Do I need an oil cooler?
 

With track season coming up in ~2 months, I was wondering if anyone has any input if we will need an oil cooler for track days.

Usually sessions are 12 minutes long. Summer temps can get up to 90 degrees.

Any thoughts?

For track use, yes.

For street, I have an HKS SC without an oil cooler with no issues.

You want to keep the oil below 125C on the track if possible. Without the oil cooler I could do 4 or 5 minutes duration time attack then cool down before another run. With the oil cooler, the temp was stable at a lower than max temp provided the vehicle was moving.

Same climate as you.

FWIW, the 2022 come with an OEM oil cooler (which also warms in the winter) that's connected to the engine coolant.

I never ran a cooler on my 2013 at the track so it remains to be seen what the 2022 oil temps will look like on the track with the extra displacement.

Ima say, probably not. Last-gen didn't need them either IMO. At the very least run an event and see what the oil temps first. Personally, for my track usage (~4x 15-minute sessions per track day), at 272F, I'm fine running 5w30 oil with 3.5+ HTHS.

Wait what???? It comes with an oil cooler?!

Yes. It has a oil/water heat exchanger that the oil filter sits on top of.

Okay, you’re right, I looked into it. So the coolant warms/cools the oil. Which means keeping water temps down just got more important.

I think I may do a new thicker radiator with some Spal fans

Stock is probably gonna be fine for coolant temps. Is for 1st gen anyway.

Again, I'd track it before assuming you need to upgrade.

I was going to say what @ZDan said.

I'd check out @CSG Mike 's build thread since he's been tracking it from pretty much day 1.

There aren't many data came out this far but some GR86 folks are seeing 250F oil temperature after just a few laps on the track, which is around the edge of the not optimal temperature. We have yet to see any data on a summer day. So I would say if you would like to drive the car to it's full capacity for more than 20mins sessions, you are likely to need a better oil cooler in the future. If you willing to do some cool down laps in the middle of the season, factory oil cooler might just work out. Just my 2 cents.

Gen1 factory race cars use heavy weight oil and oil cooler. The FA20 is also known to pull timing when oil gets too hot. So I wouldn't say gen 1 cars don't need oil coolers. It is not rare to push gen 1 car without oil cooler beyond 270F oil temperature in a summer day. It is a cheap insurance to install an oil cooler to make your car run in more optimal temperature range.

Quick question on said coolers: while they protect the engine in a heavy-duty use case, how about their impact on daily driving? Any risk of running too cold, or seeing much increased warm-up times?

Do the aftermarket coolers have thermostats? And if yes how well do they work?

I'm not interested in putting one on my car, but this is where my question for useless-to-me information led me.

A lot of them do have thermostats. The Full blown kit does, which is the one I had, so anything below something like 200, the oil wouldn’t even circulate to the cooler.

IMO 275F is fine with 5w30...

Indeed mine almost always gets up to 270F indicated at the track, even on cooler days. But temps remain in control (i.e. no "runaway" oil temp rise) even on the hottest days.

IMO, it's not "insurance". Early ('13 model year) gen 1 cars seem to be overrepresented as far as bearing failures both without *and with* oil coolers. I think the earlier cars in particular had oil delivery issues. Oil cooler won't fix that. Also there have been failures with oil coolers due to leaky plumbing (well, at least 1 I can think of anyway).

My car is almost exclusive to track days so I didn't take it into consideration. My car uses Jackson Racing dual radiator oil cooler, so like gen2 cooler, it warms oil from coolant when it is cold. But I don't have a side by side data to measure the warm up speed. My unit does not have thermostats in the sandwich plate as it relies on the engine coolant, which already has thermostats, to cool oil. But I think regular jackson racing and perrin oil cooler both has thermostats in the sandwich plate to prevent oil from over cooled. My car runs at around 190F in highway cruise in 70F ambient temperature, 230-240F on track on 100F track days.

I am not anticipating to start a conversation with you again on this topic. We cannot persuade each other. You took the risk to run your car on track without oil cooler and pushing your car beyond optimal temperature and oil pressure, that is your car, I don't want to say anything about it. For new comer who may want to drive the car in a more conservative envelop, please don't just boldly claim these conditions are OK. It didn't fail on your car doesn't mean they are good for all.

The OEM cooler actually warms the oil faster when cold (good thing) and then helps to keep it closer to the engine coolant temperature once it's warm so it's the best of both worlds.

Track performance is still TBD.

For 12 minutes sessions you can probably manage without.
Running a 5w30 may be a simpler solution than a full blown oil cooler if it's mostly a street driven car.

There haven't been any oil pressure testing done on the FA24 but FA20 testing showed 5w30 hold oil pressure better as temps went up compared to 0w20.

Oh, yet another thread on oil coolers for gen.1 with ZDan saying they are not needed :)

Coming back to the original topic of oil coolers for gen.2, most/all aftermarket options are not available / not on sale yet.
There's really not that much to discuss now.

If you want to go to the track now, the OEM cooler will be enough with 5w-30 or even perhaps good 0w-20 oil, assuming you check the oil temperatures every lap and start cooling down whenever you approach a certain "safe" temperature. It will get harder and harder to keep the car cool as summer approaches and ambient temperatures rise, but there's really not much else we can do.

Once aftermarket oil coolers from a couple of reputable brands are readily available to order then it will be interesting to see how they perform.

Almost every article about gen.2 cars specifically said this was one of the biggest updates...

With the type of oil cooler 2gen has, it would be better to not have it at all. It only makes installing proper oil cooler harder.

I'm questioning whether it is *really* "more conservative". Bearing failures are skewed to affecting primarily '13 model-year cars, and seem to happen regardless of whether there's an oil cooler or not. But the assumption is always that oil is too hot, I've heard people frantically trying to figure out how to go even cooler than 220F after spun bearing *with* an oil cooler. IMO, it's not the oil temp that's the problem in 90% of these failures, it's the oil delivery...

It seems to me that insisting that a noob "just get an oil cooler" may cause more potential issues than it solves. While costing time/$$$/effort.

I do still think that 275F is not a prob with good 30 (or 40) weight synthetic in these cars...

In the winter, oil temps are borderline.

For summer, oil cooler will 100% be needed.

This is for track use. Street guys will be fine without.

Spirited driving similar to track use.

CSG Mike,

What do you use in your car for oil cooling?

FWIW I have an alarm set to 260 F for oil temp in my turbo miata drift car, 5w-40. I change the oil every couple events. Personally, I wouldn't be comfortable running higher oil temps. 30 row setrab cooler, filter adapter plate with a t stat, no leaks or issues going on 5-6 years now. Oil gets up to operating temp as it did before the oil cooler.

I know the spec miata boys play with 270 F oil temps, but they're limited to what they can do cooling mods wise. They also rebuild motors every few seasons lol. If and when my GR order comes in, track days are on the agenda, and I'm picking up the largest aluminum radiator /oil cooler I can find. IMO, lower temps are always better.

I get things hot.
https://i.imgur.com/k0SdL5Nh.jpg



Does the FA24 have oil squirters?

We recommend knowing your on-track oil temps before stepping into an oil cooler. It's going to vary by driving technique, track, event type, and region. Adding unnecessary cost, weight, and complexity, (a potential DNF) is not a desirable direction for a track car, unless it's required.

Subaru engines in general have poor rod bearing supply because of the shared passages from main-to-rod bearings. There's no way around this achillies, unless you go to a billet crank with additional oil passages added. Making sure your oil type, brand, and weight, are good for your particular driving style, use, track, environmental conditions, etc. can be done with an Oil Analysis. That's not a guarantee of 100% reliability, but it's a step in a positive direction.

In regard to oil coolers, it's a tricky balance. The OEM cooler (or as the rest of the world calls it an 'oil heater') reduces the time it takes to get the oil up to temperature at startup. It also cools the oil, but because of the small temperature delta, it's not nearly as efficient as an oil cooler. As a cooler, it tempers temp peaks. It's absolutely does not cool anywhere as efficiently as a remote oil cooler.

When it comes to remote oil coolers there are a few things to consider. One, is that thermostatic valves don't close all the way. It will cool even when you don't want it to. This is by design to not thermally shock the engine when the valve does open fully. Some overcome this with a ball valve or even putting cardboard over the exchanger in cold temps. Size the cooler no bigger than what you need, because cold oil is far more damaging than hot oil. If you're in a colder climate, keep the OEM cooler in place when you add a remote cooler. If you're in a hot climate, remove the OEM oil cooler; this will more efficiently cool the oil, and remove a heat load from the cooling system.

The above are generalizations. If you have more specific info conditions, the conversation continues. It also assumed casual-to-regular track use. Not once or twice a year, not on a competition level.

No, but it has notched rods.

So wouldn’t the problem be solved by getting a really good thick radiator and some 1500 cfm spal fans? That would help remove the heat the water is taking on from the oem oil “cooler”

As little as I think this car "needs" an oil cooler for limited track usage, I 10x as much think it doesn't need a huge aftermarket aluminum radiator.

My gen 1 only gets barely over 200F coolant temps at the track. Doubtful the new one is lacking in cooling here. If you want cooler oil, getting a huge Al radiator and fans just to get slightly less warm coolant temps in that tiny water-oil heat exchanger isn't IMO gonna be the way to go...

The oil to water heat exchanger appears to be the same unit that is on the FA24T. The engine oil should warm up quicker on cold days, which is good for the turbo.

Keep in mind gen 2 has the same size engine bay with no additional external cooling or vents and with a 20% larger displacement engine so if heat buildup on the FA20 models was borderline, Subaru likely assessed that they will require the addition of the cooler on the bigger engine. Since they already put the cooler on the turbo engines which likely are assembled together with the na version it doesn't force them to vary production too much, keeping the cost reasonable.

Is there any evidence of engine damage (or increased wear) as a result of "high" oil temps? I've tracked Hondas and a 991 and regularly saw temps in the 250-270 range--no trouble as long as I ran the appropriate oil for that temp (i.e. not a 20 weight).

High temps aren't necessarily bad. Modern heavy duty engines are designed to pretty much spend their whole life at 120degc (250F) with low viscosity oils. Its just that the engine have to be designed for it and the correct oils that break down slow enough.

That's assuming the coolant system is becoming overwhelmed by the added heat coming from the oil.

What is more likely is that coolant temps will remain stable, but there's a thermal transfer bottleneck between the oil cooler/heater and the coolant.

Best way to know what you need is to get oil and coolant temp gauges with properly placed sensors. Not only do you want to watch how high the oil temp gets but how long it takes to get up to operating temp on a cold start. If you "improve" the oil cooling system but end up with the side effect of slowing down the oil heating process, you'll never know without timing and knowing the typical oil heating process on a stock vehicle with factory spec'd oil. That's where the potential engine damage from overcooling comes into play.

It's not quite that easy. To be anywhere near as effective as a remote cooler you'd need a larger radiator and a larger liquid-to-liquid oil cooler. The reason for this is that there's just not enough temperature delta between the coolant and oil.

I personally wouldn't go this route because it (a radiator) adds quite a bit of weight, in the worst possible spot. If you ditched the OEM oil cooler and replaced it with a remote unit, you would add only a little weight and it could be kept much lower.

Designed to last only for the warranty period?

In engines in general, yes. As temps become excessive, the oil shears down, reducing its load carrying capacity. Eventually that leads to wear, or worse.

Not a fair comparison. Honda and Porsche make much more robust engines, from a bearing and oiling standpoint. You could spit into the sump along with 7/11's finest oil and not spin a bearing with those engines ;)

Depends on the climate, maybe?

My gen.1 splashed some coolant around the pressure release valve at Laguna Seca in summer 2019 when the car was basically stock with camber bolts. It was only my 4th track day and I was driving ~10 seconds per lap slower than the 86DC stock class record, so wasn't on the throttle as much as I could. Unfortunately, I wasn't doing coolant/oil data logging at the time to know what temp it reached.

I am running a koyorad and saw a difference of 1-3F depending on the day lol. 100% not needed NA

My car's coolant was around 210F and oil at 265F Sonoma with a pace 15sec slower than stock class lap record in 2019 fall before I installed the Jackson Racing dual radiator/cooler. The cooler came with a larger CSF radiator, which increase the capacity of engine coolant cooling. Currently with a pace at 2secs slower than stock class lap record with same tires in a similar ambient temperature, the coolant rarely breaks 200F.

I think for the question whether oil cooler is needed really depends on how one tracks the car, what is one's target wear rate of the engine. We all know the HSTS and oil pressure will drop after oil heats up. Both value are crucially related to engine wear. And FA20 is known to pull timing (which drops the engine power) when oil gets heat. I go to track over 20 events per year and I would like my car can be pushed every lap I am in the session without compromises in the engine performance (tires might not keep up though). And here in California, 100F ambient temperature is quite normal in summer days. Then for me, adding better cooling is the logical choice. I do used oil analysis every time I changed oil. So far, the engine wear didn't increase even though I put much more track miles than 2 years ago when the car was mostly for streets.

For folks who said oil coolers are not needed. You might be right. No matter better cooling or not, the engine will eventually fail as long as it is being used and when the engine wear accumulated to a certain level. it is just a matter of how soon that will happen. It's your car and it's your choice to treat it in your own way. But please remember factory 86 spec race cars do use oil coolers with original engine internals. If one wants to use the car in a similar working conditions, that is a very good reference point. I wish I could buy these factory backed racecars directly from Toyota in US so I don't need to build my own.

More like 1500000- 2000000 km these days.. Which a FA20 obviously isn't, sometimes i wish they chose Toyota to do engine instead.

I will run without oil cooler for now, but i will only do short stints on track, and maybe once or twice per season, and we definitely won't see 100F here in the North. But would probably go for a cooler if it was my track day car.

Food for thought:

EDM GT86, MY2015.

Setup:

Dialed out custom Stage2 tune (UEL header), 0W_20 (Eneos, ILSAC GF5, API SN), without oil cooler.

Route:

7 km of spirited driving on a mountain road. Mostly 2nd and 3rd gear.

Result:

Seized engine --> spun bearing on conrod #1 + damaged crankshaft and cylinder wall.

https://i.imgur.com/uQtmKtS.jpeg

Lessons learned:

Using Ravenol's PAO/Ester 5W_40 and 5W_50 engine oil now (both used by Gazoo/TMG in Europe) + HKS oil cooler.
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Regarding the usage of an additional oil cooler on top of the OE water-oil heat exchanger on the GR86/BRZ22, I agree with Mike from CSG.

We've tested the Subaru copper heat exhanger on a couple of cars. It's better than not having a cooler, but 10+ min track stints and extended spirited driving overtax the small heat exhanger.

7km of "spirited driving" in 2nd and 3rd gears, so maybe 5 minutes? There are countless FT86s (mine included) that spend a LOT more time than that at the track at 270+F oil temps without coolers, covering a lot more km/miles, repeatedly, year after year...

I wouldn't conclude that this failure is due to "no oil cooler", when plenty of these failures have happened *with* oil coolers. Of course you should run oil appropriate for operational oil temperatures, were you monitoring oil temps? 0w20 not best choice for "spirited driving" in warm weather but still, for 5 minutes at a time on the street it shouldn't be a problem, given adequate oil delivery.

If adequate oil supply isn't being delivered to the bearings, it doesn't matter if the oil is at 270F or at 235F, bad things are eventually gonna happen. These engines are apparently pretty marginal on oil feed to bearings to begin with, production tolerances could result in some living decently longish lives at the track while others fail early on.

Particularly given the type of usage, I don't think lack of an oil cooler was the root cause of the problem here...