Air cleaner modification for pre-heat

[2381Buggy]

Thoughts needed on this. Not ready parts wise yet to add a factory style air cleaner with pre-heat to the buggy for cold winter temps. But this past weekend I tried something that seemed to make a difference in performance. 1600 DP 34-3 carb. My fuel system doesn't like the open little empi chrome air filter and all that cold air. As many have suggested, without the pre-heat it has caused some slight hesitation in the summer months. Became really bad a few weeks ago now that the weather has cooled. I decided to take a 12" rectangular cookie tin and cut a 2" hole in the bottom to slide the air filter base through to the carb. I then cut a 1 1/2" hole in the side for air entry. Nice and tight with lid. Not heavy. The filter is now in it's own box. Was surprised at how much better it ran in 63 degree weather than the week before with no tin. My temp gun on warm engine showed 78 degrees inside this tin vs the 63 outside. Is it possible that this " free tin" from the kitchen cabinet made that much difference shielding all that cold air? Going to try another step with this. Going to take a larger tin and cut a hole in it to slide over my tee pee exhaust pipe so that part of it is inside the box. The tin will will have the air filter in it like the smaller one but get some heat deflection from the exhaust directly into the box. Pre-heat from a different source as compared to the original set-up using the flex tube down to the lower portion of the cyl head. I know the best way would be the factory set-up, but it's kinda fun experimenting and costs nothing. I'm hoping that 78 degrees inside the box will climb due to the addition of the heat coming off the exhaust pipe.

[Brian_e]

I did this years ago and it worked great. I did another one a couple months ago on my sons '66. It was 22 degrees this morning when he left for school.

One thing that is almost more important than the warm air to the filter is making sure your manifold heat risers are working correctly. When they are working right, the two smaller pipes under the manifold should be to hot to touch. Like a header tube. Most every aftermarket header is not set up correctly to circulate hot air through the manifold.

With the manifold heat working correctly, and the hot air to the carb, it should start and run fine in any weather.

Brian
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www.type-emotorsports.com

[2381Buggy]

Brian...it was your tupperware idea that steered me to the metal tin..same principle, just don't have the pre heat hose as of this point. I do have the heat riser tubes hooked up and the attachments were custom welded in. Passenger side is right at the head and the driver's side is about 12-16'' off the head down towards the collector. But yesterday's reading showed about 145 on one side right at the intake and 122 on the other side. Not very hot. I do have a smaller hole on the left side at the riser tube attachment to help the pressure. It is odd the the heat riser outlet/fitting I welded on the passenger side of the exhaust is 185 but on the other side of the attachment for the pipe it drops to 145 or so.

[frenchroast]

Why not just get an inexpensive 73/74 air cleaner? $25. Already setup for preheat and fits nice. If you're lucky, the thermostat that controls the preheat flap will work but if not, it would be the same functionally as the tupperware box.
https://www.thesamba.com/vw/classifieds/detail.php?id=2570888

I have a 74 air cleaner for autocross and the stock for regular use.

[modok]

Good job everybody.

[oprn]

Great stuff and good ideas fellows! Thanks!
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[borninabus]

i'm pretty sure VW made something similar....
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88 Van WBX, A/T - 13 JSW TDI 6M/T - 2012 Touareg TDI Sport

[oprn]

Of course they did!

Every VW that came off the assembly line had one and the vast majority of them have been ash canned by now. The EMPI shinny chrome air cleaner is the norm to the point that most VW people today would not recognize or understand the need for and the operation of the stock one with the warm air feature.

Those of us that do are now in a situation that we have to re-invent what the factory did 50+ years ago for lack of stock parts. That is what this thread is about.

Note also in the picture you provided that the breather hose went to the dirty side of the air cleaner so that the sludge and scum that it produces does not plug up the carb. That simple detail that the factory did and the reason why has also been lost to the present VW crowd with the passing of time!
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[rayjay]

[APPLEGREENVW]

[mikedjames]

The stock vacuum plus thermo valve setup feeds the carburettor with thermostatically controlled hot air at about 80-95 degrees F at idle.

The manifold vacuum driven hot air flap is another neat idea that has been lost in history. At WOT / low vacuum the flap drops back to cold air for maximum power, and comes back to hot air feed for idle.

On my T1 with progressive I have an oil bath air cleaner, the breather connection neatly refills the oil bath with oil from any spray entering the breather. Only problem was when I melted a piston a couple of months back, the air cleaner had about half a pint of oil over the mark when it really started breathing hard...
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[2381Buggy]

Thanks for the interest. I think I have achieved success, although in a strange way. I took a large metal breadbox and and cut a 2" hole in the bottom to fit the carb via a rubber extension tube- the empi round cleaner is inside the box. I then cut another hole in the bottom and lid of the box and slid it down over the tee pee exhaust. There is now about 4" of heated exhaust pipe inside the breadbox surrounding all the air. Cut a 1 1/2" hole in the end of the box for air entry. Results: 60 degrees outside. Temp gun shows 90-92 on the box and inside the hole at idle. I've gained 30 degrees!

Keep in mind that this was rigged because I don't the factory preheated air filter box nor the lower tin or extension to hook it up. Most buggies have had the breast plate and lower tins removed. It does have a skid plate to protect the push rod tubes though. Can't wait to see how it really performs--raining today, no riding. It has to help. Next step will be to clean out the factory intake (not installed) riser ports and swap it with the aftermarket one which probably is doing little to heat the fuel

mixture.

[oprn]

I just looked up your location and I am impressed that being so far south of me you are recognizing and taking steps to correct this problem! There are so many that live in even colder regions than yours that are in complete denial that this need for intake manifold and carb intake heat issue even exists! A real guy fixing a real on the ground problem... gotta like that!

Back to your "fix" - wow that is so-o-o redneck! I love it! And thanks for the temp data to prove that it is working! You have inspired me to get the lead out of my pants and do a similar fix on my sand rail. I have a cookie tin in mind...
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[2381Buggy]

Good results. Got a good test yesterday in 60 degree weather here in the south. Getting heated air via my homemade air filter box and having heat riser tubes through the intake seem to have helped a lot. The engine ran great in comparison to the past without them. Almost no hesitation in 3rd and 4th gears. I think the gearing and taller rear tires are affecting this a little. A family member drove it and he thought it was greatly improved over what it had been.

Carb adjustments work as they should with the volume and air screws. Fast idle screw barely touches the choke valve.

Done it all like the book says.

Even started cold without hitting the gas once.

Starts at the blip of the key when hot too.

Thanks to all for the advice in this forum.

[oprn]

Now you know what they should start and run like. Very few people today have had that experiance and have accepted that poor starting and crappy cool weather running is a normal characteristic of a vintage VW. In the beginning it was not so Wilber!

Enjoy!
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[2381Buggy]

When summer weather arrives in late may, I will likely remove the air filter box but keep the heat risers hooked up. I tend to think the 80+ degree ambient heat plus the added exhaust heat would be too much.

[oprn]

Me too! And yes the intake heat riser stays.

The reason for that is that at higher rpms and heavier loads the intake is flowing so much volume that the heat riser has very little to no effect but as soon as you back off and slow down the fuel pooling starts happening again (to a much lesser degree than in cool weather... granted) and there is your heat ready to go to work for you!
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[ccowx]

If you are interested in pre-heat and drivability issues, you might want to check this thread out.

Specifically it has lots of suggestions for how to get manifold heat working efficiently. I of course like my solution best for this!! Seriously, I took a page from the stock system and found that they had simply left the intake side of the manifold heat risers as a high pressure pick up and then used some sort of lower pressure to make it suck at the other end. I wanted to avoid lots of extra piping and frankly I was too lazy to fabricate it. The low pressure side was created by using a simple baffle inside the header to direct the flow downstream, effectively sucking the exhaust gas through. I felt that having an intake baffle to direct it from that side too was overkill and apparently so did the factory, since they did not have director baffles or anything else on the intake side in any factory system that I found. Results? 128 F on the outlet side, 280F on the inlet and 90 on the heavy casting under the carb. Given that I am DEFINITELY in a cooler climate than you are, should work fine!

Chris


https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

[ccowx]

One thing I am curious about. Has anyone found any significant difference between the 1971 type independant thermostatically controlled air cleaner heat and the 1969 and earlier version where it is run off the cylinder head thermostat?

Thanks!

Chris

[Buggeee]

Can you leave a preheat air intake like this in place during the summer months or is the hot air bad at that point?

On my 66 bus, for example, the instructions are to manually close the flap to draw hot air when it gets less than 50 degrees outside, and manually open the flap when the outside air is above 50. Basically seasonally. This must have been before there were thermostats for the air cleaners.

I ask because I am working on a project 1600 dp (a beetle not the bus) that will not allow for a stock air cleaner, but will be center mounted (TBI). I have the manifold preheat tubes and think this hot air intake would also be good because I am in Ohio where the tempurature swing low.

So... should I be thinking seasonal box or permanent?
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