water temps vs iat.

[whipplem104]

So I posted this on another forum tech section with little response. I have been thinking with air/water intercooling if the goal when not driving at load or in boost is to maximize water temps or iat. I and everything I have ever read have always focused on 2 temps. Peak iat and recovery at cruise. Peak iat under load of course are the most important. But is iat at cruise or water temp the most important. I was thinking that reducing water temp in my reservoir at the cost of higher iat at cruise may be beneficial to an extent. So I got a water temp sensor for my reservoir and am watching the water temp vs the iat temps. There seems to be a very small effect on iat at cruise by water temps. In fact I was just hosing down my heat exchanger and got the water much cooler and still very little effect to iat. I am going to heat soak my intercooler and then pump cold water from my reservoir through it under load only and see what my peak temps are. Kind of a worst case scenario. This should tell me if the heat soak in the intercooler is more damaging than the colder water coming in.

[Dearlove]

i find that very hard to read and follow what your trying to say??

[duxthe1]

I find it a little hard to follow as well, but I don't think that temps at cruise are that important. The reason being is that the temp differential at cruise is much lower than it is under boost. With the differential lower, the efficiency of the I/C core is going to be lower. Assuming that your heat exchanger is as efficient as your I/C core I think that you will be chasing your tail worrying about cruise IAT.

[whipplem104]

Basically what I am getting at is that getting the water temp as low as possible in the reservoir at the expense of heat soaking the intercooler core. Of course the hotter the metal gets the more energy to cool it down again. So say you just turn your water pump off and let the core just get as hot as it is going to get. Then pump cold water through it under load. Everyone always focuses on iat recovery time after a pull at full load, which is indicative of the intercooler temps and water temp you would think. But I was monitoring my water temps and cooling the water down the fastest and getting the fastest iat recovery are not really related. So duxthe1 is right. But to what extent. Is there a point of diminishing returns.
I am wondering if keeping my intercooler core at a lower constant temperature when driving normally say running 20-30 f above ambient water through it all the time is better or worse than have the water in the reservoir be 20-30 degrees colder when I need it under load but having a much hotter core during low throttle driving.

[duxthe1]

Originally Posted by whipplem104

But to what extent.

I'd say it depends on I/C core efficiency v/s heat exchanger efficiency in the ranges of temp they are operated in. Logic tells me that you want to pull as much heat out of the I/C core as possible at all times.

If you could datalog the pre I/C and post I/C temps and plot them against pre and post water temps you could probably find a correlation you could use to optimize the system.