The M550d. Quad-Turbo insanity.

0-100 in 4.2 sec with xHP

The M550d G30 has a truly unique drivetrain, that won't be replicated nor matched anywhere in the future. The G30 LCI no longer gets built with this engine. As a matter of fact, a 3-Litre 6-Cylinder-Diesel with 4 (!) Turbos will never be built again, so what we are looking at here is the last of its breed with 400 HP and 760 Nm of Torque, straight out of factory. This power gets matched by the 8HP75 transmission (2nd Generation 8HP), which has a torque limiter in all gears exactly matched to the power of the engine. In other words, proper engine tuning isn't possible, without removing that limiter (Sure, there is some trickery possible around that limiter for Engine Tuners...but it will never work like done properly).

But removing a limiter is an easy job, done in seconds, when knowing what to do where. What our Maps do and whats the actual work, is to redesign the character of the transmission and in turn the character of the whole car. To achieve this goal we bought a M550d and used it on an every-day basis for a few months. This is the only way you get to know the small "quirks" every calibration has and understand what the engineers at BMW actually had in mind when designing the calibration. They really do an awesome job in general, but thats not the point. They have their constraints and many things are done the same way for all models, for various reasons. The calibration for a 530d matches the one for the M550d in many aspects and thats where we can start to go a more specific route and sharpen up the character. The M550d - despite it's weight and size - is a very sporty car overall and people buying such a car do have expectations, which might not always get matched by the transmission.

For instance setting the transmission to S/Sport+ (the most-sporty setting) does not really cut it for experienced driving. Downshifting when braking into corners is late (so the engine-brake never supports the car's brakes and you are left with a too high gear on corner exit), blipping is dull and the trans still hurries into the upper gears between corners. It's a bit half-baked and was clearly designed not to upset the people not having sport in mind, but just always buying the top-of-the-line model. On our Stage 3 map, there is no more compromise and 3 different mappings can be selected through the DEC (Driving-Experience-Switch) next to the gear-lever. S/Sport+ does the job on it's own when really going for it, being it on a race-track, on the Autobahn or on empty country-side roads. Selecting S/Sport tames down the brake-shifting, softens the blips, does not hold gears for that long etc. Theres now a real difference between those modes.

D/Comfort and D/Sport are also redesigned. D/Sport now combines very similar shiftpoints to D/Comfort with a more responsive behavior to quick throttle inputs and harder braking. The Trans is more easy to sharpen up shifting or shift-down 2-3 gears, depending on the driver's steering/throttle inputs, but will still use 8th Gear when just driving steady. So i's a true every-day mode, with just a bit of pepper added. This makes room for D/Comfort to be even a bit more relaxed than stock. On mid-throttle the trans will now shift up earlier for instance, as the massive torque of the M550d easily allows for that. The stock calibration just overdid it a bit in the mid-range. We also overhauled the Launch Control (which actually resides in the Transmission) and achieved a substantial increase of 0.25 seconds over the stock acceleration. Our 2-Ton-Estate-550d now runs a reproduceable and steady 4.2x sec from 0-60mph, Youtube ) opposed to 4.45 sec fully stock. Keep in mind, this is with stock power! The gain is just due to Launch Control adjustments.

The M550d joined our fleet in November 20 and after using it for 2-3 months, the actual mapping process started and took around 3 weeks in-car. This included city-driving, quick Autobahn runs and lots of experienced country-road driving. (those poor brakes..) A total of 75 maps were re-calibrated to achieve what we think is a truly unique calibration, clearly different to BMW or Alpina. Of course many changes don't surface instantly, as they will only show up over time, when getting into all the various situations on road. For example Eco-Pro now takes-off in 2nd Gear as Standard, we adjusted the nervous downshifting on the slightest incline (something BMW implements for ages now), the Lock-Up Clutch of the Torque-Converter closes a bit tighter, going full-throttle gives you the mathematically correct Shift-RPM in each mode, while pressing the kickdown releases a few hundred extra RPM etc. etc. Many of the things mentioned will trickle down to the lower models (530d, 540d and alike) over the next weeks/months. Sometimes similar, sometimes adjusted to suit the different power bands of those models.

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