so i am building my daughters first autocross and hpde car with her, an 84. purposely low L83 hp, with superb handling.

We are interested in keeping temps down. I have 3 more kids coming along and id like them to use this car when the time comes so longevity is on my mind.

i have the kc4 sandwhich cooler here to install that im familiar with and when i was starting out on track it did a great job of regulating oil temps within 8 deg C of the coolant. so i am looking to install it. i underthat some of you may not believe it does anything at all. I’ve experienced it and it does, especially at the track. Most people use it on the street and it pretty much does the same thing just at a lower temp.

So, this thread isnt intended at a discussion on the pros and cons of the water to oil kc4.

I wanted to have a brainstorming session. I think im missing something here. The feed line comes from the block. Which would be the coolest water as it has just arrived from the radiator. Makes sense to feed the cooler that way.

However, the return line….,im confused as heck. It appears that the return line from the cooler scoots over to the T into the return line from the heatercore. and here is where i am super confused.

The merged heatercore and cooler line returns right into supply the waterpump. Which immediately pumps it back into the block.

I get why the heatercore would do that. If you’re using the heater, then it’s basically a mini radiator and it at least supplies the waterpump with slightly cooled water. But the oil cooler….,that will be HOTTER. So this system seems to simply circulate the hot fluid from the cooler right into the block …where a portion of it will go right backninto the cooler.

What am i missing?

Why would the cooler not be ran into an intake manifold port right before the exit through the thermostat???

what am i missing?



Is the answer that its a zero sum game in terms of cooling?

I would have thought we’d send the hot coolant after passing theough the cooler, directly to the radiator, to be cooled again. However i understand that we would need to return it prior to the thermostat valve to ensure the engine maintains a certain temp.

So if im taking the time to plumb in a kc4 sandwhich cooler…..why would i plumb the heated outflow from the heater right back into the waterpump inlet only to skip the radiator. This reminds me of the coolant bypass on my zr-1!!!

what am i missing guys?

any ideas on where to plumb a different return line that dumps right in to the intake manifold on the way ro the radiator??

 

OK i have been working this through with some CF Friends.

My understanding of the “circuits” is fuzzy but starting to come into picture.

The pressure differential is located at the water pump. i think of it as a suction and a pressure side.

The cooler is on the pressure side of the waterpump…. the return must be to the suction side of the water pump. This is how it flows.

Now u also have the added complexity of the thermostat which is a temperature control restriction that changes based on temps.

Part of me thinks i could add a T into the upper radiator hose (downstream of the tstat) and still have the kc4 function. Only reason i would do that is a misperception that i would be able to suck more heat out of the coolant after the kc4.

What i was missing there, is that once the tstat opens up, the flow rate is such that the radiator is more than capable of extracting all that heat out. The kc4 doesnt need early access to the radiator.

Fuethermore, thinking about the kc4 as simply an extension of the blocks oil to coolant heat exchanging is helpful. It simply increases surface area where the coolant is able to extract heat from the oil.

As long as your radiator is capable of extracting all that heat, then u r good to go, and the tstat will increase of decrease flow.

 

Just throw it in the garbage and do a separate oil cooler.

 

It's very common for separate coolers to cool better on lapping events. Combined type like that KC4 are fine for the street. And maybe fine with a large radiator. There may be some growing pains as you experience what works.

In my own experience I've found that to be true and it can be really tough to choose compromises for street/track setups. I had one car drop temp fifty degrees F after removing the KC4. I know it works and I know it hinders too.

 

so basically buy the sandwich adapter that pumps oil and run it to an dedicated oil cooler. kc4 definitely does not cool by 50d. i will look at doing that.

 

No it wasn’t cooling by fifty it was heating. The car I saw that particular number on dropped oil temperature when water temperature wasn’t heating it anymore. Setup went to a stand alone oil cooler from a sandwich adapter on the oil filter.

 

I added an oil cooler based on Chumvetts suggestions as well. I suppose if you had the stock 84 air to oil cooler that would suffice as well...

I was always easily able to get my oil in the 250-260 degree range just driving on the street calmly. 275 was easy if I got a little spirited. That was with no cooler at all. Now I see highs in the 230 range.