Interesting idea... are you recommending the oil pan temp is what we should be monitoring?

 

i got a chance to talk to Jim Mederer at one of the Sevenstocks, and he kept mentioning Delta T, the oil going in to the engine needs to be cool enough to pull heat out.
putting a sensor in the pan would give you that.

i think i've seen either sensors that replace the drain plug, or adaptors to do it, so it could be really easy to implement

 

Well... to have a Delta anything, you need 2 data points. So you would need to watch the temps in 2 locations. I don't think anyone is running 2 temp sensors (pre and post X). Imagine trying to drive, monitor both temps and then do the math in your head.

 

True, but with probably any modern aftermarket ECU you don't have to watch gauges and do the math in your head. For example, if you're running a Link G4X, and have the 2 oil temp sensors installed, it would be easy enough to setup a math channel to compute your delta oil temps in real time, and use that delta-T data as part of an automated engine protection strategy. You can also have it spit out the delta-T data on the CAN bus if you want to display it on a gauge or dash as well.

To that end, what range of delta-T oil temps would be considered "too low", "normal" or "too high" for a 13B REW? I suppose it will matter where the 2x oil temp sensors are installed to be meaningful.

 

Quite the temp monitoring strategy that would be. Can't really see where it would be necessary outside of testing and data acquisition but you're absolutely right about that approach.

 

I don't think anyone would actually monitor temps in such a clunky way. 2 data points is great for data logging and to measure how well the cooling system is performing and whether it needs adjustment. If you are driving and actually racing, you aren't going to be looking at a gauge, you are looking where you want to go. You'd just want a simple warning light to indicate whether you are getting too hot, if yes, then check a gauge to see where you are at.

 

I prefer this routing; it requires less hose. Here are the brackets and fitting that you will need

Oil Cooler Parts (93+ RX-7) (banzai-racing.com)

Edit: I just noticed a typo, the 120 female flare should be a 90 off the front cover

 

10ft vs 15ft... not a huge difference in hose usage and only 1 additional fitting in exchange for a lot less clutter in the engine bay.

We never really understood the reason with mounting the thermostat right off the front cover. It's a clunky and crowded area to have such a large component.

It can be mounted comfortably and safely on the bottom of the frame rail in front of the sway bar mount. It's much more serviceable, easier to install and MUCH cleaner of an install.

 

Whatever dude. Sorry to step on your marketing attempt. 5 extra feet is a mess that doesn't need to be there. I have only been installing dual oil coolers for 20+ years, but you do whatever you get a tickle from.

 

That went left fast lol. That wasn't the attempt or intention but we will abstain from any further comments if our input came off as an attack. Simply stating an alternate method and its advantages.

 

Absolutely. Oil pan temps tell you how hot the engine oil is running, when it's starting to get hot (230-250*F) and when there's an issue with oil starting to break down at 300*F.
Using 2 sensors is ideal for understanding the cooling ability of your system and how improving the ducting or adding another cooler affects it's performance. However this is more advanced and not necessary. What is the most important is knowing how hot your engine is getting. This is why we measure water temps in the head or exiting the engine; to know how hot the engine is running. It doesn't matter if you're feeding the engine with 190*F water if the engine is actually running at 240*F (total exaggerated example). The same goes for oil. You can feel good that oil temps of 240* isn't bad in the pedestal, but in reality the engine and oil is probbaly getting to 280*F.

Agreed, but that sensor should be in the pan.

Lets make up some numbers for a simple example:

-Let's say we don't want to run the oil higher a true 250*F (in the pan).
​​​​-Front simplicity's sake, let's say each oil cooler drops 15*F of temp.

Car A with 1 oil cooler is seeing oil pan temps of 250*F. Measuring at the pedestal, it's showing 235*F.

Car B has 2 oil coolers and is seeing oil pan temps of 250*F but only 220*F at the pedestal.

Maybe car B is being driven harder or has more power than Car A, but both of them have borderline high oil temps.

If Car A only measures at the pedestal and keeps driving hard until he sees 250*F at the pedestal, he's actually running at 265​​​​*F at the pan.

If Car B (with 2 coolers) does the same and keeps driving hard until he sees 250*F at the pedestal, he's actually at 280*F at the oil pan and probably already ran into issues or blew his engine.

There are variables in how well different oil coolers and ducts cool the oil. There are variables in how much heat a given engine transfers into the oil (more power, more friction, driven harder, etc...). All that matters is how hot or cold the oil is inside the engine, not how cool the oil is going into the engine.

An old link/reference:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/oil-temps-what-optimal-oil-temp-location-sender-1002711/

 

IMO (from experience) dual 19 row Setrabs are overkill until you need dual 19 row Setrabs (track duty or really really hot ambient temps). This begs for some sort of parallel arrangement with twin thermostats vice series.

And one ducted cooler is cheaper than two unducted coolers

 

<MOD please remove if too far afield from subject>

Guess I have a simple project for my FLIR thermal camera next time I'm at operating temp. Oil pan and individual oil cooler thermal pics to follow...

 

So on the link posted to another thread, an oil plug temp sensor was mentioned. Does anyone recommend a current oil plug temp sensor? I'd be interested in having a set up like this connected to my Haltech so that I can set up a warning if the coolers are not doing their job.

 

you can probably use something like this:

https://stmtuned.com/products/stm-oi...drain-plug-m14

But it's better to pull the pan and weld in a proper bung.

 

It's crazy that Mazda didn't put dual coolers on every FD from the factory...

 

Not really crazy. 99% are not tracked and one cooler does just fine. They didn't build it like a Supra to handle doubling the horsepower with zero effort haha.

 

at this point I would think more like 90% of the FDs still on the road have been tracked at some point lol

 

90% Tracked to the point they require dual oil coolers is doubtful.

 

I tracked mine a few times in 1992, but haven't done it since. Since I have a dedicated racecar (avatar) I don't get much of a kick driving at less than 98% capability, and I don't want to wreck the FD.

 

I know it's been some time since I posted this but finally got around to installing the second Setrab oil cooler. The installation came out great including the oil temp thermostat housing.
So I went for a drive. Keep in mind that the ambient temperature today in TX was 104.
I pulled over and touched the oil coolers and they were scorching hot. Then I connected the laptop to the haltech and see that the oil temp was 190 after a drive but during the driving I see temps as low as 162. The cooler are doing their job. So my question is should it be that low with ambient temps over 100 and what would be a high temp which I should be concerned about.

Thanks

 

Doesn't matter what ambient temps are as long as your engine oil temps are fine. The thermostat will do its job if temp gets too low

 

So if it's a 185 thermostat, it closes below 185 e.g 162 then opens again at 185?

Also I forgot to mention that I'm seeing 110psi of oil pressure under acceleration. Is this fine?

 

That's how it should be working. I think ideally you would not want it cycling back and forth all the time and you want your cooling system set up well for you application to minimize that. But basically the thermostat is just turning off access to your coolers until you reach the appropriate temperature, then turning back on to keep everything at the temp range you are after. Depending on which thermostat you have, you can also change the temp threshold.

 

The thermostat isn't entirely on/off. Describing it in a high and low bypass state would be a more accurate description of how it works. Oil is always flowing through the thermostat and into both coolers, the internal plunger simply allows MORE oil to flow through them as the temperature increases.

with THAT significant of a temperature drop your coolers may be oversized for street driving conditions. What is the amount of time it takes to drop to its coolest until it reaches its hottest? So the time of a "cycle". Even with that big of a drop, you're not hurting anything and it won't cause any issue.

Put something in front of the second cooler next time you drive to block the air flow and see how your temps respond.

Having the thermostat cycle is perfectly fine, it's just doing its job and with a drop in temps like that its definitely doing its job well.