BMW M550i Tuned By Dinan is Luxury Land Missile
Time for a physics lesson.
The winding roads of Malibu offer car enthusiasts refuge from the drudgery of California traffic. They also offer an amazing view of the world. Narrow, two-lane roads have been chiseled into the mountainside, following the curvature of the rocky terrain. Some of the roads are beautifully paved, others are nearer to a rally stage. Oh, and watch out for the falling rocks. This is an excellent place to place to test a car. If the brakes don’t fatigue, the suspension keeps things in check, and the driver doesn’t into the ocean, the car checks out.
With that said, it’s time for a physics lesson, specifically, the effects of size and mass. The G30 chassis 5-series is a big car. Measuring in at 195.4 inches long, it is some 11 inches longer than the BMW M4 I recently drove up here. A car that I believe I described as feeling ‘enormous’ in the canyon roads. The M550i is not helped by the fact it is also over 800 pounds heavier than said M4, weighing in at almost 4,400 pounds.
When a road is tight, and narrow it is that much harder to navigate a two-and-a-quarter ton, 606 horsepower land speed missile through it than, say, a Mazda Miata. That said, the Dinan-tuned M550i performed admirably. The brakes never fatigued throughout my half-day road burning assault, and the M550i in general didn’t miss a beat. This all sounds obvious, but it’s worth noting that I have overheated other cars in less stringent conditions.
ALSO SEE: Dinan BMW M4 Review: 550 Horsepower of Rowdy Fun
Indeed, the M550i felt unfettered about the whole experience, the Dinan upgrades make this car lively and expressive when the going gets twisty. The Dinan ECU reflash really awakens the 4.4-liter V8 mill. This engine makes monster torque figures, 635 lb-ft of twisting force is no joke. While the standard car never hurts for power, the Dinan upgrades give the M550i stump-pulling torque. You could enter this thing in a tractor pull and probably land on the podium. It makes the car feel eager and ready. It doesn’t pull away from corners but, rather, it explodes out of the them, like a cannonball.
I previously maligned the electric power steering system in the M550i. Much like other new BMW models, the power steering is numb and distant. The steering wheel may as well be made of wood in a BMW these days, rather than firm, but nice feeling leather. BMW just has not figured out electricity, it seems.
However, I have less issues here. The difference is in the footwear. This Dinan BMW M550i is rolling on a gorgeous set of Forgeline wheels. Those shiny rollers measure 20×9.5″ in the front, and 20×10″ out back. Those big wheels allow for some big tires, specifically a set of Michelin Pilot Sport 4S, which are 265s in the front, and 295s in the rear. Unsprung weight is down, and the grip and steering feel is up, in a big way.
Match that big tire grip with the slightly stiffer Dinan lowering springs and the end result is a very poised, and capable sports sedan. A sports sedan that happens to be comfortable, and have explosive super car beating power.
To that end, although traffic was relatively light during my day with the Dinan M550i, I did run into company. A 997.2 Porsche GT3 RS, to be specific. I won’t incriminate either of us, but it was the only car that could keep up with, and ultimately shake the Dinan M550i. When the benchmark inadvertently becomes the ultimate expression of Porsche track day dominance, you have done something right.
Dinan has put some “M5” back into the the M550i where BMW stopped short, and the overall effect is truly excellent. I can’t wait to see what Dinan does once they get their hands on the real-deal BMW M5.
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