BMW has always been at the top of its game when it comes to performance, efficiency, and motoring innovation. Its diesel cars have topped the executive market, and its hybrid and electric cars offer an unrivaled range. But it’s the M-Division of cars we all turn to when looking for outright speed and motoring fun.
The naturally-aspirated M3 and M5 were the first to put out 100hp per litre of displacement. And it’s these two that have spurned a wide-fetching M-Division (albeit with the addition of turbocharging) to suit different tastes. The fact that all of them still have a lot to give, with simple remaps, makes them even more alluring.
What Is Remapping?
Remapping may not have the bling factor of new wheels or the bang of a revised exhaust, but it’s the performance added to your BMW with a simple rewriting of the software in the car’s ECU. This is done by connecting the car’s OBD port (the same connection used to diagnose engine and car faults) to an external computer and first scanning the engine’s preset software or ‘maps’. Individual parameters controlled by the ECU, like fuelling, timing, and boost pressure can then be changed with a simple BMW remap for a little more oomph.
Like all cars, BMWs won’t have their full performance potential on offer straight out of the factory (mainly to curb fuel consumption and emissions and prolong longevity). This though can all be modified (or the ECU remapped) for improved throttle response, better drivability, and what’s most important – bags of added power. While the enhancements will be more evident in something like the M2, M3, M4, M5, and XM cars, even basic diesels like the 116d with all its 116 hp on tap will see a substantial power gain and sip less fuel in the process.
Why Remap Your Car?
The obvious reason to remap your car factory ECU settings is to get more power. A remap can remove the limitations set by the manufacturer, and provide a car that has better power delivery, with a wider power band and torque where you need it. There’s better initial get-up-and-go, faster acceleration, and higher top speeds. Hard-revving cars can lose puff at the top end, and a remap can tailor power and torque to your driving habits and the road and weather conditions in which you typically drive.
Related performance, drivability, and throttle response improvements mean the car will be easier to drive, and significantly more fun. There’s also the choice of deleting speed limiters (rated at 155mph in the UK), an option worth considering if you use the car solely for track purposes. While most M-car owners aren’t particularly concerned about fuel use, a BMW remap can additionally cut down fuel consumption without sacrificing the benefits in the power departments.
How Is It Done?
Remapping your BMW is done in stages. Stage 1 usually means no additional parts are added, but there’s an increase in power and torque across a wider spread of the power band. This improves dead spots, meaning a more responsive car. The increase in torque will also mean less frequent gear changes, so additional savings in fuel. The car might however need a higher octane fuel, but the benefit is that the engine’s reliability isn’t impacted.
Stage 2 often involves having an aftermarket exhaust and uprated air intake previously installed. Other changes can include a catless downpipe and the removal of the OPF filter in petrol cars. This adds subtle to significant power gains over a stage 1 remap depending on the engine.
Stage 3 builds on the work done in the previous two stages with bigger fuel injectors and pumps to upgrade the fuelling, higher-rated spark plugs for improved combustion efficiency, and changes to the cams (with a performance camshaft, valves, and springs) for improved timing. More serious gains can be had by changing boost profiles in the turbo, expanding the rev ranges in twin-scroll turbos, the addition of a performance wastegate, and going for forged or billet internals.
BMW owners are advised to get their car tuned at respected garages and have a remap from a trusted brand that has put in the work and research for your model. Depending on the stage chosen, a BMW remap can last between a few minutes to an hour. There are also remote options available, meaning you can do the whole procedure from home, or where you see fit. These will take slightly longer and are often divided into sessions.
Comparative Examples
The previous gen F80 M3 is one of the most tuned cars in the UK. It’s powered by the S55 engine, a 3-litre inline six-cylinder petrol with twin-scroll turbos. Power output in stock form is 317 kW or 425hp in the standard car or 331kw in the Competition cars and the F82 M4 and F87 M2 that followed. All versions can go the extra mile, considering the work put into the die-cast aluminum alloy block, the closed-deck crankcase, coated cylinder walls, improved cooling, a lighter and hardened steel alloy crank, and the aluminum alloy pistons.
With a stage 1 remap, the car gets an additional 65-70 hp at the back wheels or rounds out to a hefty 500hp, with no additions required. There’s significantly improved acceleration, bringing the official 0-62mph time of 4.1 seconds down to 3.6 seconds (as tested in live sessions and on the dyno). The removal of the limiter gets the car to the equivalent of 175mph/280 km/h and is in line with the M-Drivers package that costs up to four times more (around 2000 pounds) than a stage 1.
Moving to stage 2 and the inclusion of catless pipes, the power numbers increase to 520 hp or 95 hp over stock figures. The car gets an extra push from a standstill and edges closer to 185mph or 297 kph. A stage 3 extracts all the S55 has to give. The package includes aftermarket turbos, beefier injectors, and better spark plugs for top speeds of over 190mph or 300 kph, and cuts down acceleration times by almost a second. Additionally, timing can be improved with a revised crank hub, and an aftermarket set of charge pipes improves airflow. You will need to pay for that level of performance though.
The same improvements can be had in older favorites like the E46 and E90 M3, the newer G80, as well as all M and XM cars. Stage 1 tunes and remaps are inexpensive for what they offer as they won’t require any revisions to the stock engine. The addition of parts will bump up prices in the following stages as they’re needed to provide the quoted power numbers, as well as help with engine longevity.
Final Word
Remapping software is one of the cheapest ways to get extra horsepower and torque in your BMW. Additional parts added in stage 2 and 3 remaps will open up the full potential of the car, and get you faster times around the track, and bucketloads of driving fun on the street.
