Porsche Manometer tool...any experience?

[maze]

Hi Folks,
Porsche made a manometer tool for setting up carbs and apparantly sold to dealers.
Has anyone used one of these? I'm wondering if it is better (more accurate) than the trusty synchrometer?
Is it used for other adjustments that the synchrometer won't support?

Thanks in advance
Maze

[MotoSook]

Whether you use the monometer or the synchrometer, you are still getting a relative flow rate (cylinder to cylinder comparision). Accuracy in this case is your ability to make a good comparision, and it has less to do with the precision of the device you are using. That is unless your device is wildly inaccurate causing a wide swing in measurement (i.e. very bad repeatability).

Just make sure you are using a good (not a broken) synchrometer and you should be fine.

Besides you may have better luck making your own manometer setup than finding a Porsche made setup, and a good synchrometer is not expensive.

[MotoSook]

I have never seen a Porsche manometer, and I haven't been interested in such a thing When the poster referenced a manometer, I assumed there was a 6 tube setup used by P-techs of old, similiar to the manometer setup we sometimes use to synchronize motorcycle carbs. A manometer is simple device that is used to measure differential pressure, which can infer a flow rate, or just a relative flow rate. If you want a Porsche one, I can cut up some clear vinyl tubing, put Porsche stickers on them and send you the "Porsche" setup with a bottle of colored water

[wholberg]

I used the tool in the link below to balance carbs for many years. I don't know if Porsche has special requirements, but it worked great for me on older English and American performance cars with multiple carbs.


http://www.globalintersection.com/auto-parts/store/ShowProd.asp?idProduct=131423&idRef=Froogle

[maze]

Here is the device and write up from Stoddards on line catalogue..follow the bouncing menicus...

During the 1950's, 60's and 70's, Porsche required each of their Dealer Service Departments to have this tool for tuning carburetor and mechanical fuel injection engines. Porsche realized that this was the only tool which would produce the accuracy required to calibrate air volume with adjustable throttle plates and have the sensitivity to calibrate air bypass screws for non-adjustable throttle plates. If each cylinder doesn't have exactly the same air intake volume, the horsepower produced by each cylinder will vary, causing the loss of power and shortened engine life. This is the only tool that is 100% accurate, and works with all types of Porsche, PMO, and side-draft/up-draft carburetors

[HarryD]

OK,

What I see is a standard U-tube manometer (measures differential pressure), some plugs (I would guess go into air inlet of the carb or throttle body), and a venturi that goes into the plug. The tap on the side of the venturi is connected to the manometer by the rubber tube. While the manometer is calibrated in arbitrary units, what you are measuring is air flow rate (higher air flow = higher vaccum at the venturi). The goal is to have the same vaccum at all 4 or 6 air inlets.

As already noted, a manometer is the "gold standard" of pressure measurement and as such gives very repatable results. I can see why Porsche insisted on this over some of the other devices on the market (Unisyn [the devcie listed by wholberg] or Syncrometer).