To drive with the deck lid open or not

[Asesapie]

So Ive always wondered what is right, I've heard that if you drive with your deck lid open down the freeway it helps to cool the motor better than with it closed cause it let's hot air escape faster and cool air in. But I've also heard that if you drive with the lid open it sucks the hot exhaust in and doesnt cool as good. So I just want to know so I can finally have a right answer. I guess has anyone ever tested the motor temp after driving a bit with the lid open and the lid closed?
So what is right?

[colxvws63]

Volkswagen engineers put alot of work into seperating the cool air on top from the hot air that goes out the bottom ,thats why you should have all your tins and seals in place .When you run with our lid open your just sucking the hot air back in the sealed engine compartment .Of course if you drive a baja like me ,your thowing all the good engineering out the window

[ONEBADBUG]

Open at the top, (standoffs)yes, open at the bottom, no.
Missing the tin or the rubber seal covering the exhaust, bad.
Missing the tin between the engine/trans, not so bad.
No rear bodywork, as in a baja, all the rules no longer count.
The important point is to keep from sucking the air heated by the exhaust into the fan.
I speak from personal experience.

[Doodoob]

I hate to disagree, but I have had my engine run cooler here in Las Vegas with the tennis ball on the deck lid latch. Even Gene Berg reccomends it in some situations........"One interesting note was that when I installed the 1971 system in my 1967 VW, I had to add more air intake. The convertible louvered trunk lid was required to get full cooling benefit and take advantage of the higher CFM fan. Yes, I realize that these lids are hard to find and suggest propping the trunk lid open a couple inches at the bottom if you do not have the convertible lid."
Check out the full article
http://www.geneberg.com/cat.php?name=Technical Information&cPath=2731
Also this topic is covered on the Samba.........everyone has there own oppinion. When it gets 96` or above here in Las Vegas my car doesnt like it with the deck lid closed. Put a tennis ball on the latch and it does better.

[Asesapie]

I guess I should have been specific with what model of VW I was talking about which is a bus.

[hubcapt]

I've always ran lid open or off on long summer trips in the bus, makes sense to me to let it breath. Although I've never tested it...

I do remember a thread saying that originally, if everything is in place, the designed setup is actually supposed to draw a vacuum on the top side of the engine. Without that vacuum fresh/cold air does not get sucked into the engine compartment.

[Asesapie]

I think I might just go out and test this theory by driving for like 15 min on the freeway with lid closed then open and take temp readings and see if there is a big difference