The only real downside is that tuning them can be quite difficult, as naturally-aspirated engines are usually a bit trickier to tune; costing more money, requiring more work, and netting smaller power increases; compared to turbocharged engines. If you’re willing to tune it, though, you can get quite the tasty engine.
In this new video from Car Throttle, we get to see co-host Ethan’s BMW Z3 1.9 get a comprehensive Stage 2 tune. It gets a new intake, cam timing, and an ECU tune, among other things, to make a bit more power from its small, four-cylinder engine. Then, it goes on the dyno to see how much additional power it makes.
First up, though, is to dyno-test the car before any tuning, to see what sort of power figures they’re starting with. Surprisingly, the stock — and very old — BMW Z3 with just a 1.9 liter four-pot made 148 horsepower. Not bad, considering its age, mileage, and lack of maintenance. However, after all of the mods; the upgraded cam timing, new intake manifold, cold air intake, valve cover, and ECU tune, the scrappy Z3 now makes 161 horsepower.
While that’s not a huge gain, in terms of peak horsepower, that gain is pretty consistent throughout the rev range, so the car should now feel quite a bit more responsive and engaging. It also sounds worlds better. Prior to the mods, the 1.9 sounded as if it was on its last legs. After the mods, it sounds like a racy little engine with loads of life left.
So if you’re a BMW Z3 owner and want to get a bit of extra power, while improving engine response and sound, these mods are the way to do both.