When do I need a front mount oil cooler?

[Focker]

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?

[Speed metal]

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

[colingreene]

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

[Trackrash]

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

[Discseven]

...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.

.

[roblav]

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

[RWebb]

cooler - unless you live in Nome, Alaska

[IS300]

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

[spuggy]

Originally Posted by IS300

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:

[Focker]

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

[Reiver]

Originally Posted by IS300

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

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.

[IS300]

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

[JakobM]

Originally Posted by Focker

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

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

[911pcars]

Originally Posted by Focker

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

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

[Focker]

Originally Posted by 911pcars

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?

[Trackrash]

Here is a comparison of stock SC and AN-16 hoses and fittings.

[Focker]

Originally Posted by Trackrash

Here is a comparison of stock SC and AN-16 hoses and fittings.

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.

[spuggy]

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: Mazda Racing oil cooler, new $85. Anyone ever try these?

[Trackrash]

Originally Posted by Focker

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.

The thread mentioned has a ton of good info. Mazda Racing oil cooler, new $85. Anyone ever try these?
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.

[Trackrash]

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.