thinking about a low temp thermostat for m-tuned reroute..
 

despite the reroute and a nice radiator my car runs a bit warmer than I would like. anyone have thoughts on going to a lower rated thermostat?

what can I try from a local parts store just for fun. I know many have great success with the reroute and other parts. thats cool, mine runs on the hot side. My head gasket seems fine as does the water pump so rally what else can I check?

perhaps someone has a part number of a 170 thermo or something similar I can try in the reroute housing?? it might not make much difference but a few extra minutes is happy vs worried on temps

Does it run hotter than the thermostat is rated for?

?? yeah, 2 and from the track. i forget the exact number but I start peddling at about 235f water at about the 25 minute mark.. at this point I hardly care if the motor goes boom. oil is fine dont think ive seen more than 230. thoughts? if the pump was toast no way it would last so long

Something is wrong, dont 'upgrade' the thermostat untill its fixed.

yeah, i have a track day in 2 days. I'm driving the car. I was looking for input.. no um something is wrong. wow never thought of that thanks!

the car runs fine, strong, its gets pretty hot at the end of a session, if something was really wrong I don't think it could take being pounded on for 30 minutes about 235 ish f under hot conditions .

Ok rundown the entire cooling system

How are you reading temp?

Using a different thermostat isn't going to solve anything. Figure out what's actually wrong, instead of just changing parts for no reason.

Are U going to Autobahn on Monday?

Never mind that's in 4 days

Water pump, kinked hose, excessive corrosion, or bad sender/calibration.

Sawzall + hood = Fixed.

I'm going to assume you have Hustler-spec™ ducting, or this is all pointless.

If the car already runs above the thermo temp and the thermo isnt broken, changing the thermo wont make it run colder.

yes it is sealed like a mo fo.

temp sensor on the back of the block, in the reroute housing.

the standalone sensor was moved to the front of the block because the sensor housing tube was slightly wrong size for the hose and was leaking a little bit.

the rest of the cooling system is stock, heater is stock, ducting

not 100% sure yet, I will be at autobahn on sat and sunday for sure. if the car is still running ok I will do monday also.

Are you, by chance, feeding the radiator with air exclusively from the back of the intercooler?

Are you using the stock '99 headgasket or did you switch to a '94-97?

can I test the power of the water pump somehow? could a non oem pump be less affective somehow? I have no idea just trying to talk this stuff out.

stock should I be using something else? oh my could we be on to something here?

I'm glad you've decided against changing your thermostat. I always ask the question: "Why do you expect a fully open 170* thermostat to cool any better than a fully open 185* thermostat?"

Stock undertray in place? No dummy risers on the hood? No cowl on the radiator? A/C not running?

If you're using a coolant reroute, you cannot use a NB head gasket. The coolant reroute is specifically designed to fix the problem with the NA head gasket. The NB head gasked is also specifically designed to fix the problem with the NA head gasket. If you use both the NB head gasket AND a reroute, the NB head gasket solves the original problem, and THEN the reroute RECREATES the problem that the NB gasket solved...

I thought 94-2000 was the same HG, and it changed for 01+?

Where is that darn thread with all of the different HGs pictured?

Coolant reroute issues are only for the 01+ head gasket.

not completely, but most of the air does go through the intercooler

does this sound right or wrong....

sealed the area between the intercooler and the radiator with corrugated plastic sheet

sealed the sides around the radiator

skinned the bottom of the bumper back to the stock under pan mounting point on the subframe.

built a big duct, to extend the open area around the large bumper intake to the intercooler and the non covered area on the exposed radiator and oil cooler( mounted on the frame rail and ducted to the front. )
think I should remove this part?

yeah this was my understanding as well.

yeah, well my logic was that if I could get the thermo open sooner perhaps I would avoid saturating the system with heat to the point the radiator is unable to shed the heat but if this is the case, I have flow issue, possibly caused by a faulty thermo that does not open all the way which is why I was going to change it and go for a lower temp unit while im at it.. if that makes sense.


no under tray is made by me, one between the rad and intercooler and second between the bottom of the bumper and the subframe

no risers
no radiator cowel
AC deleted

Logic is flawed. Radiators transfer heat by conduction. With conduction, the rate of heat transfer is proportional to the difference in temperature between the coolant and the air. To increase the heat transfer rate, it is actually desirable to increase the temperature of the coolant -- all other variables held constant. That's why you often see a hotter thermostat as part of trailer towing packages.

Personally, I'm not a fan of remote mounted thermostats like you find in the M-tuned kit. It can cause control issues. That's why the stock thermostat housing has that little bleed line to the mixing manifold at the water pump inlet. Not saying that's your issue, just something to consider. My reroute uses the BEGI spacer that puts the thermostat directly at the back of the head. It works really well (as per the original design intent on B6 and BP engines).

BTW, you could try running without a thermostat. Might indicate whether you have a flow/blockage problem somewhere else.

Take a picture of this.

There's one more thing with the M-tuned that I almost forgot. With the M-tuned, the coolant bleed that allows the T-stat to see true engine coolant temperature is accomplished with a drilled hole in the T-stat base. If this hole is not present (because you changed the T-stat and didn't realize how critical it was) or if the hole gets clogged, you can expect a significant delay in T-stat reaction to coolant temp. It is certainly worth a look.

you make some good points. very interesting about the temp differential and affect on cooling. when I bought the m-tuned I did not think about it enough. wish I had got the BEGI better and cheaper.

In regard to what Sav was asking, if the only air getting to the radiator has to come through the intercooler first, you aren't likely getting enough air to the radiator. Likewise, if all air entering the bumper mouth is forced to pass through the IC, you are blocking airflow.

I've had this kind of problem at the track. I moved/angled the intercooler to allow more air to get around it and to the radiator.

While true, it doesn't sound like his issues are coming from a late-opening thermostat. As you mentioned previously, the transfer rate is proportional to the difference in temp. So if he had a late-opening thermostat (and no other problems) I would think he might get spikes to 235, but then it would eventually level out.

I also am interested by what he means by 'plastic between the IC and rad'. I hope he means "sealed the sides of the IC to the rad".

I can envision a scenario where, if there is excess cooling capacity (and, this time of year, there should be), one could get into a cycle where the thermostat has a series of late-openings followed by rapid closings. This could create this kind of temperature offset on a continuous basis (the temp gauge would smooth out the spikes).

Just a theory, mind you. Threw out the stat bleed hole as something to check. I think with the M-tuned, checking the stat is pretty easy. That's one definite advantage of the M-tuned.

so the bolt holes on the bottom of intercooler, and the small tabs on the bottom of the radiator were used to attach a piece of plastic in a fashion similar to that of stock under tray. I will get a pictures today

Like this?

https://www.miataturbo.net/attachmen...ine=1367605846

Because that might explain your problem. If everything is ducted to the IC and THEN to the rad, you aren't getting enough cool air to the rad.

alright, very good thank you! i will go take some pictures of what I have.

I think I might have a better solution, I will take the piece between the ic and the radiator and drop the front on the intercooler with a spacer or something so that it will scoop air from under the IC.

yes that is what I did, your picture is correct.

So i need to rethink how I did this.

https://www.miataturbo.net/race-prep...g-ideas-69274/
the first image looks like mine.
it will be cold this weekend so it will not be an issue. only on hot humid days does the car run really hot. not as hot as the turbo viper guy but pretty hot none the less.


perhaps someone has a link to sealing the radiator properly?

my plan is to remove the attachment and see if I can drop it to the undertray skin attached to the bumper, or seal the undertray to the rad directly

All you need to do is 100% seal the opening at the front of the bumper to the rad. As long as your IC doesn't block a huge amount of the rad, it can just sit in free air (inside the ducting for the rad).

Don't quote me on that though, I've never done it, just read about the other people who have.

You could scoop air from the air dam/splitter/lip and duct it back, under the IC and up between the rad and IC to force cold air around the IC.

Alternatively you could cut the top of the bumper cover and use that high pressure area to feed cold air over the IC and through the radiator, that's been done as well. With a vented hood venting air between the rad and the block in that low pressure area, you boost this effect even more. Both have been done on here before.

mine looks similar to this.


https://www.miataturbo.net/race-prep...g-ideas-69274/

Hardly. There is nothing wrong with the M-Tuned reroute - despite what a lot of folks think, it functions perfectly and is significantly better made than anything BEGi offers.

You mean like this guy?

https://www.miataturbo.net/general-m...40/#post413249

;) Sorry, couldn't resist.

M-Tuned is a nice piece of kit. But, again, that bleed hole in the thermostat is critical for correct operation.

hey guys everything seems to be working fine. it was only about 75-80 today but the car ran awesome. what did I change? I removed a stip of foam from the bottom of the intercooler blcoking air from going under the IC to the radiator. I'm going to clean it up and make the plastic sheet have a 1 inch scoop below the IC and I think Iwill have no problems

max oil temp 220 perhaps a little higher

consistent water temp about 90-95 c give or take ,about 190F =perfect

hard to believe that this strip of foam caused my issues but it seems to be the case.

did get a oil leak, loose oil pressure sender, my fault. fixed and all is well.

when the temp outside gets to 100 i may need to revisit but I hope not

now I cant wait to start working on suspension and my tune! still needs much work but its pretty fun to drive.

thanks for all the help, lots of good suggestions and good people here!

In theory, having the thermostat away from the head is bad, but in practice it makes no functional difference.

:dealwithit:

It's a bit warmer here most of the year but I found it necessary to add an external oil cooler as I started turning up the power and running 40 or 45 minute sessions instead of 20 or 25 minute sessions. Everything gets heat soaked and baked. I may end up venting my hood eventually, but the next step I will make if I overheat again will likely be to install the larger oil cooler I have on my shelf. I went with the smaller one originally because if required less fabrication.

yeah I don't think you get very far without a oil cooler on a track car anywhere, especially a turbo. i have a b&m 8x11 core. seems good, my oil cooler duct blew out which I think accounts for slightly higher oil temps but I'm totally fine with 240 even 260 oil temps. after that I'm out.

if the ducting does not work during the heat of the summer I may need a better core but I think it should be fine. I used the same core on a car with way more power.

did you guys delete the water oil heat exchanger?

Definitely not. That is supposedly a very effective unit. Supplement it with an external unit.

The factory unit? My understanding was that it was just to bring oil up to temp a bit quicker.

With a good working cooling system a low temp thermostat may be helpful in keeping oil temps in check when using the OEM oil cooler only.
Any drawback to think about when running the lower temp thermostat (ms2 ECU)?

If you're overwhelming the cooling system with a 190 t-stat, a 180 t-stat will do the exact same thing.

Yea, that will cause you problems. I had a similar setup and had some overheating issues. Simply prying the ducting away from the intercooler about half an inch made a big difference, so I went ahead and redid the entire ducting to open up about 4" of bypass below the IC.

I know that a lower temp thermostat will not fix a cooling system that is running hoter than the temperature where the termosthat is fully open because of insufficient cooling capacuty as stated early on this thread, and i velive that running the cooling system 10 deg cooler will increase the heat transfer on the oil to water cooler and that cannot hurt on the oil temp side .
My question was is there a negative effect of runing a lower temp thermostat when running a MS2 that gives the user full controll over enrichement at the lower water temperature.

Negative of running a lower temp thermostat: Your oil will warm up more slowly. Oil temps are far more important than water temps...up until exactly the point in time where your water begins to boil. If you don't have to worry about your water boiling, then you should be paying attention to your oil temps.

I suppose that I should weld a bung on the pan for an oil temp sender before installing the motor back in the car...

Or just use a tee on the oil feed line for the turbo or sandwich adapter on the oil filter adapter.