British luxury sports car manufacturer Aston Martin has just launched a new V8 version of its new DB11 grand tourer, and while its 4.0-litre twin-turbo heart might seem like a straight lift from Mercedes-AMG, who built the engine, it’s been properly customised.
This potent powertrain, which develops 375kW and 675Nm in the DB11, is actually tailored by AMG for Aston Martin – specifically in relation to the sump, according to Paul Barritt, Vehicle Line Director Aston Martin.
“When we laid out DB11 back in 2012, we knew we were going to have this engine, and we wanted to set it behind the front axle. Because it’s a 90-degree V8, it’s a little bit wider than our 60-degree V12, and [this is] one of the reasons why the DB11 has more space in the engine bay, why the strut tops are further outboard compared with the DB9, and why the front axle is a bit further forward relative to the driver," Barritt said.
“We also had AMG redesign the sump, too, to be far shallower than on the AMG version, which really pushed the boundaries on wet sump design with the DB11. We didn’t need to go to a dry sump, because the crank centre line between the V12 and V8 has to be the same. And, besides, it would have meant more weight with the tank and pipes, et cetera.”
In the cutaway, at this week’s international launch of the car, you can clearly see the entire engine is well behind the front axle, which is great for mass distribution. In fact, compared with the DB11 V12 version, mass distribution has shifted from 51 per cent front, 49 per cent rear – to 49 per cent front, 51 per cent rear.
“The total mass saving is a significant 115kg, and what that means is the V8-powered DB11 is a bit more agile and precise, compared to the V12 version.
“Other things that we do to the engine include using our own engine management system that we do with Bosch. So, it’s a Bosch engine controller, but it has combined Aston Martin/Bosch software and a dedicated Aston Martin wiring harness, rather than an AMG lift,” added Barritt.
Coupled with those elements, the induction system is also done by Aston Martin, as well as the exhaust system, an element that Barritt said was vital to the new DB11 variant.
“One of the things we wanted to do with this car was to make sure it sounded like an Aston Martin, and not like an AMG. Not such a straightforward thing to do."
“So, our guys have worked with the exhaust system to really turn the exhaust not into more of a European-style V8. And, by that, I mean, we’ve taken away the base content that AMG tend to focus on, and put in more mid-to-high frequency content, which we believe produces a very different note.”
Aston’s own engine management system has also allowed it to re-map things like throttle pedal progression, the torque structure (the way the torque is delivered).
They’ve also listened to customer feedback from V12 owners, who wanted more separation between the driving modes (GT, Sport, Sport +), so there’s now a greater breadth of change across those settings.
In another customer-suggested revision, the paddle-shift travel has been shortened, too, making shifts quicker and easier.
“We also recognised that there was a little bit of yaw overshoot from the rear axle on the V12, so, to compensate we’ve added stiffer rear subframe bushes, as well as adding a stiffer rear upper control arm, for improved lateral stability.
They’ve also changed the steering tune, by dialling in more effort according to what driving mode the driver chooses – adding to the sportier character of the V8.
“The end result of those changes is that we have a car that steers with a greater level of precision, which actually feels more focused than the V12.”
Even the brakes have been altered, with different front pistons to compensate for the mass distribution, which has resulted in reduced pedal travel.
Outside, the changes from the V12 to V8 are minimal. The most significant, though, is that there are no centre air vents in the bonnet. The reason, is that there are ducts that blow air over the turbos to help keep temperatures down.
In addition, the headlamp bezels are darkened, rather than the clear lenses on the DB11 V12.
“All-in-all, it’s a pretty comprehensive set of changes that we have undertaken on this car and with that engine," Barritt ended with.