Oil cooler thread.
 

So apparently 260°F oil temps are too high. :td: My car needs an oil cooler before I hit the track again. I've been poking around, and I know Mocal makes some sick shit, but Summit has some stuff that's about half the price, and I like half the price.

So what's the word? What's good, what's efficient, what sucks? Should I go plate or tube and fin? Plate seems to be a little more aesthetically pleasing, and it's pricier, so I assume it's a little more efficient and a little better. I was thinking about something like this:

http://store.summitracing.com/partde...5&autoview=sku

As far as a sandwich adapter on the oil filter, I'm not sure where to go. Again, I've heard good things from Mocal, but if I can spend $50 instead of $90 I'll be a happy guy. A thermostat built into the sandwich adaptor is a must; I don't want to have to dick around with a separate one.

I was going to have Royal Brass do the lines, -10AN. I've heard of pressure drop issues with -8AN lines, and most guys seem to be using -10.

hey savington, whered you find a thermostat built into the sandwich adapter ? i was curious about a similar setup, but didn't wanna run extra an lines for a seprate thermostat.

nvrmd lol, i found it on the summit site.

but they don't have one for the miata specifically....will this one work ?

http://store.summitracing.com/egnsea...115+4294838764

Mocal sells an adaptor with either a 180F or 200F thermostat built in. The size is M20x1.5. It's cheaper than that one, too, like $90.

I know I'll be using a mocal with thermostat and a used RX7 oil cooler. Its gigantic and should cover any oil cooling issues for me.

My mounting is unique though... it'll be angled and under my Vmount radiator.

Speaking from personal experience, it doesn't take much oil cooler to get the job done. I am running the smallest bar & plate cooler that Earl's sells (3" x 4" core) and it is more than enough. With the Mocal thermostat-sandwich plate, my oil temp barely gets above 150, let alone the 190 that the thermostat is allegedly rated for.

Same cooler (different name) less money.
http://www.racerpartswholesale.com/cooler1.htm

btw- 260f oil temp is far from dangerous on synthetic. Definitely heed joe's warning.

and the Mocal sandwich plate

http://www.racerpartswholesale.com/mocal.htm

For those who have not ordered for RPW before, they rock. Great service, fast shipping.

The lines are the toughest part, anyone got a good link to some lines?

Honestly... for lines... try to find a hydraulic fittings place. Measure your lines using some clothing hanger (simulate stiff SS line) and mock up your line routes... then measure it. Then have them make the lines for you.

The lines aren't so hard. Just buy the hose ends and some -10AN hose by the foot from RPW or Pegasus and make 'em yourself. You don't need the fancy -AN wrenches, just a bench vise and a couple of SAE-sized open end wrenches. In a pinch, even vise-grips would probably work. Cutting the line cleanly takes a little practice. If you have access to a bandsaw or chop-saw, this will make life easier. Otherwise it's painter's tape and a hacksaw.

Or, as Splittime said, find a local shop. A word of advise- instead of coat hangers, use cut up garden hose. It is damn near identical in size and somewhat similar in bending characteristic to braided SS hose. You can purchase it cheaply by the foot from home improvement stores.

As an aside- anybody have a recommendation on an oil thermostat that actually works?

This thread is great.I will be doing my oil cooler soon and this info helps alot.

What are the drawbacks of -8 lines versus -10,I'm undecided on which size to go.

The external tstats are supposed to work great. They're built like a coolant thermostat (not the funky coil flap in the plate). My real concern regarding the sandwich plates with the tstat is flow. I can't imagine it doesn't impede flow. Would make more sense to have the tstat externally, but that's more connections, and hunting for a mounting point.

IMO the bigger hose is better for higher loads like a turbo engine endures. Just need to avoid using any of the tight solid bends to make it all worthwhile.

I will probably be installing an external thermostat to try and address the previously mentioned temperature problem, but...

When I first did my oil cooler install, I used -8AN hardware and had a pair of machined 90 degree elbows in the system. Some combination of the two caused a signifigant drop in oil pressure on the order of perhaps 10-15 PSI hot. I re-did everything with -10 hardware, removed the machined 90s, and also "ported" the sandwich plate, and pressure returned to stock levels. I thus conclude that the thermostat sandwich plate does not, by itself, cause a signifigant restriction to oil flow.

That's right- I forgot about the "rework".
Is your issue that it takes too long for the oil to warm up?

Mine seems to work fine- cold lines and right about the time the gauge passes 180f the lines get hot. My problem is that I still have elevated oil temps (IMO). After successive boosted runs I see 275f oil temps, which I'd expect w/o a cooler. Normal driving shows 240f.

Does an oil-only turbo elevate oil temps this much? It doesn't seem possible given the small amount of oil traveling through the turbo. What about higher oil pressures- do the reduce the effectiveness of the oil cooler? Or restrictions in the oil cooler circuit?

My bottle neck is the sandwich plate since it has 3/8" npt bungs that step up to the -10 lines immediately. Plan is to get an adapter that has 1/2" bungs... but if you're having issues with the tstat... - rob

Joe, is that during hard track use? I've seen as high as 240 on the highway in dirty air (behind trucks and such) in 100+ degree heat, and 260-270 on the track. I wouldn't have a problem using a big cooler and having the oil hover right at the thermostat opening point. I've seen other guys use decent sized coolers and only see a 15-20 degree drop; I need a 50-70 degree drop.

Anyone have some decent reading for me regarding the useable operating temps of synthetic oil? I've always heard that 260+ is too high.

I used to race with a guy that ran two v8 firebirds for 3 hour races on mobil1 at 300f oil temps. In the three years we ran the series with them they NEVER had an engine failure. They did bring 6 rears to each race though. :gay:

To answer a couple of posts at once-

I installed the oil cooler in preperation for the turbocharging as I feared that the Mitsu turbo would add signifigant heat load to the oil system, and I was also uncomfortable subjecting a journal-bearing turbo to extremely low oil pressures (as low as 10 PSI at idle when very hot, if the factory gauge is to be believed). To recap, I'm using the sandwich plate that FM sells (a Mocal part) and a tiny little Earl's cooler.

During my daily commute (about 5 miles) the oil has just about gotten up to 130-140 when I reach my destination. This is too damn cold.

On the highway, with clean air and plenty of it, the oil temperature tends to stabilize around 160-170. Also too damn cold.

Autocross runs are too short to see any real change, and I've never been to a proper trackday, but if I take the vehicle on a nice hard run, such as up the side of Palomar mountain or through the canyons under boost, the oil will peak out at maybe 200-220 degrees.

I have definately err'd on the side of far too much cooling- I suspect that the thermostat is not doing its job.

All oil temp measurements taken on an autometer short-sweep electrical gauge, sender installed in drain plug.

Joe, have you ever noticed the guys who drive semis and dumptrucks tape up part of their grills in the winter to reduce airflow? How about trying the same thing: run a few strips of duct tape across the face of your oil cooler core, limiting it's through air flow. You could then rip off the tape when/if you're going to track the car or otherwise drive the snot out of it.

I don't have an oil temp gauge in my car, but from watching the pressure gauge and interpolting temp from pressure, I would say that my oil is at temp after about 2 miles of driving. That is when the pressure gauge reaches its lowest idle and cruise positions no matter how much longer I drive.

Ben

I won't see my electric gauge come off the 140° stop for another 3-5 minutes beyond the idle settling in at its normal range of 25-27psi.

hmm i so want a oil cooler i was gonna run mine on my drain line, seemed like a good idea no?