Curious if this is an "absolute necessity" for track car?
It's a 1.6, has tons of recent maintenance and seems to run great.
I'm gathering up all my parts this winter and doing my prep this winter, just wanted to know if this is considered essential.
The PO installed one on my car for track days and said it would hold 185 all session long.
I think I may have air in the system now, because the temp seems to be flapping around a bit recently.
Stock, not really, but it certainly wouldn't hurt. Especially if you want to up the power in the future.
Concentrate on the rest of the car first. For example, a factory plastic radiator is a time bomb on a track car by this point. The reroute really works to make the cooling system more efficient, but it shouldn't be used to compensate for other problems.
Stock radiator, but only about 15k miles on it according to records.
That's good to know though. That money nearly buys bushings/sways.
Duke wrote: The PO installed one on my car for track days and said it would hold 185 all session long. I think I may have air in the system now, because the temp seems to be flapping around a bit recently.
Which reroute kit? If it's the M-Tuned you'll need to drill a ~1/16" hole in the thermostat or temps will flop all over the place with no pilot flow. Fall/winter conditions make it worse too. Not sure if/when they started supplying them pre-drilled but there's only one way to check.
Well, I believe it is a homebrew kit, but it does normally exhibit the "temp gauge looks scary for a minute or two until the thermostat opens" behaviour on cold startup. Normally it's pretty stable after that first opening, but lately it's been edging higher than I like during use and then suddenly dropping lower than the set point. I will look into the thermostat, though, and drill a small bypass hole if it doesn't have one.
Thanks.
Yep, I wouldn't worry about it a bit. The driving school I worked at a few summers back had a fleet of 7 NAs, and every one of them had bone stock cooling systems. Those things were beaten harder than a rented mule, regardless of whether it was 30F out, or 115F out. Never had one overheat on track.
Even with the turbo and full Florida heat it usually takes at least 20 minutes of flogging to start cooking the car. For a naturally aspirated 1.6 (That's a N/A-NA to you) you should not have much trouble with track work.
I never had an overheating problem with a Miata with a stock radiator on the track. In fact, I ran a modified thermostat like the Spec Miata guys do for a while, and the car wouldn't even warm up to a reasonable operating temperature, so I went back to a stock one.
On the flip side, I've seen 1.6 Miatas have trouble staying cool on the street. I'm not sure what it is, but their cooling systems are a bit weaker than the 1.8 ones, stock. It's not a huge problem and a car with a cooling system in good nick without any restrictions in the mouth of the car should be fine.
My cars were 1.8s, so that may have been a factor. Plus, I wasn't running nose to tail the whole time.
The first session of the year usually comes in late-March here. So temps usually only getting up into the 50-60s, so that should be a good initial test.
Like I said, just wanted to make sure it wasn't one of those things that was crucial.
Reviving this thread to ask Keith (or anybody else):
I've got the blower off the car for the moment, so I figured I would replace the t-stat while this is out of of the way. It actually is the M-tuned reroute kit, just with some routing changes to get the water line below the supercharger.
1) What car is the thermostat from, so I can get a new one? Or does anybody have a part number?
2) What temperature is recommended for this car? FM ubercharger with Link ECM. It seems to run around 185 degrees. I assume that's a 180-degree stat, because the temperature sensor is in the blank-off plate at the front of the engine.
Thanks!
You can actually put a factory Miata thermostat in the housing. I don't know the specific part number of the thermostat used, but it's a typical 52mm with a centered spring. Stock is 190F. A 180F version that fits in the housing is Stant 13958.
I'd run 190F on an Uber car.
Thanks for the info! Out of curiosity, why 190, Keith?
Because we have performed hundreds of hours of dyno testing with the engine at a range of engine temps and that's what performed best.
No, not really, but it seems to be the only thing people accept Because that's the range Mazda seems to like for the engine.
As long as you aren't heating up the incoming charge, or damaging parts by overheating them, an engine should make more power and be more efficient at higher coolant temps. I can't see a great reason to run a lower-than-stock T-stat temp.
Well, although I drive the car weekly in summer, its primary use is autocross and (future) track days. The one includes lots of sitting around on hot days idling, the other includes lots of wailing at sustained high load. I was thinking it was probably healthier.
I don't mean taking the stat out, or something really low like 165. Just thinking.
In reply to Keith:
Sorry to bring this back from the dead. But I was researching the coolant reroute and found this thread.
My car has the stock radiator (maybe original?). A turbo is in the near future on my 93 1.6L. Is there a specific aftermarket radiator you recomend? Or just a quality stock replacement with both fans wired to run together?
I rode in my car with the previous owner at a track day a few years ago. Every 10-15 laps (20 mins) he would have to do a cool down lap or two according to the temp gauge. He ran with the head lights popped up too because he said that would help keep it cool longer. Is this fairly normal?
I plan to do track days too this summer and I fear with the turbo it may only make the situation worse.
In reply to Woody:
It is good to be the leader!
I do have strong feelings about aftermarket radiators, and they are based on SCIENCE!
http://flyinmiata.com/tech/rads.php
As you'll see from that, radiator design is more important than simple size. In fact, big "race" rads can be worse than stock. Factory rads are a bit of a liability as they age, as the plastic end tanks will crack. Fans are important for sure - if you're running stock ones, make sure they're both running. If you do go aftermarket, make sure they're not the cheesy "slimline" ones with no torque and poorly chosen (or missing) shrouding. You want big fans and you want them well sealed to a shroud that is as far from the core as possible.
The "headlights popped to keep it cool" might work as it opens up a bit of a gap at a low pressure area. In other words, it might help pull air through the rad. But I'd consider it a last-ditch solution.
So your car doesn't have a turbo at the moment?
I've run on our local track with a 1.8 with a stock replacement radiator in 100F+ dry desert heat an no shade anywhere on the track and the car doesn't get hot. I've also tracked 1.6s with and without a turbo but in a more humid climate and again, no issues with overheating/getting hot on good condition stock systems. OK, I lied, the 1.8 is running an FM lower radiator hose.
Methinks you need to go over the coolant system that is on your car and make sure that it's up to scratch - a coolant reroute isn't going to fix a problem that comes from, say, a duff thermostat or a silted up radiator. I've also never heard the recommendation to change the fan wiring but I may miss a trick here. IIRC FM sells uprated fan shrouds that might help, too.
Don't forget to check that the undertray is present and in good condition, plus check that the airguide inside the bumper is in good condition also.
My personal preference is for running a Mazda OEM thermostat - every time I had a temperature problem with any car I tracked, it turned out it was running a crappy aftermarket unit. My current 1.8 is running an automatic stock replacement radiator, the aforementioned lower radiator hose and a stock thermostat.
Actually I'd also run with the headlights down - you want as much air through the radiator as possible so you don't want to change the airflow under the hood while channeling air through the headlight surrounds.
In reply to BoxheadTim:
Correct no turbo yet.
I will try the thermostat and check out the shrouding( I think its all there) and do a general check on the condition of the radiator and wire both fans together.
Not sure if I will get a track day in prior to turbo swap but hopefully that solves the overheating on stock motor.
Maybe with turbo I will have to order a Flyin' Miata crossflow and fans looks like a quality setup. Thanks for tips.
My stock radiator in my Spec Miata lasted about two seasons before it cracked on the filler neck. I now run a Koyo all aluminum radiator, and have never had a problem with overheating in five seasons since in the Florida heat.
One of the most important parts in the equation is the lower shroud. Without it, my car couldn't even do the 20 mins of a SCCA drivers school on the infield road course at Daytona without me having to back it down quite a bit.
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