Did a quick search but didn't really find an answer. I've got the third radiator installed and oil temp consistently sits at 210 in winter regular driving. In summer DC traffic it creeps up to 220.
My Indy says don't worry about it. Seems high but I know that outside of getting to a "normal operating temp".... Higher long term temp isn't always good.
Any opinions? As far as I know I have a stock thermostat....

 

220 is pretty darn normal in traffic. In really spirited driving, it will go higher. Oil temps aren't highest in traffic; they're higher when you're running hard.

But 220 is exceptionally normal.

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210-220 is spot on.

 

I'm in the DC area as well. After installing a third radiator and a low temp thermostat my car generally sits around 200 to 205.

 

Keep in mind that when driving in bumper to bumper traffic there's little to no airflow to the radiators, unless the electric fans are running. The center rad has no fan. Theoretically the naturalized temp in this driving condition would be same as not having a center rad. It'll take slightly longer time to get to the naturalized temp because of the extra volume of coolant in the center rad. Once you get above say 35mph the center rad should be working good. Make sure the center rad is vented. FWIW, I've tracked my .1 Carrera S for 2 years the track oil temp was at 260+. I changed the oil every 5-6 track days and sent oil samples to Blackstone Lab. for analysis. They always tell me the oil is still good.

 

Mind telling us what oil you are using? Pretty impressive that the oil can handle such abuse.

 

Redline 5w40 (the one that has the VW502 00 on the label).

 

I also track and although I change oil between events or every 3-5k miles, I get similar results from blackstone on my reports with Motul Xcess.

The third radiator doesn't do much if anything at low speeds. The lower thermostat doesn't matter either as once the coolant temp reaches 180 the cooling system is activated.

 

i installed a gt3 front end, i am about to install a gt3 rad on my car.

will post some pics here, it vents out the top rather than the bottom of the bumper. those who track have told me the generic 3rd rad kit actually produces negative lift at the front end.

 

"Negative lift". Do you mean downforce or lift? I guess airflow out the top could counter lift but don't pdk cars come with 3rd radiator and standard front end? It is nice looking in a gt3 sorta way if not necessarily cost effective. Doubt it's much of an issue unless you are trying to convince your wife you have to do it for safety's sake

 

Just for reference, OEM Mobil 1 topped out at 250F or below for me on track days. Ambient temps between 83-90F with high humidity.

 

Low temp t'stats don't help cooling. They play a role in how the car warms up. Some that open too soon prevent a car engine from warming properly... which is a death sentence in colder climates. If it opens too soon the engine might never fully warm up... even on extended drives... or simply take way too long. Expect excessive wear.

 

The GT3 center rad is much bigger than the Carrera/S center rad. My track oil temp was reduced from 260+ down to 225. Street cruising temp went down to mostly below 200. I had to make longer trips to burn off condensation in the oil because of the lowered street oil temp. Had to cut the horn bracket in order to fit GT3 center rad. I also took couple hours to straighten the bent fins on the AC condensers which restricted air flow to the side rads. And I used compressed air to blow debris out from both direction that were trapped between the fins.

 

I've got a low temp thermostat, but no 3rd radiator. At idle during summer months, car runs about 200. During autocross events, temps hit between 225 and 250.

I change oil every 4000 miles based on Blackstone reports of how frequently I should change. Blackstone analysis indicates no issues with motor at these temperatures. I use Mobile 1 for oil.

 

nevermind, I already know the answer.