Cabin heating in air cooled models

[iamthestig]

I was thinking of this the during that cold spell the last week or so whilst waiting for my car (alas not a porsche!) to defrost the screen. Now on a water cooled engine the coolant gets pumped through a heater matrix somewhere under the dash, and a fan blows air over the hot matrix to warm the cabin - simple.
But how does the heating work in air cooled cars? Obviously you could just blow the cooling air off the engine into the cabin but: a) the air comes from the wrong end to clear the screen and b) by the time the warm air get all that way it must have cooled down loads and be fairly innefective at clearing the windscreen on a heavily frosty morning or do you just c) leave the car in the garage and neaver take it out when it's below freezing?

Thanks for answering perhaps a rather silly question from an inquisitive and hopefull future owner!

[sleep envy]

There are heat exchangers around the manifolds.

Warm air from a stone cold engine in seconds on frost mornings :cosy:

ETA - the problem is losing the heat, not trying to keep the car warm. Two 50mm ducts in the sills (one either side) which channel the air to the front fans.

Edited by sleep envy on Monday 13th November 13:18

[Ian964]

There are air-to-air heat exchangers on the exhaust manifolds, and fans to take this heated air forward to the vents etc. I find that the heat comes through much more quickly than on a water-cooled car - on those cold days the air coming out of the windscreen vents was noticably warm after less than a minute.

cheers
Ian

[iamthestig]

Thanks for the replies, it had just been itching at the back of my mind for a while. So a 964 or 993 can still be comfortably used every day then - even in the deapest cold we get in british winters. Got an assement and interveiw for a new job on monday, if I get it it means I will drastically reduce my annual mileage and be able to cut down to one car. Oh and a small pay rise after the 2 years probation period, all being well I'll be treating myself to a nice Carrera 2.

[sleep envy]

iamthestig said:

So a 964 or 993 can still be comfortably used every day then - even in the deapest cold we get in british winters.

No problems whatsoever, it's the summer you want to be worried about if you don't have A/C

[evil jack]

sleep envy said:

it's the summer you want to be worried about if you don't have A/C

Be worried even if you do. Every winter, come the annual service, I spend £££££££s fixing the damn thing. ]
Every summer, the first time I need it, I find it's blowing warm air at me

[sleep envy]

evil jack said:

Every summer, the first time I need it, I find it's blowing warm air at me

Do you use it all year round?