How many cc's or how much HP before..., needing an external oil cooler in 914-6? Options

[horizontally-opposed]

Obviously, a 3.0-liter SC motor is gonna want an external oil cooler, but what about a 2.4E or S? Will an on-case cooler do the job, or is it iffy?

Also, who is using the right inner fender for the cooler spot on a /6? What size engine are you running and what temperature extremes have you seen?

Thanks!

pete

[ArtechnikA]

the old rule-of-thumb was 175-ish HP.

but a 150-HP engine used exclusively for track events in SoCal/AZ/TX by two drivers is going to need one more than a 210-HP engine in daily-driver commuter service...

i've never seen anyone use the right-fender location in a 914.6 - 914's don't have the ventilation from the horn grille to the fenderwell that 911's do. and the folks that have done airflow studies tell me air doesn't come in the turnsignal tunnel like you'd hope it would, so that doesn't buy yo much either.

a 2,4S is kinda on the edge. i think you'd need it if you spent any amount of time on the track, probably not in street/AX service.

[lapuwali]

As I recall, the 2.4E used just the on-case cooler in the 911. The T certainly did. I think only the S used a separate cooler, and it was just the simple loop cooler.

[Joe Bob]

The 2.2 in Frank runs at 225 when pushed.....180-200 otherwise....with no external cooler and NO engine sheet metal....prolly 140 ish hp.

Manfred runs a 2.0 "S" factory rated at 180 hp....have not had it on the track yet, but stays around 200 w/o a cooler in spirited street driving.

The Rocket, a 3.0 CIS 914 needed both internal and external cooling....on long trips it just kept climbing....at the the track it would climb to 220 and stay there with two coolers.

Red, has a 3.6 which has no internal cooler, has ALWAYS needed two external coolers....

[horizontally-opposed]

Sorry, meant cooler in right REAR fender...

So is the consensus that street cars might get away with a 2.4 or so without an external cooler?

And does the tail-dragger get better wind/air cooling than the 914-6 did?

Thanks,

pete

[ArtechnikA]

QUOTE (horizontally-opposed @ Feb 7 2005, 06:39 PM)

Sorry, meant cooler in right REAR fender... So is the consensus that street cars might get away with a 2.4 or so without an external cooler? And does the tail-dragger get better wind/air cooling than the 914-6 did?

rear fender is easy - it doesn't get any airflow to speak of either. i wouldn't waste the time, effort, or AN hose trying that approach unless air works different near your car than everybody else who's tried it ...

no cooler in a 2,4? yes - maybe. depends on when, where, how, and for how long the car is driven. you'll be wanting a good, calibrated oil temp sender and guage, so you get to watch it either way...

it will never be easier to plumb a cooler than when the engine and transmission are out. if they aren't, i'd probably be tempted to drive it and see if it's working for you, keeping in mind that you may be on the edge thermally, and be prepared to back off if you have to. you're planning to use a good quality synthetic oil, right ?

911's cooled better. when the '69 911T engine was put in the /6 it ran closer to the red zone than some liked. so they moved the red zone on the gauge. the 2,0 T had plenty of thermal safety margin. carbed engines tend to run a bit cooler than, say, a CIS engine. a 2,4S was a MFI engine, but MFI in a 914.6 is a challenge, so maybe you're planning something different...

[IronHillRestorations]

QUOTE (ArtechnikA @ Feb 7 2005, 03:55 PM)

rear fender is easy - it doesn't get any airflow to speak of either. i wouldn't waste the time, effort, or AN hose trying that approach unless air works different near your car than everybody else who's tried it ...

I disagree. I had a 3.0 and mounted a 25 row Mocal cooler in the rear fender, and never saw more than 210, on a long trip in the summer. I did have a Smelios cast aluminum tank though, which probably gives some inductive cooling.

Just running the oil through a cooler will provide heat transfer, and subsequent cooling.

The crux of the matter is what you plan to do with the car, where you live, and what you plan to do with the car.

[ArtechnikA]

QUOTE (9146986 @ Feb 7 2005, 07:15 PM)

I disagree. I had a 3.0 and mounted a 25 row Mocal cooler in the rear fender, and never saw more than 210, on a long trip in the summer.

what were your temps before mounting the cooler ?

[J P Stein]

Just my opinion, of course, but don't fool around. Put a good cooler in the nose. Mr. Anderson goes along with the factory's
example of a cooler for anything over 170 hp (in a 911) or so, and claims that 6s run hotter in 914s than 911s. I'm not real sure about that last bit but will bow to his expertise..

No ex coolers in the 2.7Ls (165 hp)and look what happened to them. The 2.4L, S motor has 190 hp, so there ya go. The E had 165hp, which would make it marginal. My 140 hp T in the 914 didn't need one.

[ArtechnikA]

QUOTE (J P Stein @ Feb 7 2005, 10:04 PM)

No ex coolers in the 2.7Ls (165 hp)and look what happened to them.

what happened to them was thermal reactors (lots of additional heat) and 5-bladed fans that reduced the effectiveness of the on-block cooler, so it's hard to get a good apples-to-apples picture...

[IronHillRestorations]

QUOTE (ArtechnikA @ Feb 7 2005, 06:24 PM)

what were your temps before mounting the cooler ?

The cooler was installed the same time as the engine, so I had no A/B comparisson.

I built a car for a customer, a Euro Carrera 3.0 that was built out to 3.2 with 9.5/1 pistons, and GE60 cams. I did the whole front cooler thing for that car with a custom steel front shroud. The car was used for autocross, DE, time trial, and on some trips. The owner told me he never ever saw over 200.

I know Dave at GPR has a Motronic 3.2 in his car, with no external oil cooler, and doesn't have any problems, but it is a street car.

If you are going to do track events, then I agree with JP. But if it's just autocross, then I'd opt for the rear quarter install. Main reason I went that way, is I used the car for trips and didn't want to loose any trunk space.

Bruce A. does say that much of the cooling you get in the factory set up with the hard brass lines, is inductive cooling from the lines. His favorite oil cooler is the 27 row brass unit, which is nothing like the "radiator" units most of us use.