Ecology has had actually a massive affect on automotive engineering over the years. We’ve reached a point where our need for safe transportation came head come head v the ecological results of having actually millions of ice cream vehicles milling about the globe. Different countries and states began implementing different rules to deal with the issue.

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California spreading the somewhat notorious Super Ultra low Emissions automobile standards, which were later embraced in part by the commonwealth government. BMW SULEV technology is arguably one of the most exciting results of these regulations. It was effective, however at what cost? Let’s find out.

What specifically Is SULEV Technology?

Eco-friendly cars and also strict emissions standards space something world generally associate with Europe. Together it transforms out, California is the promised land for those that think cars need to emit cleaner fumes. The entirety SULEV or supervisor Ultra low Emissions auto standard began in Cali to save metro areas totally free from harmful particles.

This comes together no surprise considering the traffic thickness of Los Angeles, san Francisco, and also other extremely populated cities in this state. However, the whole SULEV instance had thrown a wrench into the cogs that the automotive sector when it first appeared. This standard quickly became the norm back in the early 2000s, forcing auto manufacturers to adhere to new rules if they want to market cars in California or merely pound sand.

Designing a 90% “cleaner” automobile than the existing LEV (Low Emissions Vehicle) was a difficulty for everyone, consisting of BMW. The large from Bavaria wasted no time. Lock have easily redesigned a part of the lineup to meet the brand-new demands, starting with the 2003 BMW E46 3-series.


BMW’s take on SULEV Vehicles

BMW was among the many auto manufacturers that immediately jumped on the SULEV issue, in search of a quick fix solution. The firm wasn’t about to style a whole brand-new engine simply to fulfill the ever before so strictly emissions standards, so they decided to modify their existing lineup instead.

The first engine to be revamped is the legend M54. This inline-6 powerhouse was the go-to choice for a full selection of BMW’s lineup in ~ the time. It to be the obvious choice for a SULEV conversion.



The newly redesigned motor was labeled M56 and also installed in cars sold in claims where SULEV to be the norm. However, together time walk by, the M56 started mirroring sure signs of weakness.

It to be more facility than the M54 as result of the enhanced emission criter requirements, however the M56 suffered from numerous of the same concerns as the M54. The only distinction is, those problems were much more expensive to solve on the SULEV versions.

A good example that this would certainly be the valve cover. To meet the SULEV norms, BMW go ahead and also swapped the composite valve cover because that an aluminum one. The M54 has a known concern where it twists the valve cover, resulting in oil leaks. The aluminum one doesn’t leak due to the fact that it was, well, do of aluminum.

But, the crankcase ventilation valve that comes built into the cover to be its very own weak point. Here’s the kicker — BMW wouldn’t let you replace only the broken valve. In spite of assigning a component number because that this component, girlfriend can’t bespeak it. Instead, you have actually to acquire a whole new valve cover.

Another thing that changed was the fuel rail and the injectors. BMW supplied a whole different setup on the M56, which method that her going after relatively rare parts (read much more expensive), should any of the injectors start to provide you trouble.

Overall, if you’re going come buy a 325i or 330i E46 3-series, make certain that the vehicle you’re gaining isn’t a SULEV version. Even though BMW only sold these in California, Massachusetts, brand-new York, and Vermont, you’ll sometimes find SULEV execution in various other states as their owner migrated.




What renders a BMW auto SULEV?

Although the M56 was the first of that is kind, the wasn’t the last. BMW’s SULEV selection evolved end time. The engine chin is just a component of a much larger puzzle. There room many much more components that had to be redesigned to an increase emission performance.

The Fuel System

The fuel mechanism overhaul on SULEV car is more than likely the main culprit behind the less than mainly reputation the BMW’s early on SULEV vehicles. If us go earlier to the infamous M56 E46 3-series, we’ll find a totally closed fuel mechanism that features an incorporated fuel pump and an integrated “long life” fuel filter — both located inside a close up door fuel tank.

In other words, friend can’t accessibility any of these components. Instead, if your fuel pump failed, you had to acquire a whole brand-new gas tank, which to be an $8,000 task at the dealership. Compare the to a an easy fuel pump replacement job on a traditional E46 3-series, and you’ll know why M56 equipment cars space disliked, come say the least. Also, together these cars are nearing the 3rd decade of their existence, those so-called long-life filter are largely clogged up by now.

Fortunately because that everyone, BMW witnessed the error of their ways and made some much-needed changes to the E90 that come after the E46 3-series. Back upgraded and also beefed up, the fuel system on E90 and later models are much simpler to service.

Intake System

Next, we have actually the intake device with an upgraded waiting box. BMW’s SULEV vehicles come with an additional carbon inside wall filter whose task is to save the excess hydrocarbon buildup from finding its method into the atmosphere. The PCV device is likewise different on this cars and features a couple of more components and complications.


The exhaust on SULEV car is a whole different beast compared to the continuous versions. BMW went ahead and installed a catalytic converter in ~ the very end that the exhaust manifold. They’ve likewise fitted details cars, such as the E46 3-series, with double downstream cats and upstream oxygen sensors.

Cats on these cars likewise require a warmup before they have the right to reach their maximum efficiency. Castle are built to burn the greatest amount the residual particles once the whole system has actually reached the optimal operation temperature.

Engine Cooling

When it comes to the cooling system, BMW SULEV cars use a few special components. Because that one, the radiators are different.

They attribute a unique manganese oxide coating and come complete with an combined sensor developed into the radiator’s core. Needless to say, you can only use this distinct radiator if you need to replace yours. Utilizing a standard radiator will result in your automobile throwing codes.


The advantage of SULEV Cars

So far, us went pretty hard on the entirety Super Ultra low Emissions automobile concept. Sure, one of these deserve to turn into an countless pit of despair as soon as things walk sideways, however there are additionally a couple of benefits to this cars.

The entire civilization is in the center of experiencing a paradigm transition when it comes to technical progress. Any kind of future technical development will require to have actually an environmental component. By operating a SULEV vehicle, friend are ending up being a part of the solution.

Even though this might not sound like much from her perspective, that small dent your car is putting right into the whole global warming problem matters. It’s a snowflake in a farming snowball that is slowly but surely gaining inertia.

How to Tell If your BMW is a SULEV Model?

Recognizing whether your car is SULEV or no is easier now 보다 it provided to be v the first E46 3-series models. With those, every you should do is pop the hood and take a quick look in ~ the valve cover. If it’s aluminum, your automobile is a SULEV.

With more modern-day models such as the E90, F30/31 3-series, and others, there room fewer visual indicators. The pure best method to inspect is come look for the emissions tags in the engine bay. Depending upon what auto you drive, that tag will literally state it’s a SULEV vehicle, or it will list the engine designation. If you recognize which engine is in her car, you deserve to view the supervisor ultra-low emission auto engines online and see even if it is yours is on there.


The Verdict

Buying a offered BMW is a procedure that usually calls for a most homework unless you desire to finish up with a problem that might not be fixed also if you start throwing parts and also money in ~ it. It’s no mystery that this cars room on the expensive side as much as maintain goes. If friend live in California or any kind of of the says that i charged the SULEV criter for emissions, your only option is to expropriate that her maintenance will certainly be more expensive.

But, if friend live outside these states and have the option to buy a non-SULEV BMW, carry out so. You’ll conserve yourself a the majority of money and headaches ~ above repairs.

Where to find Quality BMW SULEV Parts?

Here at, we treatment for all BMWs, consisting of SULEV ones. To discover Genuine and OEM parts for your precise vehicle, definition your particular SULEV version of typical BMW models, head end to our digital store. Make certain to input her car’s data as accurately together you can into our navigating tool.

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Once you do that, our mechanism will fall a list of components that enhance your car. If girlfriend have any questions or if you’re not sure whether a specific component will, in fact, fit her vehicle, don’t hesitate to contact us. We’ll help you find the appropriate car component and obtain your beemer earlier on the road.