This 6.0-litre Twin-Turbo V12 Is The Most Powerful Diesel Production Engine Ever!

Imagine you are an Audi executive back in 2006. You want to get American buyers out of their petrol V8 cars into your economical diesel TVI cars. How do you do it? Well, they went big, creating the most high-performance diesel engines the car industry had ever seen. On the racetrack, they put diesel engines in these things, quickly followed by the most insane diesel road car ever devised, the Audi Q7 V12 TVI. In this video, we'll explore this absolute mammoth of diesel performance, why Audi went so crazy with their diesel tech, and the ultimate world-beating race cars that sat alongside the road cars. We'll get up close and personal with one of the most extreme diesel race cars Audi ever made, when petrol cars didn't stand a chance. Let's begin with the state of play back in the mid-2000s. Audi was having a good time of it with their TDI brand in Europe. They were selling well, but they wanted to go bigger. They wanted to attract the American market. They decided upon a pincer movement, incredibly cool, top-level endurance racing cars powered by diesel, and then also creating this thing, the 6-litre V12 Q7. Diesel race cars and V12 SUVs, could those two diesel things be cool enough to win over the Americans? Before we explore this behemoth, Audi wanted to make diesel cool, so they started on the racetrack. Up until then, petrol was seen as pretty much the only way to go. In fact, Audi had been dominating since the turn of the millennium with petrol prototypes, the savagely successful R8. Despite winning six of the last seven Le Mans 24 hours with petrol, in the name of showing off their diesel tech, Audi was willing to completely tear up their race car technology and start again, using the so-called fuel of Satan. Was it genius? Was it lunacy? Pioneering technology generally sits right slap bang between the two, but doing the maths, it occurred to the Audi sport engineers that diesel wouldn't just work, they could make it world-beating, and would you know it, they nailed it. Q, the Audi R10 TDI, an utterly dominant diesel race car. These Q7s are notoriously sketchy to maintain, so while we're here, I've plugged in my Carly, let's do a diagnostic check on it. The diagnostics are done, and this car's only got five issues. That is by far the smallest amount of issues we've ever found on a car that we've plugged Carly into. Clearly, Audi UK look after this thing incredibly well, maybe a bit too well. They're all simple issues. It says the health status is bad, but basically any issues has that coming up. Radio, central electronics, information electronics, tyre pressure control, and what's cool is you click on these and then you fire up the smart mechanic. They'll tell you what it thinks is wrong with the car and how to fix it, so you can either have a go yourself or take this diagnosis to your local garage and get it sorted. Carly also has a car history checker. It's in the free version and you have unlimited number of checks for the cars that you own. You simply punch in the reg of the number and it'll give you the full history of your car, so you can see if you bought yourself a dud. Click the link in the description below and use the discount code drivetribe24 to get 15% off your Carly adapter. Thanks to them for sponsoring today's video. I never thought I would do a diagnostic check on a Q7 V12, but it just happened. The engine they decided to develop was a twin turbo V12 diesel that would go up against the V8 and V10 petrol engines of the other prototypes. The other competitors seemingly had an advantage. Petrol engines were more powerful thanks to revving higher and they were also more responsive. They were more compact as a design. That means it could sit lower and further forward in the car for better weight distribution. Also, petrol is the most tried and tested technology in racing, so on the face of things, it's going to be more reliable. Yes, even on a racetrack, diesel engines would be more economical than petrol engines, but Audi needed more than that. They needed more to guarantee success, so they set about ticking off all the disadvantages of diesel engines. Number one, diesel engines are too heavy. Audi opted for a featherweight aluminium block. Tick. Number two, diesel engines don't create enough power, they're all just torque. Audi made sure to develop the engine to rev higher than most people would initially think. More revs means more horsepower. Also, they used cutting edge fuel injection technology to not only increase the engine's power, but also make it more efficient and the twin turbos on the engine were cutting edge at the time too, which increased throttle response, which meant suddenly a diesel engine was responsive. Number three, diesel engines are big cumbersome things. They're not nice and compact like a petrol engine. Audi developed this V12 to be at a 90 degree V angle, much more than a normal V12, so it could splay out and spread its weight across the car. They could also mount it lower in the car. Suddenly, the weight distribution was where it needed to be for a top level racing car. Suddenly, Audi Sport had tackled every supposed downside of the diesel engine versus petrol, and then knuckled down on its strengths to really turn the screw on the competition. Despite being the most powerful diesel of its size, circling back to the torque output of 1,100 newton meters, that allowed the car to pretty much be in any gear out of a corner, and it would accelerate strongly out without much bother at all, also meaning it could rev lower and be more reliable over 24 hours. Petrol injection is around 50 to 60 PSI. Audi used the cutting edge common rail diesel injection to reach 23,000 PSI, making for better power and economy. Common rail is an upgrade to direct injection because the higher injection pressure produces a finer fuel spray that burns more efficiently, is generally less noisy, and can potentially make more power if calibrated properly. Speaking of economy, the Audis could stay out on track for an average of 14 laps without having to fuel up. The record was 16 without a fuel stop. In would go 90 liters of Shell V-powered diesel, and they'd be off for another massive stint while the Jub V10 petrol cars were chewing through fuel at twice the rate. That V12 diesel race engine was incredibly reliable too. Audi managed to smash through 10,000 miles on their engine dyno, deciding that 650 horsepower and 1,100 newton meters were sensible values to race at, and it worked. Not only did the Audis spend barely any time in the pits in the race, they were the fastest and most fuel-efficient cars on track. That is an unbeatable combination, hence why a V12 diesel Audi led every single lap of the 2006 24 Hours of Le Mans. That's pretty amazing. Smashing on the racetrack was great, but Audi executives wanted to make sure that it was converting to TDI road car sales, so they decided to take the V12 twin-turbo diesel formula and build a road car. This road car. To this day, this is the only V12 diesel production car ever made. No one else has been insane enough to give it a go. Back in the 2000s, diesel was having a good time of it. Governments were telling us how economical it was, but to petrolheads, it was seen as slow, sluggish, and just simply not responsive enough. Audi's V12 diesel race cars were nailing it on track, but they felt they needed a road car product to ensnare people away from their 5-litre V8 petrol cars, so they made this. I've parked up at Girardo & Co. to have a look at this engine. We will come back here later in the video to show you something very, very special. You'd like to think that there's some Le Mans 6-litre V12 in here, but I'm sad to say there apparently isn't a single component shared between the two engines. Similar technology, but not a single millimetre of crossover. This thing should be looked at instead as a build-up of the V6 or V8 TDI engines that are in the lower-spec cars. You can imagine them taking the 3-litre TDI and modulating up to the full 6-litre V12. This engine wasn't initially put in the Q7. It was made and inserted into an R8 that had an elongated wheelbase. The thinking there being if the race car was cool enough, maybe they could get Americans excited about a diesel supercar. Thankfully, they had slightly more sense and decided to put it in something that could take over from, say, a Ford F-150 or a Dodge Ram. Americans love the Ram TRX that we had on the channel last year. This was the equivalent back in the day, but diesel. These days, we have thumping great SUVs like the DBX 707 and the Urus Performante, but back in 2008, this thing blew away the competition in the power and torque stakes. Step aside Cayenne Turbo S, its V8 couldn't compete. The V12 puts out 500 brake horsepower and 1,000 Newton meters of torque. That's not too far away from the diesel race car. This may be the only V12 ever put in a car without spark plugs, but it packed a punch and still does today. Despite weighing 2.7 tonnes, it'll do 62 miles an hour in 5.5 seconds and smack into a limiter at 155 miles an hour. The thing is, the diesel Audi racing cars were so far ahead of the curve that that era of Le Mans was just a joke with the Audi domination. Being that far ahead of the curve in racing, good thing. I think this car, the Q7, was too far ahead of the consumer demand curve, which on the road is a bad thing. It wasn't too long after this that well-off families wanted to be seen in the most powerful versions of their big massive SUVs. Maybe if this thing had come out maybe five years later than it did, maybe up in the R15, R18 era, it may have had a better pickup and sold better. Sadly, despite all of Audi's intentions, this car never actually made it to the States. Due to the financial crisis that hit in 2008 when this car came out, they decided it wasn't worth the bet and didn't send any of them to the US. It never even got the chance to tick that box over there and get people over from their V8. It was only sold in other markets. This thing is so rare that I reckon I could turn up to most Audi dealerships in the UK and they will have never have seen one of these things. Let's think about this thing in the context of its day. Brand new, this was £94,820. For an SUV nowadays, that's pretty par for the course. Back then, that was a shitload. The V12 TDI Q7 was nearly double the price of the next car down, the V8 TDI. That's a lot. It was 20 grand more than a Porsche Cayenne Turbo S. The big PR torque figure was 1,000 Newton meters, but the engineers at Audi have since said that the engine could have actually gone much further. It's the automatic gearbox that's the weak point, so they had to restrict it. Imagine what this thing would be like. In fact, let's just floor it. Let's scare it. Oh, okay. Okay. Yeah. That, that is torque. My God. Does it feel not 60 in five and a half seconds quick? Oh, it does. Oh, it does. Coming into today, I did wonder what a V12 diesel would sound like. Does it sound like a V12? No. It just sounds like a V8, really. It sounds like a very, very beefy V8, but it doesn't need to sound good. When you've got performance like this, great move from Audi are the brakes. Now, that can be seen as another potential crossover with the racing car, being carbon ceramics. It honestly feels like an engine that should power a dreadnought battleship. It doesn't feel like it should be in a car. Audi UK are going to have to explain themselves on the seat cover front. These are absolutely horrendous. What makes them worse is how beautifully spec'd this car is. Brown paint, brown leather interior, and then the seats are this beautiful cream leather. To accent the interior, teak in the doors, center console, in the boot. The entire boot floor is teak. I wonder if the starting price was 94 grand. With all of this, surely this is a 100 grand car. Back in 2008, that was a lot of dosh. If you've ever owned a Q7 V12, get in the comments. Tell us about your experience. I imagine it was incredibly financially painful. Now, we have managed to bag ourselves an Audi diesel race car for today's video. Not an R10, but a car that benefited from year after year of performance diesel iteration. First, there was the V12 R10, then the V10 R15, and then this, the R18. Picking back up the diesel racing story, TDI just kept winning. Apart from a Peugeot blip in 2009, the guys and girls at Ingolstadt were untouchable. Just like before, from R8 to R10, they didn't rest on their laurels and completely changed up their concept again. Wind tunnel testing proved that they should move away from the open-top R15 and switch to a closed cockpit. The engine shrunk even further. The ACO was desperate to slow the Audi diesels down to give everyone else a chance, so power was reduced and capped at 540 brake horsepower. That's why from the V12 and V10 before it, the Audi engineers opted for a V6 single turbo for the R18. This 3.7 liter V6 was 25% lighter than the V10 before it. When you add in the fact that they switched to a carbon fiber casing for the gearbox, a one-piece carbon fiber monocoque for the chassis, and the first introduction of a shark fin on a racing car ever, you could see the R18 as an amazing feat of engineering optimization. The R18 was so optimized that it came in well under the 900-kilogram minimum weight that the regulation said, so they had to apply lead ballast to make it fair. There was a reason for that obsession with lightweighting, and it was the fact that the hybrid LMP1 era was just around the corner. They could have got 540 brake horsepower quite easily from a V8, but they decided to opt for a V6 knowing that up front, there would be some hybrid gubbins in the near future. Getting that amount of power from such a small engine was another amazing accomplishment from the Audi Sport team, and it creates it thanks to some more innovations. Down in there, that is a hot V turbo. Now, we think of that as a fairly standard thing on some road performance cars now, but back then, this was cutting-edge technology. Instead of having the turbo, say twin turbos would be down either side there, they swap with the intakes. Down here, you've got carbon intakes on either side, and then there's a single turbo right between the 120-degree V of the V6, so they've splayed the V6 right out to fit that turbo in there. That means it can spool up better and can create power quicker. All of that power was transferred through another innovation. That gearbox back there was electronically actuated instead of being pneumatic for quicker shifts. It is such a privilege to sit in this chassis, and you can see it's the real deal. I've actually got two stickers in here, one over my shoulder, which is scrutineering for the Sebring 12 hours, and then I've got an Audi Sport Team UIST Sebring map of the circuit right in front of me. What an amazing machine this thing was. Now, one of the big complaints back in the day from the drivers was its visibility that led to those massive crashes. If I close this down, if I imagine my race helmet on, so my vision immediately does this. It is postbox out the front, especially with this sunstrip coming down. That is tiny. Then the mirrors either side can genuinely see. If I sit back in race position, probably maximum two feet outside that right rear wheel. Same on the left. That is sketchy. The visibility was so bad, but the drivers have actually added this really nice little tidbit here. That is a makeup mirror that's been glued to the carbon door. They've blanked off this half so they can't see themselves, but the other half suddenly gives them, I'd say, about eight, 10 feet of visibility outside of the right rear wheel. That will have helped a lot. This is, being a Le Mans car, technically a two-seater. It's all done by a simple volume size, but technically that is the second seat. It's full of electronic gubbins. This is essentially my air con, but yes, it meets the two-seater Le Mans regulations. There's some really nice other tidbits in here. There's a sticker, Varna, Sonja's little sister, Sonja being the Le Mans winner. Then the actual chassis code there, R18107. This car is Gerardo. This is a real deal. In the first year of the R18 though, they were non-hybrid and this is one of them. That's why it's possible for this chassis to be privately owned and sold here at Gerardo & Co. Without the hybrid gubbins, it is much easier to maintain. It's still by no means cheap, but you don't need a full factory team to start it up and keep it running for a season, something that this car will be doing soon. By staying away from electrification, this car is much more approachable and usable as a historic racer. You could see the R18 Ultra as the ultimate performance diesel machine before it became the R18 e-tron and started relying more on its flywheel hybrid system. It's also the prettiest Audi prototype, in my opinion, as the later editions of the R18 got real ugly. Sadly, the R18s experienced some enormous crashes in their tenure, but this one made it through unscathed, driven by the biggest names in endurance racing at the time, Christiansen, McNish, Capello, Lotterer. The only downside of the R18 mentioned by the drivers was the fact its visibility wasn't as good as the previous open-top prototypes, but then again, it didn't matter too much because no one was overtaking them anyway. Performance diesels are dead and they're probably never going to make a comeback, especially in racing with all of diesel's PR issues. Audi, however, are about to make a massive motorsport comeback, not at Le Mans, but in F1. They've recently bought out the Sauber F1 team and are going to try and punch for world championships, try and do a Mercedes rather than a Toyota, Jaguar, or BMW. If they know what's good for them, they'll turn up with a twin-turbo diesel F1 car. Why not? It's worked for them in the past. If you like this video, give it a thumbs up. I've been Mike, and don't forget to subscribe to DRIVETRIB.