I would imagine your entry end tank filling with oil far before any oil would reach the exit end tank through a row given the resistance to flow.

This was my conclusion as well when investigating whether the oil cooler configuration I wanted to do would yield any issues. Lots of conjecture on the internet getting repeated by those who read the same thing from someone else on the internet, while the manufacturers maintain that there should be no problem with an upside-down orientation.

FWIW, mine is mounted this way as well and I too have hit it with an IR probe after full warmup and seen even temperatures on all four corners (+/- 2-3* F). My car sits sometimes for a couple weeks at a time.

In fact, there was a period of time after setting up the new config that I thought that the mounting orientation was causing high oil temp spikes - I later discovered that the culprit was a failing oil temp gauge, and the temps had been perfect all along, but during that time I tried at least four different mounting orientations, (right side up, upside-down, side-feed, side-feed with cooler @ 45* slant) and saw the same oil temp behavior each time.

-Ryan

One could also argue that the orientation of the oil filter would matter (the trapped air would mean less filtering area)...

Remember the pressure, even if no air would escape at all, you would still only have 20% of the volume as air (e.g. 70psi cold).
Add some flow of a viscous liquid and it will move the air out quite rapidly.

Ahhhh . . . the origins of our ITT High Quality Gauges thread!

Just got done reading the thread so far, and placement of an oil cooler is also a concern to me. Mostly from a perspective of safety from outside damage. In front of a wheel could mean a fender bender could more easily disable the engine. On the steering rack means a mild track off could disable/destroy the engine. Stacked with my intercooler, AC Condenser, and Radiator seems very subpar. Perhaps not if I deleted my AC, but until I can move to a different house without parking limitations to get a different DD, I am keeping the AC.

I've got the full suite of water cooling solutions, but need oil cooling now. (gt2560, 8-10psi, tracked in 60-90F ambient temps, still DDed)

There are two options that I've reasoned out based on all my reading, and I'm interested if anyone can shoot holes in the theories and tell me why either, or both, won't work, or is dangerous.

A) Tap the oil pan twice, one feed one return, and install an automatic transmission oil cooler pump, feeding oil to a 20-30" long heat-sink style exchanger that would be mounted in the transmission tunnel on the passenger side of the PPF (bolted to the PPF of tunnel wall). Would be in air flow from the engine bay exit and/or underbody airflow. In theory, I could mount more than one to increase a dual pass to a quad pass. I'd be just reducing pan temps, but that should still be effective in overall cooling?

Advantages:
- It will be safe from outside damage
- Doesn't rely on engine oil pressure, so drainback and fill aren't a problem.
- Doesn't impact engine oil pressure regardless of what lines are used
- Is at the level of the oil pan, so draining and filling have no extra complexity or considerations other than volume
- no thermostat needed, the pump power can simply be run through a 180F oil temp switch. Doesn't run if lower, runs if higher. If fluttering would be a problem, I'm sure there is an electrical solution that would solve it.
- Can add an independant filter

Disadvantages:
- Lower heat shedding capability vs a force-air-fed traditional heat exchanger
- Higher weight added from pump, though at least it would be really low and centered
- Tapping our oil pan is already difficult enough



B) Horizontally mounted behind the front right headlight, with a corresponding ducted vent in the hood immediately above it to use the low pressure zone for airflow management.

Advantages:
- Ease of access but still safe from damage, except perhaps tools dropped on it
- Can be tilted in any orientation to ensure that the exit is at the highest point.
- Doesn't impact the airflow through the intercooler/radiator set.
- IF I could duct air from a fog light up to it, and straight out the hood without letting it get to the rest of the engine bay, it should be extremely efficient

Disadvantages:
- If I can't give it it's own ducted air supply, then hot engine bay air would be the only air it sees, but this wouldn't be any worse than post-radiator mount options.
- Mounted high, so drain back and fill concerns would exist


Anyone see any big problems with either of these?

I've been discussing that location, passenger side of the transmission for a little while. My orientation consideration was horizontally with the air exiting from the bottom side. The air inlet would be from a shroud on the topside fed by a 3" air duct from the front bumper mouth or the front bumper cover. Something like this could be easily ducted to the cooler because both are rectangular:
https://www.miataturbo.net/attachmen...ine=1409098272

Where'd you get that? Dimensions?

E.g. http://www.summitracing.com/int/parts/hre-re206 , but that might be too small.
https://www.pegasusautoracing.com/gr...oupID=DUCTBUMP
or Setrab Oil Coolers - Oil Cooler Duct and Bracket
https://www.miataturbo.net/attachmen...ine=1409325442

How about a simply slanted installation in free air next to the tranny?
Air isn't that much hotter there than in the front of the car (but I'm still used to 30F lower ambient than some of you).

Are there any really long oil coolers out there (20" long and low&thick), suited for a long and narrow space?

Yeah, this is one of the options I've found: http://www.summitracing.com/parts/der-13262/overview/ (various sizes from 12" to 26" long, single pass and dual pass)
https://www.miataturbo.net/attachmen...ine=1409326323

Zero idea about the quality, but something like that would work for mounting in the transmission tunnel. Such a design is also better suited to general airflow along the body, rather than through a core. As I noted above though, I entirely expect that the efficiency should be noticeably lower than a more traditional through-core exchanger. Less fins and all that. Although, you could install more than one, depending on placement.

This is the only other kind of option that would work, and I've seen them used for power steering fluid coolers. Usually shorter, but much higher fin density. It would be harder to get airflow through the fins though, so I don't know how the efficiency would actually end up comparing to. These kind exist with and without the external framing, though the ones without are the shorter ones.
http://www.summitracing.com/parts/der-13225/overview/
https://www.miataturbo.net/attachmen...ine=1409326323

Consider that these have a lot less internal surface contact area between oil and metal, than the usual oil coolers. Thus it probably has a lot less capacity.
These designs are typically used for power steering fluid, which has a lot less heat load than engine oil.

Yup, understood. I doubt anything like that could ever compare to the heat extraction capability of a through-core exchanger. Mounting location is what makes them something I consider. Any extra heat extraction is better than no cooler at all (which is where I'm at currently), but the main reason I haven't tried this is because I figure it is probably still less heat extration than I would really need.

I'd guess at maybe a 20F drop in oil temps with something like that. But just a guess. That's where "I'm a noob and you guys are the experts" comes in to play :)

You could mount that one Niklas posted anywhere you wanted if you could get the hose ducted to it. I'm still thinking the shape of the RX7 unit would be better because it is long and slender.

https://www.miataturbo.net/attachmen...ine=1409327492

Agreed, though it's hard to mount that anywhere to get serious airflow without just stacking heat exchangers again. Mounting the RX-7 cooler to the front crash bar as just a big heat sink (that some people do and see effective temp reductions from) is what got me pondering other heat sink-style options.

Then clamp it to the PPF as a heat sink, a lot hotter than the crash bar, but probably a higher air flow around it.

One though; Rear of front fender and use the mandatory air outlet mod as airflow (splash guard necessary)?

Nah, the guard you'd need to keep it from being destroyed in one day by road debris would also block nearly all the airflow to it.

In your case, of course it would be killed. But the pressure in the wheel well is not small, and with a uncut fender, you might get some flow by ducting a pressure relief through a cooler, even with a protective guard.
This would of course reduce the aero advantage of cutting the fender.

But no room for anything than a very narrow cooler where you normally install the frog arms.

I'm not digging any of these from a KISS standpoint. Also, Miata tranny tunnels are friggin' hot! Sixshooter has been making this point gently as he talks about ducting, but I'm telling you that ducting cool air to that location is definitely needed to see any worthwhile cooling. Don't fear heat exchanger stacking if it gives a better, simpler install.

So instead of an oil cooler for your diff and trans(I will eventually, but funds are not permitting presently), how positive would sectioning off the diff/tranni from the exhaust and using a a gold reflective film on the outer layer?

I realize that much of the heat is from the abuse of the diff/transmission ITSELF and not the exhaust, and that heat soak will eventually catch up with you, but it's just a thought on possibly offsetting more external heat from making the necessity of an oil cooler more apparent.

Diff and tranny needs more cooling fins, not reduced cooling by applying a reflective layer.
Wrapping the whole exhaust will help some.

Sorry, maybe I made myself unclear. I am saying create a panel to divide between the exhaust and the trans/diff(more difficult for the diff).

Wrapping the trans/diff in reflective tape wouldn't be as effective.

Just throwing ideas out there as I'm occasionally thinking about solutions I'd possibly apply.