Why Remapping A Naturally-Aspirated Car Is Totally Worth The Money

This is my bone-stock (except for the obligatory CT stickers) BMW E46 330Ci. Its silky smooth 3.0-litre, naturally-aspirated straight-six engine makes 228bhp in the book, which is plenty of power for the type of driving I do. But, as I’m sure you’ll all agree, if there’s a quick and relatively affordable way to squeeze a few more stallions out of the stable, then I’d feel that I’d be doing my car a disservice if I didn’t explore it.

That’s why I got in touch with Superchips and headed to their HQ in Buckingham to see what the guys could achieve using only chip tuning.

Before the Superchips guys got to work, my car was given three runs on the dyno to establish a baseline power figure. Surprisingly, the dyno produced a reading of 228bhp, meaning that the engine in my 10-year-old 330Ci hadn’t lost a single horse power.

After the dyno run, the guys asked me what redline I wanted the engine to have (it’s 6500rpm as standard), and talked me through the map. Then, the tried and tested Superchips tuning map was installed via a laptop through the car’s OBD II port (this took no longer than two minutes), after which the car was ready to be put back on the dyno to see what changes the chip had made to engine performance.

As you can see from the graphs above, peak power increased by 8bhp to 236bhp, but it’s lower down in the rev range - at 5156rpm - where the biggest gains were realised by 14bhp.

While these numbers might not seem like much on paper, it’s the way in which the car now delivers its power that has transformed the driving experience. Because the majority of driving (even if you’re going flat out) happens at revs far below peak power, my 14bhp increase at 5156rpm now means that the point in my rev band that gets the most abuse, is more alive and punchier with fewer power flat spots (that’s obviously aided by my useful increase in torque).

As for the 6500rpm redline, Superchips upped that figure to 7000rpm, which now means that the engine stays in its sweet spot after every upshift.

To conclude...

Remapping my N/A 330Ci proved to be a quick, safe and relatively affordable way (something like this will set you back £229 all in) to transform the driveability and fun of my previously strait-laced coupe.

Sure, the car’s not suddenly an M3 rival by any stretch of the imagination, but I now love driving it more than I ever have done. And for me, that’s money well spent.