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Thread: Miata Cooling Design Question/Issue

  1. #21

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    Quote Originally Posted by Yamahaman444 View Post
    Also, I typically run the car with the AC on, so that both fans are on, helping out cooling I believe.
    Huh?!?

    The theory of running both fans when driving at Auto-X speeds is valid (not needed and not helpful at track speeds).

    But turning on your AC? Never, ever. Assuming your AC is charged and functioning, there is no better way to overheat a Miata than to add load to the engine and preheat the air with a hot condenser.

    For Auto-X, find a way to run both fans WITHOUT engaging the AC compressor. People usually wire the AC fan to turn on with the normal cooling fan.

    Also, your OEM temperature gauge is a liar. It's non-linear and will stay in the middle even as your water temp is creeping past 220. By the time it's indicating hot, you're HOT!! This is on purpose to minimize warranty service. Install an aftermarket temperature gauge if you want to know the truth.

  2. #22

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    Just one more data point before throwing $$ at it. Check you main fan. This fan is knownto fail at this kind of mileage. To see it spinning is not enough. It gets weak with age. Wear a heavy and try to stop it. If is stops easily, it is bad and it is your over heating issue. Also, check your secondary fan. If it doesn't kicks in when the a/c is on, you will over heat b/o the extra heat from the condenser and extra load. Don't ask how I know!
    Gabriel

  3. #23

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    Quote Originally Posted by hornetball View Post
    Huh?!?

    The theory of running both fans when driving at Auto-X speeds is valid (not needed and not helpful at track speeds).

    But turning on your AC? Never, ever. Assuming your AC is charged and functioning, there is no better way to overheat a Miata than to add load to the engine and preheat the air with a hot condenser.

    For Auto-X, find a way to run both fans WITHOUT engaging the AC compressor. People usually wire the AC fan to turn on with the normal cooling fan.

    Also, your OEM temperature gauge is a liar. It's non-linear and will stay in the middle even as your water temp is creeping past 220. By the time it's indicating hot, you're HOT!! This is on purpose to minimize warranty service. Install an aftermarket temperature gauge if you want to know the truth.
    Are there any aftermarket gauges that the stock wires just harness right in and fit in the OEM gauge spot in the dash?

    Ahhhhh that's what I read. No AC because it preheat the air. Yup yup. Thanks for that!

    No issues in a few weeks. We'll see how autox this weekend goes

  4. #24

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    Quote Originally Posted by Yamahaman444 View Post
    Are there any aftermarket gauges that the stock wires just harness right in and fit in the OEM gauge spot in the dash?
    I've seen some people get pretty crafty with putting aftermarket gauges into the stock gauge pod. I just pull the radio (can't hear it anyway) and mount gauges in that location on my Miatas. Also, the 2 1/16" gauges are a perfect fit into the eyeball vents.

  5. #25

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    The fan on a Miata only generates as much air as driving 12 mph. So if you're overheating on-grid or in stop/go traffic, then it can be the fan. If you're under 12 mph, usually the RPMs are very low and the fan can handle that.
    Once you're moving more that 12mph, then it's not the fan.

    I saw a NA with its hood up on the way home the other day on I35W north of 114 and stopped to help. It was overheating. She'd been downtown in stop and go traffic, no issues. Her fan was working.
    When she got on I35W, the fan was no longer of consequence, but the missing bottom tray was. All the air at 65 mph was going under the radiator. Needless to say, at 65 mph she was probably running 3,700+ rpm. The fan couldn't handle that.

    Rogue is right about the pressure test. Most of the autoparts stores will loan you the tester.
    Does the '97 have an oil cooler, always check those little hoses from the back of the block and throttle body. Even though the previous owner says he changed all the hoses, those don't usually get changed as they're a PITA to get to.

    Search Miata.net, there's a fix for the temp guage to make it linear. Or just get the kit from Advanced Autosport. I have their oil pressure.

    OR get a ODB-II reader, it will show the water temp. I have a Bluetooth adapter and the Torque phone app. Works great!
    Last edited by EricJ; 07-12-2016 at 03:33 PM.
    '99 Emerald Green - 2015 NASA Texas TTE Season Champion (showing up is really 100% of it)

  6. #26

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    I've got a couple of used belly pans I'll let go cheaper than new if you want to grab one quickly/cheaply.
    Polished Turd Racing

    Mick wrote: "I think Jerrett is the best autocrosser I have ever seen naked."

  7. #27

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    Awesome guys. See, this is what I wanted.

    I'd love a used belly pan, thanks. Will PM soon

  8. #28

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    Hoping to get a pan from Ozmdd as soon as he pms back. Had no issues with overheating while doing Autox, even while in the 95 degree heat. I think everything is alright but I know the belly pan will help more.

  9. #29

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    Quote Originally Posted by Yamahaman444 View Post
    Hoping to get a pan from Ozmdd as soon as he pms back. Had no issues with overheating while doing Autox, even while in the 95 degree heat. I think everything is alright but I know the belly pan will help more.
    Belly pan isn't that important at autocross speeds. Much more critical at highway speeds where air tends to compress under the nose of the car. This pressurizes the engine compartment if there is no belly pan, which impedes radiator airflow. The R-package front spoiler also helps with this issue (you can find cheap knockoffs on E-bay).

  10. #30

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    Quote Originally Posted by Yamahaman444 View Post
    No undertray. I read it helps with airflow especially at lower speeds, correct?
    You need one. This is where I would start. Speaking from experience here.
    Smile
    93' LE #1136 - FM II
    250k miles

  11. #31

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    Thus why I am getting one. Also thinking about getting some turn signal vent conversions? For the front indicators.

  12. #32

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    Turn signal vents are primarily for cosmetic purposes. For cooling, make sure your radiator is up to the task (sufficient capacity and not old) and then it's all up to airflow through the radiator. That means sealing the "mouth" to keep air from dodging under or around the radiator. It also means a belly pan to help smooth flow and create a pressure differential from the front side of the radiator to the back side. Turn signal vents add pressure to the back side of the radiator -- not what you want. If you want vents for airflow, you want hood vents, which are obviously more difficult to do.

  13. #33

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    Ozmodd, is a pan still available? Still interested in buying.

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