As you likely know, pukka "Jota" cans have never, ever been legal in Germany. German Jotas were badge-only, no special engine internals, no special exhaust. "Real" Jotas were never homologated for legal road use here, those badged as Jotas were registered on the former 3CL homologation.
New regulations cannot be applied to older vehicles, with a few exceptions concerning safety, such as brake lights. This applies mainly to pre-war vehicles, as most post-war vehicles had the equipment still in use today. If your Jota has passed its TÜV inspection sporting Jota cans, it is down to the pure goodwill of the inspector. At a roadside check, the authorities can/will check noise according to what is stated in your vehicle documents. If your Jota was imported and registered in Germany after its registration elsewhere, it would have to comply to all german regulations in force at the
time of its first registration, irrespective of where it was first registered. Of course, nobody will seriously inquire what cams and pistons are fitted, but exhausts are just too obvious to ignore.
Strictly speaking, a vehicle not complying to regulations in certain aspects can be impounded on the spot. This can often be witnessed on sunny summer weekends in Barweiler, just up the road a bit from the Nürburgring. Happily, classics are mostly immune, with cops usually turning a goodwill blind eye, unless you've really, really over-cooked it. Moreoften, their equipment will not cope with olden days technology, measuring procedures have changed, just as the limits themselves.
Many owners argue that because they have an absurdly loud standstill noise level (Standgeräusch) entered in their documents, they can therefore legally race around the countryside making a nuisance of themselves. A lesser-known fact, is that this noise emmission is not regulated at all! What is regulated though, is the noise on the move (Fahrgeräusch). This cannot be altered from what was in force and entered on the day of first registration and remains the limit for any particular vehicle thoughout its life. Simple physics dictate that a bike making 105dB at standstill at certain revs, cannot possibly be any quieter when driving at the same revs. The "Fahrgeräusch" limit for old '70s/'80s clonkers will be somewhere around 84-89dB. TÜV inspectors are quite willing to change the "Standgeräusch" in vehicle documents when "approving" exhaust systems, but won't touch the "Fahrgeräusch", simply because they are not legally allowed to. So, no matter from which angle you look at it, you're stuck with what's been entered in the documents. No
legal modern aftermarket exhaust system is allowed to be louder than the regulation applying to the vehicle to which it is to be fitted, on its day of first registration. What the owner does with baffles or dB-eaters etc is his business. it's his own neck he's sticking out.
Reminds me, I really have to do something about my insanely loud 3C exhaust...
piet
