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Title: Turbo Lag's Not Dead, It's Just Gone Electric: Audi's Risky GambleThe European Uni... Title: Turbo Lag's Not Dead, It's Just Gone Electric: Audi's Risky Gamble
The European Union's relentless push for emissions cuts has cast a long shadow over diesel engines. Market share has plummeted from over 50% pre-Dieselgate to a paltry eight percent this year. That puts diesel behind even plug-in hybrids, a first. But Audi, stubbornly, isn't ready to pull the plug. They're betting that a new electrified turbo setup can keep the TDI relevant.
Electrification: A Jolt to the Old Diesel?
Audi's new 3.0-liter V-6 diesel, debuting in the A6 and Q5, pairs a mild-hybrid system with an electrically powered compressor. It’s not the first time Audi's offered 48-volt V-6 diesels, but it is the first time the MHEV hardware works with an electrically driven compressor. The compressor, strategically placed behind the turbocharger and intercooler, is supposed to eliminate turbo lag.
Audi claims the new V-6 diesel offers response comparable to an electric car. Bold words. The engine delivers 295 hp at 3,620 rpm and 428 lb-ft from 1,500 rpm. The maximum boost pressure of 3.6 bar builds nearly a full second quicker than its predecessor, and the compressor wheel spins about 40 percent faster, hitting 90,000 rpm in just 250 milliseconds. All this, they say, translates to sharper response off the line. The mild-hybrid system adds a temporary 24 hp and 170 lb-ft.
The A6 Sedan, equipped with this engine, sprints to 62 mph in 5.2 seconds. The Q5 does it in five seconds flat. Impressive figures, but the diagram illustrating the drivetrain’s complexity has me wondering about long-term reliability. (And I do mean long-term. How will these systems hold up after, say, 8 years? 10?)
Durability has supposedly been improved, and fuel efficiency is up. But let's be clear: this isn’t an all-new engine. The "EA897evo4" codename confirms it’s the latest evolution of a Volkswagen Group diesel first introduced in 2010. It even powered certain Porsche models before they abandoned diesel after Dieselgate. The EA897 was, indeed, part of the emissions-cheating scandal. How much of this "new" engine is just lipstick on a pig?
Audi insists this latest V-6 is its cleanest yet. It can even run on hydrotreated vegetable oil (HVO), reducing CO₂ emissions by up to 95 percent compared to conventional diesel. Made from used cooking oil and agricultural by-products, HVO is already being used in diesel cars built at Audi’s Neckarsulm and Ingolstadt plants in Germany.
The Ghost of Turbos Past (and Present)
The original Porsche 911 Turbo, debuting in 1975, became infamous for its turbo lag. Step on the throttle, and not much happened until the tachometer needle swung past 3500 rpm, then kaboom! The car leaped forward. This on-off nature led to the "widow-maker" reputation. A fearful mystique developed. Was the Turbo inherently flawed, or did it just require a highly skilled driver?
Even with "only" 253 horsepower (less than a modern minivan), the original Turbo was feared. Porsche engineers in the mid-1970s didn't have modern tech like stability control or computers optimizing fuel injection. The original Turbo also weighed only 2825 pounds, compared to today’s Turbo pushing almost 3700 pounds. Turbo lag added another wrinkle to a car that already had its engine behind the rear axle.
Car and Driver noted in its first test of the Turbo that the difficulty was "in trying to utilize handling that frequently and rapidly varies between the two extremes of insistent understeer and sudden oversteer."
I've seen the arguments rage in online forums for years. Some claim the "widow-maker" reputation is overblown. Others insist it's a beast that will bite you if you're not careful. What's interesting is how rarely these arguments are settled with data. It's all anecdotal, subjective.
And this is the part of the report that I find genuinely puzzling. Why is there so much romanticizing of cars that are fundamentally dangerous? Why is there such a resistance to technology that improves safety and performance?
A Risky Bet on a Dying Breed?
Audi's gamble is this: can they make diesel relevant again by electrifying the turbocharging process? Can they eliminate turbo lag and deliver performance that rivals electric cars? The numbers are promising, but the complexity of the system raises concerns about reliability. And, frankly, the entire exercise feels a bit like rearranging deck chairs on the Titanic. According to Audi, their new V-6 diesel engine has zero turbo lag.
Is Audi pouring resources into a dying technology? The market share numbers suggest it is. But Audi has a long history with diesel, and they're not ready to give up without a fight. Whether this fight is worth fighting remains to be seen.