It should come as no surprise that a babied car is going to perform differently on the dyno than one with more than 300,000 more miles on it. But what is the cost of all those miles? Can your car keep its power while you drive it hard and often?
The guys at LegitStreetCars did their best to find out, comparing their 409,000 mile E39 M5 to another with less than 80,000 miles on it.
Now, the cars aren’t exactly the same. The high-mileage M5 had its exhaust and catalytic converter removed while the other one remained stock. It also had the mass airflow sensor disconnected and an Alpha N tune. These changes were replicated on the the low-mileage car to even the playing field.
So what were the results? When the same ECU modifications were made to both cars and the mass airflow sensors were disconnected on both of them as well, the delta between the two was around 20 wheel horsepower. That’s really not all that much.
Seems to me that the lesson from this video should be clear. Drive your car and treat it well. It doesn’t pay to let your car sit inside all the time, especially when you could be out enjoying it.