44 IDF Choke Size for 2165cc

[VW&MGman]

Hi All,

Need your advice here. I have a 2165cc that I use in my road race Beetle. It currently has 36 mm chokes and I was wondering if you I should increase the size to 38s or 40s. Max RPM I run it to is about 6500-6700.

Engine specs:
78 x94
DRD L6 heads 42 X 37.5
9:1 compression
1 5/8 A1 exhaust
SLR R302 cam (529" lift, 302 duration)
Dual 44 IDFs

Thanks for you input

[67rustavenger]

Chokes should be 2mm under the intake valve diameter.
You'll have to rejet and make adjustments after the choke change.
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[Ohio Tom]

38's will be a nice jump in power.
Jet accordingly.

You can run the 40's, but that's for every last bit of power up top.
It will start to hurt the low end going that big.

[VW&MGman]

Thanks for your input.

So I found 38mm chokes on CB's website.

If install new larger chokes, do I have to enlarge the carb paper gaskets as well to accommodate the 38mm chokes?

Any recommendations on jetting sizes for idle, mains and airs? Just asking so I can make one order from them.

[GMendoza]

Paper gaskets do not need to be modified since the diameter of the paper gasket hole and outer diameter of the venturi is the same.

In theory, going to a larger venturi requires a larger main jet, no change to idles or airs BUT you really need to hook up a wideband o2 sensor to see what your a/f ratio is doing then adjust accordingly.

[modok]

There is normally no venturi gasket.
increase the size of the jet in proportion to the venturi change.
If venturi is 5.5% bigger, then make the main jet 5.5% bigger too, at least, probably the next size UP from whatever that is.