Engine temps Too cold or good?
 

So on the Dnyo the car never went past 168f on the ECU. Mind you she was on there for close to 5 hours. Few breaks in between. Afterwards while driving home the stock temp gauge was under the 1/2 way point from what it would normally be dead center. Stop and go traffic it's at the 1/2 way spot on the gauge. Got a Koyo racing radiator and the mazmart water pump. Getting a temp gauge soon to see what it's really sitting at.

Fuel injected engines tend to make the most power and have good economy in the 190-195 range. The only real advantage to running that cold would be preignition resistance and less localized boiling... I say thats too cold. Our thermostat doesnt start to open until around 180f to allow coolant to circulate through the radiator.

I'm betting you have a 160F thermostat installed. In my opinion that is a little too cool. The only time I recommend those is in a road race car that is constantly on the throttle and temps creep up during the track session. I recommend a 180F for most fds.

Hmm ya not sure. I'm getting a temp gauge installed soon. So I'll be able to actually see the temps. Will have to watch them to really see what is going on.

pull the thermostat and see what its stamped

If it was on the dyno for 5 hours how could the thermostat be an issue. It will open up when it gets hot just like a 180 degree does and as the car keeps getting flogged it will stay hot.

I've seen the ECU temperature sensor lose its accuracy with age. You may want to replace it.

If a thermostat is too cold for the application and the radiator is efficient enough, it is possible the car might never get hot. I've had fd's that wouldn't get warm enough in the winter where the double throttle would never even open.

I can see that. But I don't see that happening during a 5 hour dyno session.

What if the car has a 160F thermostat That's old and spring is wearing out so it opens prematurely..?

Dyno session or not, if the thermostat opens sooner it will keep the coolant colder...


J.

Have you seen them failing and read higher, as well?

So, what temperature did it run before the dyno session? If it was normal, the thermostat failed in the stuck open position during the testing. You can linerize the stock gauge, which will add one more bit of temperature information at a critical spot in the engine not covered by the ecu temperature sensor or an after market sensor.

exactly are you running a thermostat?? when are your fans turning on ? :scratch:

It is the stock thermostat. 185 degree fan switch. I do hear the fans turn on. Esp once she gets parked from driving in the city. The low temps seem to be while driving on the highway.

a real water Temp gauge I think will be a good idea , because my car runs under half way when its at 80C which is operating temps . 86C is thermostat fully open

I can recall maybe 2 or 3 going bad on various vehicles I've seen. Both read lower. On new cars, the ECU is smart enough to throw a code if the sensor is reading too low or high, because it has a water temperature model.

If you've got one of those infrared thermal sensor thingies with the red dot, you can get a ballpark reading from using that as to what the temperature should be. Like warm the engine up with the radiator cap off, point it at the coolant and compare the reading to what the ECU sensor says.

Been a while... So was looking at taping the throttle body coolant line Like Dale Clark did to install my AEM water temp gauge
https://www.rx7club.com/3rd-generati...d-idea-392910/

What I found is on the diagram attached where the hose is coming off the engine to go to the throttle body (what i wanted to tap) isn't there. It's headed right back to the WP. So the throttle body coolant line was deleted. Is that ok?

Edit: I added another diagram to show.

thanks
Carl

Yes that's fine, lots of people do it without any major issues...

And you still can install your gauge sensor in that line because it routes it back to the WP.


J.

Cool thanks. I havn't seen much of any info on deleting that line in the 10+ years on the forum. if it stops raining here I may just get it done this weekend.

So I finally got around to installing the temp gauge. And there is a 40 degree diff in temps. So the ECU actually thinks it's cold when it's not. Once the engine get to 190 the fans kick on and looks like the thermostat is working as intended also. Temps will go up close to 200 and slowly drop back down to 180ish. This is all in the driveway idling.

So I did some calibrating in the ECU. 170-200f is within +/- 3 degrees now. So she should run better now. Going to have to check the other temps out.

You should just change the sensor... its probably bad lol

thewird

Good point. But I don't think it was calibrated with the ecu either all settings where stock out of the box for temps. She's been running like this since the day i got her back. And it was a new sensor put in doing the rebuild. I'll look into it.

The Adaptronic should have the correct water temp calibration out of the box. It only doesn't have an intake temp calibration unless they fixed that.

thewird