Hot Air Socket 911

IXLOR8 · 10-21-2005, 07:43 AM

Question: Which will provide the best engine cooling for a 1974 Porsche 911S 2.7 engine? Do not use heater in car.

1) Keep the car original - with heat ducts and hoses going to heat exchanger intact.

2) Remove hoses.

3) Block the 2.5" opening on driver and passenger side.

4) Place block off plate on driver side and place hose from passengerside to heat exchanger.

5) Who knows?

Thanks

911pcars · 10-21-2005, 08:40 AM

1. Remove dead animals and environmental trash from under engine cooling shroud.
2. Ensure fan belt isn't slipping
3. Remove A/C accoutrements (deck lid condenser, compressor belt, delete using A/C
4. Use max-rotation engine/fan pulleys
5. Add external (fender-mount) oil cooler w/fan

The above are listed in order of increased fund dispersement.

... and a myriad of other engine cooling devises.

Hope this helps,
Sherwood
http://members.rennlist.org/911pcars

IXLOR8 · 10-21-2005, 08:55 AM

Any comments on the heat ducts? When I got the car, no hoses were on it. The driverside duct was damage. The PO gave me a 12 inch hose, but it is not long enough.

What is the best route at this time?

304065 · 10-21-2005, 09:07 AM

You don't say whether you have upgraded from the five blade fan to the eleven blade fan. If you haven't, do.

You either need to run the hoses down to the heat exchangers or cap the outlets. Blowing air through the heat exchanger clamshells keeps the exhaust pipes cooler, even if that air is vented overboard. Guys who use headers, well, the headers are open to the underside of the car.

My advice to you: keep everything original. I don't use the heat in my 911 race car but I sure do use the defroster when it rains. And it rains a lot.

IXLOR8 · 10-21-2005, 09:15 AM

My car has a 11 blade fan installed. Thanks for you feed back.

Thanks

Rock

ErVikingo · 10-21-2005, 09:33 AM

Sherwood,

How about a trick install of an MPC unit ???

911pcars · 10-21-2005, 10:59 AM

"How about a trick install of an MPC unit ???"

Here's one for the brakes on a series-leading TransAm factory jag.

The pump assy. mounted in the rear:

Inlet passage for brake duct:

and one for a 930 intercooler:

Sherwood

ErVikingo · 10-21-2005, 11:59 AM

Could it be used to mist the fan to achieve a higher cooling factor?

Not sure if it would have an effect on the alternator.

Surely appreciate your feedback and thansk for the pics !

911pcars · 10-21-2005, 01:58 PM

Juan,
If you're aware of the limitations of this for prolonged use (see my previous post), yes it'll work.

I've noted in past threads that when water is introduced at the fan inlet, the centrifugal force forces water droplets outward to the fan housing where it tends to collect. However, it eventually evaporates due to the air flow - better when engine speed is higher. Evaporation causes the air temperature reduction.

A better idea might be to point a couple of nozzles into the upper shroud (pick two strategic areas to drill). The alternator sees rain water and water vapor during normal operation, so no harm there. This isn't like we're aiming a garden hose into the engine.

I wish I had some pics of such an install but I don't.

Sherwood

ErVikingo · 10-21-2005, 02:26 PM

Thanks Sherwood. Reading Grady's posts on the "rubbermaid solution" got me thinking that using an MPC would be better.

Cheers, Juan

svandamme · svandamme's Garage

the block-off setup actually does cool a lot better
mine has no external oil cooler
before the rebuild, wihout the blockoff, on a hot day , it would get hot(ter) , now after the rebuild, with blockoff, i have to gun it really hard to get it above 100 even on a hot day... i'm sure the rebuild has something to do with it , but i'm talking 20C difference before and after, so i'm pretty sure the blockoff has something to do with it since that's the only modification on my cooling system...