Track Oil Temps Way to Hot!
 

My FC has zero oil temp problems around the street, but after around 5 minutes of aggressive tracking my temps are around 250. Oil temps are taken in the pan.

My current oil system is just the stock cooler, old and never cleaned. I have never changed my oil thermostat either. I am running Castrol GTX 10-30.

My predicament is that I am still in an apartment and don't exactly have a great workshop in witch to fix the problem. So basically I am looking for a one and done situation. While price is a factor, I put far more importance on fixing it so I can have more time on the track during track days.

I see 4 possibilities:

1. Clean up my stock cooler, replace thermostat, run synthetic. Hope it solves the problem...

2. Run double stock oil coolers in parallel. (Where does the second one even go? In front of the first one?)

3. Run one big replacement in the stock location. Anyone have any suggestions as to which cooler to run?

4. Run double coolers in the brake duct area. Need suggestions again...


I figure I am not the only one to have come across this problem so someone else should have some insights for me.

Thanks much!

Twin coolers.
http://www.reganrotaryracing.com/fc/fcpart28.htm

HTH,
Crispy Regan

Ducting air through the coolers is extremely important..... I'm running a pair of stock oem R1 coolers win a 99 spec bumper. They're not very big, but properly ducted I've had zero oil cooling problems even on 100 degree days and running 15+ psi. (temps post cooler of 205 F)

^It's an FC Rich ;)

Crispy

The twin stock coolers work well. It's what you'll see on many top ITS class cars. The link posted by Crispy shows the basics but it's not an optimized setup.

You don't want the coolers stacked in front of each other as they have done. You want clean, cool air for each. You also won't want to stack the 2nd cooler on top of the OE cooler and block flow to the radiator. On a street car is going to be hard to stack the 2nd cooler under the OE. That's the way we position them on a tack car with the stock under tray removed and a new splitter/under tray and ducting added at a lower (probably too low for the street) height.

One solution I have seen that may work well for you on a dual purpose car was to lay the 2nd cooler flat, parallel to the ground, and duct the exhaust of the cooler out under the car. This requires a separate inlet duct sealed to the top side of the cooler, but it takes up less space.

Aside from all that, take the time to clean the coolers before you install them. Ultra sonic cleaning is fairly inexpensive and will help flush any sludge out of the interior. You'll also want to spend time trying to get all the road grime out of the exterior of the fins. We eliminate the thermostats in the coolers for a track car just to eliminate a potential failure point. I really don't see them as a harm to flow or cooling.

Another, maybe easier option, would be the large single cooler ISC Racing sells. It's basically the size of two stock coolers stacked on top of each other. Sells for $500, which seems to be a pretty decent price. ISC has a lot of racing experience with the RX-7 and generally sells parts that work well for a decent price; though I have no experience with this cooler. Again, I'd hate to stick this thing upright right in front of a radiator. I'd be more inclined to try to lay it flat on the floor, duct air to it, and exhaust it out the bottom. http://iscracing.net/whats_new.html

Personally, I don't really think 250 in the pan is a problem. In my race car, I drilled and tapped my oil filter housing and have my temp gauge there. When racing hard it reads around 230-235 for oil after it goes thru the cooler and before entering the engine. I suspect yours are about the same. I have a stock GSL-SE 13b and I have just the one stock cooler that has never been cleaned. My engine builder says my temps are not a problem. When you see your temp getting up around 290-300 in the pan then you have a problem. Just my opinion... you're results may vary.

Crispy/Ludwig, Thanks for the link and insight. I will look into these options. What material did you use for the additional ducting? I am running the Shook Motorsports radiator and its quite big, after that I don't have anything close to a problem with the water temps. Of course blocking some of its airflow might cause the temps to creep up but it may be an allowable hit.

Jimeby, I am using 250F in the pan as thats the information available on the Mazda Motorsports. They recommend 250F as the maximum limit and 195F - 235F as the normal range.

I have an FC but I see what your saying. My bumper is a bit messed up and there is a small gap between the bumper and the undertray. Its something I want to address with a new bumper but haven't gotten around to it. And don't really want to deal with the hassles of repainting or aftermarket fitment.

Aluminum sheet mostly. Fiberglass is pretty easy to work with too.

^ditto - Aluminum sheet.
I had a front splitter with a dedicated duct from the splitter under the undertray running to the rearmost oil cooler so each cooler got it's own airflow.
HTH,
Crispy

In case you hadn't seen it:
https://www.rx7club.com/west-sale-wanted-classifieds-195/twin-oil-cooler-sat-up-927871/

Looks like it's still FS.
Regards,
Crispy

Those coolers are in series not parallel. Not a big deal if you need two coolers. just needs to be plumbed properly

Duct it. Use thin aluminum sheet. The concern with it behind the rad is less about heat and more about limited airflow. I used a stocker for a number of years on the Turbo FC and the oil was good for the most part until I got the boost up and heat soaked the intercooler, driving up intake temps. Cleaning it out probably isn't a bad idea either.

-Trent