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

[DRPHIL914]

fan seems like it doesnt come on until about 220, i have a variable rheostat but thats the soonest so i might change this

I used a 190 deg thermo switch inline before the cooler.

On at 190 off at 175 (what ever temp you choose it goes off at 15 deg drop)

https://www.pegasusautoracing.com/group.asp...ID=SETRABSWITCH

great, thanks for the tip.

[porschetub]

I never got motivated to try it out later in the day (beer). And today has been hot as f....udge.

Rear mounted coolers can probably do the job under the right conditions, but they'll never approach the heat displacement of front coolers (which are a PITA...or at least require cutting).

The problem I primarily have with front-mounted coolers is I really, really, really don't like having engine-pressure oil all the way to the front of the car, all the way through a thermostat/cooler system, then all the way back to the engine. There's just too much opportunity for pressure loss and introduction of air into the system.

Dry sump? Sure, no prob, there's a stage to drive the engine oil and its circuit is local, and another stage to drive the oil forward and then into a sump tank. I use a 2-stage CB Performance dry sump on my race car.

I know "it's done" but I don't like it in concept. So I run an aft cooler on the street car. It seems to do the job (I may try a Track Night in America event later this year to see if it's "enough").

Well done Greg,my experience with thermo couplers indicates your reading should be pretty accurate,wow never expected those temps for one minute.
Wonder if anyone has removed the rear valance to see if there is a drop in temp as per the Porsche factory race cars or was that done for another reason (IMG:style_emoticons/default/confused24.gif) .
Cheers for your efforts.

[GregAmy]

Tonight's tests, removing the duct. Probe is in a hole I drilled on the side of the enclosure that comes with Tangerine's cooler:



Conditions: ambient 84F, sun going down so also low on the horizon like last weekend (but of course on the other side of the car... (IMG:style_emoticons/default/wink.gif) ). Same route, slight descent toward the Sound, then reverse course for a gradual climb home.

After the thermostat opened, right before the fan kicked on:



After the fan kicked on and all temps were stabilized. Oil temp was at 214F:



All four graphs:



Spike is when I pulled off the highway and worked my way back around to the other direction.

Conclusion? My intake duct was a bust, made the problem worse.

Now I'm wondering what would happen if I cut Tangerine's enclosure down half-height (lot more work to get that out, trim it, get it back in. But not impossible...)

[Olympic 914]

(IMG:style_emoticons/default/popcorn[1].gif)

[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?

[BeatNavy]

Greg my duct work was a total bust as well. And I spent a fair amount of time to fab it and was pretty proud of it.

This is great info. From mine and others' experience I draw the following conclusions so far: a) a rear-mounted cooler can help, but it's not likely to get temps below 210, and that's WITH lots of air movement from motion, and b) hot day without moving you're likely to climb to 225+.

That doesn't mean we can't do better.

(IMG:http://www.914world.com/bbs2/uploads_offsite/media.makeameme.org-17042-1596019932.1.jpg)

[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