Quote:
Originally Posted by V8SuperBeetle
THANKS for all the help and suggestions. I'm actually reconsidering my original radiator setup plan.
New plan. I'm going to lay the radiator flat / horizontal and use the factory vents that take advantage of the low pressure system behind the car to draw air into the "engine compartment to cool the air cooled engine, but in my case it'll cool the radiator. Also, I'll build some ductwork to direct the airflow through the radiator and out of the underside of the car which, in my mind, will keep the hot air from the exhaust and engine out.
Lastly, if I find myself in need of a little more air flow to radiator I'll get some deck lid stand offs.
I'm thinking I might not need them because the later model vw deck lids have vents to increase air flow, or is it to let hot air out from the engine? |
I think the air flow is the wrong way round. You need to suck the air from the underside and vent out from the top. I agree that the vents under the rear window are in a high pressure zone, as is the decklid vents on a super but to a lesser extent. You could add a cowl over the decklid vents as per a 70's bug that would create a low pressure area, similarly with a roof mounted lip.
A further consideration is that in traffic the cool air will be under the car with the hot air on top. If nothing else there will be a natural flow up from the bottom to the top (hot air rises) so assisting the cooling through the rad. with your system as soon as you stop the air flow will reverse unless beaten back by the fan.
In the desert/off-road world there will be serious consideration given to sucking up debris that would clog or damage a radiator. For a street car this isn't a real consideration unless you intend to regularly blast up unmade tracks. In the '80s I used to campaign a road rally Imp - a rear engined water cooled car with an engine driven fan attached to a radiator that sucked air from below on the left hand side. Given the proximity of the LH rear wheel the rad stayed remarkably clear even when it was used in anger down muddy farm tracks.
i think that you will find that you will need a fair amount of vent so initially take advantage of all the outlets including drilling holes in the number plate panel and standing the number plate off to assist in air flow.
Clive