Thom

Thanks Chris.
I would second Jeff's comment - the AC condenser does gather lots of filth and dust throughout the years, after mine was removed the coolant gauge has been showing cooler than ever before.

Are the original oil lines actually M22 or M26 like Jeff said earlier?

333pg333

What is deemed a suitable track temp? I saw 114c max last time out. This equates to 237f so I think this seems in a good range for track temps. Didn't use any oil on the day which is a surprise. Pressure never dropped below 2.5 bar at worst.

Duke

My oil temp never exceedes 87c at the track, even on a track day earlier this year with over 30c in the shade.
edit: This is with an RX-7 cooler up front.

Thom

Duke, what oil do you use and what oil pressure are you seeing on idle fully warmed-up?

Duke

Castrol Edge RS 10w-60. Fully warmed up, around 2,5 bar @ idle perhaps but not sure.
I measure temp in the sump with a sensor in the oil drain plug.

Thom

Do you drive with the undertray on?
When using a temp sensor in the oil drain plug, driving without it makes a huge difference in the readings.

Duke

With the tray.

333pg333

That's interesting. I was around that mark at our cooler ambient track earlier this year, but got up to a fair bit higher last time out on a warmer day. Having said that it must depend one where you have the sensor located too.

Duke

When I had the sensor in the turbo drain the temps were a LOT higher.

Oddjob

I have seen 240F(115C) to 260F(127C) in the pan during 40-45 minute sprint races. Moderate ambient temps, maybe mid 80's F. If you lose air flow to the coolers (running nose to tail w/ another car) it obviously increases oil temps pretty quickly. This is hotter than I would like, but I dont know that it is "too" hot, to the point of breaking down the oil, losing pressure and damaging bearings.

87C (189F) is very low oil temp for a track driven car. Thats below the opening temp of the oil thermostat, so the engine is not even pumping oil through the oil cooler(s). I recall the 3.0 blocks have a higher oil capacity, but is there any other reason that your motor would run significantly cooler than standard 2.5 turbos?

Duke

I agree, it's very low. I have a peak/recall temp gauge and it has never been above 90C.
Hmm when I think about it, I have a Lindsey oil pan baffle installed so it might be that most of the circulated oil is kept out of the drain plug. Less circulation at the drain plug would reduce oil temps there due to the air cooling around the pan.

Would be interesting to install a temp sensor in another place for comparison.

Oddjob

I would still think there would be enough oil mixing and conductive heat transfer that the sump temp would be pretty uniform, but I dont know that to be certain.

I had done some testing with a type K thermocouple (Fluke) some years ago. Was trouble shooting a problem, but also used it to check confirm/calibrate my in-car gage. Found that the cars typically run (temp in the sump) right around the oil therm temp rating* when driven on the street on a warm day.

*[there are two temp ratings on the oil therms; the originals were somewhere around 100C, the newer replacement therms are around 95C]

Have you done anything to your cooling system? Larger radiator? Lower temp coolant thermostat? Is the turbo liquid cooled?

Jeff N.

Hotter or cooler? I have all the trays installed on my car.

Duke

First of all I have a high compression engine so combustion is more efficient and less heat is radiated. Ballbearing turbo with very little oil running through it, low temp thermostat and fan switch, large effective hood vent, large intercooler with low intake temps, coated engine bearings with less friction, coated piston crowns to reduce heat transfer etc.
Plus some other things I probably forgot

Thom

Jeff, driving without the undertray allows for better cooling of the sump.
Don't quote me on this but I think I read somehwere that in some favourable conditions (cold weather, cruising on the road) the cooling would be so drastic that it would prevent the oil to even reach its operating temp.
Now that I think back about this I'm going to try it next weekend and see what happens.