The engine mount is fixed to the side of the engine and made of cast aluminum. This is a great place to grab on and move the engine around, but make sure your hands are out before settling the mount onto its pad.
Installing the S54 engine is the easiest part of the operation. The oil pan and other parts are similar enough that it drops right in. The challenges come with the various sensors and other connections that differ from the E36 line.
The stock radiator is a good unit, but those plastic tanks are prone to cracking. If you’re investing the money in an S54 engine, buy an aluminum high-performance radiator. They don’t cost much.
This custom radiator incorporates shrouding, an electric fan, and a separate aluminum overflow tank. This does a much better job for a performance build in the long run.
You can see how all the fittings are TIG welded on the custom radiator. If you want a new water temperature gauge or electric fan thermostat, this is the way to do it.
Once all of the connections are made to the S54 sensors, the DME calibrates itself to stock parameters, but most builders choose to take the car to a tuner at this point for custom programming.
The fuel charge in an engine does its work by expanding as it burns, pushing a piston down in the cylinder. Once the fuel charge has accomplished this task, an efficient engine evacuates spent exhaust gases as quickly as possible, although turbocharged cars scavenge a bit more energy out of the gas on the way out. The exhaust system performs this very simple function, and the exhaust is a great place for you to easily bolt on some low-cost horsepower and torque.
Tip: A note of common sense: Always replace all gaskets and worn fasteners when replacing exhaust components. Exhaust leaks are easy to avoid and a pain to fix.
But before you work on the exhaust, bear in mind that the exhaust system is also a critical emissions control system. Both federal and state laws govern what you can and cannot do to your car.
The catalytic converter has been the cornerstone of automotive emission controls for the past 35 years. Controlling emissions from street cars is an important environmental concern. Cars today are far cleaner than in decades past, thanks in large part to improvements in catalyst technology.
The catalytic converter is a muffler-type device that uses a ceramic or stainless steel alloy web that holds reactive catalyzing material (usually palladium or rhodium). When the exhaust gases pass through the catalytic converter and heat the catalyst, a chemical reaction occurs that helps change carbon monoxide to carbon dioxide, and helps to burn off any unburned hydrocarbons that remain in the exhaust stream before it exits your car.
The exhaust system does much more than just produce a sexy sound. This is a critical performance item in the build, and you should consider your purchases carefully, and in concert with the other engine modifications.
A replacement high-flow catalyst can really help improve airflow through the system, which means more power under your right foot. If you drive on the public roads, be sure to stay on the right side of the law by running a catalyst. Modern ones have no performance drawback.
For a modern car designed to work with at least one catalytic converter, the presence of a catalyst does not mean you can’t increase horsepower. The entire engine management system is designed to work with the catalyst and provide good performance. If you are concerned about the catalyst being restrictive, or you think it might be plugged-up, you can buy a new high-flow replacement unit.
Prices for new direct-fit catalytic converters for E36 models range from $500 to more than $1,000, depending on your model, so this is not a decision to be made lightly. Aftermarket “universal” catalysts cost much less and may be welded into place, but results vary widely. At a minimum, make sure that the inlet and outlet diameters for any aftermarket catalyst match those on your car. And bear in mind that with older cars such as the E36, some changes may have already been made to the factory parts. Check your car’s actual system. Also, check to be sure that any aftermarket catalyst fits in the available space and does not knock against the car’s floor-pan. In general, you are better off spending the money on a direct-fit catalyst designed for your E36.
Although extreme high-performance applications generally include removing one or more catalysts from the exhaust system, it is a violation of U.S. federal law to do so on a car registered for use on public roads. Moreover, removing the catalysts makes it harder, if not impossible, for your car to pass emissions testing, and removing the catalyst on any OBD-II car (1996 and newer) will likely cause a check engine light.
Be aware that an illuminated check engine light is an automatic emissions testing failure on all OBD-II cars. Simply clearing the light and driving to testing while the light is still off does not bypass this requirement, as the OBD-II system reports that the car has not driven enough miles to report reliably on engine condition. Testers see this and fail the car for emissions testing wherever such tests are required.
Legal Aspects of Catalytic Converters
The laws that govern catalytic converters are strict. It is illegal to remove a functional
