Hello,
Just wondering. I'm using a rather streamlined air scoop for my classic Beetle. Its supposed to force more air into the vents above the engine lid.
I don't have a temp gauge so I can't know for certain whether it "works".
It seems to work I think.
There was some disagreement in one of the forums about the effectiveness of the air scoop.
What do you think?:o
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Owner of a 1964 VW Beetle, 1641cc engine, etc..
I think you should get a temperature gauge and do a comparison. 🙂
Kruizin Kol
My feeling is that it's one of those great ideas that sounds fantastic in theory, but doesn't work so well in practice.
If the airflow over your VW's roof at speed was smooth, or laminar to use the technical term, then yes it may have a slight ram effect. It would gather in the flow to the height of the fibreglass lip, and channel the air in through the louvres.
BUT - the airflow over the rear of your VW is NOT laminar. Even over the smooth curved roof there is turbulence caused by the step over the windcreen. But it's sort of smoothy over the roof at least.
When the air reaches about the top of the back window, it tends to pitch over, swirl and become completely turbulent. I have seen wind-tunnel shots of this done with smoke, but you CAN see it if you watch a VW driving at speed through pouring rain.
The end result is that, with the turbulent swirling flow by the time the airstream reaches the louvres, a scoop will probably not make much difference. The fan is doing the work by creating a low pressure region at the back of the fan shroud, which draws the air in.
More effective is a whale-tail (ugly as they are) as they are further out in the airstream and they cause the (turbulent) flow to slow, increasing the static pressure. Sorry for the tech talk - my old pilot training is coming out.
Some may even argue that vent slot scoops even act as an obstacle to the fan drawing in air - who knows. But the fact is - after VWs being driven and modified for many years, you don't see the scoops on sale much any more.
Hahaha!!!! Phil, I can just imagine you hanging out the passenger door, standing on the running board at 80mph in the pissing down rain!!!!! :o:o:o 😀😀
Kruizin Kol
I pop the decklid open at the top in summer and it seems to run about 20deg f cooler in a hot Brissy summer
Hmmm I know someone who could help with that...
Well maybe in my younger days Col...actually I meant looking at another VW driving, not your own!
Yes the engine lid standoff trick works well. It works because you are enlarging the area of the air intake, so the fan has access to more external air. There is little or no ram effect at speed at all.
If you have any overheating problems check that the engine is in good tune, that all the tinware is in place (very important!!!) and is airtight (also important!), that the spark plug seals are tight, that the cooling fan is unobstructed, that the engine is free of gunk buildup on the cylinders and heads and that the thermostat flaps are in place in the fan shroud.
A properly setup stock doghouse cooling system can handle a 2.3L engine (albeit with silastic on the tinware and a rare FI shroud).
The only other issue is the decklid, the early decklids didn't have any slots in them so putting a late style engine in there such as a 1500/1600 and/or a doghouse fan will starve for air and run hot.
The factory had slotted decklids for the 1500 and up (they had it without slots for one year and changed to the 2 slot lid thereafter i think)
Jon
how much would it cost to put in a temp gauge for the classic beetle?
Do they sell oil dipstick temperature gauges?
______________________
Owner of a 1964 VW Beetle, 1641cc engine, etc..
