Correct Operating Temps
 

I tried to search this but couldnt find anything, maybe I was typing wrong idk. I've had a suspicion of my rx8 running too 'hot' for quite some time but only had the stupid OEM dummy gauge to help me decide.

I had an opportunity to use my friends dashhawk to observe some temperatures that I wanted to ask about.

My car is waiting to have the transmission replaced, so I just plugged it in at idle for roughly 10-15 minutes and observed.

What is an ideal intake / coolant temp?

At idle after 10 minutes, my intake temp was 190 degrees and the coolant was at 208 degrees.

Granted, the car was idling in 80 degree weather but still seems a bit high.

Please let me know where these temps should fall so I can monitor it to watch for issues.

My current Mods

-RP Gutted Cat
-K&N V2
-Air duct in bumper (deedub style)

Thanks.

"Correct" operating temps are highly relative to your ambient operating environment and duration of operation.

My numbers below are typically for this time of year in my area with temps in the mid-80's with fairly high humidity after about 1/2 hour of highway driving at cruisng speed:

Coolant temp - ~ 192 degf
Oil Temp - ~185 degf

Note that at idle, post-warmup, you don't have the benefit of cooling airflow from movement, but then your fans are most likely on and your engine isn't as stressed as when driving.

Having said all that, 208 degf coolant does seem high for an idle in 80 degf ambient. Check to see that you are getting proper thermostat opening and therefore adequate coolant flow. Also check to see if your radiator is "air bound" (flow impeded by trapped air). And of course check to see if you have fan operation, although note if your flow is impeded the sensor that inputs coolant temperature to the ECU may not be sending proper data and therefore the ECU may not be turning them on.

208 at idle does seem a bit high.
Your car should be fine until you're upwards of 230°F at which point you'll see the OEM dummy gauge move and that's when you're approaching dangerous temps.

how long since you flushed the coolant system?
If it's been more then 2 years, I'd highly recommend doing that and going with a higher water concenration.
Probably something similar to 70% water, 30% coolant, and throw a bottle of water wetter in there while you're at it.
I would also recommend getting some type of gauge or readout so you can keep a closer eye on your temps. AccessPort, RB gauge pod, dashhawk, Scanalyzer, etc etc.

yep!

Def needs a coolant flush, no doubt about that. Hasnt been flushed yet...... Car sits most of the time so it's been neglected which is completely my fault. BTW, the guy whos doing my trans work is also compression testing it just because so we'll see. Coolant flush is definately happening as soon as I get the car back in a week or so.

Thanks for the great replies, Im going to look into more ways to keep this motor cool.