It’s a common assumption that BMW’s M models reign supreme in terms of track performance and outright speed. However, anecdotal evidence from forums and real-world experiences suggests that there might be a dark horse in the BMW lineup: the Z4 M40i, especially when tuned. One user’s experience highlights just how potent this roadster can become when its performance is enhanced.
According to a forum contributor, their tuned Z4 M40i, boasting an impressive 450 wheel horsepower (whp) and 500 wheel torque (wtq), delivers acceleration that is described as “ungodly” when compared to their previous M2 Competition. This significant power bump transforms the Z4 M40i into a track weapon capable of outperforming the M2 Competition, not just in straight-line speed, but also in cornering prowess. The driver reports effortlessly taking corners at higher speeds than they could in the M2 Competition.
Several factors contribute to this surprising performance. The Z4 M40i shares the width of the G80 M3 but distinguishes itself with a shorter height, length, and wheelbase, making it the lightest car in BMW’s current lineup. These dimensions are critical for agile handling and contribute significantly to track performance. The example of the 330hp Toyota Supra outperforming the 405hp M2 Competition at the Nürburgring underscores this point; the user, having driven both, confirms comparable acceleration and cornering speeds between the Supra and their tuned Z4 M40i.
The user posits that with further tuning to 500whp, the Z4 M40i could potentially challenge even a stock G80 M3 on a track. They argue that the inherent advantages of a smaller, lighter car with superior turning capabilities and lateral acceleration could outweigh the horsepower advantage of the M3/M4. The assertion is made that the G80 M3’s Nürburgring time might be more attributable to its extra power than superior cornering speeds compared to a lighter, more nimble platform.
While the M3 and M4 are often considered the kings of BMW’s performance lineup, their size and practicality come with compromises in weight and agility. For those prioritizing pure driving thrills and track performance in a BMW, particularly in a convertible form, a tuned Z4 M40i presents a compelling, and perhaps unexpected, alternative. The notion of a hypothetical Z4 M emerges as the ultimate track-focused M weapon, suggesting that sometimes, less weight and more agility can triumph over sheer power and traditional M pedigree.
