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.

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.

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.

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.

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?

If you have tip in knock cruising, then this probably wouldn't solve it.

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.

Just because the thermostat opens at 160 doesn't mean that the water will remain at 160.

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.

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!

y8s, do you mind sharing where can one buy the stant t-sat?

Thanks

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.

Hell...

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

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

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.

Thank you.


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.

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:

http://abefm.smugmug.com/photos/90183214_Gy5KP-L.jpg

And here's the other one I have.

http://abefm.smugmug.com/photos/90183197_rHA56-L.jpg

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.

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.

Matt, what I was asking is: if you had to buy one of the 2; would you buy the super or the regular stant?

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.

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.

Can't you change the point in which the car comes out of warmup mode with MS?

probably, but it's a better idea to just change the thermostat.

What kind of weather was there when you installed your MSPNP? Around here we face 90* to 100* temps for mostly all year round.

BTW, excuse my ignorance but; what is a cooling plate?

Thanks

When I installed it, it was maybe 60 out, but when it was tuned IIRC it was about 80.

It's just a little piece of metal at the front of the bay to force air through the radiator instead of escaping over it.

MS has fixed numbers for the increments for warmup - i.e. 100, 120, 140, 160, but each of those increments has an adjustable cell for % of added fuel - 110% being 10% added fuel. So, I would imagine that w/ a 160* thermostat you could set 160* to 100% (meaning no added fuel) and then voila, no extra fuel added anywhere near 160* or higher.

For people with a good cooling system, it seems to me like it could be beneficial for the car to operate at 160* if their cooling system could keep it down in that area for the majority of the time... but I know very litte.

-Ryan

Ok, thanks Koto!

I think it'd be the opposite, with a good cooling system you can run the 180 and not overheat, with a bad system you might need the 160 to compensate for lack of rad.

BTW, ThePass - I'll be moving out to Monterey in August, we should cruise n stuff.

Edit - you're welcome, Rafa!

You could, but why run a motor at a sustained 160*, when the normal operating temps are 180-190. Your rings will love you in winter. If this was the case on my car, I'd fab a radiator blockoff plate to achieve the correct temps....or not bother with a 160* Especially with the huge Godspeed.

Yeah, here's the question: WHY a 160?

If 160 is better, why not a 120 instead? Then you'd have that much more headroom.

If I could build anything I want, it would be a 200 (210?) degree car that gets to 210 is 20 seconds with heaters, and never gets to 211.

If you dump heat at the rate the car is making it, you're in good shape. If you're not, get a radiator/fans/*ducting*(worked wonders for me. I had my fans unplugged for a week and didn't know!), and a high flow thermo.

You asked for it, you got it. Let no man say that I am not thorough:

lmao!!! Good video!

Man, superstats suck. How was the beer?

:bowrofl: haha Joe that was great. looks like i'll avoid the superstat

If all you do is change the thermostat, sure the water temp will eventually reach the point at which the fans run. The fans are what controls the max temp. There's also low temp fan switches that are supposed to be used in conjunction with the low temp thermostat. In the turbo Miatas I build I use a Billion 65*C (150*F) high flow thermo and 78*C (173*F) "on" switch. In conjunction with a large Koyo radiator, coolant temps never hit 180*F.

Heat in the cylinder head is the cause of most detonation. While just running a cooler thermo and switch may not do anything for you, being able to advance the timing or run more boost will. Keeping the cylinder head cool is the key to making big power.

Joe, I had no idea you had it in you. I'm very impressed.

Here's what we learned:

1. "super" means balls

2. the temp rating of the thermostat means when it *starts* to open

3. heat transfer by radiation and convection is significantly less than by conduction when using a stove top.

Great work Joe!

I seriously lol'd at the video, excellent work Joe!

Does anyone know by any chance what part number is the NAPA thermostat Abe refers to?

Thanks

From the look of it, it appears to be identical to the Stant 29868. (the one that's always on the left in the video) I'd bet it's the same part.

Pretty good, actually. That Racer5 IPA was given to me by a friend whose total beer knowledge consists of "There's Budweiser, and there's that strong stuff Joe likes."

The scene where I'm drinking the beer was actually three beers long, edited down. I think there's one cut where you can see a second bottle on the countertop. As a result of this, the quality of my diction decreased somewhat for the couch scene (it took four takes to get that one right) as well as the VO that goes with the measurements at the beginning.

I learned one other thing as well- IBM makes amazingly durable hard drives. Just for kicks I plugged those two units in this morning, and they still work!

Fantastic
 

I couldn't stop laughing for an hour.

Are those the choice clothing styles of Joesph? No wonder all the dynos turned him away.

This thread has taken an epic turn. I didn't believe that was Joe at first, but nobody has questioned it, so...

I'm speechless. I can only manage lols.

Joe, who was the shady looking guy in your kitchen?

Man, I should have come up for that. Oddly, I remember my thermo just cracking at 160, and being fully open at like 165. It was really quick. I imagine the temps weren't increasing too fast at the top, as in there was enough time for the thermo to react? I'm pretty surprised at how slowly that opened, not fully open till well into the 200's. I think I might repeat it if I crack open my cooling system....

FYI, if you put in a colder thermo for no reason, engine wear aside, your heater will suck. I know this doesn't seem like a big deal, but all the times I'm going down the road with the heater on full, just waiting to feel it.... I regret the decision even more - only the knowledge that I'm suffering right alongside my bearings keeps me going.

I don't remember the part number, but the cheapest 160* thermo from NAPA was the one. NAPA brand. It might even say NAPA on it, or have the part number stamped in it, check the pictures I posted, my smugmug page for highres images.

the NAPA 160 is a #42 IIRC.

Am I the only motherfucker here that doesn't drive his Miata in the winter?

I don't drive your miata in winter. I don't drive mine in winter either, but we don't have winter here. And it's a lot more civilized than my other transportation:

http://abefm.smugmug.com/photos/56131637_LzEwe-L.jpg

So, Joe: Perhaps your experiment would have gone better if you'd had the good beer you'd made with your own two hands there instead? I'll try to at least bring by some bottles and the 2 liter growler sometime soon (next weekend if you think you can spare the time from other duties)

a stripper owned that bike

Joe's early 90's shirt combined with Ludacris makes for a very entertaining video. As for the thermostat, I had a 180 Stant in my Jeep and swapped it out recently after I would overheat on small climbs. Tested it on the stove and it didn't even open. Went back to the 195 after reading up on it and the cylinder walls like to be warmer to get best fuel economy.

I'm curious how old that thermo was... They don't seem like the sort of thing that would go bad, but the one I took out of my car was kinda corroded.

Is it possible for a motorcycle to be gayer than a Miata? We now know that it is. :D

It was an interesting shoot. And I wasn't kidding about the analog 1/2" camera either- it's a Panasonic AG-456. To make matters worse, the drum motor died halfway through, so I had to drag out my old VCR and use it as the recorder. Basically, here's what the setup looked like:

http://img29.picoodle.com/img/img29/...pm_634563e.jpg


Next weekend would be ideal if you want to come up. Actually, if you can bring that machinist's rule with you, we can do the head.

Boy, everybody hates my shirt... My mother says I'm handsome!

The two in the video were brand new. In the first scene, they're sitting on my workbench still in the package.

And actually I exaggerated somewhat about the performance of the superstat. The regular one started to open just after 180°, and the super started to open about 5 or 10° later, but after initial cracking it moved much more slowly than the other.

Ok, I caught that.

Coincidentally, I got some pink dice to hang from it's windshield.

I'll check with my scheduling dept, I should be able to make it up there. Perhaps a highly pressurized container in which to open the beer, in case it tries to gush like 1/2 of the bottles have would be good.


Sometimes, you have to be the bigger man, and not say what Joe's mom tells you. This is one of those times.

I actually meant the guy with the jeep. :-) So I assume you're going with a 180 then? I was more curious about the fully open one. But I will say that in my own OEM vs NAPA test, I was very unimpressed with both the rate and the total opening of the Mazda part.



P.S. God damnit, who started the nasty rumor that it's my birthday? Like, 25 people have told me happy birthday. It's tomorrow. I'd like to continue my "still basically in my 20's" delusion that one more day. I'm sure tomorrow, at 31, my back will go out and I'll go bald.

Meaning you're a bottom? :giggle:


Hmm. Perhaps we can just attempt to uncap them very gently. Ie: give it just a touch with the opener to break the seal and hopefully let the pressure down gradually.

Not that I'm a supporter of thread-drift, but..... I was more concerned about the growler, not sure how easily I can pop that lid. But I'll try. :-)

Perhaps this is part of the cause of the poor cooling performance of my car. Where did you source the 29868?

BTDT. I was the first geek to buy and boil a bunch of different thermostats and found the regular Stant opened most, back in 2001, but no video, LOL.

The Superstat (and the factory stat) are designed the way they are to reduce the temperature undershoot after initial opening during warmup.

The factory stat continues to widen past 100°C, til about 103°C IIRC.

Interesting comment and very plausible; Here's a snippet from the GTX, JDM/EDM, FSM which had a turbocharged BP from the factory and utilized a two stage thermostat. If the image is too large, bitch at me and I'll resize it.
http://home.comcast.net/~silentbob34...ethemostat.gif

Good find. The slot in the factory and superstant act as the sub valve, by opening only a tiny bit in the first 5°C or so.

For you control system types, the dips are oscillations. The subvalve (or initial) operation has a lower gain than the main valve, reducing oscillations, during cold weather or when the radiator coolant is cold (during warmup). Cold weather means the system gain is higher, thus the need for lower gain in the subvalve operation of the t-stat.

You wouldn't by any chance know where one could buy this t-stat right?

It is the OEM thermostat. This is why I always recommend using it.

The one I got from Pep Boys has the sub valve too.

Many thanks!