the e12 USA 5 series did not use a cat. not until the e28 did cats show up on the m30 engine.
Scott -- you cannot drive a car with carbs and avoid being accused of doing something that is bad for the environment. The reason carbs disappeared is that they cannot be made as clean as fuel injection when the engine is cold. Thus, they are dirtier when you first start and run them. Also, when you hit the accelerator hard, they dump a large amount of fuel into the engine and this too is not as clean as a more precisely metered fuel injection system. And indeed the fact that the carbs expose a certain amount of fuel to the atmosphere in order to use the pressure differential between the atmosphere and engine vacuum to emulsify fuel means that our cars release gasoline fumes after we shut them off. No 1970s system is going to change these things and make a carbureted car as clean as a fuel injected car with a closed fuel system.
Moreover, I strongly suspect you could not find anyone to get a 1970s system to work perfectly in one of our cars. In the US, the vast majority of them were junked long ago, and I doubt even the factory would have maintained the expertise for a US/Canada only system.
As to the concern expressed by your shop, my understanding is that the EPA fines pertain only to the removal of catalytic converters. I don't think BMW employed catalytic converters on the e9s, so your shop should be able to remove the other stuff. Of course, I am not a lawyer so take this for what you paid for it.
To put some historical context and arcane trivia into the discussion, by the early 1970's California required smog inspections for DMV registration purposes on all American make cars 1955 and newer, and all Foreign make cars 1965 and newer. Cars with small engines (below 1000cc), and diesels are examples of cars that were exempt. For the most part this meant installing a PCV valve and closing off road draft tubes for those cars built before PCV valves were factory installed. In the mid 1970' s State law was amended to require retrofitting approved NOx control devices on nearly all 1966-70 year model cars. Approved devices included one that consisted of two rubber plugs to close off the vacuum advance, retarding the static ignition timing, and decals warning the driver not to exceed a certain speed. This program was ill conceived, technically flawed, and was discontinued part way through the one year implementation cycle. Occasionally one comes across a 1966-70 year model car with evidence of being once fitted with such a device. One might argue that the discontinuance of the NOx program allows the car owner to legally remove the NOx device without risking penalty.
At present, while 1975 and older year model cars are exempt from smog testing for registration purposes here in the Golden State, consider that our elected officials who generally vilify internal combustion engines can always try and change the law pushing back the exemption age to include cars presently exempt. Consider further that cars registered in metropolitan areas are required to be inspected every other year while cars registered in rural counties are generally not subjected to that requirement.
For 1976 year model and younger cars, when an engine is replaced with one from a different car the newer of the two engines will dictate what the Smog Referee Station will require to pass certification, to the extent that an replacement engine block can be identified by cast/stamped date codes.
As stated above, independent of California law, the Federal Clean Air Act does prohibit removal of factory installed emissions equipment from any year model car.
Lastly, from time to time someone floats the idea of installing road side sniffers as a way to ferret out gross polluters on the basis of actual emissions in low air quality areas. If such a Draconian measure were to ever see the light of day, I would expect that enforcement would involve an administrative process where the "offending" car is actually inspected and run through the traditional smog certification process with reinstallation of the removed emissions equipment and civil penalties being part of the outcome.
Based upon your information, it seems like it would be crazy for me to uninstall anything.
This afternoon I intend to call all of the Boise shops The claim to do carburetor work
stevehose said:These cars are not environmentaly friendly, removing the "emissions" stuff won't make them any less so after 45 years of leaks, inefficiencies, dripping oil, diff fluid, tranny fluid etc.
Don Lawrence suggested I remove the smog control "stuff" on my 74. He said they don't do much and merely hurt performance. He rattled off quickly what was involved, but too quick for me to write it down or remember.
My questions are:
Thanks.
- is there a resource/list of the smog control things that can be removed and how?
- would it help performance?
- is it legal to remove these?
As others have mentioned, the major piece of emissions-related hardware is the EGR (exhaust gas recirculation) system. There is a good likelihood that yours is plugged or non-functional and therefore has little impact on engine performance other than extraneous weight. If the EGR valve were to stick in an open position and the exhaust manifold feed tube connection were not plugged, chances are you would notice a rough running engine. Some later models were fitted with thermal reactors bolted to the cylinder head that were intended to operate like catalytic converters. Of all the emission control hardware that could be detrimental to engine performance and longevity, these thermal reactors were probably at the top of the list. From what I gather, your engine is not so equipped.
As indicated by the diagram below, the remaining "controls" include carburetor jetting/settings and ignition timing modifications, all of which could be dealt with by most competent mechanics with simple hand tools. Using the European model for comparison, it can be argued that the biggest impediment to improved performance on your '74 North American engine is reduced compression. The Euro model had slightly increased compression (9:1 versus 8:1 ), resulting in slightly increased torque and horsepower.http://www.e9coupe.com/faq.html
Virtually all stock engines from the early '70s could benefit from some mild tuning tricks and most of those stock engines that are still on the road could probably benefit from a valve job and and new rings. However, even the lowest compression M30 engine provides more than adequate torque and horsepower for daily city and highway driving.