I stand corrected.

 

I think both of you are right. It is not the most efficient location for oil cooling. But it also is easy to mount there and seems to work well. If it isn't enough cooling for your oil. Move it in front of the rad

 

Have you posted details on this? I am planning to do the same thing. If you have, link please, if not, mebbe you could throw some details into the oil cooler tech thread so we don't clog up Ed's thread?

 

It's in his build thread. He uses a laminova core (I think) in the return line to the radiator.

I think it's an OK setup for a street car/drag car, but I have a feeling you will be really taxing your cooling system with 20-30 minute track sessions. Only one way to find out though. Your radiator will be doing a lot of extra work though.

I'll have before and after oil temp data for behind the radiator mounting sometime in the next few months. I have the sensor installed, just need to wire it into the megasquirt.

 

It's a mocal large water/oil heat exchanger. Was almost 500 bucks, but it just works. Also packaged in the engine bay very well, and doesn't block airflow to the radiator in any way.

Picture of it, it's right by the intake manifold.

 

It works, so I'm happy with it. Heat has to go somewhere, if you use an air/oil heat exchanger it reduces airflow to the radiator so that hurts the radiators performance too. No free lunch.

 

Except when it's mounted behind the radiator....

I would not personally be interested in adding more work for a Miata cooling system meant for track use.

 

Pat doesn't do track days, does he?

--Ian

 

No exception. You mount an oil cooler after the radiator, some air has to flow the radiator core AND oil cooler core, which will decrease air flow through the radiator core in that area. Same as if it were before the radiator. Exactly like resistors in series in an electrical circuit, the resistances add and the order they are in does not matter. Put a sheet of cardboard in front of radiator or behind it, both block air the same. Same is true for that oil cooler you installed.

Pat's car is a daily driver that sees the drag strip every weekend. I don't do 30 minute track sessions, most here know that.

 

If you're going to tell me that an oil cooler placed nearly an inch behind the radiator core blocks just as much flow (or even close to as much) as one placed in front of the radiator, I'm gonna have to start paying even less attention to your theories.

Anyway, seems like yours is a great solution for what you're doing, though I'm not quite sure why you need an oil cooler at all given your use case. Extra insurance? I expect you were monitoring oil temps prior to cooler installation considering your propensity for logging (and MANY gauges).

 

Why would it be different? There will be a pressure drop going across each heat exchanger, the order doesn't matter. You believe this is wrong, why?

You are stating I'm wrong, and thus saying that the mass flow of air through the heat exchangers will be different depending on the order.

Have you measured airflow for each configuration? Or calculated the pressure drop for each configuration? Or measured the pressure drop across each heat exchanger? Or temp of the air after before/after each heat exchanger? Did you account for the temp/air density change for each exchanger in each configuration to see what affect that has?

My guess is you have done no calculations, no measuring, no testing, but you're telling me I'm wrong without anything to back it up. I've done all of this.

I installed a very large oil cooler to keep the oil temperatures in check. I have this "theory" that keeping the oil temps at 210-220*F under all operating conditions will extend engine life. I also have this theory called "I measured the oil temps and they were too hot on the track before installing an oil cooler", another theory called "viscosity drops with temp", and another theory called "I measured oil temps after installing a cooler and verified they are at target under worst case loading".

 

I don't have any aftermarket gauges in my car at all, maybe you're thinking of someone else? I do log all the things though, I've measure the temperature/pressure of everything.

Pressures measured: Fuel/oil/coolant/intake manifold/pre-intercooler/post-intercooler/post big turbo/post air filter.

Temps: thermcouples for water exiting engine, water temp in/out of radiator, air temps ambient, air before radiator, air after radiator, before condenser/after condenser, oil pre and post cooler, oil sump temp, Air temps at every stage of the system (air filter, turbo in/out, intercooler in/out, etc.

So yeah I do know what the temps look like on my car. When you measure temps before/after and then change something (like heat exchanger placement, or shrouding, or fan on/off/low etc) you can actually measure the affect, and quantify it. I highly recommend it if you want to actually find out what works best. Or pick up a book on heat transfer and start reading. Or both.

 

a) first, I'd like everyone to note that I asked for continuation of this oil cooler discussion to happen in the oil cooler thread

b)the question isn't how much airflow is blocked by an oil cooler either in front of or behind the radiator.

The question is whether, for track use, a system that dumps oil heat > thermostat heat into the radiator, which has airflow not blocked by an oil cooler either in front or behind it, is effective in track situations which have been proven to work with an oil cooler situated behind the radiator, which both receives air heated by the radiator (and the intercooler) and poses a flow restriction to the cooling air moving through the intercooler/radiator/oil cooler stack.

This is what interests me, and makes me think it will work for my car on track. The coolant volume is quite a bit greater than the oil volume. The deltaT we are removing from the oil is only 60F at worst; if the system works as I expect it to, that 60F figure will never be seen, and will be on the order of 30F (as it will be continually pulling heat out of the oil once the oil hits thermostat temp, it shouldn't build to the highs I have previously seen). The radiator will see greater airflow and will therefore have higher heat rejection capabilities. The intercooler will also see higher airflow, as there is one less heat exchanger in the stack.

There is the added benefit of no negative side effects on streetability, and decreased time to oil warmup temp once the coolant warms up.

 

I was referring to your clusterfuck of gauges on your main tunerstudio screen from the 'idling on big injectors with OEM ECU' thread.

Richard,

That all makes sense. It still seems that the best route is to use an air-to-air heat exchanger which is not in front of or behind the radiator. But I hope my current setup works fine.

 

Will have to compile some pics and videos from the last track day, but for now, just a quick followup post on the oil cooler:

Previously I had oil pressures at 38-39 psi on track at 6000 rpm. Now at the same RPM nets me 57 ish psi on track. The only change being the cooler! Definitely a worthwhile change. That old RX7 core just doesn't flow enough for this particular setup.

I'll be posting the old stuff in the classifieds with a link here -- maybe someone wants it for another project. Sandwich plate, lines, and cooler (though I wouldn't recommend using the cooler itself).

 

Weird to see your post neg propped, possibly just haters?

I thought it was a valid response. I'd even like to compare some ARTech EFR dyno's vs the ones I quoted for the upper rpm dip

Also, could A/R be a factor? mid range vs upper?

 

Well, thanks. I thought so too, which is why I made the follow-up post.

If it's simply that the turbo is below its efficiency range, that doesn't make sense to me since it flows more air at the higher RPM and if anything should perform better at that RPM, no?

I just don't get it, so I'd love for the neg proppers to come out as to why my comment was stupid. Not whining about the props cuz props don't matter, but neg props are an indication that I'm not on the right track.

 

I didn't neg prop you and don't even really care about that whole topic, but I'm fairly certain it's not running out of steam or choking up.
I'd be surprised if anyone could "choke up" that manifold or turbo on a BP. it'd take more than 400hp, that's for sure.
My guess is that the wg is just getting blown open, or the turbo is being run so much lower than it's efficiency range it's just simply falling asleep

 

Must be. Hmm. Oh well, not particularly important, and I'm sure Andrew's manifold and DP is not the culprit. I'm mostly just curious.

 

You were right, I agree. Sometimes people don't agree with you, even though they can't prove they are right or that you are wrong, so the props system is a great for these folks.

To answer this question: If your setup didn't fall off as much up top, then it flowed better or was tuned better (or both).

Also just realized this is the thread where you talked about heat exchanger stuff, did you ever measure or calculate anything regarding heat transfer on your heat exchangers?