Oil cooler tech
#181
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Data point. Ran 4 hours this weekend at ambients of 98F (it's been a cool Summer here in N. TX). Running at SM record pace in a TTD car (going slower due to the heat), was seeing temperatures as follows:
1. Water temp stable at 205F (Ron Davis aluminum radiator);
2. Oil temp measured at the sandwich plate (20-30F hotter location than oil pan) stable at 245F.
1. Water temp stable at 205F (Ron Davis aluminum radiator);
2. Oil temp measured at the sandwich plate (20-30F hotter location than oil pan) stable at 245F.
In my turbo car - with an oil cooled turbo - with a cheapo Trucool 24-row heat exchanger for the oil, BUT with ideal airflow (NOT behind the radiator, sitting in front right corner of car behind bumper, dedicated ducting in and out independent of radiator/intercooler air path) in similar ambient temperatures (~100* F) I see 230* F oil temp.
Naturally aspirated (much less heat), with a better heat exchanger (your Canton is same style as mine but double the surface area), you're seeing more oil temp. That doesn't paint a very supportive picture for the oil cooler behind the radiator config.
It will certainly work - as in, it will cool the oil more than if you didn't have an oil cooler - but it's not ideal and I think that is what Andrew was getting at.
-Ryan
Last edited by ThePass; 07-13-2015 at 12:41 PM.
#186
Not to instigate here, but this requires an opposing data point to put it in perspective:
In my turbo car - with an oil cooled turbo - with a cheapo Trucool 24-row heat exchanger for the oil, BUT with ideal airflow (NOT behind the radiator, sitting in front right corner of car behind bumper, dedicated ducting in and out independent of radiator/intercooler air path) in similar ambient temperatures (~100* F) I see 230* F oil temp.
Naturally aspirated (much less heat), with a better heat exchanger (your Canton is same style as mine but double the surface area), you're seeing more oil temp. That doesn't paint a very supportive picture for the oil cooler behind the radiator config.
It will certainly work - as in, it will cool the oil more than if you didn't have an oil cooler - but it's not ideal and I think that is what Andrew was getting at.
-Ryan
In my turbo car - with an oil cooled turbo - with a cheapo Trucool 24-row heat exchanger for the oil, BUT with ideal airflow (NOT behind the radiator, sitting in front right corner of car behind bumper, dedicated ducting in and out independent of radiator/intercooler air path) in similar ambient temperatures (~100* F) I see 230* F oil temp.
Naturally aspirated (much less heat), with a better heat exchanger (your Canton is same style as mine but double the surface area), you're seeing more oil temp. That doesn't paint a very supportive picture for the oil cooler behind the radiator config.
It will certainly work - as in, it will cool the oil more than if you didn't have an oil cooler - but it's not ideal and I think that is what Andrew was getting at.
-Ryan
Nothing is ever ideal. Everything is a compromise. Your compromise was doing more work to the car + being more succeptible to debris + more oil pressure drop from longer hoses with more bends and a smaller oil cooler. Your car also has V-mounted radiator and intercooler. You did a heck of a lot more work to optimize the mounting locations to see the coolest possible air temps (highest possible DeltaT) than I did.
My compromise was to knowingly accept hotter air into the oil cooler -- which I remedied by increasing the oil cooler area (Q ~ DeltaT x Area). BTW, the Canton oil cooler IS a TruCool that's been marked up . . . grrrrrr.
Not sure if you are measuring at the pan or at the sandwich plate. If you are measuring at your oil pan, then our performances are pretty much the same. No matter what, we are both far away from the 300F we need to be worried about.
You are putting more heat into the oil than I am due to turbo cooling and increased bearing pressure, but not nearly as much as you think. You do have much greater water cooling needs though. Aside from going out the exhaust, almost all of the waste heat from combustion goes into the water jackets in the block and head. Oil temperature increase is mostly a product of bearing friction -- spin any Miata engine between 5000 and 7500RPM continually (even at part-throttle like we do when fuel tuning) and you'll see the oil temperature shoot up. Oil temperature is much more linked to RPM than power. This comes as a surprise to a lot of people out at the track -- they don't expect they need oil cooling unless they have made power mods, when in fact they need oil cooling as soon as they start continuously operating at RPMs that are much higher than normal street use.
Last edited by hornetball; 07-13-2015 at 03:28 PM.
#188
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Absolutely agree, everything has it's own set of compromises.
-Ryan
#190
Yes, that's what I meant by "Q ~ DeltaT x A." Q is heat transfer and A is basically how big the exchanger is. It's a simple and direct relationship, makes for easy calculations. In fact, I'm going to use Ryan's data compared to mine to calculate my approximate post-radiator air temperature since I've never measured it.
Last edited by hornetball; 07-13-2015 at 03:30 PM.
#191
Let's assume Ryan needs 20% more oil cooling due to cooling the turbo and increased bearing pressures (this is a complete swag, BTW, would be great if someone had real data). So, if I'm rejecting 1Q to the air, Ryan is rejecting 1.2Q.
Ryan runs a 24-row Tru-Cool (A). I run a 48-row Tru-Cool (2A). Ryan had 100F ambient and 230F oil going to the oil cooler. I have 245F oil going to the oil cooler. Filling these into the equations:
Ryan: 1.2Q ~ A x (230 - 100)
Hornet: 1Q ~ 2A x (245 - ?)
Work the simple algebra and we have:
2 x (245 - ?) = 1.2 x (230 - 100)
245 - ? = 1.2 x 130 / 2
? = 245 - 1.2 x 130 / 2
? = 167F post-radiator air temperature
If the assumption is Ryan only needs 10% more cooling, we get 173.5F. If he needs 30% more, 160.5F.
My radiator in this instance is rejecting the heat from a 140HP engine. Given similar air flow, more HP means the radiator will increase the air temperature more if the engine is able to run at the same temperature.
Last edited by hornetball; 07-13-2015 at 03:31 PM.
#194
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<p>Looks like that is the standard mocal thermostat plate. So you would need a set of these:</p><p>Sandwich and Take-Off Plates - Mocal Sandwich Plates</p><p>Part #: $15.99</p><p>And then new 10an hosing.</p>
#195
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Trackspeed Oil Cooler Kit
#196
You're better off removing the FM kit, selling it complete, and buying our DIY kit. The only thing from the FM kit you'll keep is the adapter plate itself.
Trackspeed Oil Cooler Kit
Trackspeed Oil Cooler Kit
#197
This link was posted in the cooling thread but belongs here:
Project S2000: Part 23. Testing Air Temps Through Coolers and Vents
Just keep in mind, mounting the oil cooler post radiator is a compromised location as you are sacrificing air flow and delta T vs. having a dedicated fresh-air feed. So size accordingly. Also, in the link, the author placed his oil cooler directly against the radiator -- but it is recommended practice to have at least 1/2" of air space between heat exchangers to allow the air to adjust to different fin configurations.
Another lesson learned for me, if you are using the less-expensive Tru-Cool type cooler, make sure to use vibration isolation (like this install with wellnuts -- https://www.miataturbo.net/build-thr...8/#post1242422). I experienced a split core due to vibration. I don't think this is an issue with the more robust Sertrab type coolers, although Andrew's kit includes rubber isolated brackets, so . . . . Good idea regardless?
Project S2000: Part 23. Testing Air Temps Through Coolers and Vents
Just keep in mind, mounting the oil cooler post radiator is a compromised location as you are sacrificing air flow and delta T vs. having a dedicated fresh-air feed. So size accordingly. Also, in the link, the author placed his oil cooler directly against the radiator -- but it is recommended practice to have at least 1/2" of air space between heat exchangers to allow the air to adjust to different fin configurations.
Another lesson learned for me, if you are using the less-expensive Tru-Cool type cooler, make sure to use vibration isolation (like this install with wellnuts -- https://www.miataturbo.net/build-thr...8/#post1242422). I experienced a split core due to vibration. I don't think this is an issue with the more robust Sertrab type coolers, although Andrew's kit includes rubber isolated brackets, so . . . . Good idea regardless?
#200
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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?
<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?