oil cooler needs more direct air

[bubba1810]

The oil cooler is 25 row cooler and is located up behind the rt fender and the bulk is behind the headlight. It works pretty well but I feel it would work better if it had more direct air flow. I don't want to use a fan as I never drive in heavy traffic. I live in the mtns of Colorado. I want to build an air box to direct the air flow at the cooler. It would fit below the horn mounts and bend up to the ft lower portion of the oil cooler. I have a air flow director replacing the running light on the ft rt so it already get more direct air. The oil temp under normal driving runs about 210. When driving hard it gets up to 230. I want the oil to be cooler under hard driving. The air box would direct outside air directly at the cooler. Interested in opinions as to effectiveness.

[cmcfaul]

what year car?

[Reiver]

Bubba, lots of unknowns but I'll swag it.
I've an '83 SC 930-10 (9.8-1 comp) with a Carrera oil cooler unit that has the block off around it and a small scoop in place of the right bumper running light.
I generally run about 195 in Az this time of year...in the 80's ambient. I don't see 210 unless I am hammering it.
If there is no block off around your cooler (setrab maybe) the air goes the path of least resistance ...around.
In the summer I also block off the bottom section with a piece of extruded PVC panel (I've moved the horns for clean air) and generally get 100 degrees above ambient so 100 ambient 200 oil temp.
I do have the stock fan that is switched on the dash so I can control when.
I don't think I've ever seen 230 degrees and usually 210 even when 110 ambient.
So yes, blocking off and forcing the air thru the radiator works.

[pemz0r]

I bought aluminum ducting from Home depot. it's easy to bend and mold. I use it for my 1966 SWB.



I have also seen this...

[Alan L]

I'm not sure what cooler you have - but the 'trombone' ones were never greatly effective. Not sure more airflow would make a heap of difference. But I have a trombone one and don't have any cooling issues , even in hot temps (30+C - which I think is getting close to 100 F).
You want to check the main cooler on the engine is working properly and the thermostat in the cooler line is working properly.
Regards
Alan

[Flat6pac]

If you think about it, there is more to the oil cooler than just the row cooler in the fender. The multiple row cooler was deemed not much of an improvement over the trombone.
Reality is the lines along the right side, if cleaned, becomes part of the total efficiency of the cooling system. Time spent with some steel wool works miracles for efficiency.
The front bumpers on I believe 86 on, has a notch on the underside right to allow more flow to the cooler area.
Bruce

[bubba1810]

My car is a 1975 911 S coupe w upgrades to SSI exhaust, 92 mm JE pistons, sc grind cams, nickies cylinders, new oil pump, 9.5 compression, new head studs w helicoils. Engine totally rebuilt and machined by Ollies. The oil cooler is a Setrab 25 row.

[infraredcalvin]

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[KTL]

Get a wide inlet duct that you can mount below the front valance, with a hose nozzle on the back of it. The hose from there can be routed to a receiving nozzle in a shroud that covers the leading side of the cooler. Butler Built makes a lot of ducts and you can find shrouds from other brands of coolers

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New Racing Parts - Oil Cooler Duct and Bracket

[cmcfaul]

On a long hood, pre 74, its very difficult to get air to the fender cooler because the battery boxes are in the way. No room for a fan either.

Chris

[chris_seven]

I have always found auxiliary cooling to be an interesting subject but 911 are a particular challenge.

The engine mounted coolers do benefit from having a substantial air flow and have reasonably 'solid' oil which provides a good heat exchange mediumas they are on the pressure side of the system.

The Auxiliary cooler takes oil from the scavenge pump which is likely to be well aerated and then passes it though a cooler with minimal air flow under the wing.

Hardly surprising that they don't seem to work too well.

The 1969 and some of the later models also have a louvered plate which tends to trap air and must reduce the local Delta T which can't help.

The older trombone and tube coolers which were not shrouded may be better than some of the later coolers with protection plates.

Using Pressed Plate Coolers such as Setrab or Mocal doesn't seem the best idea as this style of cooler does need forced air to function well.

Tube and Fin coolers which are criticised by many Plate cooler suppliers seem to have some merit as they will radiate more heat into stagnant air.

I used to use one of these coolers under the deck lid of my 1965 Rally Car which always ran cool.




More recently we have been looking at wire wound coolers and we have one mounted in the engine bay of a 1967 912 fitted with a Carrera 3 motor. It uses partial flow from a sandwich plate mounted under the filter and has been quite good.



The next step is to make an underwing version and to fit an air/oil separator at the end of the hard line and improve mass transport into the cooler.

We are also making hard lines with a 'Turbolator' spring fitted to try to make the oil contact the tube wall more efficiently and again improve heat rejection along the tube.



Finned tubes are OK but if the oil flow along them is streamlined and the oil is aerated their benefit may be small.

[Ducman]

IMO go straight for a better cooler like the wide mouth Carerra style from ERP. You can spend a lot of time and money on lesser coolers and ducts and in the end be marginal. Based on your engine I would think you drop one in and not have to do anything else.