Miata Engine Cooling 101 (FM Live)
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- čas přidán 6. 04. 2023
- The summer heat is coming. This week on FM Live, Brandon discusses how to prepare your Miata for the heat with cooling upgrades from FM. Everything from our Crossflow Radiator and coolant reroute, to airflow kits to even more aggressive measures like oil coolers and hood louvers.
0:25 - Why you don't want to Overheat
1:09 - What temp is too hot?
2:00 - How to know if you're overheating?
3:50 - Cooling System Theory
4:38 - Identifying a Cooling Problem
9:46 - Tips to Improve Your Engine Cooling
10:00 - Radiator Caps
11:05 - Coolant Reroute
13:36 - Crossflow Radiator
15:45 - Fan/Airflow Kits
19:28 - Oil Cooling
21:58 - Louvers
25:25 - Customer Questions
FM Radiator Cap
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FM Crossflow Koyorad Radiator
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FM Exclusive Coolant Reroute
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FM Stage 1 Airflow Fan Kit
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FM Stage 2 Brushless Airflow Fan Kit
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FM Stage 3 Dual Brushless Airflow Fan Kit
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Oil, Differential and Transmission Cooler Kits
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Fender Vents
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Hood Louvers
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#cooling #summeriscoming #heat #management #heatsoak #engine #BrandonFitch #live #weekly #video #FMLive #miatalife #street #track #summer #race #cooling #airflow #oil #fluids #coolant #tips #parts #performance #miata #FM #FlyinMiata - Auta a dopravní prostředky
I've got everything except stronger fans. My big fix, for higher track coolant temps, was routing my heater core outlet into the upper radiator hose, with an inline thermostat so the car still warms up. Outside of the oil warmer coolant, I've now got only "cooled" coolant entering the mixing manifold. All that hot coolant normally just gets heated up even more by going under the exhaust and then back into the engine! To be fair I've also got a header blanket, trying to block some heat from my supercharger. On the cooler days, less than 80-85f, my temps were fine. This was the fix for those sunny 90-100F days with high humidity.
Very helpful talk.
Not mentioned in this talk, or discussed much anywhere on the various Miata Forums, is the role of the coolant return pipe on an NA engine that takes the coolant returning from the cabin heater, and routes that coolant to the lower side of the block. This coolant return pipe is bolted straight to the exhaust manifold near cylinder number four. This bolted connection conductively heats the pipe. The return pipe also receives significant radiative and convective heat from the rest of the exhaust manifold. This small but significant short circuit of heat flow from the exhaust manifold into the returning coolant is intentional and by design.
The purpose of the heat transfer from the manifold to the coolant return pipe is to help bring the engine coolant up to operating temperature quickly during engine warm up, when the engine is started in winter in colder climates. This short circuit creates the following problem: the heat transfer from the exhaust manifold to the coolant return pipe never stops. Some heat from the exhaust manifold is dumped into the return pipe, continuously, whenever the engine is running. The hotter the manifold, the greater the heat transfer.
If you live in Southern California, or in a similar temperate climate, the engine block rarely cools below 50 F even in the winter. Warm up is quick in the Southern States, and occurs in just a few minutes. For these locations the heat transfer from the exhaust manifold to the return line does more harm than good.
I drive a 1.6L normally aspirated NA6 here in the local mountains. In the first 20 minutes on California's famous Angeles Crest Highway, the rise in elevation is about 4,000 feet, or around 200 feet per minute. On a hot day with the air temperature above 95 F, towards the end of that 20 minute ascent, I am controlling the position of the temperature guage needle with my foot on the accelerator. I back off the temperature goes down. I accelerate the temperature rises.
On this car radiator cap, hoses, thermostat, water pump and fans are all in good condition. The radiator is a 37mm Koyo. I use a 2/3's water and 1/3 glycol coolant mix.
This brings me to the following question: The last time I was replacing the water pump, I slipped a DEI aluminized, reflective, tubular, heat shield over the coolant return tube. These DEI sleeves have a proven ability to significantly reduce both radiative and convective heat transfer into the tubes and cables that they protect. Following the install of this insulation, my impression is that engine is not as quick to over heat in summer, on Southern California's famous desert ascents, such as the Angeles Crest, and the Grape Vine.
What do you think Brandon?
To promote rapid warm up, Mazda designed in a thermal short circuit between the exhaust manifold and the coolant return line. If your engine never gets truly cold, what you experience mostly is a thermal short, dumping waste heat into your engine. An insulated, reflective sleeve goes a long way towards limiting the radiative transfer into the coolant return pipe. Do you know of other instances in which this has been done?
My update to a Koyorad radiator solved my overheating issues on my 1990 w/99 engine.
That's great! Glad it helped!
On older radiators a layer of corrosion and a film of road dirt tends to build up on the fins. Pressure washing removes some of this, but not all, and can fold over the fins if not done carefully. I would expect a bump up in performance, with any new radiator of good quality over one that has been in service for a decade or more, especially if the old radiator was a 'generic' or 'discount' part.
Koyorad has a deserved reputation. Their fits & finishes are terrific. The welds are nicely done. The weight of the sheet metal in the filler neck and ports is good. Their engineers will have considered carefully the thickness of the fins, the size of the gaps between the fins, and this kind of thing in order to maximize heat transfer. They make a good product.
Thanks, Brandon!
You're welcome!
The factory radiator came with a foam strip on the bottom of the radiator that closed the gap between the radiator and the pan on the bottom of the car.
Do you recommend replacing / retaining that when replacing the radiator?
Does your radiator come with any ducting for the bottom between the radiator and the pan?
The reason I as is that it seems like if the strip isn't there it would allow lots of air to bypass the radiator creating high pressure in the engine compartment and allow back flow when the fans run sitting at idle.
Looking at it from both ends what temp would you say would be to cool, my self having a race car with 1.8 vvti stock engine we remove thermostat as have been known to fail occasionally.
Is there any benefit to adding addition factory fan, the factory rads all have the mounts on them. It seems adding a second fan is cheap, easy and effective...or am I wrong. Thank u!
I've seen some scoops for ND transmissions. I really am interested to see if there's any data behind them. If you guys could take a look, that would be awesome. Seems like a low complexity solution that I'm sure many would appreciate.
If one uses e85 on a turbo miata na, instead of 93 octane are there any benefits with cooling knowing that e85 combusts at a lower temperature??
Great vid. Thank you. I guess I just have to replace my brown capped rad before making my trip this summer.
Be safe and keep an eye on that!
@@FlyinMiataVideo you'll see my order. Don't worry. Haha I have to change my fluids aswell. All in prep for matg. Assuming you'll will be there?
@@38tech We plan on being at both MATG and Reunion this year!
@@FlyinMiataVideo nice!
On a turbo street car would you recommend a 180 degree thermostat over the 195? In the summer mine gets warm
The lower temp thermostat opens sooner, which means that it takes that much longer for the coolant to heat up after the thermostat is open. This can* delay the onset of overheating.
Basically, it doesn't make your cooling system more efficient, but it gives you a slightly wider window of time before your engine overheats - if it's going to overheat.
I've been tracking for years with a timing advance and in hot weather with a stock style AT radiator with 70/30 (water, water wetter an antifreeze) and a 16 psi cap. Car is mostly a track car but has AC condenser etc is still very streetable.
That rad is getting up there in years now and I am thinking of changing it preventatively.
Any reason to consider upgrading vs swapping with the same thing that's been fine for the better part of a decade?
If you haven't had any issues, you're probably going to be ok with your current set-up, but a good aluminum Cross-flow radiator will definitely be more efficient and should last longer than the stock-style plastic tanks.
Would vents be a good modification to all cars (assuming correct placement) is there any downside to adding them?
Vents wouldn't hurt in most situations, but probably aren't needed for a mostly stock or daily driven car. The biggest downsides to louvers would probably be cutting big holes in your body work and inviting all the dust, water and debris from the environment into your engine bay.
I’ve got a stock 94 NA.. my stock temp gauge bounces up and down. When I’m moving the temp drops, when I’m stopped or climbing a hill the temp goes up… ive wired both my fans to come on and also got a fan shroud as well. I’ve recently changed the thermostat and the temp gauge sender since I thought it was a possibility that they are bad. It’s still doing the same thing on the temp gauge, what could be wrong?
Give our customer support team a call or email, they'll be more than happy to help you trouble shoot!
Does the 30/70 glycol/water mixture referred to at about the 6 minute mark mean 30% concentrate or premix?
30% undiluted coolant, 70% distilled water.
Does a front splitter provide any substantial cooling benefit from added, upward air flow?
Good aero and ducting will push the air where you want it and provide downforce, but unless you are running really aggressive ducting on a race car, you probably won't notice any cooling benefits on a street car from a splitter.
@@FlyinMiataVideo I should have clarified that my question was regarding a track car.
Are there any particular differences for the ND platform (temps, gauge accuracy, etc.)?
Not that we are aware of. The gauges are digital, so could possibly be more accurate, but we haven't tested it.
@@FlyinMiataVideo An FM product I'd be very interested in seeing would be performance data on the digital gauge or Mazda Connect screen!
I've considered doing the coolant reroute but I've heard of a lot of people having issues with overheating after it, how come
We've never heard of any issues with overheating caused by using our re-route kits. Without testing and specifics, we could only speculate why that might have happened with some other kit.
P0128 - Can you elaborate why this most commonly happens?
2003 SE, No leaks, mixed right, stock intake, FM coolant reroute, new CSF rad, new cap, new t-stat, air evacuated, stock fans (working), new temp sensor, new intake air temp sensor.
Please reach out to our customer support team directly via phone or email, they'll be more than happy to discuss your issue and help you troubleshoot. Thanks!
What coolant do you recommend?
Any name brand, properly mixed, high quality coolant should work great for most people.
I have a 99 with no AC, and only one cooling fan. I’ve been to the track twice, both times in kinda high temps 75-80 F days, both days I overheat after 10-15 mins on track. In normal operation it’s flawless. Was missing the stock bellypan, installed that, no improvement. Should I install a second cooling fan? Would that help since it has to do with A/C? I don’t even know when the normal fan is supposed to cycle on, I sat letting the car idle for like 20 mins and it never came on, is it possible that that fan is not working? I don’t know how I wouldn’t be overheating in traffic if that were the case. My rad is also recently replaced with a stock unit
What are high temps to you? Are you running aftermarket gauges? If so, where is the sensor located? Are you force-inducted or NA? I'd start with running a 70% water to coolant mixture since water dissipates heat better than coolant. What's your radiator cap rated at? About 16 PSI is stock. Is it popping off before that? Are you running stock fans? A well-designed airflow kit along with a crossflow radiator would go a long way for track use. And finally, removing the A/C condenser (if you still have it) in front of the radiator would help with airflow through the radiator.
@@FlyinMiataVideo I meant high ambient temps, 75-80ish on the days I was running. I don't have engine temps but the dial was pinned and when I pulled into pits the coolant was boiling in overflow tank. It's NA, completely stock. And I don't think it had an A/C condenser to begin with, I think A/C was deleted in options when ordered. There appears to be some kind of stock air ducting into the radiator on the front bumper. I know crossflow would be better but I wouldn't expect a stock car to be overheating. I will flush the coolant and put the 70/30 mix as you recommend in the video. Do you know when the stock fan is supposed to cycle on? Haven't been able to find that info. Would it help to add the second fan and maybe wire them to a switch to be on continuously? Or would that make no difference? Thanks for reply
@@Ferraridude13 The primary fan should come on around 203F and the secondary a bit higher than that but before 230F since that's when bad things can start to happen. I'm not sure on a stock fan setup but I've done some crude testing and our Stage 1 fans still pull air through the radiator around 90 mph. My test was to see when the rubber flaps started to open up and I was doing pulls on the interstate. Since I didn't know if I had a tail or headwind in the test, we didn't think it would be a good idea to add it to the product description. In general, for track use, we think two fans on a well-designed airflow kit can still help if your speeds are 60mph and under or if you're in a lot of traffic. You also might check to make sure that you have good voltage and ground to your fan. If it's under battery voltage by a decent amount, it probably isn't spinning as fast as it could. If everything checks out good and you don't want to upgrade any of your cooling system, start shifting earlier and stay off the rev limiter. More revs make more heat.
how do you test a rad cap?
The testing machines typically cost over a hundred dollars for one which is properly calibrated. Since a good quality cap, with standard pressure, typically costs less than ten dollars, and the probability that a new one is going to be 'good' is very high, most of us just replace the cap when we are doing any kind of service to the cooling system. The caps have a limited service life. The seals compress a little over time, and release at lower pressure than when they were new.
Immediately after you turn you engine off, the coolant in the engine stops moving, and there is still considerable heat in the cylinder head. If you hear boiling of the now almost motionless coolant which is sitting in the still very hot head, immediately after engine shut off, it is almost certainly time to replace your cap. A cap that holds the coolant at the stock pressure (or higher pressure) will suppress the boiling if you have no other cooling system problems.
What has been your empirical data on the longevity of a radiator cap? in years or mileage?
I have two SPAL fans rewired so they always turn on with the turn of the ignition key with a cheaper all aluminum radiator. SPAL is a big name in the BMW racing world. It pulls too much power for the stock wiring.
Oh! I forgot to ask, what the difference between direct heat and radiated heat.
Part of me wants an Elise. And then I remember FM doesn't make parts for the Elise. Major drawback.
Most of us here are big fans, but unfortunately, Miata parts won't fit on them ;)
So my radiator is brown, has white residue by the joint and has damaged fins. I suppose you've gonna sell at least one radiator with this video
Be careful, that sounds like a time bomb waiting to happen!
start selling some more turbo kits for NA you havent had any for years..instead of trying to sell us coolant re-router
We've regularly restocked NA/NB turbo kits, but the limited quantities sell out very very fast! Sorry if you've missed out! Don't worry, we're working very hard to get more inventory back on the shelf as fast as possible. For more info or current ETAs, please reach out to our customer support team and they'll be more than happy to share any info we have. Thanks!
@Flyin' Miata Is it true that a super charger is better for the street? I see some videos where the people say they wouldn't do a turbo again.
Maybe save the turbo for the track ?