Oil cooolah

[ZDan]

Originally Posted by finch1750

I'll leave this here fwiw as well. It's old and may not be accurate of their current status, but worth considering imo
https://www.ft86club.com/forums/showthread.php?t=113722

Thanks for bringing this up, this is a very real concern! Even if an oil cooler is a great idea, you can rest assured that unless you have your own supply of quality parts, and a shop, and have experienced talented workers available to you, you are going to be *at the mercy* of your suppliers and installers. And believe it or not, getting you to the track on time with a proven tight and reliable setup is almost certainly not a big priority for them...

[Ultramaroon]

Originally Posted by gtengr

By way of 1 and 3, you're also saying oil pressure <45psi @ 7000 rpm is acceptable, because that's where it's going to be or worse at 270 F, even with 5w30.

But it might be. That was my point earlier. For even the powerplant engineers, the ultimate test of the design is to take experimental data slowly running a sample population of engines to destruction.


Some sort of equilibrium is reached around 5000 RPM where oil pressure plateaus independent of temperature/viscosity. This was not a secret when the engine went to production. ...I hope.

[gtengr]

Originally Posted by ZDan

This thread https://www.ft86club.com/forums/showthread.php?t=91820 ? Of course oil viscosity and hence oil pressure will drop with rising oil temperature. I don't see any demonstrated correlation between oil temps and pressures vs. actual engine reliability, longevity, MTBF established here, though. )

So basically you're not going to accept anything as evidence except the sort of testing that can only be afforded by an OEM.

Originally Posted by ZDan

addendum: The *really* interesting thing to see is that with 5w30 oil, the pressure at ~272°F *without* an oil cooler is the same as the pressure at ~250°F *with* an oil cooler! (see plot at bottom of this post)

What you're seeing is likely the pressure drop from the cooler. That cooler oil is also doing a better job of cooling the bearings, and the mass flow rate would be higher at the lower temp.

Originally Posted by ZDan

I'm not saying I'm an expert. I am suggesting that Ford has metric f**k-tons more actual hard data and analysis regarding the ramifications of operating engines at these oil temperatures than the most experienced drivers have.

Yet there is zero evidence that data is based on or is a recommendation for extended high rpm use on closed course. The car's factory brakes/fluid can't even put the car into the situation we're examining, yet you're confident the owner's manual rec's are based on it. You're also neglecting that the Mustang has a completely different oil system that could have enough capacity to maintain pressure throughout that range.

Originally Posted by ZDan

But is it *really* being conservative to add multiple potential failure points that could result in leaks or even fires, to mitigate an unknown and uncharacterized risk of reduced engine life occasionally running higher oil temps? I don't think anyone on these forums can say.

A lot of things go out the window in the track environment. You say uncharacterized as if there is actually a magic number threshold. Even an expert is not going to be able to tell you that 44.23 psi or whatever is the threshold beyond which accelerated wear is a guarantee.

Originally Posted by ZDan

I'll take 45psi
From that other thread https://www.ft86club.com/forums/showthread.php?t=91820 :

Looks like running 5w30 with no oil cooler should give about 49psi at 7000rpm at 272°F. And running the same 5w30 *with* an oil cooler gives about the same 49psi at 7k at 250°F! So the pressure drop due to the oil cooler looks to be about the same as the pressure drop from running higher oil temperature without the cooler!

More than ever I'm convinced that oil coolers are not necessary to casually track these cars...

The person who took that data drew a different conclusion: "Now that we've seen how well it works on our car, we'll definitely be pushing everyone to run an oil cooler if you're tracking your car in the summer. As much as we love doing engine swaps for people, we'd rather not do it because someone spun a bearing from letting their oil degrade."

A couple other threads with data:

http://www.ft86club.com/forums/showthread.php?t=76760

http://www.ft86club.com/forums/showthread.php?t=64801

Originally Posted by Ultramaroon

Some sort of equilibrium is reached around 5000 RPM where oil pressure plateaus independent of temperature/viscosity. This was not a secret when the engine went to production. ...I hope.

To me, the logical assumption here is that the pump is unable to maintain pressure beyond that point. And if that's true, the situation is made worse by brushing off the observed pressure drop running at 270 F. Seems logical for the oiling system of a $25k new car.

[Ultramaroon]

Originally Posted by gtengr

To me, the logical assumption here is that the pump is unable to maintain pressure beyond that point. And if that's true, the situation is made worse by brushing off the observed pressure drop running at 270 F. Seems logical for the oiling system of a $25k new car.

Or that the entire front cover of the engine was designed to maintain some minimum pressure and the rest is bonus.

[gtengr]

Originally Posted by Ultramaroon

Or that the entire front cover of the engine was designed to maintain some minimum pressure and the rest is bonus.

The only factory pressure spec I'm aware of is min. 7.3 psi @ idle and 73 psi @ 6000 RPM at 186 F oil temp. Seems quite a leap to think 270 F temps on a road course were part of the considerations for setting up the oiling system on a $25k car. Especially considering the factory 0w20 oil pressure/rpm ratio pretty much follows the 10psi/1000 rpm rule of thumb for the range of oil temps (max ~230-240F) that would be seen on public roads.

[Ultramaroon]

Originally Posted by gtengr

The only factory pressure spec I'm aware of is min. 7.3 psi @ idle and 73 psi @ 6000 RPM at 186 F oil temp. Seems quite a leap to think 270 F temps on a road course were part of the considerations for setting up the oiling system on a $25k car. Especially considering the factory 0w20 oil pressure/rpm ratio pretty much follows the 10psi/1000 rpm rule of thumb for the range of oil temps (max ~230-240F) that would be seen on public roads.

I've been through the same mental exercise. That's a single reference point. That temp which btw, is 176 F (80 C), is specified because, in shop conditions it's a reasonable "normal" temp to maintain. It's reasonable to extrapolate from that single point the expected pressure at much higher temps.


It's also the reason I designed my oil cooling system with enough power to maintain that 180-190 degree operating temp in the most punishing conditions. I have to turn it down to below half capacity for DD. I figure either way I can't go wrong, and I have a much better feel for what it takes to keep the oil cool and viscous.

[jflogerzi]

Originally Posted by finch1750

I'll leave this here fwiw as well. It's old and may not be accurate of their current status, but worth considering imo

https://www.ft86club.com/forums/showthread.php?t=113722

I can echo this although not as exterme. Took several emails about 2 weeks but finally got a tracking number. If you do goes this route just peice everything yourself.

Sent from my ONEPLUS A5010 using Tapatalk

[ZDan]

Originally Posted by gtengr

So basically you're not going to accept anything as evidence except the sort of testing that can only be afforded by an OEM.

The evidence I'm being provided with doesn't tell me anything I need to know! Oil cooler lowers track oil temps from ~272°F to ~250°F, OK, but what does that really mean? My guess is engine reliability/longevity is only *barely* affected for a street car that does occasional track days.

What you're seeing is likely the pressure drop from the cooler. That cooler oil is also doing a better job of cooling the bearings, and the mass flow rate would be higher at the lower temp.

Of course the pressure drop is due to the oil cooler. Yes, 250F oil should be "better" than 272F oil, but again no one is able to quantify how *much* better.
Regarding mass flow rate, it's gonna be very close to identical. I mean, how much do you really think the density of motor oil changes between 250F and 272F?! About 1% by my calcs... This is negligible compared to the temperature difference, that's the real "benefit". But again no one is able to quantify what that benefit is. If it's the difference between my engine living 200k miles vs. 180k miles (and I would guess that this is an exaggeration), I do not care...

The car's factory brakes/fluid can't even put the car into the situation we're examining, yet you're confident the owner's manual rec's are based on it.

The appropriateness of running factory street pads at the track is a completely different, totally unrelated subject!
Source is the Factory Service Manual, not the owner's manual. It makes no recommendations, it simply states that oil temperatures up to 279°F are "normal". I've already theorized on what that might mean.

You're also neglecting that the Mustang has a completely different oil system that could have enough capacity to maintain pressure throughout that range.

We have data on the FT86 that shows that it is indeed able to maintain the same oil pressure without an oil cooler as with an oil cooler, so we already know that we're not losing oil pressure by not running a cooler.

A lot of things go out the window in the track environment. You say uncharacterized as if there is actually a magic number threshold.

??? Nowhere do I say or suggest that. Of course there's no magic number threshold. My POINT actually relies on this fact. There's no step-function between 250F and 272F oil temps that implies that you MUST run an oil cooler.

Even an expert is not going to be able to tell you that 44.23 psi or whatever is the threshold beyond which accelerated wear is a guarantee.

Well we're at the same oil pressure with or without the oil cooler anyway, so I don't know what your point is here.

The person who took that data drew a different conclusion: "Now that we've seen how well it works on our car, we'll definitely be pushing everyone to run an oil cooler if you're tracking your car in the summer. As much as we love doing engine swaps for people, we'd rather not do it because someone spun a bearing from letting their oil degrade."

I disagree with his conclusion. No engine or oil expert would tell you that good synthetic oil "degrades" any significant amount from operating at 272°F.

To me, the logical assumption here is that the pump is unable to maintain pressure beyond that point. And if that's true, the situation is made worse by brushing off the observed pressure drop running at 270 F. Seems logical for the oiling system of a $25k new car.

Simple fact is that higher temperature oil has less viscosity, so for a given volume flow rate the pressure drops. With the oil cooler, the oil pressure drops the same amount but for a different reason: resistance in the oil cooler itself.

There is no one correct answer that applies to all people who track these cars. Endurance racing a track-only car, I'd run a cooler. For my usage, I still do not see any meaningful benefit to doing so.

[gtengr]

Originally Posted by Ultramaroon

It's reasonable to extrapolate from that single point the expected pressure at much higher temps.

Seriously? That gives you a theoretical pressure, not necessarily a suitable one. You can extrapolate what the pressure corresponds to at 320 F. Does that make it a good idea to run that temp on a road course?

[Ultramaroon]

Originally Posted by gtengr

Seriously? That gives you a theoretical pressure, not necessarily a suitable one. You can extrapolate what the pressure corresponds to at 320 F. Does that make it a good idea to run that temp on a road course?

Yes, seriously. I don't follow where you're going with this. I'm not talking about french fries.

[gtengr]

Originally Posted by ZDan

Of course the pressure drop is due to the oil cooler. Yes, 250F oil should be "better" than 272F oil, but again no one is able to quantify how *much* better.

250 F oil "should" be better than 272 F, but it has to be expressed in terms of shortened engine operating hours to 2 decimal places and have an OEM manufacturers name on the letterhead before you'll even consider it as anything beyond conjecture.

Originally Posted by ZDan

The appropriateness of running factory street pads at the track is a completely different, totally unrelated subject!

Right. The owner's manual, I'm sorry service manual since you think that actually matters, applies to extended operation on a road course, even though the car can't reasonably get to that point with a stock setup. I'm not sure how you think that makes sense, or how you can imply there is no difference in operating at temp X on public road vs. operating at temp X on a road course. Not to mention it's a different car with a different oiling system.

Originally Posted by ZDan

I disagree with his conclusion. No engine or oil expert would tell you that good synthetic oil "degrades" any significant amount from operating at 272°F.

You don't think he was just talking about the negative effect on oil pressure? Or do you really think he meant the oil itself is breaking down?

Originally Posted by ZDan

For my usage, I still do not see any meaningful benefit to doing so.

Cool, don't use one. It's your car you don't have to. Run a blower with E85 and crank it up to 400 rwhp. Some engines can take it. No one can say for sure at what torque rating the rods let go, so it doesn't matter what you do as long as your engine stays running. Amirite?

[gtengr]

Originally Posted by Ultramaroon

Yes, seriously. I don't follow where you're going with this. I'm not talking about french fries.

Well bless your heart.

[jflogerzi]

I think this topic has run it's course. Guys let it go. People will run their cars the way they choose.

Sent from my ONEPLUS A5010 using Tapatalk

[Bonburner]

Just track your car hard without an oil cooler and pay little to no mind on your oil temp/pressure and do an oil analysis. See if any excess wear. If no wear, then you're fine at your level of use/track.

On that note, I recall seeing someone track their car 14k miles on the same oil and I think no cooler and got an oil analysis that said no excess wear.