• An in depth look at the new Audi 4.0 TFSI twin turbo direct injected V8 - Bore, stroke, and other internal specifications

      Audi released a new video and pictures of its 4.0 TFSI twin turbo V8 direct injected motor. This engine is going to be an important part of the Audi lineup to come (and for Audi tuners!) as it it is going in many models including the S6, S7, S8, and the Bentley Continental GT. In the S6 and S7 it is in a tune range of 420 horsepower. Bore and stroke are 84.5 x 89.0 respectively with a cylinder angle of 90 degrees.

      The block is silicone and aluminum which makes for a motor that weighs 485 pounds. Compression is relatively high at 10.0:1 and the turbos of the twin scroll variety.

      This power does not come at great expense to efficiency thanks to cylinder deactivation technology employed. This system only works during low RPM (between 960 and 3500 rpm) and when coolant temps are about 86 degrees Fahrenheit. 25 to 35 percent of max torque is available when the system is activated. It works by shutting off cylinder 2, 3, 5, and 8. This basically creates a V4. The pistons of course in the deactivated cylinders still move due to the crank.

      When the driver gets back on the gas the system deactivates basically instantly making it imperceptible to the driver. Unfortunately, the system is always on and can not be disabled by the driver. When it is engaged, the motor does run a bit rougher and it is noticeable.

      What about the tuning potential?

      This is the most important thing we want to know. Audi is already getting 520 horsepower out of this motor themselves. We have not seen specifications on the internals of the motor but we would assume internals are forged. We also would expect the internals for all the motors even in various states of tune to be the same although we do not know this yet for certain. We have many more questions about this motor and will have to wait until Audi releases more info but this at least is a nice starting point for learning about what is going to be a very popular tuning platform.

      This article was originally published in forum thread: An in depth look at the new Audi 4.0 TFSI twin turbo direct injected V8 - Bore, stroke, and other internal specifications started by Sticky View original post
      Comments 2 Comments
      1. Payam@BMS's Avatar
        Payam@BMS -
        That is awesome! this thing is gonna be sick. Variable camshaft timing,and two turbos with DI. That is sick.
      1. Sticky's Avatar
        Sticky -
        I read something about the turbos being in the V but looking for more info on that.