More Rear Mount Oil Cooler Questions, Setrab Setup Options

[BeatNavy]

Remember that for an oil cooler to do its job, it has to be able to shed heat to lower temperature air. It's hot next to the trans and just above the exhaust, so not much heat differential to work with. And limited airflow under there too.

Very true, it's all about the heat transfer. I've thought about trying to take ambient temp reading around the cooler (above the heat exchangers) to get some idea of the differential. I may find that in my case, at least, that there is minimal actual difference with a rear mounted cooler. The alternative, as you pointed out, is front mount, which generally involves body / bumper mods.

[Porschef]

Might be time to take it out for a bit of thrashing; any issues might show up whilst. If not, you’re prolly good to go... (IMG:style_emoticons/default/beerchug.gif)

[Dominic]

Here is a picture of my set up when I first installed it (before the engine was installed), this large Setrab cooler is the Only oil cooler for my 2270 engine, I'm using a DTM shroud so there is no stock oil cooler. I currently have a 180 degree sensor that turns the fan on and I can not get the oil temp over 180 degrees. It does have an oil thermostat plumbed into the system, and it works well since the CFR header exits on the drivers side and there are no exhaust pipes under this oil cooler. I actually need to buy the 190 degree sensor to bring my oil temps up a bit.

[90quattrocoupe]

Anyone thought about putting a head shield on the top side of the exchangers?

Greg W.

[BeatNavy]

Anyone thought about putting a head shield on the top side of the exchangers?

Greg W.

It's crossed my mind. But that's about it.

Good news on my setup: no leaks best I can tell. Bad news: temps are still on the higher side of what I would like (assuming my gauge is correct). I'll run with it for now and look into better airflow and/or heat shielding.

[mepstein]

Anyone thought about putting a head shield on the top side of the exchangers?

Greg W.

Aren't the heat exchangers already a heat shield for the headers? If air is running through them, the exterior should stay pretty cool.

[GregAmy]

Aren't the heat exchangers already a heat shield for the headers? If air is running through them, the exterior should stay pretty cool.

Mine are horribly hot, you can't even get your hands near them.

There's a TON of heat stagnating under the backside of these cars.

This is on mine. It's now covered in adhesive-backed reflective insulation.

It's finally stabilizing the temps around 215-220 (in the line exiting the cooler) on 80+ days.

[Olympic 914]

Aren't the heat exchangers already a heat shield for the headers? If air is running through them, the exterior should stay pretty cool.

Mine are horribly hot, you can't even get your hands near them.

There's a TON of heat stagnating under the backside of these cars.

This is on mine. It's now covered in adhesive-backed reflective insulation.

It's finally stabilizing the temps around 215-220 (in the line exiting the cooler) on 80+ days.

Do you still have the original oil cooler in place? No gauge sender in the taco plate?

I guess it depends where you are reading the temp.

As I understand the oil flow -

(1) its picked up from the sump,

(2) through oil pump then to the oil filter


(3) through the stock oil cooler

(4) on to the bearings etc. through the oil galley.

If you are reading the temp inline after the aux cooler your oil temp should drop some more after going through the stock cooler, before going into the engine.

Using a sandwich adapter, after the oil filter the oil goes to the aux cooler then back through the stock cooler to dissipate more heat before going to the bearings etc.

By having the sender for the temp gauge in the taco plate you are reading the oil temp after it has gone through the engine and lubricated/cooled it.

[GregAmy]

Do you still have the original oil cooler in place?

No. Replaced with Tangerine block and thermostat, lines come out of that.

No gauge sender in the taco plate?

Yes, factory sender in taco plate feeding factory combo gauge. The gauge correlates directly with a Mainely dipstick.

I guess it depends where you are reading the temp.

The 215F is being measured by a Race Technologies sender in the cooler exit line back to the engine, feeding the datalog into my Microsquirt (which controls the fan).

So I have three methods of oil temp measurement and they all correlate with each other.

I can add a fourth if you think it'll help... (IMG:style_emoticons/default/wink.gif)

(IMG:style_emoticons/default/beer3.gif)

This is just a good excuse for building an engine over the winter, take advantage of the Microsquirt setup. Shhhh, don't tell the wife....

[GregAmy]

As I understand the oil flow -

At the risk of diverting Rob's thread...you got me to thinking more about this.

My combo gauge and Mainely dipstick agree on temperature, so I'm pretty confident of that. I've rechecked the calibration on the R-T sensor and I have a long history of their sensors in my race cars, so I'm confident of it as well.

But here's the thing I cannot explain.

As noted I'm using the Tangerine block/thermostat and external oil cooler, and measuring the oil temperature on the outlet line of the cooler.

And yet...the temperature is the same or very similar as that in the sump.

Chris Foley and I have gone back and forth on this, and I'm very very confident that we actually have it in the cooler exit line.

But this makes no sense.

I've checked and rechecked the oil cooler lines, and rechecked the sensor calibration.

So this means that either my temp sensor is wrong, the cooler is doing nothing, and/or the ports on the thermostat block aren't what we think they are (but Chris built the block so I'm pretty sure he knows which way they go).

One thing for sure is that between adding the cooler, adding a fan to it, and ducting air to it, my oil temps are stabilizing around 215F on the Mainely dipstick at highway cruise with the fan on 100% of the time.

Everything else is up for grabs.

[MJHanna]

So Im kind of lost on all the tin you are putting around the cooler. I dont understand the way you mount it. This is my sebert cooler with two pull fans on the back side. I have them wire to just a switch that i flip on if I see the temp going up. Which when we are moving is not that offen. Not the best pictures but I think get how its mounted. Car has been coast to coast including going through the desert with no issues.

[MJHanna]

more pics

[MJHanna]

last one

[GregAmy]

"No issues" meaning exactly what temperatures and how are you measuring them?

What's the front end of that tube connected to?

[jd74914]

And yet...the temperature is the same or very similar as that in the sump.

...

One thing for sure is that between adding the cooler, adding a fan to it, and ducting air to it, my oil temps are stabilizing around 215F on the Mainely dipstick at highway cruise with the fan on 100% of the time.

When you say highway cruise, what do you mean? Flat road, 65 mph is probably only using 30 hp, so your thermal load is pretty low and the cooler may be taking just enough energy out to keep the oil cool, but not show any crazy temperature difference.

If you really load the thing up (say 65 mph cruising up the hills on 84 near exit 68), do you see any temperature differences?

[BeatNavy]

At the risk of diverting Rob's thread...you got me to thinking more about this.

Greg -- Not diverting at all. I'm finding this interesting and useful.

I've never really had a reason to doubt my oil gauge and sender match, but I would like to correlate / validate if possible. I've got a laser thermometer, but it's hard to tell how best to use that to get something accurate. Get the car up to temp, put it up on the lift as soon as possible while warm, and hit the sump plate with the laser thermo? I've tried reaching under the car, even while it's running, but I'm not convinced I'm getting something accurate. The numbers I AM getting are lower than the gauge (my sender is at the taco plate location).

I also have a Mainely by Design dipstick thermo, but for some reason it won't fit in the oil filler tube that's on this case (IMG:style_emoticons/default/blink.gif)

I've even thought about taping a cooking thermometer underneath the trunk just to get some idea what ambient temps are under there to see what heat transfer potential there is without adding ducting. I think you described it, Greg, as a lot of hot air "stagnating" under there. Sounds about right.

[GregAmy]

If you really load the thing up (say 65 mph cruising up the hills on 84 near exit 68), do you see any temperature differences?

Jim, I live just off I-91 in Middletown off exit 20 so my "test track" for each of these changes has been south on 91 down to around exit 8, then back up. As you know, the land slowly descends toward the Sound. I try to keep the speeds consistent both directions, around 3400/72mph.

With just the cooler, no fan, and Tangerine's surround/mount I was into the red coming north, somewhere around 250F+ and it was 245F when I stopped to check the dipstick. I did not like that at all and baby'd it home.

Removed the cooler surround and it went down about 10-15 degrees but it was still touching the red when I stopped and it was 235 on the dipstick.

I added a fan and had it on 100% of the time and it made very little difference, maybe 5F.

At this point I wanted to get some hard info so I added the temperature sensor into the cooler line and input it into the Microsquirt to log. That seemed to confirm the other numbers. At the same time I also leveraged an output of the 'Squirt to control the fan relay, coming on at 220 and off at 190.

I am figuring I have some strange aero going on under there, stagnant air along with exhaust heat, heat from the engine cooling, heat from the transaxle (I do have new air diverters inder the firewall). I stick my hand under there behind the right axle after pulling off and it's friggin *broiling* under there. That's when I built the ducting (it's just roof flashing riveted into box structures...I call it my monococque). That dropped the temps down to my current level of roughly 215-220 doing the long climb from North Haven to Middletown. I added adhesive-backed insulation to the box later, didn't seem to make much difference.

I'd also like to note that last couple of years with the stock cooler (and stock D-Jet) I was having a very similar oil temp problems this time of year with increased ambient temps. That's why I installed the cooler over the winter (the stock one was not blocked or leaking). So I'm fully aware that I may have some other issues with the engine resulting in this problem.

I'd really like to get enough spare BTU capability to be able to take it to a track day, but I don't think I can do it in the current config.

I'm way open to ideas.

[GregAmy]

Rob, next time I'm driving I can shoot the IR onto the oil change and taco plates and see how well they correlate to the dipstick.

I like the idea of a cooking thermo to check air temps under there.


Edit: as a somewhat-related aside, I'm also surprised at the enginecompartment/air intake temps on my car. I've got the Intake Air Temp sensor inserted into the bottom of the stock D-Jet air cleaner, and I'm regularly seeing IATs of 130F+ at cruise, and that's with the rain tray removed...so that's all going into the intake for cylinder/head cooling. And that's with all new seals all around the engine tin...

[Olympic 914]

I've even thought about taping a cooking thermometer underneath the trunk just to get some idea what ambient temps are under there to see what heat transfer potential there is without adding ducting. I think you described it as a lot of hot air "stagnating" under there.

Really like this idea. (IMG:style_emoticons/default/idea.gif)

I may try this myself, using a WiFi endoscope to view the temperature changes.

It would be interesting to others results.

[GregAmy]

Did a couple things today.

- Attached a flexible brake duct hose from the D-Jet snorkel and tye-wrapped the other end to the engine grill so it was pulling in outside air. Intake air temps went from 130 yesterday to 105 today. I bet I could get that even lower with insulation on the airbox. It's hot in there.

- Rob, my IR was showing 205 at the oil change plate and the case right next to it, when the dipstick was showing 212.

Greg