When do I need a front mount oil cooler?
 

I'm building a 3.2 short stroke (I know, not another 3.2ss thread...) and I'm wondering if I need to upgrade to a front mount oil cooler.

The car is a 1979 SC coupe that I will be changing the front bumper to the IROC style bumper from TRE with the center mount opening.

Engine build details are as follows:

• 98mm Mahle P&C (PS98-014)
• 964 grind cams
• twin plug
• SSI heat exchangers
• 46mm PMO carbs

Car will be a sunday driver, likely no track use, just some spirited summer driving. I live in Vancouver, BC but the car will see ambient temps in excess of 100F for trips in to the Okanagan.

What i'm trying to figure out is if I need to swap out the trombone and go with a dual pass mishimoto or similar to fill out the front bumper opening.

Thoughts?

The trombone was mariginal at the best of times as far as I know... A real cooler will work better in any case. Running an IROC style bumper? Get a cooler and fill that hole :P

you 100% need a oil cooler up front with that motor.

Well, I guess you could wait and see. But with that front bumper, you may as well do it right and add the cooler.

http://forums.pelicanparts.com/uploa...1572710408.jpg

...Data from tests done on never-rebuilt '85 3.2 ltr running in Miami. Cooler in this case is in front fender. "Slow" is around 35 mph. "Fast" is between 55-70 mph. Temp sensors are located on hard lines just behind fittings to & from trombone/cooler. Water-misting is exploration into evaporative cooling the practicality of which is still being looked at.

.

190 to 200 HP+ should have front cooler... based on '70S.

cooler - unless you live in Nome, Alaska

what about a Carrera cooler in the fender????
how do they compare???

It's smaller, and has poor/obstructed airflow compared to a big FMOC - however, with a fan, it will work better stopped in traffic.

The short answer is that you need more oil cooling either when the motor generates more heat than the cooling system can dissipate - eg when the overall temperature of the system climbs uncontrolled - or when the operating temperature of the oil stabilizes at a level that is "too hot".

With high ambient temps, a FMOC is very useful. I registered 220-230F cruising on the freeway with one @ 100F - whereas at 80F ambient it would run 180F and will only hit 210F under boost. Briefly.

Stopped in traffic is a scenario that is often overlooked, I think. I've seen oil temps of 250F stuck in traffic - usually while holding 2000 RPM for air/oil flow. I added a CHT for EFI - after a few minutes hot-idling, CH temps are much higher than if you're moving. After 10 minutes, well over 200C.

Yeh, I run a full synthetic:

http://forums.pelicanparts.com/uploa...1572822768.jpg

Thanks everyone. I'm thinking I'll go with the large Mishimoto dual pass cooler. Should look good and provide more than enough cooling.

https://www.mishimoto.com/dual-pass-oil-cooler-large.html

In my experience they are excellent...grafted one into my 83 Euro SC (204 hp stock with SSI's etc. a bit higher.. 9.8-1 compression )and drive in Phx in the summer..often in 110 ambient. runs 195-205 in that kind of heat.
I switched the fan so can control its use...usually sitting in traffic...highway never need it.

oil
 

here is a photo of my vent moved the turn signal back , where the running light was...
now have direct vent to the carrera oil cooler
http://forums.pelicanparts.com/uploa...1573409227.jpg
http://forums.pelicanparts.com/uploa...1573409227.jpg

Absolutely need a cooler:)
This is a nice cooler indeed! but link is overpriced IMO
Also, despite the advert text, the pressure drop would be bigger on the dual pass version vs. a single pass version with double area. Nice cooling (due to longer path way), but increased pressure drop due to less cross section area. I like a long and FAT single pass best, but this is a very nice cooler also.

Very optimistic mark up of 377 EUR IMO even before Brexit:) The cooler is ~75$ retail on ebay without the logo
https://www.ebay.com/itm/Universal-Dual-Pass-Bar-Plate-Oil-Cooler-Large-Silver-Core-18-5-x5-5-x1-58/202712252445?hash=item2f3297801d:g:8AQAAOSwHDdc0kL q

Most of all intercoolers and oil coolers come from the same factories, also the one saying UK, US or German made etc.. Cores out of very few Asian suppliers (like it or not) sold to world wide importers who then OEM fabricate to car manufactures or aftermarket. Most of the time only end caps are welded/added locally, hence the "XX made". This looks like a straight import IMO with lifetime warranty added for the cost (but when does an oil/intercooler ever fail besides car crash!?!) Same pattern for many other segments btw these days, tig welders, fishing rods etc....only 5-10 core/hardware factories world wide...ends up as 50-1000 "local" brands. All branded and painted/packaged differently but same few core suppliers.

I understand why we most often buy local to avoid the hassle of importing, just saying good money can be saved on these nice coolers with little effort IMO;)

Sounds like an oil cooler for water-cooled engines. Your preferred oil cooler will want minimum -12AN hose/fittings for decent oil flow and space to house it in the valence/bumper.

BTW, the "trombone" cooler is just a loop of brass tubing that helps transfer some heat; it isn't really an oil cooler although it tries. It was already borderline with 2.7 engines.

Unless you prefer experimenting, why not use one of the proven coolers used in hot rod 911s for the past 40 years?

Sherwood

Is there really oil coolers for water cooled v. air cooled? Other than the CSF and Setrab, I haven't seen any coolers with -12 lines.

I don't want to sound argumentative especially when I'm asking advice, but given that immediately after the fitting, the cooler chokes down to the diameter of the cooling tubes, is the difference between -10AN and -12AN that significant?

Here is a comparison of stock SC and AN-16 hoses and fittings.
http://forums.pelicanparts.com/uploa...1573535994.jpg

Thanks, that's helpful.

Could you use a -12 to -10 adapter so that you are running -12 lines back to the fender?

Just trying to see what other options might be out there.

Many guys have used RX7 oil coolers on the track. Think they have -12 fittings; pretty sure PO said that was what the one fitted to my car was originally. It cools plenty - to the point I mask it off in winter.

Discussion here as to whether -12 lines (like the external oil lines are) or -16 (like the factory used on their oil coolers) are necessary: http://forums.pelicanparts.com/porsche-911-technical-forum/929797-mazda-racing-oil-cooler-new-85-anyone-ever-try-these.html

The thread mentioned has a ton of good info. http://forums.pelicanparts.com/porsche-911-technical-forum/929797-mazda-racing-oil-cooler-new-85-anyone-ever-try-these.html
Here is my setup. This is a Mazda cooler modified with AN-16 fittings and internal thermostat removed and blocked off. Works fine when the car is moving even on the track and at 90 deg ambient with my "new" 3,0. Stop and go traffic is another story.

To answer your question. There are coolers with -12 or metric fittings out there. Maybe others will chime in with what is currently available for front mounting. IMO, I would not even consider -10s. FWIW, I would have used metric fittings on my Mazda cooler, IF there were available back when I did my setup.

http://forums.pelicanparts.com/uploa...1573673452.jpg

FWIW, here are the metric hose ends on my -16 hose where they connect to the factory pipes where the trombone used to be attached. BAT has these hose ends.
http://forums.pelicanparts.com/uploa...1573674158.jpg

Earl's, Fluidyne and perhaps other coolers are also offered in -12AN inlet/outlet sizes. Most oil coolers (with small inlet/outlet ports) are designed for use with water-cooled engines.

As you can see from Trackrash's comparison photos, the factory fore-aft lines (ID) are about the same as -16AN hose/fittings. -12AN is the minimum size to limit system pressure drop. Luckily, most of the factory hard lines have smooth interior walls.

Compare with a -10mm AN hose/fitting dimensions:
http://forums.pelicanparts.com/uploa...1573678227.jpg

BTW, here's a good article on choosing and installing oil coolers:
https://www.pegasusautoracing.com/document.asp?DocID=TECH00133

Sherwood

Thanks for all the advice guys. I think I better understand the requirements now.

I like the Mazda oil coolers, largely because of their cost/performance ratio. They've kept my SC race car's oil where it needs to be for years now. My approach has been to drill holes in the end tank after closing the stock openings, and have AN-12 fittings welded in. But Gordon's approach has me thinking if ever I need to do this again: He used the thermostat hole for one of the fittings, turning the cooler "upside down" from how I have, for some reason (location of bits and pieces to mount the cooler)have done it. If you can screw a standard fitting in there, that much less to pay the tig welder.

His design solves one of the problems with a cooler in this location - routing the lines so they don't bump into parts of your aftermarket IROC or similar style front valance (or full fiberglass bumper). Coming out the top looks to give you more room, at least in the picture with the bumper removed.
I guess it wouldn't work for me in my SC with its comforting aluminum bumper in place, though.

http://forums.pelicanparts.com/uploa...1573777336.jpg

I've always used -12 hose and fittings, as it is just a little bit smaller ID than the Porsche tubes/fittings. Were I to do it again, I guess I'd consider the extra cost and (for routing purposes) OD of the -16. But -12 works. Dash-10 not really a good idea.

:)

I have M30 Alum Weld Bungs that can be used for the RX-7 coolers if needed....


http://forums.pelicanparts.com/uploa...1573778987.jpg

http://forums.pelicanparts.com/uploa...1573779019.jpg

Threads are hard anodized and are $25ea. I also make up custom Metric Oil Lines for the early Porsche models.

http://forums.pelicanparts.com/uploa...1573780140.jpg


For info please email me.

Len.Cummings at verizon.net

:)

:)

Thought I would bring this back, as I have had inquiries for coolers in longhood 911's, and the one shown above will clear a 73 RS type bumper and fits as factory.

Len.Cummings at verizon.net

:)

We sell a couple great cooling options from CSF Performance Coolers if you're going to an IROC bumper they have a single and dual pass front mount cooler or if you want to go the fender cooler route they just recently released an upgraded fender cooler as well.

One data point:

I tracked my 1978 911SC (JE 9.5 CR, 964 cam, SSI, 2in-1out, 180 RWHP) in the summer in Texas with an Elephant Racing wide mouth cooler (plus stock on-engine cooler) with no problems. Air was ducted to the cooler through an opening in the valence (no fan). I never had temps go beyond 210F, typically lower.

Please do not use Mishimoto they are made in china garbage that frequently have to be replaced.

I used the Mazda cooler. Changed the fittings to 16ANhttp://forums.pelicanparts.com/uploa...1624647241.jpg
http://forums.pelicanparts.com/uploa...1624647241.jpg

I am running two front oil coolers on my 930. One is a Carrera and the other is a 28 tube cooler. It's what I had and one tends to cool better when moving slower (28 tube) and the Carrera has better cooling capacity due to the fins (no fan).

Obviously you don't want to run too much cooling or you can oil mayonnaise (I hear). Has anyone run a thermostat (Mocal) between the 1st and second cooler?

This came as a thought when I was running a 930S front cooler along with the Carrera cooler.

I’m running a 44 row Setrab fender-well cooler with a large and super strong fan. Also have a duct cut in the front valance for more flow. Here in the Atlanta area, when pushing things during summer, even with the fan going I see 230F+. The fan does cool things when I’m off it but once it’s heat soaked it doesn’t go under 200-210F. Engine is pretty hot, twin plug 10.5:1 2.8L with DC65 camshaft and PMO 46 carbs, headers etc, somewhere around 260-275bhp. I wanted this car to retain the early Carrera look but in hindsight it probably does need a front cooler. The SC/RS front valance would be what I would run with the chonkiest huge front cooler there is. 8000rpm gets things hot

If you don't already have one, install the factory oil thermostat (or equivalent) in the supply line from the engine. If you haven't looked, they're usually in front of the RR tire.

Part #7
http://forums.pelicanparts.com/uploa...1630855401.jpg

Sherwood

John - it doesn't really make any sense to run a second oil thermostat anywhere, including between cooler 1 and cooler 2. More plumbing for no benefit I can see, as the factory thermostat will be closed until the engine reaches operating temperature (about 190*F). Of course, it never completely close - some oil always flows forward. Then it opens. The thermostat doesn't operate like some kind of laboratory system, where something must be kept within rigid limits at all times. So you should get the same temperature regulation regardless of how many coolers you plumb into the system.

And the engine mounted cooler has its own thermostat.

Thanks Walt for the response.

You can always go bananas and duct it through the hood! :)
Keeps the oil from a 3.6 (no internal cooler) at a constant 220 even at hard extended work.
Last weekend I did a 1.5h stint, only ~75ish ambient but still. Maybe peaked at 225.

http://forums.pelicanparts.com/uploa...1631519697.jpg


http://forums.pelicanparts.com/uploa...1631519719.jpg

Magnus - doesn't this through hood outlet for front center coolers mean you can't have a spare tire up front?

I like this setup for cooling, and in my car which races with very few rules on body modifications I did just that. Two 964 coolers mounted side by side and plumbed in parallel and exiting out a sort of NACA duct shape in the hood are all the cooling my 2.8 needs, so the engine mounted cooler is converted to an oil filter.

http://forums.pelicanparts.com/uploa...1631575988.JPG
http://forums.pelicanparts.com/uploa...1631575988.JPG

But I can't do that on my SC race car - rules I run under don't allow it. But there is adequate room for the hot air to vent backward if you mount the cooler as far forward as you can in the valance's cutout. True, it can go under the car, affecting aero. But my class has rules which limit aero modifications anyway. And a street car's owner ought not to worry much about aero at sensible highway speeds, as long as it isn't way out of balance.

Underneath the car is exactly where you want it to go .
The early 70s style rsr bodywork mod behind the cooler got the rough shape ok(just needs smoothing ) , add some channeling underneath and then a rear shape to add diffusing would need to be added .
The rear is the real problem due to the lump of engine being back there …

No! Underneath the car is exactly where you don't want the air to go! The best place for the air to go is out of the hood near the front of the car and over the bodywork.

The last place you want the air to go is under the car. It is better to have it go into the frunk than under the car....

Yeah right .
Inverted wing Scott .
Inverted wing …..

This should get interesting.

Don't lots of race cars - NASCAR, for instance, as well as Porsche factor race cars - run front spoilers which are almost on the ground? To keep air out of that space, because they want a low pressure under the front, and a higher pressure above it?

A typical Porsche silhouette is a sort of a non-inverted (i.e., regular) wing shape, isn't it?