Suggestions on how to cool the engine down through air flow? I’m in the process of adding an external oil cooler but also looking at ways to redirect the air flow in the engine compartment to be more beneficial in cooling the engine.

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The whole engine lid is fresh air intake. Don't think you can force that through pvc. I'm going to regret commenting on this. Oof.

Move the heater duct hose out of the way for starters.

Already did, just reading some of the forums in reguards to if its more beneficial to draw air in through the engine top screen or pull the hot air out?

Somewhere here’s a college engineering study of the 914 airflow and it shows the rubber flaps under the body creates airflow bottom to top.

914 Areodynamics mentioned above

Thanks for the information, I will read up on it! Have a great evening.....I read the articles, a lot of valuable information. thanks for direction/education.

Back in the day an engineer/914 owner tried just about everything to add cooling, the best he did was a small scoop, passenger side, running into the little side grill over the battery. But even that was such a small improvement he ended up removing it.

If it's a race car you can duct a big hose from the front, through the cab passenger side, directed right at the fan.

A few have added side grills like on a boxster, total hack IMHO.

Thanks Mark for the suggestions....

Seem like this would be easy to do since its a exercise purly of aerodynamics ???


But since its aircooled the car needs to be moving

There is no cooling soultion to a car standing still.

I always thought naca ducks rocker panels were the hot ticket .

But if i run into kelly johnson , ill ask em


A upside down reverse winglet on the sail panel would in theory
Funnel air down thru to the engine rain tray area

Would that even help?

Elliot ?









This


Coming from a guy who has a big/4
With under the trunk setrab fan cooler
And no temp guages ,only the red oil light .

So ive contemplated this before

Wouldn't you want to funnel all available fresh air twards the oil cooler
Not ? Engine compartment

Great thoughts! I would think funneling fresh air to both the oil cooler and the engine compartment would be the best of both worlds!

Why do you need more cooling in the first place? What have you done to the engine to make it run too hot?

It’s an oil cooled motor. Do a great job at that and get a temp gauge.

Same thing i said to my mechanic but he said all i need is the
Red oil light and that

" guages are just for show "

You are joking right? what makes you think they aren't cooling @ idle...the fan is turning and there is little load on the motor @ that stage. bad sealing in the engine bay causes the motor to draw hot air from underneath @ idle and under load,the following are normal causes and others,
poor fit of engine tin on engine,
bad plug wire seals,
bad engine tin seal,
dirty oil cooler,inside and out,
dirty engine block around cylinders and underneath,
wrong engine timing,
jammed up cooling flaps,
blocked fan,
wrong valve clearances,
worn out motor,
etc etc others may add but that's it mostly.
Remember driving 14,000 kms around most of the lower part of Australia in a Bus,properly sealed engine bay and keep it tuned,never had an issue...no different with a 914.

All are good points! As it was posted there are a lot of things that would contribute to higher than normal engine oil temps. Mine isn’t running at temps that far out of norm but it Cain’t hurt to improve on the system to get the temps down a few more degrees, if it would add to the longivity of the engine. At this time my 73-2.0 is pretty stock with fuel injection. Again thanks for all the comments/suggestions.

I put a fan on the oil cooler for my 930. Really made a difference with the oil temps.

Click to view attachment

For the 914, how about adding these to the engine hood?

Click to view attachment

And adding those fan would be to pump air in
Or remove hot air out ?

check out Tangereen racing aka Chris Foley has a top mounted fan system
but i can tell you that with my oil cooler cleaned and a new aux oil cooler mounted i have not had annissue with oil or head temps at all since then- if you have stock tin, and all the proper under side tins you should not have a problem. i live in SC, and at 95 degrees with the extra aux oil cooler my temps dont exceed 210.

The 914 takes cooling air in through the engine lid, and expels it out under the car. It is important to keep the cooler air on top of the motor from the warmer air under the car. That's one of the reasons why we have engine tin and seals and such. Those should be in place.

Make sure all of the holes in the engine tin and fan shroud and such are plugged. Especially the hole on top of the fan shroud where you would look to set the ignition timing.

There are flaps inside the engine tin. They not only block cooling air flow when the engine is cold so that it warms up faster, but they also direct air through the oil cooler when the engine is warm. Some folks thought it would be a good idea to leave the flaps out--it isn't. Make sure they are there; you should see a shaft that goes across the engine in front of the oil filler tower.

If you can get more air into the engine bay, that can help with cooling. The ducting that Charlie Davis did a number of years ago (that's the one that was referred to above) did help some. Changing to a GT-style engine lid (where the solid front half is replaced by more mesh) can help a bit as well. I am told that putting up a deflector across the rear of the roof to direct air toward the engine bay helps significantly when at speed.

In ~73 or so, the factory put some deflectors at the front edge of the engine bay along the floor pan. Those create some turbulence under the car and evidently help pull air down through the engine, helping move heat out a bit.


I will echo some of the earlier posts, though: Why do you think you need more cooling? Any data to back that up?

--DD

Besides what Dave has said, a couple of people have reported lower temps by removing the rain tray. Not big changes but more like 5 degrees.

The horizontal cooling system is more suited to modified engines, but my thermostat takeoff for external oil cooler has much more application to stock or improved engines.
I'm convinced the stock cooler is horribly inefficient, and removing it in favor of an external cooler is the best way to improve oil cooling. It has the added benefit of increasing cooling air to the cylinders/heads.

I’m on a bunch of forums related to older cars and I see a theme. You just asked the internet to outsmart Porsche/VW engineers. Only three things can come of this. First, you could discover something the engineers wanted but the bean counters nixed because the cooling was ‘good enough.’ Second, technology could have come up with something new and demonstrably better. Third, the ‘bro’s’ show up, and they’ve all got opinions.

Improve your cooling: pull your engine and disassemble for a reseal. Get rid of all the leaves and mouse nesting materials you’ve accumulated over the last 40+ years. They’re preventing your cooling system from working. Maybe even replace the oil cooler. Get rid of any stupid all the way to the ground spoilers that keep the air from getting to your fan. Put the air deflectors back on. Check your timing, it can effect temperature. Check your injectors. Are they all gummed up? That makes the car run lean. Lean is hot.

In short, maintain the intended cooling system. Until you’ve done this, there’s no point coming in here and asking us ‘bro’s’ if we know what to do.

You can start from the assumption that the Porsche/VW engineers knew what they were doing and the car worked well when it came out. If yours is stock as you say, something is preventing an effective system from working as intended. Don’t modify it, fix that!

I’ve cleaned my engine compartment and thoroughly went through and sealed any holes. Engine seams to be running in acceptable temp range. No further issues..thanks

Except there is the engine in between, with cooling tin and rubber seals all around it. Wouldn't that would prevent airflow in that direction?

Dave Darling can correct me if I’m wrong, I think the flaps create a low pressure area so that air from the top of the car can more easily get to the cooling fan opening.

Yes. I'm wondering if "bottom to top" was a typo, since the whole design of the cooling system, including the flaps, is to create/assist airflow from top to bottom.

Yup, they help pull air down through the engine. They don't push air up, which would be the absolute last thing you'd want anyway!!!

--DD

It amazes me after all these years on this forum, some people still don't understand which way the air flows.

Clue: if you still don't get it. It does NOT flow upward.

I’m running a dual grilled lid with no rain tray. Stock oil cooler on a 138hp 2056 with oil temps running 220 or so. Good air flow and stock oil cooler seem to be enough foe now, but planning to re-install the external cooler I had on the turbo motor for a little extra cooling when autocrossing in 90+ temps.

With the rain tray in place there's very little space for airflow around the tray ?? If that is enough for cooling a stock motor, why do we worry? If it overheats it must be a mechanical part failed somewhere? I'm asking to learn, not being an engineer and just a shade tree mechanic.

My tray is off 1/2 the year but the rain season is ahead.

Naca ducts or a parallelogram cut into the sail panel area to channel air to the dead zone.

OK, for some experience in thinking outside the box (sorry, no pictures). I ran a 72 914/4 2.0 in SCCA GT-3 in the late 80's, while still street legal, drivable and a killer auto-x car. The fan had all the fins except the four to support the rim removed by the PO (who had set it up as a Time Trial car in CA). In order to cool the cylinders for street use, we put a heater blower fan from a late 70's 911 in the rear trunk, blowing air through two ducts, one to each side of the flat 4 connected to the engine tin. We installed a head temp gauge just to monitor it, and while I can't remember the readings, overheating the cylinders was never an issue. The fan was wired to run continuously with the ignition on.

Another creative solution I saw while running the PCA track events at Texas World Speedway in the 80's was a 914-6 with a huge vinyl water bag placed in the frunk with water lines routed to the engine compartment to spray a fine mist onto the cylinders of each bank. Instead of a water pump, the bag was encircled with bungee cords to provide pressure to squeeze the bag to keep the water flowing. Obviously, the water needed to be refilled periodically, but it was sufficient for quite a number of laps on the track (think August in south Texas for a measure of the ambient temperature!). While this obviously is not a streetable solution, it certainly is different from anything else I've seen here!

Incorporating a small supply of water and a very small high pressure pump using misting nozzles to spray a fine mist into the main cooling fan for short periods when overheating could be presumed would work very well as evaporating water is a great heat sink.

and have been thinking about this, some setup that would spray a fine mist directly into the cooling fan (simplest) when the head temp sensor hits a certain #. Might be perfect for street cars on hot days going uphill when temps start to push toward 400.

The Dakota Digital gauge I'm running has an adjustable alarm, I'd have to look into it further to see if it can trigger an additional system

Ah, your idea triggered my old memory enough to recall that the vinyl water bag did indeed squirt the water into the fan, an obviously much easier setup.