We have had Unleaded emissions regulations here since since 1976 (more specifically, NOx tests) -- and with carbureted turbo cars too.

Basically it means running the mixture at 14.7:1 and fitting a catalytic convertor. The test is usually at a steady 35 mph (~50 kph). Small but effective modern cats will fit on a stock 1200 where the factory 1200 resonator (as in the GX) was placed. Inexpensive too. For example http://www.summitracing.com/search/part-type/catalytic-converters

Sigma turbo was a drawthrough 175CD Stromberg, as I found when researching the 175CD Stromberg on my turbo engine. But that was early 80s before ULP and the associated emissions tests - you can bet one of them would not have passed the post 86 ULP emissions tests you have to pass with an aftermarket turbo conversion.

Dont forget that the Peter Wherret Sigma Turbo cars were local modifications with a weber that they specifically made for turbo applications in a twin downdraught format just like the ones everyone fits to 1200's.

We also had Mazda MX5's made in Australia only with a Turbo conversion but they just nicked all the bits of the Turbo GTX Model so it came with a Warranty because it was effectively a Factory option using Factory parts and that engine spec was used locally in the later Ford TX3 model Laser second gen models.

Nothing is impossible just have to research the viability cost and engineering wise but you do end up with something unique and if legal it adds considerably to it's value for resale.

Trav depends how much you like it you could go turbo LPG and not be liable for emission testing? then you could also be using e85 added to the LPG for higher numbers.

In Brazil they use these babies, very cheap and better monitored LPG delivery for very cheap including ECU, correct me if Im wrong anyone but this looks like a bargain product much better than the horrible GR throttle bodies which everyone Ive heard of has troubles with.
http://www.lpgshop.co.uk/4cyl-ecu-lpgtech-tech-224-new/
http://www.lpgshop.co.uk/4cyl-ecu-ag-centrum-zenit-pro-obd/

There was someone selling a first reg in oct 1968 510 with sr20de and carbs, could that need engineering without emissions or all pollution motors need it regardless of the year?

Quote:

yes they have...

Well the rules have changed over the last few years so maybe easier in the past. Also from what i've read its easier for certain mods in QLD and there is a loophole around the emissions test due to no facilities available. But yes im sure there are PLENTY out there who register as carby then do their turbo conversion and take the risk. Hell there is a recently built heavily modified 13bt 1200 sedan running around Sydney that i believe is not engineered.

Trav

Ah, so the many turbo-with-carburetor builds on this site have never been certified. Haha, no one has ever admitted that.

Glad we don't have rules like that here (though California EPA does). Most states that test only have to meet emission specs at idle and at 35 mph, nothing in between. Which is doable with a carburetor.

Well that puts it to rest. L18_B110 i apologise for questioning you. I was told that as the motor never came with a factory turbo variant, its considered as a custom built turbo motor and needs to meet modern emission standards and not just that of the original year. Fail. Oh well back to n/a we go.

Trav

You could always convert it to E85. It will handle a LOT more boost and the Nox and CO levels will drop by 18 and 20% respectively. Formaldehyde levels will go up, but they wont be testing for that.

I haven't looked for years, but it used to be that cars had to meet the emission requirements of the later of the two years of manufacture.. car or engine. Say it's a 1971 car with a 1988 engine, the car would have to pass 1988 regs.

Looks like things have changed a bit since then.. Help me out with this one then.. To put a turbo on the original A12 would require a cat conv. and emissions test?