Oil cooling test --- Stock trombone vs Mocal radiator

[Discseven]

Edit: Results for trombone, Mocal, Mocal with dual fans + water are on page 4, post #67.



Test bed is '80 911 with '85 3.2 . Oil cooling system is currently entirely stock. On hot days in stop & go traffic (Miami), oil temps can get out of hand. For the sake of engine preservation and when traffic seems to promise cooked oil... I'll detour, accept delays, and on occasions be late to events in order to avoid oil-BBQ. Why I've waited so long to attend ithis... no use to ask. Have now bought into a Mocal in order to end oil temp frustrations. After receiving Mocal... very nice looking unit but... it's small---volume of oil it holds is not as impressive as envisioned. On this lacking basis as I see it, am now questioning if trombono (with it's greater oil volume) might thermally outperform the Mocal in hand. Trick to this is possibly stupid-simple---clean trombo down to bare metal and install bumper air scoop. Rather than guesstimate, will get numbers to know.

With two uber sensitive digital temp sensors in hand, number collection is near---possibly today provided life not getting in way. Rain may also delay things. Sensors read from -30 to +800 dC so no problem with whatever temps are had (supposedly.) Both sensors have been compared against a mercurial thermometer for relative accuracy. While digitals read about 2.5 dC higher than thermometer, the digitals do temp-match each other. Plan is: put sensors on oil plumbing just behind fittings leading to trombo. This allows Mocal to be swapped in for trombo while sensors remain untouched. To complicate things just a bit, am inclined to get more than a simple perspective into what's going on in regard to in-fender oil cooling. This means looking at pipe temps under a few different hardware set ups. More, am going to test each set up at two different operating speeds.

Test scenarios:

• Dirty trombone
• Clean trombone *
• Clean trombone with bumper air scoop**

Mocal now takes place of trombo...

• Mocal with bumper air scoop closed ***
• Mocal with bumper air scoop open
• Mocal with bumper air scoop's air directed towards Mocal ****

* This trombone has never been cleaned to my knowledge. Will bring it to bare metal by wire wheeling it.
** Air scoop installs in place of right front running lamp. Is a new install.
*** Scoop's inlet is taped shut.
**** Deflector is positioned in wheel well to improve air flow from scoop's outlet towards Mocal. Seems a good idea but whether I do this or not is questionable. The horns may interfere with this being a simple mod... Could take hours to sort out. Will see.


For convenience, I've long-wired the sensors to their respective digital displays---displays will be located in-cabin. Wiring will be blue-taped to outside of car. I'll take display pics on the fly at 35 mph, then at 70. To allow oil temps to stabilize before taking readings, plan is to drive each speed for 12 minutes or so beforehand... Longer if pipe temps are still climbing, or still dropping.

Car's oil & filter have close to 600 miles. 20-50wt is installed. New oil temp sending unit was just installed. Oil temperature overlay was just placed on gauge. Bumper air scoop was just installed. Tank level at operating temp is midway between low and full hash marks on dip stick. Was thinking to include Spal/fan in this test but decided to see where temps were before getting into a Spal.

Will post pics after testing's done.

.

[lvporschepilot]

This will be interesting. thanks for doing this.

44 row cooler or 50 row on hand?

[chrismorse]

Hi Karl,
It is always nice to see someone take the time to put numbers to such hotly contested issues.
Couple of thoughts, summer temps in Florida are probably scorching, but it might be important to record the ambient air temp for each trial, in case the time of day/weather change significantly.
Does the mocal cooler have a gasketed, sheet metal shroud to duct all the air through the cooler like the Carrera cooler does. Another, almost no cost improvement would be to close up the bottom of the fender area to prevent air bypassing the cooler.
Lastly, get more air to the cooler by cutting fog light size hole(s) in the valence, (might get vilified for that last one).
chris

[Reiver]

I know the answer to this one already.

[GH85Carrera]

Hey Karl, how about adding a fan to the Mocal once it is in place, as one more piece to test.

On my 85 911 it came with the Carrera cooler of course, but it did not have the fan. I added a fan and a manual toggle switch to turn it on. On my trip back from Savannah, GA in August of 2011 my engine had never been rebuilt. The air temps were all 100+ degrees. On the highway running at 75 or so the temps would rise to 210 and keep climbing. I flipped on the switch, and saw it slowly decline to 210.

The common thinking is that on the highway the fan is not needed. I proved to myself that is not true, the fan even helps at highway speeds. I went through a couple of iterations of turn the fan off, cruise down the interstate and the temps went up. Flip on the fan, it dropped and held steady. Turn it off, and it went up.

I do not have the scoop.

I just drove to Key west. I have never driven so far at 35 MPH and stop and go traffic. I never saw temps above 210, but my engine is rebuilt, and all cleaned up on the engine.



This is before the rebuild. It had 150,000 miles of crud and gunk keep things warmer. It for sure runs cooler now that it is all cleaned up.

[RSTarga]

The trombone was marginal on a 2.4, on a 3.2 it does almost nothing. Any well ducted radiator style cooler will out perform. The 28 tube cooler is a very good option if you don't want a radiator. I've had them all trombone; turbatrol; carrera, 28 tube. In Miami, your best option is the carrera with a fan.

[IROC]

I had a Mocal with a fan and it was marginal with the 3.2. I should qualify the term "marginal", though. The Mocal/fan with my 2.7 was awesome. Temps would rarely rise above about 180-190F and even stayed under 200-210 on the track.

The Mocal/fan with the 3.2 would run 190 or so at the slightest hint of a hot day on the street and it would get to 230F on the track. I didn't like that. Oil temp paranoia.

One thing for sure - the Mocal in the stock fender location needs a fan.

I installed a Mocal cooler in my front IROC bumper (eliminating the Mocal in the fender) and it is awesome. I routinely run less than 180F even on hot days. Picture after driving ~20 miles on a 90F day of "city" driving (almost home from work on a summer day):

[Discseven]

Originally Posted by lvporschepilot

This will be interesting. thanks for doing this.

44 row cooler or 50 row on hand?

IV...

Not sure what "rows" are. If you're referring to the number of tubes running from one end to another... I'll count them tomorrow.

Originally Posted by chrismorse

Hi Karl,
It is always nice to see someone take the time to put numbers to such hotly contested issues.
Couple of thoughts, summer temps in Florida are probably scorching, but it might be important to record the ambient air temp for each trial, in case the time of day/weather change significantly.
Does the mocal cooler have a gasketed, sheet metal shroud to duct all the air through the cooler like the Carrera cooler does. Another, almost no cost improvement would be to close up the bottom of the fender area to prevent air bypassing the cooler.
Lastly, get more air to the cooler by cutting fog light size hole(s) in the valence, (might get vilified for that last one).
chris

Chris... I am recording ambient. Mocal is sold as radiator, two hoses, and mounting hardware. I made and installed a debris shield. Pics to come. Interesting idea on closing bottom of fender---that's provided there's air entering fender from ahead. "Cut a hole..." Now it's a body sculpting project. I'm notorious for converting small projects into big---not doing that this time! (Maybe.)

Originally Posted by Reiver

I know the answer to this one already.

Cudos for letting the cards play out here Reiver!

Originally Posted by GH85Carrera

Hey Karl, how about adding a fan to the Mocal once it is in place, as one more piece to test.

On my 85 911 it came with the Carrera cooler of course, but it did not have the fan. I added a fan and a manual toggle switch to turn it on. On my trip back from Savannah, GA in August of 2011 my engine had never been rebuilt. The air temps were all 100+ degrees. On the highway running at 75 or so the temps would rise to 210 and keep climbing. I flipped on the switch, and saw it slowly decline to 210.

The common thinking is that on the highway the fan is not needed. I proved to myself that is not true, the fan even helps at highway speeds. I went through a couple of iterations of turn the fan off, cruise down the interstate and the temps went up. Flip on the fan, it dropped and held steady. Turn it off, and it went up.

I do not have the scoop.

I just drove to Key west. I have never driven so far at 35 MPH and stop and go traffic. I never saw temps above 210, but my engine is rebuilt, and all cleaned up on the engine.



This is before the rebuild. It had 150,000 miles of crud and gunk keep things warmer. It for sure runs cooler now that it is all cleaned up.

Fan was considered Glen but am putting that off. Want to see where numbers come in without one. Don't see any issue with adding one downstream. Switch to fan is good idea---surly a fan doesn't need to run all the time. I bead-cleaned my 930's engine when doing a rebuild and thermal performance gain was dramatic...



Little over 100k miles. Would overheat if left standing at idle.




Beaded... could idle forever and never get to mid gauge.

Just missed you in KW. Was there a few days ago.

Originally Posted by RSTarga

The trombone was marginal on a 2.4, on a 3.2 it does almost nothing. Any well ducted radiator style cooler will out perform. The 28 tube cooler is a very good option if you don't want a radiator. I've had them all trombone; turbatrol; carrera, 28 tube. In Miami, your best option is the carrera with a fan.

Appreciate the input RS. Carrera with fan keeps coming up as THE preferred solution. I should have done more research before diving into Mocal.

Originally Posted by IROC

I had a Mocal with a fan and it was marginal with the 3.2. I should qualify the term "marginal", though. The Mocal/fan with my 2.7 was awesome. Temps would rarely rise above about 180-190F and even stayed under 200-210 on the track.

The Mocal/fan with the 3.2 would run 190 or so at the slightest hint of a hot day on the street and it would get to 230F on the track. I didn't like that. Oil temp paranoia.

One thing for sure - the Mocal in the stock fender location needs a fan.

I installed a Mocal cooler in my front IROC bumper (eliminating the Mocal in the fender) and it is awesome. I routinely run less than 180F even on hot days. Picture after driving ~20 miles on a 90F day of "city" driving (almost home from work on a summer day):

With trombo, on 95 dF day, my temps are over 200 dF IROC. Am with you on OTP!

.

[Discseven]

Completed trombo tests today. Ran out of time to deal with Mocal. Tomorrow should see Mocal done. Will post results/photos when test is complete.

[chrismorse]

I have seen a huge number of threads covering the control of oil temperature, many of them just barely keeping keeping it under big numbers until hot days/bigger or hotter engines, etc. (tracking always goes beyond original design parameters for engine and brake cooling).
Stop for a minute and think about the majority of the hot rod water cooled daily drivers, (non Porsche) - the radiator is almost always oversized for the job and the temps almost always stay rock solid, the thermostat controls the flow, so the temps stay at 185, 195, 210, or what ever the design temp is, then, the auxiliary fan pops on with slightly elevated temps, or with an switched on.
This is my rationale for proposing, Go bigger than you think you might need, let the thermostat do its job and reduce your stress about what "too damn hot" oil temps are doing to your guides, or magnesium case.

Hopefully, more will follow in Karl's footsteps, quantifying cooling options, so, others, like myself, with limited experience can benefit from some real numbers, not hopeing that a step up will be enough to avoid a $10-15K rebuild.
Rant Ends,
😄 chris

[fanaudical]

Neat thread - thanks for doing this.

I have a Morales cooler on my 2.7. I have yet to run out of cooling capacity.

[Discseven]

^^^

Update

Removed trombo today and started Mocal install. Didn't get far. Supplied bottom mounting bracket for Mocal is useless---unless hole is put in tub and rather large spacer is used to span gap between tub and Mocal. New hole in tub for this... not happening.



There's already a factory threaded hole for mounting trombo. Will fab new bracket and use factory's hole (for Mocal.) Take another day to sort this and get testing done.

.

[GH85Carrera]

Originally Posted by Discseven

^^^

Update

Removed trombo today and started Mocal install. Didn't get far. Supplied bottom mounting bracket for Mocal is useless---unless hole is put in tub and rather large spacer is used to span gap between tub and Mocal. New hole in tub for this... not happening.



There's already a factory threaded hole for mounting trombo. Will fab new bracket and use factory's hole (for Mocal.) Take another day to sort this and get testing done.

.

So you "know a guy" that can make some brackets and gizmos.

Knowing you, your bracket will be better than Mocal could make for a reasonable price. Thanks for all yer work on this.

[Discseven]

^^^ Thanks for that Glen. Will say bracket I made for test was just that, a test bracket. Before spending hours on that part, I wanted to see if Mocal was worth it.




Results:


Trombo

Testing begins in 90 dF ambient and ends in high 80s. “Slow” speed is around 35 mph in 5th gear. “Fast” is around 55 mph in 5th gear---was not possible to drive faster on 95 due to traffic congestion. “Air Scoop” is unit that takes place of passenger's side, front running light in bumper. AC is always ON. Temps are dC measured at Inlet pipe | Outlet pipe. Following the individual readout pics I've plotted all numbers for a universal perspective. Trombo testing done 8.21.19.


Dirty Trombo


Slow


Fast


Clean Trombo


Slow


Fast


Clean trombo with air scoop


Slow


Fast



Mocal

Testing is in 90 dF ambient. AC is ON. Same speed runs and gear as Trombo. AC is ON. Mocal testing done 8.23.19.

No Scoop


Slow


Fast

continued...

[Discseven]

With Scoop


Slow


Fast






I've run out of time to post reference pics to project. Will do that later today.


.

[IROC]

Are you using a fan with the Mocal? Radiator-style coolers don‘t work well at all unless you are forcing air thru them. In the fender-mount area of a 911, a radiator style cooler is going to be a liability unless you add a fan and seal off the areas around the cooler to ensure proper airflow. The factory Carrera cooler is a good example. I finally gave up on my Mocal in the fender-well area as it just doesn’t work well once you‘re trying to reject the heat of engines over 180 hp or so...

The Mocal with a fan is a great option for replacing a trombone on a 2.7.

[Reiver]

I have a Carrera unit with fan on my 3.0 Euro SC....two days ago...ambient temp 105 degrees and an 80 mile round trip to Phx area ...average speed enroute 74 and then stop/go in town.

The highest temp seen was just below 210 in stop go/say 205ish. Highway 195 to just under 200.
I have a switched fan and use it in town.

If you do not get good results with a radiator it is because of airflow...going around/under (not properly blocked off) or no airflow (fan). If air can get around the radiator it is worthless and I see to many mounted just hanging in 'space'.

I also put a block off underneath....plastic mounted to the Rad mount....this makes the radiator keep my oil about 100 degrees over ambient. In the cooler weather I remove the lower block off or the oil will remain too cool. I run 185-190 cooler weather.

[86 911 Targa]

Originally Posted by Reiver

I have a Carrera unit with fan on my 3.0 Euro SC....two days ago...ambient temp 105 degrees and an 80 mile round trip to Phx area ...average speed enroute 74 and then stop/go in town.

The highest temp seen was just below 210 in stop go/say 205ish. Highway 195 to just under 200.
I have a switched fan and use it in town.

If you do not get good results with a radiator it is because of airflow...going around/under (not properly blocked off) or no airflow (fan). If air can get around the radiator it is worthless and I see to many mounted just hanging in 'space'.

I also put a block off underneath....plastic mounted to the Rad mount....this makes the radiator keep my oil about 100 degrees over ambient. In the cooler weather I remove the lower block off or the oil will remain too cool. I run 185-190 cooler weather.

Can you please post a drawing?

G.

[Reiver]

Originally Posted by 86 911 Targa

Can you please post a drawing?

G.

Presently it is on the car and this is an old pic, I have EB motorsports SCRS bumper/valance in place now so I have modified that piece (shortened) to fit that and it would not fit the stock set up, I also welded the mount in place so it may also be a bit dif than stock
....I used 3/16th in flexible plastic sheeting and made a cardboard mock up first...very easy to do and the plastic is easy to score/cut with a box knife.
The two nuts are screwed onto the Carrera rad mount screws that project below the mount...they are already there and long enough.
This combined with a scoop (in place of the running light) or the opening on the SCRS bumper is extremely effective in forcing air where you want it.

I used this …PVC Closed Cell Expanded Plastic Sheet 1/4" x 24" x 48" - Black it comes in dif thicknesses and is great to form with a heat gun for all kinds of interior jobs too...handy stuff...can also be cut carefully with tin snips.

[Discseven]

Originally Posted by IROC

Are you using a fan with the Mocal? Radiator-style coolers don‘t work well at all unless you are forcing air thru them. In the fender-mount area of a 911, a radiator style cooler is going to be a liability unless you add a fan and seal off the areas around the cooler to ensure proper airflow. The factory Carrera cooler is a good example. I finally gave up on my Mocal in the fender-well area as it just doesn’t work well once you‘re trying to reject the heat of engines over 180 hp or so...

The Mocal with a fan is a great option for replacing a trombone on a 2.7.

No fan on this Mike. Point is to see where numbers are before dealing with a fan. Seems the horns need to be moved to make space on the forward side of Mocal to make space for a pusher. Or, puller can be mounted on rear side but that will face wheel---not sure if that's a pro or con.

.