Which is better for cooling engine oil, a plate cooler or tube cooler? Again, we're talking about a BB in the 500 - 600 hp neighborhood.

 

When ever you are talking about cooling it is all about surface area! The more surface area the better... more area = more heat transfer and more cooling.
I would look at the over all surface area of the cooler, I don't think tube or plate makes all that much difference. If the cooler dimensions are the same and the number of passes are equal then the plate is probably better because an oval gives more surface area than a perfect circle... of course that is assuming alot about the dimensions of the tube and plate...ie the radius of the tube being equal to that of the height of the oval....ie: squish a larger dia tube so that it is the same height as a slightly smaller tube and you back my theory. Of course it could be exactly the opposite and a smaller tube has been formed (squished) so that it's longer dimension is equal to that of a larger dia circular tube and thus the tube now has more surface area...
Anyway, like I said it all comes down to surface area, go with which ever has the most

 

 

Unless it's a poor or "cheap" design, a stacked plate and fin cooler will have much greater heat tranfer capacity for a given frontal area than a simple (and cheap) tube and fin arrangement.

Just look at the coolers on race cars and aircraft. Ever seen a tube and fin type? In particular, oil coolers must have a lot of surface area for the oil passages because oil tends toward laminar flow because of its relatively high visconsity, so a 3/8" tube through fins won't cool the oil very efficiently because laminar flow prevents the oil on the inside from contacting the tube walls and oil itself is a poor heat conductor. A stacked plate design has much more surface area for the liquid passages, so it will tranfer more heat.

Go for a high quality Aeroquip type stacked plate design and don't buy on price alone. Also try to get some heat transfer data. Manufacturers publish charts that show actual heat transfer based on oil and air flow rates and oil and air temperatures. Since you have four independent variable the charts can get rather messy. You can assume your oil flow rate is about 3-4 gallons/minute at 250 degrees inlet temperature. Use vehicle speed to estimate air flow velocity and assume worse case ambient air temperature. From the BTU heat transfer, you can compute the reduction in oil temperature.

Duke

 

Thanks Duke. I was leaning toward the plate type cooler but as I am unfamiliar with the quality of cooling performance of either type, I thought I'd ask. Thanks fellas.