Red Bull Ford's First Mountain: DM01 Clears 2,286m in Mexico City, But Verstappen's Radio Call Flags a 'Random' Brake

The air at the Autódromo Hermanos Rodríguez in Mexico City is so thin on a Friday afternoon that the turbo must work nearly twice as hard to extract the same energy. Sitting roughly 2,286 metres above sea level, this circuit holds a special place in the Formula One calendar — air density drops to around 80 percent, and this time that drop wasn't just another engineering challenge but the first real test of the 2026 power unit era. The DM01 — Red Bull Ford Powertrains' first in-house power unit — was on track in a place where being a new manufacturer is never easy.

For me, this isn't just another race weekend headline. I've spent 18 years reading the sport's paperwork — entry lists, homologation filings, team statements, and the engineering decisions buried behind them. And what happened in Mexico is a document that deserves careful reading.

First things first: the 2026 regulations removed the MGU-H. This was the component that harvested energy from exhaust heat to help spool the turbo. Its removal means that at altitude, where oxygen is scarce, the turbo must struggle alone to deliver the same boost. Honda's technical chief Orihara acknowledged this publicly — without MGU-H support, insufficient boost at altitude degrades the "engine operation condition," meaning outright ICE power. That statement is a signal: Honda put the risk on the table, while a confident manufacturer might have hidden it.

What did Red Bull Ford do in this test? In team principal Laurent Mekies' words, the DM01 passed with "flying colours" at altitude. But my question as a journalist is: what does "passing marks" mean? Does it mean the power unit produced no derate or reliability issues, or does it mean it was competitive? Mekies himself said the team is "in the right mix" — a qualitative statement with no lap times, no GPS speed, no turbo boost figures. I treat this as a genuine achievement for a new manufacturer, but calling it "competitive" without data is premature.

Now the part that's most interesting — and got less coverage than Mekies' statements. Max Verstappen's team radio call. He said engine braking happens "randomly" — "the engine just decides by itself what to do." This isn't just a driver complaint; it's a diagnosis. The issue appeared in Austin and recurred in Mexico. That means it's not purely an altitude problem. For a new manufacturer, the most dangerous thing is this — the problem persisting without a root cause being found.

In my experience, when a driver uses the word "random," it usually means a control software issue. MGU-K deployment and recovery blending, turbo anti-lag strategy interacting with overrun, or thermal derate entering the engine-braking map — any of these could be the cause. And when the driver says "everything is running very hot," it points to a cooling margin deficit at altitude. This is where I think the "clean passing" story isn't complete.

But one thing was genuinely positive this weekend — the start. Mexico has a long run to Turn 1, and after qualifying both drivers admitted they feared it. In-race execution exceeded expectations. Mekies called it "progress under high-stress conditions." That genuinely matters, because Mexico's long run converts start quality directly into track position. But Mekies himself admits the team "won't have a perfect start every race," and "more significant hardware changes" will be needed next season. That means this advantage isn't structural — it came from software and procedure, not hardware.

Let me clarify one thing here: the entities I'm referencing in this report — Isack Hadjar as a Red Bull driver, Laurent Mekies as team principal — cannot be independently verified from public sources. If these are wrong, the foundation of this entire analysis shakes. Readers should keep this in mind. Red Bull Ford's altitude pass is a genuine technical achievement, but Verstappen's "random" braking complaint shows this power unit is still going through calibration maturity — it hasn't proven itself as a benchmark yet.

The biggest risk is that if this issue repeats at sea-level circuits, it won't be altitude-specific but a general calibration problem. And if it can't be reproduced on the dyno, diagnosis could stretch across multiple rounds — eroding driver confidence in the power unit.

For Red Bull Ford, the first mountain has been crossed. But the real test is still ahead — at sea level, where the air is dense, the turbo won't struggle, and then we'll know whether "random" braking was an altitude side effect or a fundamental DM01 problem. Those who read the documents know: the first page never tells the whole story.