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-   -   Oil cooler tech (https://www.miataturbo.net/race-prep-75/oil-cooler-tech-80234/)

sixshooter 09-10-2015 09:08 PM

Oil cooler tech
 
Is that measured on the pre or post cooler part of the sandwich?

hornetball 09-10-2015 09:18 PM

It would have to be pre, because the post cooler route goes through the filter and then into the block through the central pipe.

250 pre-cooler is nothing to worry about.

Joe Perez 09-10-2015 09:28 PM

2 Attachment(s)

Originally Posted by hornetball (Post 1265065)
It would have to be pre, because the post cooler route goes through the filter and then into the block through the central pipe.

https://www.miataturbo.net/attachmen...ine=1441934897

Depending on the design of the plate, and its orientation, it's possible to take a measurement either pre or post-cooler.

This one, for instance, has ports on both sides:

https://www.miataturbo.net/attachmen...ine=1441934897

hornetball 09-10-2015 09:29 PM

Brainfart.

sixshooter 09-10-2015 09:32 PM

Oil cooler tech
 
Yep, that's like mine and why I asked.

aidandj 09-10-2015 09:37 PM

Mine is just a sandwich plate. Just for gauges/spacing.<br />
<br /><br />What temp should I be worried?
<br />Rotella T6

Arca_ex 09-11-2015 12:52 AM


Originally Posted by aidandj (Post 1265079)
Mine is just a sandwich plate. Just for gauges/spacing.<br />
<br /><br />What temp should I be worried?
<br />Rotella T6

I'd start thinking of pulling off or doing cool down laps at like 240... running a boosted Miata with no oil cooler is kind of asking for trouble.

aidandj 09-11-2015 12:54 AM


Originally Posted by Arca_ex (Post 1265194)
I'd start thinking of pulling off or doing cool down laps at like 240... running a boosted Miata with no oil cooler is kind of asking for trouble.

<br />
<br /><br />
<br />I have a 25 row setrab.
<br />I was refering to where the temp was taken.

Arca_ex 09-11-2015 01:30 AM

Oh. I'm assuming that temp is before the oil cooler so then that means I have no clue for your scenario.

patsmx5 09-11-2015 03:27 AM


Originally Posted by aidandj (Post 1265006)
Oil temp question.<br />
<br /><br />At the track today, I'm seeing 250 indicated in my sandwich plate. I know 250 is getting hot when its in the pan but my sensor is in the plate. What temp should I start doing cool down laps?

Not miata obviously, but a lot of high performance german cars go into limp mode in the 270's *F (dropped rev limit to about 1/2 of normal, HP down to ~25% of normal_ and stays there until oil is in the 250ish range. My C63 shuts the party down at 275, drops revs to 3,500 max, upshifts to highest gear, will remove your control to manually downshift it, power drops to about 100hp.

Given the fact that many of them shut it down around 270, I would think beating on it all the time near say 250 is probably a bad idea. If you did it, I'd swap the oil afterwards.

aidandj 09-11-2015 07:47 AM

Isn't oil at the filter 10-20* hotter than the oan?

sixshooter 09-11-2015 08:06 AM

The question remains, is this oil temp prior to the oil cooler? If yes, and the oil is then being dropped to 220-230 in the cooler then it is in the acceptable operating range for T6 synthetic on the track. I would back off at about 260-265F. Racers often run higher in the heat of battle if they must, but they rebuild engines more often.

It typically gets slightly more difficult to get hotter as the temp increases (unless you have real shortcomings in the cooling system) because as the difference between ambient and the oil temp continues to grow the cooler actually cools a little better, all things considered. Don't cook your engine.

aidandj 09-11-2015 10:16 AM

Is pre cooler.
<br />I will be changing the oil and sending a bit to Blackstone.

patsmx5 09-11-2015 02:00 PM


Originally Posted by aidandj (Post 1265230)
Isn't oil at the filter 10-20* hotter than the oan?

Dunno. The main source of heat into the oil is from being sheared in the bearings, then it gravity drains into the pan. If you could measure the oil temperature going into the oil pump, whatever temp the oil is once it's in the pickup tube, it's not going to get any cooler unless there's an oil cooler it's pumped through. Oil pump will heat it some, resistance flowing through oil passages, filter restriction, heat from surround engine components/block, etc.

I read online that the "normal" spot to measure oil temps is in the oil pan sump, so that's where I put my sensor. I wonder where the germans put theirs? I'll look for it on my mercedes next time I change the oil.

sixshooter 09-11-2015 02:05 PM

I would think the hottest oil would be coming from the bottom sides of the pistons and the oil control rings since that's where the fire is.

GraemeD 09-11-2015 07:29 PM


Originally Posted by sixshooter (Post 1265401)
I would think the hottest oil would be coming from the bottom sides of the pistons and the oil control rings since that's where the fire is.

iMO you are correct, but then you take that hot oil and compress it, compressing anything makes it hotter.

aidandj 09-11-2015 07:35 PM

<p>Wouldn't the best place for a temp sensor to be post cooler, so you know the actual temp of the oil going into your bearings?</p><p>Then you can look at the properties of your oil and see when you should shut down.</p><p>I also have the issue of not trusting my oil temp gauge, because my coolant gauge wasn't exact out of the box.</p><p>Oh well. Good thing its a 1.6</p>

patsmx5 09-11-2015 07:42 PM


Originally Posted by GraemeD (Post 1265530)
iMO you are correct, but then you take that hot oil and compress it, compressing anything makes it hotter.

Hottest oil and "most heat added" are not the same. I agree hottest oil is probably the oil stuck to the cylinder walls and pistons.


Originally Posted by aidandj (Post 1265533)
<p>Wouldn't the best place for a temp sensor to be post cooler, so you know the actual temp of the oil going into your bearings?</p><p>Then you can look at the properties of your oil and see when you should shut down.</p><p>I also have the issue of not trusting my oil temp gauge, because my coolant gauge wasn't exact out of the box.</p><p>Oh well. Good thing its a 1.6</p>

Best depends on what you want to know. If you want to know how well your cooler works, then a sensor after the cooler is probably best. If you want to know how hot the oil is right after it just cooled the bearings, then short of having a thermocouple installed on the crankshaft, the sump is the next best place to measure it.

aidandj 09-11-2015 07:43 PM

<p>But why do I care how hot the oil that just cooled my bearings is? Don't I want to know how hot the oil that is about to cool my bearings is?</p>

codrus 09-11-2015 07:50 PM


Originally Posted by GraemeD (Post 1265530)
iMO you are correct, but then you take that hot oil and compress it, compressing anything makes it hotter.

Oil is a liquid, not a gas, you're not compressing it.

Oil will get a bit warmer when pumped due to friction, but that's pretty low (low friction is, after all, the main point to having oil).

I suspect it doesn't really matter all that much where you measure it. Personally I change the oil before every track day, because the cost just isn't significant compared to everything else.

--Ian


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