By know, you’re almost certainly aware that the BMW Z4 M40i and Toyota Supra are built on the same chassis and use the same engine. So any good news about the Supra is good news for the Z4. Which is why it’s very exciting to learn that a simple ECU tune can bump up the Supra’s power to 420 hp.

According to Piston Heads, British tuner Litchfield has already developed an ECU tune that can bump the B58 I6’s power from 335 hp to 420 hp. That’s a huge power gain from just an ECU tune. Admittedly, the 420 hp is a dyno-recorded number and the car’s factory-claimed 335 hp is just what Toyota says it has. We’ve already learned that the Supra makes a lot more than the claimed stock 335 hp. Still, 420 hp is an impressive power figure in such a car.

Considering the fact that the Toyota Supra and BMW Z4 M40i sport the same engine, it stands to reason that the same tune can be applied to the Bimmer with little-to-no modification. The North American-spec Z4 M40i makes 382 hp and it’s a proper little rocket. With 40 more horses, it would be seriously quick. That’s more than the BMW M2 Competition in a car that’s already faster than it on track.

There’s been a lot said about the Toyota Supra and BMW Z4 M40i and how they are good to drive but not truly great. However, it seems as if both cars have excellent tuning and aftermarket potential. Especially when you consider that Litchfield was able to coax another 30 horses out of the Toyota Supra with an exhaust upgrade. Apparently Litchfield has been working with both Milltek and Akrapovic to develop its own exhaust systems.

Litchfield isn’t just stopping at ECU tunes and exhausts, though. The Gloucester-based tuner is also working on an oil-cooler upgrade and some chassis upgrades as well. So Toyota Supra owners should be happy to know that there will be quite a few new upgrades for their cars coming quite soon.

[Source: Piston Heads]