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Old 05-23-2008, 01:49 PM   #1
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Default Let's argue about 160 degree thermostats

From searching, I found that most of you think 160s are a bad idea. 160s are pretty common for people to install on boosted cars, no matter the model, why would Miatas be any different? Spec Miataers like 160s as well.

It might not be the best idea with a stock ECU but with Megasquirt or something there shouldn't be a problem. What floors me is that people say there's no benefit at all but it's common sense that lower temp coolant running through the system keeps the cylinder walls slightly cooler and would help with knock.
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Old 05-23-2008, 01:58 PM   #2
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Doesn't necessarily mean your temps would be cooler. It would just open sooner. Once it's open it doesn't open more.

Personally on most cars I've tracked with including sr20 drift cars, and spec miatas, I end up gutting the thermostat.
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Old 05-23-2008, 02:17 PM   #3
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I'm running 180 on mine.

BenR pretty much said it. A lower-temp thermostat will start to open sooner (thus slowing initial warmup) and if your cooling system is not overtaxed, then your average operating temperature will go down.

On the other hand, if you are overheating with a 180 or 195 thermostat, it signifies that your cooling system is not adequate, and lowering the thermostat temp will not fix this. You need to add the capacity for more heat transfer from the engine to the atmosphere- big aluminum radiator, reroute, intake ducting, etc. Or it could be something really simple like a bad radiator cap.
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Old 05-23-2008, 02:19 PM   #4
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OK, simplified scenario. Say you were cruising and your stat opened at 160. Your system temperature would be 20 degrees cooler than if it opened at 180. Lets say you average 200deg WOT on full boost.

At those temps the stat doesn't matter. But it takes longer for those temps to reach 200, so it DOES matter. Also, tip-in knock is a problem, and if you're cruising at 160, you're running cooler than you would at 180 so it helps with that.

Edit: even if your cooling system is overtaxed, it will benefit you some as long as your system is capable of cooling to 160 while cruising. Starting from a base of 160 rather than 180 would help somewhat.
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Old 05-23-2008, 02:21 PM   #5
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Quote:
Originally Posted by StankCheeze View Post
OK, simplified scenario. Say you were cruising and your stat opened at 160. Your system temperature would be 20 degrees cooler than if it opened at 180. Lets say you average 200deg WOT on full boost.

It would just take longer for it to reach normal operating temperatures. consider from 70 to 160 takes me maybe 2 minutes and stabilizes at 190, why do i care if it takes an extra 5 seconds to reach 190?
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Old 05-23-2008, 02:24 PM   #6
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If you have tip in knock cruising, then this probably wouldn't solve it.
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Old 05-23-2008, 02:38 PM   #7
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first you need proof that engines running 20 degrees below operating temp are better. I doubt that claim can be universally made.

second, more important than temperature they open is how much they open. the regular (NOT SUPERSTAT) stant t-stats open far wider than most. test them sometime in boiling water. you want flow area for better flow, not lower temp opening.
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Old 05-23-2008, 03:45 PM   #8
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Just because the thermostat opens at 160 doesn't mean that the water will remain at 160.
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Old 05-23-2008, 04:09 PM   #9
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Quote:
Originally Posted by y8s View Post
the regular (NOT SUPERSTAT) stant t-stats open far wider than most.
This is an interesting observation, as I recently bought a 180 SuperStat (45868) in preparation for my upcoming reroute. I wonder if I ought to purchase a regularstat instead, or if the additional opening of the regularstat might actually cause greater instability of the system owing to the increased flow in the re-routed configuration?

Decisions, decisions... I guess at a minimum I'll buy a regularstat and boil them both.
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Old 05-23-2008, 05:11 PM   #10
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and you will video the boiling and post it to you tube which you will then embed in this thread for posterity.

damn joe, you're an awesome guy!
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Old 05-23-2008, 05:49 PM   #11
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Quote:
Originally Posted by y8s View Post
first you need proof that engines running 20 degrees below operating temp are better. I doubt that claim can be universally made.

second, more important than temperature they open is how much they open. the regular (NOT SUPERSTAT) stant t-stats open far wider than most. test them sometime in boiling water. you want flow area for better flow, not lower temp opening.
y8s, do you mind sharing where can one buy the stant t-sat?

Thanks
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Old 05-23-2008, 06:02 PM   #12
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and you will video the boiling and post it to you tube which you will then embed in this thread for posterity.
Well, if I can figure out how to upload video shot on my old 1/2" Panasonic camera I will. I'm not the kind of guy whose cell phone takes pictures.

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do you mind sharing where can one buy the stant t-sat?
Hell...

http://stant.com/brochure.cfm?brochure=5024

That list seems to have been truncated at "M". Pep Boys also carries them.
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Old 05-23-2008, 06:53 PM   #13
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make abe do it. he has a camera or two ya?

Rafa: most auto parts stores here carry that brand. They're probably similar to your local store brand.
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Old 05-23-2008, 06:54 PM   #14
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Quote:
Originally Posted by Joe Perez View Post

http://stant.com/brochure.cfm?brochure=5024

That list seems to have been truncated at "M". Pep Boys also carries them.
Thank you.


Quote:
Originally Posted by y8s View Post
first you need proof that engines running 20 degrees below operating temp are better. I doubt that claim can be universally made.

second, more important than temperature they open is how much they open. the regular (NOT SUPERSTAT) stant t-stats open far wider than most. test them sometime in boiling water. you want flow area for better flow, not lower temp opening.
Your caveat about the t-stat not being a SUPERSTAT one seems to imply that the super doesn't open wider than most while the regular stat one does. Is that the case?

Sorry but I need to buy a thermostat asap.
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Old 05-23-2008, 08:03 PM   #15
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Shoot, I thought DID take a picture of them in the water, but I guess I didn't. Ah, well. I'm supposed to be able to host video, too, but I haven't messed with it yet.

Anyway, here's the one pic I do have:



And here's the other one I have.



They don't tell much, but I can say that the NAPA one opens at LEAST twice as far. Probably more. My guess at the time was that the flow would be 4x through it. The leftmost is my original thermo, the middle a new one from mazda, and the right the napa part.

Only I think it's a 160. If I had it to do over again, I'd get the 180, my car is always cold and my poor bearings probably don't like it.

Also, I remember somewhere in my deep dark past hearing in thermodynamics that you want the 'ambiant' temperature to be as high as possible for peak efficiency. Then again, that's a close cycle heat engine. :-P Nonetheless, the longer they make cars, the higher those temps get. I doubt you'll find a modern ferarri with a 140* in it. More like 200 or 205.
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Old 05-23-2008, 08:25 PM   #16
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yeah but modern engines need to worry about super low emmisions. i've been toying with getting a 160* thermostat myself, never thought about one flowing more. in my mind if you can stay stabilized near 160* with normal cruising then it would be just a little bit more of a margin of safety.
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Old 05-23-2008, 08:39 PM   #17
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Quote:
Originally Posted by y8s View Post
make abe do it. he has a camera or two ya?

Rafa: most auto parts stores here carry that brand. They're probably similar to your local store brand.
Matt, what I was asking is: if you had to buy one of the 2; would you buy the super or the regular stant?
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Old 05-23-2008, 08:47 PM   #18
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From the pic above, the answer seems to be NAPA, not Stant.

Anyway, if you're a hi rev toona and you can make your car run perfectly, then, yeah, you're gonna be better off with a higher temp in your motor. I'd personally like the extra headroom.
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Old 05-23-2008, 08:59 PM   #19
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I had a 160 in mine, until we installed my MSPNP and noted that temps usually stayed under 159* and didn't make it above ~165* unless I flogged it hard. In this scenario I was in warmup mode for the overwhelming majority of my drive, wasting fuel.

I put a 180* back in and it works fine, Jerry at DIYautotune (Foundsoul here) even commented during my dyno session that the car managed heat really well. Only cooling mod is GS rad from the groupbuy and a $40 cooling plate.

The spec miata angle is a moot point IMO, there's only so much they're allowed to do, plus the cars in SM see much more abuse than a street car.
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Old 05-24-2008, 12:47 PM   #20
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Can't you change the point in which the car comes out of warmup mode with MS?
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