I'm posting this as a discussion on another BBS has centered around cooling. Specifically, what the best setup is for 81-85 RX-7s given the two setups, 1. the oil/water heat exchanger and 2. seperate oil and water coolers.

My question is that I have always heard it is better to use the radiator from the oil/water heat exchanger setup and the oil cooler from the seperate coolers setup. The reason being that in the stock seperate coolers setup the oil cooler blocks nearly 1/3 of the radiator, and haveing a bigger radiator lets more air go straight through the radiator without first going through the oil cooler. Is this true? Is it better to mix the two setups, having the bigger radiator and the oil cooler? Anybody have good tech as to why this is, other than a larger unobstructed cooling area for the water?

TIA,
Chris

 

Actually, there are 3 types. You missed the pre-82 style wherein the oil cooler is below the radiator. That is the short radiator. The tall radiator with oil cooler in the front is the GSL-SE.

 

Ahhhh, okay. I wasn't counting the GSL-SE since our rules don't let us run anything from them. But, thats good to know!

 

Although your rules won't let you run anything from a GSL-SE, you can still copy it.
Since all '83-'85 12a/13b ran the same radiator, the tall one, then you make some simple brackets and move your 79-82 oil cooler 4 inches in front of the radiator. Have some longer oil hoses made up and you are done. By going with the tall radiator, you have little more room to add a electric fan.

John

 

Air cools better. Its better to have air cool the oil and to have air cool the coolant. The thing Mazda tried with the coolant cooling the oil wasn't a good idea. Not as efficient as having air cool the oil. If you have a radiator with an oil cooler built in, that is fine. Most vehicles with automatic transmissions don't have a seperate oil cooler for the tranny fluid, the tranny fluid flows through a seperate chamber in the coolant radiator.