Prinz carb jetting

[adi]

I have a really useless manual for my Prinz, that doesn't seem to tell you much at all, and what it does tell you doesn't make sense.

It has a table for carb jetting for the Prinz IV. All the jets are identical except the mains and a/c jets.

It specifies that:

Prinz IV before 47.76880: Main 130 , Air Correction 230
Prinz IV after 47.76881 and SportPrinz: Main x120 Air Correction 130

As you can see, its rather a big difference!

However, I don't know how to tell which one mine should be. Currently it has the 'later' jetting Mx120 and a/c130, but I think it's running a little lean at the top end possible, so I am wandering if it should have the 'earlier' style jetting.

But I don't understand what 47.76880 means. It doesn't look like a chassis number, or an engine number, and certainly not a date, so how the hell am I supposed to know if my car is pre 47.76880 or post 47.76881?

Anybody know why the change was made anyway? Was the engine changed somehow?

How come the air correction jet on the 'pre 47.76880' version is so huge? 230 is massive. Unless its a typo in the book? There are a lot of other typos, so it wouldn't surprise me.

[richard]

language timothy 

[Big Al]

My data from a quick spec book is that having got the later P4 Solex 34 PCI carb rather than a Bing you have two choices

Before 47.76880 Main 0130, Air correction 230
After                   Main X.20   Air correction 190 - helpfull as what is x?

Bodyshell 47.76880 is pretty old so I would think it is the first P4 with differing bumpers, lids and so on. Your car is almost certainly a post 76880 shell. That would suggest main jet 120 and air control 190. However these Solex carbs have a known fault. They shear across the metal of the flange giving a curved face to the manifold junction. The fact it has a stud on one side and a bolt the other does not help. The mod was to alter the carb to a pair of bolts to stop the stud failing. The gasket was replaced with a machined one using o rings to get a gas tight seal. Also the gasket paxoline spacer normally has an airway in it. I never really understood the need for this as it goes against normal tuning rules to have an air leak beyond the carb as it reduces the ability for accurate metering of the mixture. There is a further issue of heat convection leading to vaporisation. Thus the o rings offer some insulation and an electric pump will vent off excess gas. Done we found the cars performed very much better. The Solex is a bit crap but better than the Bing. It would be tempting to put something like a Reece Fish on to see what happened.