp)


  4. #14
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    Quote Originally Posted by MetroMPG View Post
    I measured a ~3% improvement in fuel economy at just 80 km/h (50 mph) steady speed cruising with a grille block vs. none in my Firefly (Metro). That's in line with results others have seen in steady speed testing.

    YMMV, of course -- the potential gains will vary from vehicle to vehicle. The Mirage's grille opening is already more optimized than my Firefly's was, so smaller gains to be found there.
    I was wondering what was the temperature when you did the testing? I mean were you live it is very cold all year around?

    I have tested blocking on Prius and C and the difference if there were one was less than margin of error. It did shorten the engine heat up cycle in cold <60F weather, so improvements were obvious on morning commute. BUT to make the difference where OP lives you'll have to wait 'till November for temperatures get that cold.

    My take on shatters is that back in the day they used to put manual ones, and I wish they still did. You could also get a bra with adjustable vents, but I guess if you were to sell them now it would be asking for class action lawsuit.

    As is Mirage has pretty low drag, any additional improvements are unlikely to result into real life MPG gains. Sorry for being skeptical if 54MPG Mirage isn't good enough and you want better, wait for Elio.

    BTW your write up on tests of CVT and 5MT Mirage influenced me on not getting CVT, thanks!

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  5. #15
    Definitely cooler here than the southern States. Which is why blanket statements don't really work. It's going to depend on that plus many other factors. YMMV.

    Quote Originally Posted by cyclopathic View Post
    As is Mirage has pretty low drag, any additional improvements are unlikely to result into real life MPG gains.
    FYI...

    Thread: Mirage aero mods for better fuel economy: 4.5% improvement @ 90 km/h / 56 mph


        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 63.2 mpg (US) ... 26.9 km/L ... 3.7 L/100 km ... 75.9 mpg (Imp)


  6. #16
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    Quote Originally Posted by MetroMPG View Post
    Definitely cooler here than the southern States. Which is why blanket statements don't really work. It's going to depend on that plus many other factors. YMMV.

    Quote Originally Posted by cyclopathic View Post
    As is Mirage has pretty low drag, any additional improvements are unlikely to result into real life MPG gains.
    FYI...

    Thread: Mirage aero mods for better fuel economy: 4.5% improvement @ 90 km/h / 56 mph

    What I meant is driving in dense commute traffic would not allow you to take advantage of these improvements.

    Theoretically there would be no benefits of hybrid-electric recovery if I were to coast to all stops. Unfortunately most of the time there is very little opportunity of free coasting. Similarly the aerodrag reductions will not benefit much in city driving.

    You may see the gains in test condition but not so much in real life. YMMV

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  7. #17
    True. Fortunately for me, my test conditions are my real life. I put almost all the miles on my cars on the open road.

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 63.2 mpg (US) ... 26.9 km/L ... 3.7 L/100 km ... 75.9 mpg (Imp)


  8. #18
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    Quote Originally Posted by MetroMPG View Post
    True. Fortunately for me, my test conditions are my real life. I put almost all the miles on my cars on the open road.
    Lucky you. The closest we've been to you was Cape Vincent but didn't have time/passports to cross over.

    Funny that the best MPG reading I've seen so far were on flat interstate in dense traffic @~60MPH. There is alot to be said about intentional and unintentional drafting.


        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


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