Coupe Oil Cooler Option

[Dave Tabor]

Hi Folks,

I'm at 14,000+ miles on my Coupe #17 and thought I'd post some oil cooler details.

My motor is a FRPP 302 (x302b) carbureted (QuickFuel 650 mechanical secondaries, annular booster). TKO600 (0.82 5th grear). 2015 Mustang 3.55 IRS.

I ran one HPDE with no cooler and oil temps went up to 260F+ (conventional oil) in 20 minute sessions.

I then added a Derale Cooling Products 15845 dual fan unit on the inside of the engine compartment, just above the steering rack- with an undercar scoop to direct ambient air to it. Still late in a 20 minute track session temps were 240F+. During a ~36-minute rally run at ~100 mph (~3850 rpm) temps crept up to 260F+. And my oil temp gauge scale is not linear nor accurate up there. Pictures of the Derale cooler and where is was mounted are attached- you can see the top of the aluminum air scoop near the battery.

It seems to be sustained rpm that gets the oil temps up there. Coolant stays ~190F. RPM does it: perhaps valvetrain heat and/or oil is moving too fast through too small a cooler.

I just set up a cooler like I've seen on one of the original cars. It's a Setrab SET-625-7612. 6 extra rows over the Derale.

I don't like feeding it 'hot' radiator air but it won't fit where the Derale was mounted (pics of the Derale cooler and where it was mounted). However I can go to an even larger Setrab cooler with the same width/fittings.

Initial road tests - all temps taken with sensor in the pan, analog sweep gauge, driving several miles on the highway in-gear that provides the rpms below- these are not under any real load- just driving at 60-75 mph.

2500 rpm: 160F
3000 rpm: 160F
4200 rpm: 220F

These numbers are about 25 degrees F below what I was getting with the Derale cooler under the same test conditions.

I'm calling it good until the next track day.

Dave
Gen III Coupe #17

[AC Bill]

Curious as to where your oil temp sensor is located? To me, those oil temps seem pretty darn hot.
My roadster's SW oil temp gauge only starts to read at 140. Even after some sustained spirited driving on a warm day, it barely makes it to 150-160 range. It's a EFI 302 with 3.55 rear. My sensor is in the oil pan.

[marshallmosty]

I had a 331 based 302 in a road race Mustang (American Iron Series with NASA) and it would typically see 260F but creep to 300F during some of the longer races. Those I talked to indicated that as long as you are using a quality synthetic oil and oil weight to go with your bearing clearances, that "under 300F" was just fine. I never had an oil related issue with that methodology in 15 years of open tracking that car with a variety of powerplants ranging from an essentially stock 302 to the 331 that put down 335HP/375TQ to the wheels.

We would always say that if you aren't at 240F oil temp, it's not ready to race. LOL

For reference I had a 7qt Canton road race pan and the oil temp sensor was in the rear sump of the pan.

[Dave Tabor]

Curious as to where your oil temp sensor is located? To me, those oil temps seem pretty darn hot.
My roadster's SW oil temp gauge only starts to read at 140. Even after some sustained spirited driving on a warm day, it barely makes it to 150-160 range. It's a EFI 302 with 3.55 rear. My sensor is in the oil pan.

all temps taken with sensor in the pan, analog sweep gauge,

[Skuzzy]

You do not want to run your engine hard with oil temperatures below 220F. The oil has to get that hot in order to burn off moisture. If you are running blended fuels, moisture is a natural by-product of the combustion process. Oil needs to stay hot enough to boil off the moisture or acids will form.