ZENITH 32 NDIX

[Drù]

Hello all,

as someone knows I'm trying to build a precal  VW from my '64 Beetle.

To find out some more hp from my engine I bought a beautifull Zenith 32 ndix carb and now I need some help from you about my last purchase ...

My engine is a 1200cc. and I don't know which are jets [and so on] I have to install.

Does anyone have any suggestion for me ? 

Thanks in advance

Drù

[Zach Gomulka]

Love the Zenith! There is some good information on the Zenith in the How To Hot Rod VW Engines book.
First of all... there are 2 different types used on VW's, the type originally used on Porsche's in dual carb applications (ends with a "R" or an "L" signifying left or right), and the type designed for a single carb application. The single carb is usually marked PO1O, and has a slot in the base connecting the two bores. Supposedly, the Porsche type will work well on a plenum manifold, and the other works well on an individual runner manifold. Mine is an individual runner, PO1O, and I am very happy with the performance.

My motor is an original 1600 dual port, with a header & glasspack, Bosch 010 w/ Pertronix, and of course the 32NDIX. I have it set on "kill"
The carbs normally came equipped with:
24mm venturies
130 main jets
50 idle jets
140 idle correctors
55 pump squirters
180 (I think) main correctors.

After much trial and error, I ended up with:
25mm venturies
125 main jets
40 idle jets
140 idle correctors
40 pump squirters
180 (I think) main correctors. A LM1 wideband a/f ratio meter helped me end up with that combination

[Zach Gomulka]

One more thing... They also came with a 1.75 float valve, I replaced that with a 1.50, and that solved a problem I had with the carb "sweating" fuel. Also, changing the air correctors seemed to make no difference, at all.

It's a great carb. I had mine running well for over a year with the factory jetting (except I used a 40 idle jet), and it ran like a stock carb, except bigger and better! Combined with the header, it took .7 off my 1/4 mile time. I average about 23-24 mpg around town (I have a heavy right foot and an old motor), and I think around 27-28 on the highway (I cruise at 75-85mph)

[Drù]

Hi Zach,

thanks for the precious info that you have given me.

I also discovered that the correct version to mount a single carb was the P010 and fortunately I found it. I'm happy you have confirmed this.

Next weekend I will unmount the carburetor to clean it and I will check the jets and venturi size.

You said that you have a 1600cc and then you have successfully changed the sizes of jets and venture, do you think that the standard setting is correct for 1200cc ?

Was difficult to find everything you need to have the correct setting ? I ask this because here in Italy Zenith are not so common ...

Cheers
Drù

[Zach Gomulka]

Glad I could help! The standard jetting should work just fine, but you may have something to gain by properly jetting the carb like I did (mpg, hp, driveability). Zenith parts are not so common here anymore either, but I was very lucky to get a box of jets with the carb when I bought it. Everything else I needed I found through a Porsche carburetor specialist.
Good luck, let us know how it works out for you!