Oil temps when tracking my 2015 Subaru WRX?

Status
Not open for further replies.
Joined
Aug 13, 2015
Messages
3
Location
Denver, CO
Hello! Long time lurker, first time poster!

I have a 2015 Subaru WRX and was planning on attending a few HPDE track days with it. Right now I'm considering picking up an aftermarket air-to-liquid oil cooler for the car and wanted to get a few opinions from the collective minds here on BITOG!

For reference, the car has somewhat of an OEM liquid-to-liquid oil cooler/warmer that is placed right below the oil filter. It basically just routes coolant through the "warmer/cooler" in order to both warm and cool the oil. Here's a pic for reference:


On the street, the OEM oil cooler seems to do just fine. With outside temps in the mid 80's, my oil temps stay around 200-210dF while in town and rise slightly to 205-215dF on the freeway. However, a couple of quick 3rd/4th gear pulls quickly result in oil temps jumping into the mid 220's range.

I've done a bit of searching to see what kind of oil temps people are seeing while tracking these cars. One guy claimed that while only pushing it to about 7/10ths his oil was hitting 230dF and he backed off... several have claimed their on track oil temps were in the 240-250dF range, which sounds about right to me, given what I know about the car.

The car is running Subaru recommended 5w-30 synthetic. I won't be competitively racing the car, but would like it to hopefully hold up to ~20 minute sessions on track.

There are a couple of aftermarket air-to-liquid oil cooler kits available that I'm thinking about getting and both types are direct bolt-ons:

#1. One is a kit that works in conjunction with the OEM liquid-to-liquid oil warmer/cooler- http://www.mishimoto.com/subaru-wrx-oil-cooler-kit-15.html
-On average this kit seems to run oil temperatures roughly ~25dF lower than normal.
-It keeps the OEM warmer/cooler in the loop, which could in theory help to heat cold oil a bit quicker in the winter (although this effect is diminished by the extra cooler), as well as cool it a bit more under high stress conditions.
-Although I've seen several reports of people running oil temps in the 178-190 F range with this setup on the street.
-Its slightly cheaper than the #2 option, which is a plus.

#2. This setup bypasses the OEM warmer/cooler and instead uses a thermostat to control the flow of the oil to the cooler- http://www.mishimoto.com/subaru-wrx-thermostatic-oil-cooler-kit-15.html or http://perrinperformance.com/i-13427996-oil-cooler-kit-for-fr-s-brz.html
-Both the Mishimoto and Perrin setups are very similar.
-People generally see around a ~20* F reduction in oil temps with this setup.
-They both come with a 185* F thermostat, but can be spec'd with a higher temp 200* F thermostat instead.
-Doesn't offer quite the same amount of cooling as the #1 setup (still better than stock), but it should be easier to control minimum oil temps.

^^^For reference, all of the kits listed above can easily be found for well under their MSRP prices. Also, the #1 option cannot easily be used with a thermostat (best of both worlds) due to hood clearance issues.

My questions:

1. With oil temps in the 240-250* F range (on track), would you invest in an aftermarket oil cooler for occasional track days?

2. If so, which option listed above would you go with? I'm leaning towards the #2 option, just for the ability to more easily control minimum oil temps.

3. Since some people are reporting 178-190 F oil temps for daily driving (#1 setup), are these temps too low? Any potential issues with running oil temps that low? I'm especially concerned about oil temps not even getting that high during the winter here in Denver, CO.

4. Is the extra cooling worth the slight loss in oil pressure? Oil pressure at peak seems to drop from around 90psi to around 85psi.


Thanks in advance!

-Brandon
 
Last edited:
I tangled with one a few years ago. It was hot out in the 90Fs. She had to quit early because to 300F oil temps on each outing. Car was stock. This was probably around 2004 or so.
 
Use a 0w40 or 5w40 for occasional track days.

I'd skip the cooler until engine mods increase power excessively.

180-190F is not too cool, so aftermarket cooler isn't an issue.
 
Collectively, the wife and I have now owned 3 WRX's (2004-mine, 2013-hers & 2015-mine) and an STI (2006-mine). The new WRX has an entirely different engine (FA20DIT vs EJ25) and transmission (6MT vs older 5MT in WRX's) than the older WRX's. It's now direct injection, has a twin-scroll bottom mounted turbo, ect. It also has a slightly higher oil capacity vs the older EJ25 motors (5.4 vs 4.5 quarts). They don't feel very alike anymore and I prefer the new one. The newer engines seem to run a bit cooler...
 
A little oxidation?

And why japanese cars has ridiculously small oil filters? Look at that in a 2, even 3 liter engine ...
 
Last edited:
I wouldn't do anything. There have been a lot of discussions about this on the Forester forum. 190 is not too cool.
 
I know this may not answer your question fully. I have never owned a Subie but have owned 4 Evo's from 2003-2013 and tracked all 4 of them. Yes Oil temps are something worth keeping an eye out for, but and I say but, if your car is not getting too warm coolant wise, I would not worry about it.

The one thing I did notice though on my Evo's was when I ran Redline 5w30 vs Mobil 1 Gold Cap 10w30 my oil temps dropped 20C Consistently. Why? I have no idea, but my data logs confirmed what my gauge was saying. This happened not on 1 of Evo but all 4.

So my recommendation would be to run a high quality Full Synthetic oil at least for Track days. Unless you push Boost up or are on the track in 100F+ Weather, I really dont see you having any issues.

Very Nice Car, Enjoy it, and Just let it cool off of bit after a few laps, keep the engine idling and let it cool off a bit you should be good.


Jeff
 
250F+ is fine for tracking. I would probably switch to a 5w40 or m1 0w40 for occasional track days and make sure the oil stays under 290F

My fb25 can be 230f+ on the highway.

I'd back off on anything that adds complexity to the oil system.

Not to mention they would void your engine warranty.
 
Last edited:
Originally Posted By: Jeffs2006EvoIX
I know this may not answer your question fully. I have never owned a Subie but have owned 4 Evo's from 2003-2013 and tracked all 4 of them. Yes Oil temps are something worth keeping an eye out for, but and I say but, if your car is not getting too warm coolant wise, I would not worry about it.

The one thing I did notice though on my Evo's was when I ran Redline 5w30 vs Mobil 1 Gold Cap 10w30 my oil temps dropped 20C Consistently. Why? I have no idea, but my data logs confirmed what my gauge was saying. This happened not on 1 of Evo but all 4.

So my recommendation would be to run a high quality Full Synthetic oil at least for Track days. Unless you push Boost up or are on the track in 100F+ Weather, I really dont see you having any issues.

Very Nice Car, Enjoy it, and Just let it cool off of bit after a few laps, keep the engine idling and let it cool off a bit you should be good.


Jeff


Good recommendation and a great quality ester based oil!
 
Thanks for the general feedback guys!

So the general consensus is:

-Leave it alone
-250 F is not terribly high for a track session.
-190 F is not too low for normal driving either.
-Make sure to use a high quality oil and it should be alright.

Got it!
 
Last edited:
Did a track day in my 15 wrx last fall. Ambient temps were upper 50's and the max oil temp I saw was 235ish. I had a 50/50 mix of old pennzoil ultra 5w-40 and 5w-30 and oem filter. Shouldn't be any issue at those temps and a good oil. I probably wouldn't feel that comfortable with subaru 5w-30 oil however. I would say put the money into stainless brake lines, better brake fluid, and better pads.
 
Agreed that the temps are not too high and to run any oil that isn't Resource Conserving (i.e. not the recommended GF5 5W30). In under 2,000 miles of normal driving conditions, your oil probably has a good bit of fuel contamination and is likely a 20 grade.
 
Last edited:
Status
Not open for further replies.
Back
Top