Factory oil cooler effectiveness
 

Alright, so I've been reading a ton of threads back and forth. Some say it's all you need, even with a turbo! On track days, their oil temps never pass 250F, that for a 200F water temp it's "practically a refrigerator".

Other people say you absolutely need an oil cooler with ducting in order to get proper oil flow.

Another problem, I wanted to see about deleting the factory oil cooler on my turbo NB2 and replacing it with a 1.6 oil filter joint and a sandwich plate going out to a regular oil cooler, but I can't find an oil sandwich plate that fits onto the block. The ones I have found are too big and the o-rings don't properly seal against the block, they're designed for a 3" oil filter where our cars use a 2.5" oil filter.

So what's the deal? Is the factory oil cooler all I need? And is there a sandwich plate that'll work? Let me know!

I’m running the FM/Sebtrab cooler and needed to use a spacer. I shortened the threaded tube and made spacer a little thinner then the original heat exchanger. I needed the spacer so oil lines would clear the block. FM does sell an eliminator spacer kit. I do not like the oe heat exchanger because it is restrictive and the coolant lines are a failure point.

Can you link me what this spacer kit is? I haven't seen it on their website.

Just want to add not to use a sandwhich plate for a turbo feed or oil temp/pressure sensing. Not accurate for temp and pressure and non-filtered oil for the turbo is not good.

I already have the turbo tapped off the oil pressure switch/VVT pipe with a tee and that's good to go. Putting the temp sensor in the oil pan and pressure sensor is also teed-in with the oil pressure switch.

I wonder, is the spacer actually necessary? It looks like it might not be necessary. I have a 1.6 oil filter joint that will allow me to put the filter directly on the block without the oil cooler, and I can put the oil filter sandwich plate on that.

With -8 and 90deg ends out of the adapter maybe with -10 hose probably not. I ran -8 but did not want to make new lines with 90 fittings and also did not want 90’s right out of the adapter. Also you lose most of the positioning options. The threaded tubes can be cut and deburred to any length

What if you ran one of these and put straight fittings right on the hose?

https://finishlinefactory.com/produc...ter-90-degree/

It IS kind of a sharp turn compared to a -10 AN 90, but it shouldn't be TOO bad.

IMO too many fittings.

Eh, once those are on they pretty much stay on, especially if you use some PTFE threadlocker or blue loctite.

I know they're not needed to seal, but they do help with vibration and stuff and keeping them from loosening up.

The factory oil heat exchanger is more effective as a warmer than a cooler.
after cold starts the coolant warms up much quicker than the engine oil so helps to pass heat into the oil.

its usefulness as a cooler is neglible.

Those that say they don’t need an oil cooler on the track must be changing gears at 4000rpm, turbo or not.
it’s rpm that heats the oil much more than the power being output. Ie a 90hp Miata revving to 7500rpm every change will heat the oil way more than a 200hp Miata changing at 5000rpm.

as a real world example, sans oil cooler my 130whp track nb barely manages a full lap of a fast 2min circuit without nudging the oil temp into the red zone on my innovate oil temp gauge. This is with Alloy radiator, coolant reroute, good quality oil.
With an oil cooler I can run 30 min sessions in 100deg days without Issue.

Rascal is right about RPMs generating heat.

It is possible to run at over 300whp on track in a hot climate here in Florida. I use the factory oil cooler/warmer and a large cooler in the nose of the car. The cooler is ducted. The lines to and from it are oversized to reduce losses due to drag. I'm using a sandwich adapter similar to this https://www.ebay.com/itm/NEW-Aluminu...UAAOSwVtZaNP5T. The factory cooler/warmer gives necessary space off the block for hoses and fittings of adequate size, in my opinion.

Thicker oil has greater viscosity and shear strength but also generates more heat at higher RPM. So that's a balancing act.

It's getting harder to keep the driver cool than the engine and brakes, finally!

Facts

I know of at least one person who lost an engine on track due to leak at the factory oil cooler/pre-heater or the coolant lines running to the cooler/pre-heater. For my own car I left the cooler/pre-heater in place and deleted the lines. It's just sitting there as a spacer for other things.

Just as a note for anyone following along with this thread, nobody here likes the cooler kits with the -8 lines. We've got multiple folks on the forum who have documented a reduction of oil pressure with the -8 and got it back re-plumping to -10. I myself had one of the Thompson filter relocation kits that is the darling of m.net and I lost about ~10psi on the top end at the track, as measured from the oil pressure port on the side of the block. Remember that's just a remote oil filter block, add an oil cooler to that circuit and that's just going to get worse. The -8 stuff is probably fine for street driven folks but if you are doing any serious track time, its -10 or GTFO.

The FM Oil Cooler Spacer looks like it solves the problem of getting something like the Mocal oil thermostat up off the block so you can fit -10 lines in there, but $71 + $13.50 for an o-ring (not included, not linked, not described, thanks FM!) seems a little ludicrous (but about on par for FM.) Mocal has their own series of spacer adapters for this purpose and I believe the one that should work for the Miata is Mocal PN SPA1 (I'd recommend verifying that before purchase.) You can find these for around ~$50 online. And yes, they include an o-ring :giggle:

I’m not sold on the -10 unless the runs are long, maybe 4ft each. The factory heat exchanger is very restrictive. More restrictive then 3ft of a -8 line. The net result is the system oil pressure which could be logged if someone had pressure sensor in the main oil gallery. From my gauge with a boundary stage 1 it seemed to maintain over 65psi with the FM kit and oe exchanger. Now that I have eliminated the oe exchanger and stepped up to a stage 2 I highly doubt a small pressure drop from the -8 line will be a factor. One thing to consider is the volume of the system and how it is mounted. I have seen systems cause oiling problems because they trap air. That’s why I personally do not like to mount external oiling components higher then the pan rail.

Also if I did it again I would piece together my own system and forego the thermostat in the adapter. I have checked my system and the oil temp rises fast. Although I do live in an area that rarely sees temps below 40 and most of the time it’s over 70f.

Boundary recommends using -10 hoses

We run the factory cooler on our Champ Car and it keeps the temps down to 240-260 depending out outside air temp and water temp. We don't run an aftermarket oil cooler because it cost "points" (dumb rule, but I digress). Its not as efficient as an aftermarket cooler, but it works both ways. We've never tested without the cooler to see what its full effect is, but we're pretty sure they'd be much higher.

The reason I eliminated the factory heat exchanger is because the coolant lines are a liability and the cooler itself is very restrictive. On this build I tapped the pan for a temp sensor and will report back with the oil temps.

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I would not advise arranging your supplemental oil cooler with lines entering from below so that it allows draining of all of the oil when you change it. If the capacity of your cooler and lines is one quart and you start with 4 quarts in your pan at startup then your expensive, high RPM track engine will be operating with only three quarts in the pan during normal operation. The volume will certainly be less than that in sustained high RPM operation during high G-force events when it relies on gravity and limited pathways to get the oil from the head back to the pan.

I prefer exchanging 4 of 5 quarts in my system when changing oil over running a quart, or however much it is, low.