Well not that it matters for winter all that much, but my car is running much hotter than any of my friends cars with similar mods/power/etc. In the summer when it was 100F+ out my car was hitting coolant temps of 215F and oil temps of 225F just cruising on the highway at 70mph...when I was going faster the temps were a little higher so I kept it at 70 mph. I know summer time rotaries...bad combo, but I was just going to a bbq.

Anyways even a few weeks ago we had a warmer day and it was about 85F outside and just cruising around in my car I was seeing coolant temps of 190F, sometimes 195 and this is without me going WOT at all. Oh and my oil temps were around 205, which isn't bad I think.

My car:
88 TII

-Streetported motor

-microtech lt8s ems

-Super Koyo dual pass radiator (the expensive as hell one )

-black magic 2800cfm e-fan

-running honda coolant at about 80/20 water/coolant mixture with 2 bottles of water wetter. (read up and self tested and this seems to be a pretty good mixture)

-running a large bar and plate fmic 35"x11"x3" with 2.75" inlet tanks (probably blocks air I know..)

-Using an n/a hood as I read that it's better for cooling/airflow with fmic

-stripped emissions, a/c, ps, etc.

-BNR stage 3 turbo (gets red hot from semi spirited driving

-I had my car tuned to run pretty rich as my tuner doesn't like risking anything since CA has some shitty gas.

-Running a stock exhaust manifold now..

-Shineauto front bumper which has a larger opening for more airflow

-I've used some sheet aluminum to make sure the air is being directed to the radiator

-Still have my oem under engine plastic pan

-new waterpump from kragen

Is there anyone who has a theory as to why my car runs so hot? Myself and my mechanic are at a loss as to why it runs warmer than all of our friends turbo rotaries..I'm half tempted to core out my damn thermostat because this is bullshit..I'm pretty sure I can't even take my car to thunderhill like I want because It'll probably overheat.

 

Heat wrap the DP, that helped my temps out a bit

 

But just a note of my BNR...like I said the hotside gets RED HOT like super REDHOT, so I wasn't sure if containing that heat even more would be such a great idea. If it is hell I'll throw a turbo blanket on there too.

ANyone want to chime in?

 

If its getting red hot, then I'd use a turbo shield rather than a blanket. Rapping the DP should help also. I also looked for the Aerodyne Industries hood adapters that raise the back of the hood about 3/4inch off the car. I always loved using those. Seemed to help quite a bit with underhood temps.

 

Anyone else have any input? Also my mechanic has never worked on or rebuilt a motor for 3mm apex seals which I run, could that affect the temps at all?

 

double check your timing.

 

3mm seals shouldn't effect temps at all, I also have those in my TII.

 

maybe it's the tune? i have never gotten my turbo to glow or start to get red. this is just a possibility, not saying your tuner is bad but maybe the egt's are too high. which would cause the motor to run hotter. i have driven my car with a smaller front mount than yours, GT35R, microtech, koyo, in the summer and temps never got over 195-200 while cruising.

 

one thing i did do is when i bought a new thermostat i drilled a few tiny holes, i don't know if that would make any difference.

 

Where are you measuring the temps? Where is the sender?

190-195 is about normal operating temperature for the engine. The thermostat will actually try to keep the coolant temps around that level. Are you seeing big swings in the temps as you drive around, are are they fairly consistent?

Is your thermostat an OEM Mazda?

What aftermarket gauge do you have? Even on better gauges, I've seen the sender off by 5 degrees or more. How confident are you in your gauge installation? Low voltage to the gauge can cause the reading to be off.


-bill

 

If the temperature is creeping when on the highway, it's a problem of airflow of a bad thermostat.

Sounds like the FMIC may be blocking airflow.

Try creating a duct in the bottom of the underbelly tray to scoop air from under the car and duct it to the rad.

 

I'll try the scoop Idea out. The gauge is a Defi 60mm...the thermostat is less than a year old and it's oem Mazda. I think I will try and replace it again as well. I don't remember where I had the sensor reading at, but will check once I get home.

The turbo got red hot with Steve Kans tune and with my new tune as well. Higher egts are related to the car being tuned lean correct? Because both the Steve Kan tune and my current tuner both tuned the car fairly rich.
EDIT: Also the temps don't swing around a lot. They just creep up and my e-fan is working it's *** off trying to keep them down. In the summer I have to have the fan set to come on around 170F so it gets an early start on cooling...I have noticed that even when sitting in traffic my e-fan will be on and the temps don't really drop below 195F even with the fan blasting.

 

Does the turbo only glow under high load? If that's the case, it's normal.

If it glows all the time, its due to too much fuel, not enough timing, or both.

 

what e fan are you running? if you have to start the fan that early then it seems it might not be enough cfm's.

 

Check your water pump for tears(on the bottom side, signifies malfunction). The heat wrap would help. So would a vented hood, but I think your thermostat is getting stuck open. This means your cooling system has no time to pressurize or sufficiently cool the water in the radiator. The effect would be overheating at cruising speeds. And don't drill tiny holes in it.

 

So I ended up drilling into the thermostat...I figured I had had enough of the overheating. Now my average coolant temps are around 175F, but this is also in the winter and it's 50 something outside. Do the gurus think that this will help keep my temps down on the race track? I'd hate to throw down $200 to have to sit out due to heating issues..
*******Oh also I finally found a stock upper heatshield to put back over the turbo to shield my intake manifold from the heat.
Here's a picture of the thermostat:

 

Thoughts? Anyone have some input on my drilled thermostat?

 

thats not a good Idea.

The cooling system needs to pressurize its the only way the water in the system wont boil over.

buy a new thermo cuz that one is shot. and add some water wetter. I notice that always help me with temps, (sorry I just saw you already have it in the system)

Grab some washers and stick them on your hood hinges that will raise it up and might help out with some airflow.

wrap your DP......I ceramic coated mine and then wrapped it.

Make a shield for your turbo or install one...this should bring your temps down a bit more and maybe all the other **** wont heat soak.

only thing that I can think off is maybe a Vmount might do the trick and maybe upgrading to the Taurus Fan. the dual speed one. I have heard of that bringing your temps way down.

Good luck

(Edit) You have the stock manifold? I think this might be a factor in your temps. Seeing as how the OEM mani is restricting it could be blocking it enough to cause the rather high temps

 

About your e-fan. Do you have a shroud for it? I know it won't help with highway driving, but it's a thought.
https://www.rx7club.com/2nd-gen-archive-72/diy-electric-fan-shroud-808292/

Also, check out rotorwiki.

I know that on piston engines, highway overheating is a sign of head gasket failure. Have you put any thought into the coolant seals being bad?

 

I was just stating that it ran hot in traffic/cruising/etc...but now my thermostat is drilled...so I need to go for a spirited drive to test it out. If this fails I'll go back to my oem undrilled one.