Weber 32/36 air cleaner options

[Sahara]

Hello all. My 75 2002 has a Weber 32/36 carb fitted to the stock air box and air cleaner, I believe they simply widened the cut-out for the stock Solex and shoved it in there. Would I gain any performance by switching to an air cleaner like the one pictured? When I was shopping for 2002's I noticed the vast majority of those with aftermarket downdraft carbs had aftermarket air cleaners as well. 

Edited September 27, 2018 by Sahara

[Simeon]

In a word, no. The stock air box has a greater surface area of quality (paper) filter and the design has a tuned length that may help torque. A ‘cigar box’ might flow more in theory if it has the right filter element but is likely to be a lower quality filter as it can’t match the surface area of the paper filter. 

['76mintgrün'02]

The stock filter also has the ability to draw in cooler air through the snorkel.

 

This internet expert did some math:

http://home.windstream.net/bsprowl/CarbMythFact.html

 

"Air temperature directly effects power.   Cool air is denser so a more air (oxygen) actually enters the engine.   A 7.2 degree change in air temperature causes a 1% horsepower change.   So if the air temperature under your hood is 180 degrees and the air temperature in front of your hood is 90 degrees then by ducting the cooler air to your air cleaner inlet you can give your engine a 90 degree incoming air temperature drop for a 12.5% increase in horsepower (90/7.2 = 12.5)."

 

[backeis]

Interesting! Has anyone tried fitting a Weber downdraft to the snorkel?

['76mintgrün'02]

1 hour ago, backeis said:

Has anyone tried fitting a Weber downdraft to the snorkel?

 

Yes.

 

 

[thinksound_mike]

I ditched the stock air cleaner and the one that came with the Weber 32/36 for an ITG filter. I like it and it provides more surface area for air to flow (top + sides) vs the weber air cleaner.

http://itgairfilters.com/category/megaflow/

[Mike Self]

I attacked my OEM filter can with tinsnips and a Dremel tool when I converted from Solex to Weber about 1979.  Since the OEM rubber grommet would no longer fit, I made a new seal from closed cell foam (think it was packing from a computer shipping box) to seal the space between the air filter can and the carb.  I made it just a little thicker than necessary so it would compress and seal tightly. 

 

Been working just fine for 39 years, and the comments about colder air from outside the engine compartment are true.  If they weren't, why would BMW (and all the other manufacturers) bother?

 

mike

[7502]

I'm using some rubber U channel stock material on the cut OEM cover, also have a second flat seal around and on top of the carb body. Been experimented with various sizes of U channel, just installed this piece this morning it's slightly thicker with a deeper channel making a better fit. Rubber's not a good material for this application but it lasts for six months or so then I cut another one. I have 10 feet of this stuff so until I come up with a better solution it's fine.

 

[Sahara]

I’ll probably keep it as is then, guys. I am strongly considering moving to side drafts, looking at the Top End Performance single Weber 45 kit. Thoughts on that? For those unaware it’s a 2 into 4 intake manifold that lets you use one weber side draft instead of the usual pair. Not as powerful but Top End claims a negligible difference in power on a stock motor between 4 to 4 and 2 to 4. The big advantage is that one doesn’t have to sync the carbs and it clears the stuff in the engine bay that usually has to be moved to fit 2 Webers. 

[Road trip]

23 hours ago, '76mintgrün'02 said:

The stock filter also has the ability to draw in cooler air through the snorkel.

 

This internet expert did some math:

http://home.windstream.net/bsprowl/CarbMythFact.html

 

"Air temperature directly effects power.   Cool air is denser so a more air (oxygen) actually enters the engine.   A 7.2 degree change in air temperature causes a 1% horsepower change.   So if the air temperature under your hood is 180 degrees and the air temperature in front of your hood is 90 degrees then by ducting the cooler air to your air cleaner inlet you can give your engine a 90 degree incoming air temperature drop for a 12.5% increase in horsepower (90/7.2 = 12.5)."

 

So at 10 below zero my car hits 250 hp ?

[Jbaumshelter]

10 hours ago, thinksound_mike said:

I ditched the stock air cleaner and the one that came with the Weber 32/36 for an ITG filter. I like it and it provides more surface area for air to flow (top + sides) vs the weber air cleaner.

 

I would love to see a picture of this setup. What ITG filter did you use? There are a few options on the page that you linked to. 

 

*Never mind on the question. I found it. It's the 3JC20. Still would like to see a pic if you can.

Edited September 28, 2018 by Jbaumshelter
I found it

[thinksound_mike]

11 hours ago, Jbaumshelter said:

 

I would love to see a picture of this setup. What ITG filter did you use? There are a few options on the page that you linked to. 

 

*Never mind on the question. I found it. It's the 3JC20. Still would like to see a pic if you can.

 

Here's an upside down photo (sorry). You have to wash the filter once in a while and spray it with Rock Oil after. I forget the part number but it looks like you found it. It comes with an adapter plate for the Weber 32/36 and a spacer; which you may or may not need. I liked the idea of reusing the same filter and having more surface area for air to flow. I know that the stock air cleaner could have been made to fit, I really just wanted it out of my engine bay. It's much easier accessing things without it in the way. The filter is attached by single thumb screw in the front so it's really easy to remove too. It also stays in place, which is something my stock weber brackets didn't do.

 

 

 

 

[kbmb02]

11 hours ago, Jbaumshelter said:

*Never mind on the question. I found it. It's the 3JC20. Still would like to see a pic if you can.

 

FYI - there's a newer style ITG filter - 'dome' shaped - I like the profile for improved air flow between the top of the filter and the under-side of the hood. I like this vendor, too. -KB

 

https://itgfilters.net/collections/itg-jc20-megaflow-air-filters

 

 

[SoKvlt]

Anyone know where I can get my hands on one of those JAM adapters for a single carb? 

[1972_Targa]

Another option:

 

https://www.piercemanifolds.com/product_p/99217.090.htm