Warm Air Intake for progressive carb

[bokuglen]

I have a Weber progressive center mount in my 74 bus. I'd like to make a nice warm air intake, pulling air off the exhaust manifold, to make it run better in general. I've seen a few ideas on the forums, but wonder if someone has other ideas and photos to post?

[busdaddy]

https://www.thesamba.com/vw/forum/search.php?searc..._chars=200
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[alman72]

all the pics of the cookie tin mod/hack are dead links.....Another reason to put your pics here on the Samba!

[Wildthings]

Get the stock air preheat tin that pulls air off the right front cylinder, you can find it in the classifieds from time to time. The cylinder heats a lot faster than the exhaust. When I built my system almost thirty years ago I used the right heater box as a heat source but later changed it to use the stock 72-74 tin. This is my early setup which I ran for years but later altered.

I also have a heated manifold using hot exhaust gas from the left side of the muffler. Just adding the preheated air should take care of any icing issues and then modifying the operation of the power valve in the carb should take care of any remaining bog (assuming the carb is tune pretty well to start with).

The center section of the manifold is doubled walled, so the heat gets right to the base of the carb.

[busdaddy]

[Rodmullet]

Well, I don't have pictures handy at the moment....

My bus still had the original warm air "donut" attachment for the original air cleaner....it is on the right front (front is front) of where the single carb is. I, using some real hacks (small tin pineapple can and a clamps) attached a piece of flexible metal tubing to this hot air source. Had a big cookie tin....attached hose to cookie tin adapted to enclose air cleaner. Mine is very basic....I'm sure most here could do it much more gracefully,

I also made a tent of sorts out of reflectix bubble wrap insulation that loosely surrounds the intake runners all the way to where the intake bolts to the heads, this actually trapped enough heat to keep the runners very warm to the touch...I'll try to find or take some pictures tomorrow.

[alman72]

[Rodmullet]

Well, I took some pics of mine....again, not real elegant, but inexpensive enough for experimental purposes...if I am happy with how the bus runs, I can spend a few bucks and get fancier. Couldn't get a shot of how the hose attaches to the warm air intake for the original dual carb air cleaner, as the there's a ton of stuff in the cargo area and the bus is in a very tight parking space. Hope it helps.

Ran very well when the temps were in the fifties and a bit damp.

Rod

[Wildthings]

[Rodmullet]

The beauty of this is that it is easily removed as the weather changes...over about 60 degrees or so it isn't necessary.

[vwwestyman]

When I had the progressive carb on my Bus, I just sorta shoved the tube into the hot air intake from the head. It still had the rubber donut/gasket there, so I found a tube that fit tightly into it.

I never built anything special by the air cleaner, I just bent the tube so it was aimed right at and pressed against the air cleaner a bit, on the assumption that it would suck in some hot air. I don't know how much it really worked...

That's why I installed fuel injection!
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Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[orwell84]

I wonder how carburated airplanes provide heat for carbs. Usually carb heat is switched on before takeoff as icing can cause insufficient speeds for takeoff. I think it is also used during landings in the event that maximum power must be used to climb quickly in case of a missed approach.

[vwwestyman]

Some big diesel trucks have air intake heaters.

Here are a couple examples, google Intake Heater for lots of others. I have no idea how hot they get, but something like this might be worth experimenting with if you want to make these carbs work.

_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[bokuglen]

[Wildthings]

[Wildthings]

Any idea as to the actual application for this heater? Looks to be fairly easy to install.

[vwwestyman]

I think it was from a Ford truck. I just Google image searched "intake heater" and saw it.
_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Rodmullet]

Bokuglen

I've only done short trips (7 miles) with the reflectix...I suppose it could get hot enough to melt, but it isn't wrapped tightly, it is more like a tent to hold some heat in. As I recall, the reflectix was not that warm to the touch, but the intake runners were quite warm after my test runs. My original idea was to get some very lightweight sheet steel or aluminum and make sort of a tent or tunnel to serve the same purpose ( to direct some of the heat from the heads and engine case to the intake runners)....but the reflectix was on hand for test purposes, and is easy to form to the shape I wanted...the reflectix website says max temp is 180 F. , so it is probably a good idea to do some temp checks. Someone much smarter than I am probably knows how hot the engine bay gets at operating temperature.

For the cookie tin, which does direct some quite warm air into the carb, I just cut the bottom of the tin the same way the air filter base is , then just sandwiched it between the carb and the bottom piece of the air cleaner. I used a pretty big cookie tin, as well.

Hope that made sense.

Rod

[Wildthings]

[aerosurfer]