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Posted by: r3dplanet Aug 22 2013, 02:48 PM

I'm new to Weber carbs. I have in my possession a pair of Weber 44 carbs, but I need 40s. Here and there I've read that these carbs have the same body but can be switched from one size to another by swapping parts.

If true, which parts? Gotchas?

Anyone care to specifically conceptualize this for me?

Thanks,
Marcus

Posted by: SirAndy Aug 22 2013, 03:42 PM

You can choke down 44s by running smaller venturis and downsizing your jets etc.

Posted by: tomeric914 Aug 22 2013, 05:38 PM

Which is the beauty behind Webers.

Here's a link to a chart of what comes from the factory for Webers:

http://www.cbperformance.com/SearchResults.asp?Cat=152

44's come with 36mm venturis, 40's come with 28mm venturis. The smallest I've seen that you can get down to is 32mm for 44's.

http://www.cbperformance.com/SearchResults.asp?searching=Y&sort=7&search=weber+idf+venturi&show=90&page=1

Posted by: Mblizzard Aug 22 2013, 07:41 PM

I did this for my 1.8. Went with a 28 vent and a fairly large idle jet. Ran pretty well. The cool that was that I just upped to a 2056. Changed a few that is and they work on the 2056.

I went through a lot of trial and error to get mine right. It could be worthwhile to have them professionally set up.

Posted by: wndsnd Aug 23 2013, 03:29 PM

I am going through this now.

I bought brand new 44IDF's from Pierce Manifold for a 2056+ build I am commissioning. In the mean time, I am going to run them on a 1.7.


They came with 36mm Venturi's
60 idles and 135 mains

Pierce recommends for the 1.7
30mm Venturri's #71507.300
55 idles (74405.055) and 125 mains (73401.125).

We shall see how they run!

John

Posted by: DBCooper Aug 23 2013, 04:14 PM

Hey John, is Pierce cool or what? Totally under the radar unless you want Webers on your V8, but I love those guys.

Posted by: Racer Chris Aug 23 2013, 06:06 PM

try
30 vents
47 idles
110 mains
140 air corr.

55 idles are way too rich for low speed running.

Posted by: CptTripps Aug 23 2013, 06:31 PM

I had 44s in a 2.0 and it was a bit temperamental on the throttle. Set it up with 40s and it ran like a champ. Great move.

Posted by: wndsnd Aug 23 2013, 06:57 PM

Too late - Pierce ships quick!

Posted by: wndsnd Aug 23 2013, 06:57 PM

I do too..... Mr. Racer Chris turned me on to them......