Under Trunk Temp., Addition to Oil Cooler Thread. Options

[Olympic 914]

So on the Oil Cooler thread the suggestion was made to place a thermometer under the trunk to check the temps to determine possible difference for cooling efficiency.

I don't know if anyone had done this before. So I broke this off into a new thread for future reference.

One of the Oil Cooler threads

http://www.914world.com/bbs2/index.php?showtopic=347075

So yesterday I did this.

Using a Wifi endoscope taped to a magnetic tool holder with a thermometer.

Placed parallel to the Setrab oil cooler to sample the air temp without the fan blowing directly on the thermometer










And went for a drive. My GF rode along to monitor the temps and take notes.

The outside temp was 80 rising to 85 yesterday.

Idling in the driveway the temp rose to 125, after 2 miles of two lane roads 30mph it had dropped to 120.

at 4 miles stop and go it was still 120, Oil temp 200 CHT 340

onto a two lane road for 11 miles with speeds from 30-50 mph air temp was between 118 + 120 deg Oil temp 212 CHT 322

at this point I stopped for 2 minutes to mimic sitting at a long light or in traffic.
the air temp rose to 140 deg Oil temp 210 and CHT 337

Pulled onto 4 lane and accelerated up to 70 mph. After 1/2 mile the air temp had dropped to 125deg oil temp 209 and CHT at 370.

mostly level with some slight grades.

Turned around at 23 miles

Air temp holding at 125 deg Oil temp 213 CHT 330

The battery was low on the endoscope and I had turned it off on the way back, and when I turned it back on I discovered that the duct tape had loosened and I lost my thermometer.

My setup is a 2056 9590 cam Djet. , Oil cooler is Setrab 119 fanpack 180 deg oil thermostat and 190 deg sensor for the fan. Exhaust is SS HEs and a Triad muffler.

When running in normal summer heat the fan runs constantly.

If any one else decides to do this Please add your results here.

Tom

[Craigers17]

You win some ....you lose some....progress is never made standing still. That said, you've got a rear mount set up that is working properly, and the oil temp is consistently stabilizing at 214. Looks to me like you've already won.... but I'm guessing you're now trying to optimize for track use?

[GregAmy]

but I'm guessing you're now trying to optimize for track use?

Pretty much, yes.

My initial foray into this wormhole was because I was seeing 255-260 (needle into the red on the stock gauge) for the last several years while on the highway. That usually became a problem this time of year, July/August, as it was extremely sensitive to ambient temps (never a problem on cool days).

So the first install was over the winter, using the Tangerine ducting you see there but without a fan. Long highway run last Spring saw temps into the red again.

I took the Tangerine duct off, still no fan, and it reduced the temps about 10 degrees, to around 240-245.

I added the fan and reinstalled the Tangerine duct, wired hot to the ignition, and it came down another 10 degrees.

These were all measured via the Mainely dipstick, and correlated to the factory oil temp gauge using the common JPG we've all seen for what the temps are on that gauge.

At this point 225-230 wasn't hateful, but there was nowhere left to go when the ambient temp rose later in the year. So I bought the inline oil temperature sensor and input that into the Microsquirt and then used one of the MS' output to control a relay for the fan.

I reinstalled the Tangerine duct, added my "southern" duct, and config'd the MS to switch on the fan cooler at 215 and off at 190. I found that once the fan came on it would stay on, and the oil temp wouild stay right at 215; that indicated to me that I could control the temp to 215 on the highway but there wasn't enough BTU removal to reduce it (it cooled down below the "off" point when not under load). I did find recently that if I changed the fan set points to 220/200 then the fan would bring the temps down to 214-215. So I think I've reached a stasis there.

So that's about where we are. The current setup is sufficient for street use, but I'm of the theory that there's not a lot of BTU capability left in it. This will not be a high-use track rat; it's a driver street car. But I would like the opportunity to take it to a TNIA event once or twice a year.

There may also be something specific to this engine. I noticed that if I pull over at a rest stop and let it cool to 190F, then blast off for a full-acceleration run dwon the on-ramp to merge onto the highway, I can add 35 degrees to the oil temps within 15 seconds. Maybe that's normal?

I may take it to a TNIA event soon and see for myself if my theory holds. Who knows, it could be that as the gets hotter the cooler will pull a lot more BTUs out. Worst case I run 225-235 on the track and that's fine. As long as it stays well below the red I'm happy.

Greg