Oil Cooling

[bullethole]

So I'm not happy where the temps in my race car are.. they are regularly at 250. I've checked both thermostats and they are properly functioning (and installed correctly). I currently have the 82 SC Stock open cooler on the passenger side, and a carerra cooler on the drivers side, with fans connected on both of them. I've got good air flow into the coolers So I'm thinking of adding a 3rd under bumper cooler. I'm not sure what cooler to get, elephant has many sizes of setrab coolers. Any guidance as to which size one to put in would be greatly appreciated.

[HawgRyder]

Whenever you deal with air flow through the coolers....always imagine water being the fluid.
Any leaks for water (allowing some to bypass the rad) will reduce the cooling effect.
Sealing around the rad...and smooth flow through...are very important.
Next...look at the flow lineage (the angle of attack to the rad...and the size of the openings).
Imagine the amount of air going through...and allow for slight expansion of that air flow (hot air expands)...so...the tube out must be bigger than the tube in.
When building formula Fords... we used a wind machine and little pieces of video tape (taped to the bodywork) to determine the optimum placing of the coolers.
You will be surprised at the results of changing the big headed bolts for smaller smooth ones!!
Also...don't expect the air to exit just because it enters....you must have a clear channel to get rid of the hot air (no obstructions...and no 90 deg turns) keep it smooth.
Good luck
Bob

[jrolstin]

+1 to this... I wanted to do something similar in Formula SAE but we only had the resources to do virtual testing... (Solidworks Floworks CFD) - this isnt practical unless you know someone who has an accurate CAD file of your car... lol

Originally Posted by HawgRyder

Whenever you deal with air flow through the coolers....always imagine water being the fluid.
Any leaks for water (allowing some to bypass the rad) will reduce the cooling effect.
Sealing around the rad...and smooth flow through...are very important.
Next...look at the flow lineage (the angle of attack to the rad...and the size of the openings).
Imagine the amount of air going through...and allow for slight expansion of that air flow (hot air expands)...so...the tube out must be bigger than the tube in.
When building formula Fords... we used a wind machine and little pieces of video tape (taped to the bodywork) to determine the optimum placing of the coolers.
You will be surprised at the results of changing the big headed bolts for smaller smooth ones!!
Also...don't expect the air to exit just because it enters....you must have a clear channel to get rid of the hot air (no obstructions...and no 90 deg turns) keep it smooth.
Good luck
Bob

[Deadeye]

My '87 track only 911 has the two carrera coolers (one on each side) and does not get above 220 degrees. I do not have fans or headlights to restrict air flow and baffles in front of the coolers to force the incoming air through the coolers. You should have sufficient cooling capacity just need to get more air through them.

[Joe Bob]

Cooling depends on capacity and airflow. Thermostats only regulate when the oil goes to the cooers after the oil temps reach 180F or so.

Fans actually restrict flow at speed and are best at bumper to bumper speeds.

To lower temps, increase flow and/or capicity.

[Grady Clay]

Exactly where and how are you measuring the oil temperature?
How have you calibrated your measuring instruments to ensure accuracy?
Can you record the temperatures during a track session?
Where are your events? Big difference between Phoenix in July and Seattle in October.

Please post images of your thermostat and oil plumbing.
Are the coolers in series or paralell?
What is your engine? There is a big heat dissipation difference between a turbocharged 3.6 and a ‘spec 2.0T’.


When (if?) considering a center-front cooler, get a significantly ‘larger-than-necessary’ one.
It is easy to block-off some of the airflow. It is not easy to rush out and get a larger one if needed.
The only ‘downside’ is increase cost. Additional weight is desirable low and in front and can be offset with rear weight removal.
Do not add a ‘minimal’ center cooler and retain the fender coolers. Poor design, excess weight, unnecessary plumbing and far more susceptible to weekend-ending track damage.

Have you installed a safety fuel cell yet?
If not, be sure to configure the fuel cell mounting with proper airflow for a center-mount oil cooler and air ducting for the brakes.


Best,
Grady

[bullethole]

engine is a stock 3 liter. thermostats are standard plumbing.. the coolers are in series.. into the stock open cooler, out to the 3.2 cooler and back. I'm measuring temp at the guage in the car (I have the guage with the temp on it and the correct sensor (been in the car for 5 years now) and with an IR thermometer at the sensor on the engine block. I have a FuelSafe fuel cell in the car already (have had this for about 4 years now), its the one designed to drop right into the tank location and uses the stock filler neck. Its strange that this only started occuring this year, previously 220 was the max it got (even when I lived in TX). Now I did add EFI to the car, but I have the tune on the rich side, and when i looked at the loggging i took from the MS back in August the AFR's were all about 13:1 so it is rich (realizing that a lean mixture will be hotter)

Brakes are ducted from the front valence.

I was thinking about directing the air flow better, but as I said, I've not had problems before this year.

[bullethole]

Note, no difference with or without the fans. (other than when parked if I leave the fans on it cools down nicely).

[bullethole]

BTW weight is not an issue.. I have had to add weight to be in GT5S anyhow (can't afford the motor that 4S would take to be even close to potentialy competitive (not to mention that I suck).