Oil to coolant heat exchanger

[EcoCivic]

Originally Posted by Piotrsko

Heavy acceleration yes, floor it not so much because you will still have temp differences that can cause failure. Bearing surfaces are ok however.

Unknown. Could be a emissions strategy.

I was told they do it to limit the engine’s power while it is cold to prevent failure or excessive wear, but who knows if that’s true.

It will also upshift earlier at full throttle when cold. Instead of revving to the 7K RPM redline before it shifts, it will only go to 5K or so then shift when still cold. But at part throttle it will shift later when cold to help warm the engine up faster.

[EcoCivic]

Originally Posted by MeteorGray

My Mazda specs 0w20. I wonder how thin they're going to get? Is there any -20w-00 out there? Maybe when the new Ice Age hits.

I know that there are 5W and 0W racing oils out there. As for standard oils, some cars now use 0W16 oil. I wonder how much the oil viscosity actually affects efficiency within reason.

Realistically the fuel efficiency difference between, say, 5w20 and 5w30 oil is probably under 1 percent from the research I did, under most conditions anyways.

[EcoCivic]

Well I have an update. I got a 30 plate 3/4 inch heat exchanger that I recently installed. I got a sandwich plate and made my own 10AN oil lines to run oil through the heat exchanger and rerouted the heater hoses so the coolant runs through the heat exchanger before the heater core. Looks like a huge improvement in temps so far, but I only ran it for about 2 minutes total, so not sure yet.

The problem is that my sandwich plate has a defective flare fitting that is causing my line to not seal correctly and drip oil, so I had to take the sandwich plate off for now until I can get a replacement fitting for it. So far the results look very promising, I will report back when I get a replacement fitting and I am able to run it for a while though.

[EcoCivic]

Update: I finished installing the heat exchanger setup and it works very well now that I finally got the AN fittings to stop leaking oil. I seem to have gained about 40-50 degrees on my oil warmup. The oil was warmed up to around 100 degrees at best once the coolant warmed up before I installed the heat exchanger, but now That I installed the heat exchanger the oil is warmed up to around 140 to 150 degrees once the coolant is warmed up, and within 5 minutes or so it is up to coolant temp of around 180-185 degrees. The oil temp always stays within a couple degrees of coolant temp while driving down the road.

This setup is also very effective at cooling the oil off. I ran the oil up to around 200 degrees and turned the radiator fans on, and within a minute or two it was back down to around 185 degrees. That will sure be nice in the summer here! I don’t know what the oil temp was reaching before because I had no gauge at that point, but surely much hotter than the coolant.

I am happy with the results of this 30 plate 4 X 8 inch heat exchanger brick, but with the results I am seeing from this I don’t think I would be happy with the results of an OEM style oil cooler between the oil filter and the block, I don’t think something with that little surface area that a lot of oil bypasses would do what I wanted. But if someone has a vehicle with that type of oil cooler and you would like to do testing to see how effective it is that would be cool!

[teoman]

I wonder if you could route a warm air intake to pass over the oil cooler to enhance engine warmup.

[EcoCivic]

Originally Posted by teoman

I wonder if you could route a warm air intake to pass over the oil cooler to enhance engine warmup.

Not really, I installed an oil to coolant heat exchanger rather than a typical radiator style oil cooler. And even if I could, I am not interested in heating up my intake air since I went through great lengths to keep it cool for performance reasons, including building a heat shield to separate the air filter from the rest of the engine compartment. This is the unit I chose https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[serialk11r]

Originally Posted by EcoCivic

I know that there are 5W and 0W racing oils out there. As for standard oils, some cars now use 0W16 oil. I wonder how much the oil viscosity actually affects efficiency within reason.

Realistically the fuel efficiency difference between, say, 5w20 and 5w30 oil is probably under 1 percent from the research I did, under most conditions anyways.

I think the answer is it affects efficiency quite a bit, but it's got a bit of a negative feedback loop built in.

Thin oil has less viscous drag, which means it heats up less at the same temperature and load. Thick oil has more, so the friction heats it up and brings up the temperature, lowering the viscosity. If you have very effective oil cooling and a large sump with thick oil, you're definitely losing fuel efficiency in a noticeable way.

Some engines are built with bigger bearing tolerances so they need the high viscosity. As far as I can tell, it's better if you don't need to rely on this effect, e.g. F1 engines which run a 0 weight or something (but they also need to be pre-warmed). Putting thicker oil in an engine built for thinner oil is only useful if you can't keep the oil temp under control in severe load conditions, e.g. pouring some 50 weight in at a track day if your oil temps are like 300F.

[teoman]

Originally Posted by serialk11r

I think the answer is it affects efficiency quite a bit, but it's got a bit of a negative feedback loop built in.

Thin oil has less viscous drag, which means it heats up less at the same temperature and load. Thick oil has more, so the friction heats it up and brings up the temperature, lowering the viscosity. If you have very effective oil cooling and a large sump with thick oil, you're definitely losing fuel efficiency in a noticeable way.

Some engines are built with bigger bearing tolerances so they need the high viscosity. As far as I can tell, it's better if you don't need to rely on this effect, e.g. F1 engines which run a 0 weight or something (but they also need to be pre-warmed). Putting thicker oil in an engine built for thinner oil is only useful if you can't keep the oil temp under control in severe load conditions, e.g. pouring some 50 weight in at a track day if your oil temps are like 300F.

I recall reading on bobistheoilguy.com quite the opposite. (no personal experience).

The explanation was that if you have thinner oil, it flows more removing more heat.

[serialk11r]

Originally Posted by teoman

I recall reading on bobistheoilguy.com quite the opposite. (no personal experience).

The explanation was that if you have thinner oil, it flows more removing more heat.

Again depends on operating conditions. On the track, the oil can get so hot the bypass doesn't activate at 7000rpm and 50wt oil thins down to what 20wt would be at normal temperatures. As long as the bypass doesn't activate, you have the same oil flow (since the viscosity is a little higher, you'd expect a slightly different distribution of oil flow between different parts of the engine).

On the street your oil is never getting hot like that unless you're driving way too fast, so it makes sense to go one grade thinner (if your engine can live at 270+F on 50wt oil, it'll be fine at 220F on 40 or even 30).

[EcoCivic]

The oil cooler/warmer is still working great, no issues. I do have a question about oil viscosity though. Normally I use 5W30 since I am making an estimated 20-30 HP above the stock rating and I frequently run the car hard, but now that I have effective oil temp control I am starting to rethink whether I wouldn't be better off with a 0W20/5W20 oil.

With this cooler the highest oil temp I see during normal use is no higher than 190 degrees, so I'm thinking adding the cooler is pretty much already the equivalent of using one step above the factory recommended oil grade if not probably better. Thanks