4B11 vs 4G63? | 1170HP & 53 PSI++ Of BOOST Worlds Fastest EVO X! [TECH TALK]

Running 1170HP, 680 ft-lbs of torque and in excess of 53 PSI of boost, the English Racing Mitsubishi EVO X is pushing the boundaries and leading the pack to be the fastest Mitsubishi Evolution X in the world. Driver Myles Kerr discusses some of the challenges that come with pioneering a newer platform and where he sees the 4B11 being superior to the proven but now dated 4G63 power plant. Despite what a lot of people think, it does take more than just a healthy bank account to get this done.

This Extreme Turbo System built EVO X runs Golden Eagle sleeves, stock stroke GRP Connecting Rods, a modified factory crank, GSC Power Division valvetrain and S3 cams, a Precision 7685 turbo and the MoTeC M150 with John Reed Racing modification brings it all together. The team had some huge drivetrain issues before getting the weight down and the car now runs a Graf h-pattern 5-speed dog box, Shep transfer case, Driveshaft Shop shaft and rear axles with a Mitsubishi 300GT rear diff. The power is currently a fixed 50:50 split and in the clutch department, an Exedy triple carbon clutch and Magnus Motorsports slipper system keep the launches consistent.

Andre and Myles also discuss why the biggest turbo isn’t the best, where there is still more weight removal to be done, the 4B11’s advantage of the 4G63 at low to medium power levels and the sweet spot for turbo back pressure when it comes to drag racing.

At the TX2K 2019 event, Myles and the EVO set a new record with an 8.167-second pass at 180.79 MPH so the team is on track and creeping closer and closer to that 7-second pass.

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  • Andre Simon's profile image
    Hey DAVIDNJ, I'm not sure I'd say the cam over bucket in the 4B11 is necessarily better (although I know Myles did). Both have their pros and cons and you're absolutely right that bucket diameter is the limiting factor on what you are able to do with the cam grind. The advantages of the 4B11 head in my opinion are more inline with the dual MIVEC and improved port and combustion chamber profiles compared to the 4G63. Right now the cam profiles available for the 4B11 are not as extensive as the 4G63. I can't say if that is a valve train geometry issue or it's because there's not enough demand right now for bigger cams.

    F1 engines use a finger follower arrangement but one of their main drivers is that they need to go to extreme lengths to reduce mass in the valve train given the rpm ceiling. It's not possible to produce a cam over bucket valve train as light as a finger follower given the required bucket diameter those engines would require.
    - Andre.Simon New Zealand
    13 months ago
  •  's profile image
    Why would the flat tappet buckets of the 4B11 be better than the roller cam on rocker arm of a 4G63? Just looking at the GSC S3 specs, the roller cam has much more lift in a shorter duration, and the R2 has a greater major intensity and even more lift with even shorter duration. My V8 experience is that lifter diameter is important and roller cams blow flat-tappet cams, like the 4B11, away. Why would this be different here?

    Sidebar: don't F1 engines have rockers with a de facto roller cam, instead of a roller using a DLC-coated rounded contact on the rocker, directly over the valve?
    - DavidNJ USA
    13 months ago