Adjusting Webers

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07-03-2004, 05:33 PM
jaudette3

Adjusting Webers

Greetings....

My '70 S has Webers installed in place of MFI. They're out of tune and I don't of anyone here in Bend who knows how to adjust them properly. So I need to go ahead and learn how to do it myself. Does anyone know where I can find printed information on these carbs, including how to set them up.

I have compiled and published information on tuning Solex's, Webers and Zeniths for the Technical Section of the the 356 Registry website, but I don't know squat about the Webers used on 911's. Should be able to figure it out though with a little help.

One other thing....

The '70 also has headers in place of heat exchangers. It has what appears to be a stock muffler, but is definitely a lot louder than my '73 S that is equipped with MFI and heat exchangers. Is the difference in loudness due to the Webers vs. MFI, or the headers vs. heat exchangers. (My guess is that it's the Webers, as I find birds and other small animals stuck to the grille of my engine lid when I stop <g>).

Thanks,
John Audette
07-03-2004, 07:55 PM
Porsche Rescue

I don't believe h. exchangers vs headers will have any effect on sound. Must be the carbs.
The basic Haynes 911 manual has basics for adjusting 3-throat Webers. Haynes also published a Weber manual which is even better. Not all that difficult. UniSyn or equivalent is the only tool you need.
07-04-2004, 06:43 AM
sithot

A fellow Porsche enthusiast told me once that "Carburetor is a French word meaning "leave alone"." :p

Tom
07-04-2004, 07:00 AM
ttweed

Quote:

Originally Posted by jaudette3

Greetings....
Does anyone know where I can find printed information on these carbs, including how to set them up.

There are some setup and tuning guides available from PMO. Go to this site for links to them.

Quote:

It has what appears to be a stock muffler, but is definitely a lot louder than my '73 S that is equipped with MFI and heat exchangers.

You will definitely get more intake noise from carbs if they have rainshields and/or open-element air cleaners instead of the stock metal air cleaner shrouding with single snout. I would also look at the muffler closely, especially the top, which will require removing it from the car. It is very possible it has been cut and internal baffling removed. There will be a tell-tale welded opening in the body if so, and that is often done to the top side, invisible when installed, so as to support the "plausible deniability" of any modification when inspected by authorities- "Why no, Officer, it is a factory stock muffler...."

TT