Please help me understand FIA App J/K Basics

[pigiron]

Although I have 35 years of club motorsport under my belt I am a newbie to historic cars would really value some advice regarding how to read FIA App j and K.

Here is what I mean;

Say for example we have a car homologated in 1976 in group 2 (Improved Touring Cars), it's homologation papers describe only the standard car as it left the factory, i.e. there are no improved or alternative parts listed.

In the appendix J of 1976 it states that the engine induction and elements are free....

Now does that mean that one could replace the single carb with a twin side draughts?

Or .... because the above hypothetical twin side draughts are not specified on the homologation paper, one cannot?

If, I am right, does "Free" mean that the manufacturer was free to replace the standard single carb with an alternative but he then was obliged to list it on the homologation paper in order for it to be used?

[zefarelly]

All you need to know is, take a standard car for inspection, get papers, take it home, strip it, do what you like, enjoy.

[Bruce Chambers]

The point of the homologation papers was to list the standard specification, then depending on the class of racing the car was being prepared for certain elements of the standard car had to be retained and others were free. That doesn't mean that because induction in period was free in a given class that you are free now and could say use modern fuel injection, but what you can do is fit twin choke side draught carbs in place of the factory fit downdraught if the model was run in period in the apporiate class, in FIA sanctioned international competition with those components fitted. So the starting point has to be was the model entered in events on the FIA calendar in period and then establish the specification and modifications employed.

[pigiron]

Thanks for taking the time to reply.

So if I understand you right, as far as the modifications are 'period' and comply with Appendix J then I am OK?

My fear is being turned away at a meeting by a scruteneer because the carbs are not actually listed/shown on the homologation paper.

The model in question was homologated in G2, as far as I know it has no competition history, is that a potential issue?

[morninggents]

What car/model are we talking about?

[Tel 911S]

Group 2 regs of the period [ your G2 = 1970/71 ] did allow various freedoms .
In the case of carbs etc this did mean that they could be replaced with any others available .
And now Appendix K usually says that the App J of period applies , so in theory on a car of that age you can use any carbs that were available in period for Gp2 spec .

But the problem comes with which set of current events you are planning to use the car in .
FIA events will be to App K , then App J of period , & then Homologation details .
But some FIA events specify Gp 1 rules only .And will usually require a HTP , which can come expensive .

Some Historic series have their own sets of rules , which might be anything from FIA App K to whatever they have decided .

So it might be best to find which events you want to do , see what their version of Historic rules are , & then do your research to find what is actually allowed .

It is a real minefield to find what is right .

[Bruce Chambers]

I was assuming that from the opening message the requirement was that the vehicle was going to comply with FIA Appendix K and get an HTP. That being the case I don't think it is sufficient for a carburettor to have been available and legal within Group 2 of the applicable period Appendix J, it also needs to have been used in an FIA sanctioned event , in period on the model concerned. What vehicle are you building/planning? With that information I'm sure the combined brains of those here can come up with some more specific advice.

[zefarelly]

most cars were homologated twice, gp1 was bog standard and gp2 'modified'

modifies will be whats on the papers, usually a list oif redundant standard parts and a few options are listed at the end, like wheel widths, carb choke sizes etc.