How I’m Setting Up My BMW 128i for the Track

Two weekends ago I ran my 128i on track at GridLife's Big Streets Special, and my initial impressions will greatly help with future strategy planning. I was able to pinpoint exactly what the scrappy little coupe needs for its excellent chassis to shine through, even though the overachiever in me was a little bummed about the lap times I put down. But hey, the fixes I've planned will hopefully remedy that.

Here's the best lap I was able to lay down in the first session, a 1:36.22. Later in the day, after my GoPro 8's battery died, I was able to secure a 1:36.01. Before you ask: Yes, I do talk to myself out loud on track sometimes.

The venue was the Willow Springs International Raceway's Streets of Willow (SOW) track, in the counterclockwise configuration (CCW). This was my second time ever running on SOW CCW, though I've put down countless laps running clockwise (referred to as CW, naturally). I love the overall flow, turn two's braking zone, and the high-commitment, high-reward chicane and braking zone leading into turn 10.

However, because this was CCW, I was far less familiar with the correct line, braking zones, etc., so I didn't have the best control scenario for judging the 1er. Still, I got a good feel for the car, wasn't too terribly far off-line during the two sessions I ran, and was able to experience something that so many E82 BMW owners complain about behind the wheel.

But before I get to the car’s downsides, there are several positives to how the 1er currently feels on track. It was so confident and composed under heavy braking with just Hawk HP+ brake pads, high-temperature brake fluid, and OEM rotors. Additionally, turn-in was confident, steering feel helped communicate what the tires were doing, and low-end torque was so reassuring. 

For a factory suspension that's 85,000 miles old, body roll wasn't as bad as I thought it'd be either, and the car genuinely felt smaller and scrappier than its 3,300-pound curb weight would suggest. The BMW 1 Series really is an underrated track car. I was stoked on consistently braking hard and late from 100-103 mph into turn one, lap after lap, which helped make up for some of the 128's shortcomings.

Well before exiting the hot pit to start my first session, I had a good idea of what this car needs to handle better. 

Owners complain of understeer, which is rooted in a lack of camber adjustment, mushy rear subframe bushings, a front sway bar that's too tiny, and more. Understeer is when the car continues plowing forward, instead of turning in, when the front wheels are turned. So when I say camber adjustment, I mean adding more negative camber, which effectively tilts the top of the tire inboard toward the engine. This improves turn-in and corner grip, as the tires are more in contact with the pavement under cornering.

Luckily, my 1 Series came with front control arms from a contemporary M3, which add about 1 degree of negative camber. Those put me  in a better situation than if it were all stock behind the front wheels, but this thing absolutely needs more. I was able to experience people’s common complaints firsthand and realized that it's a very real, yet very fixable issue.

Thus, fixed camber plates that add 0.7 degrees of negative camber are on order. I also have rear subframe bushing inserts from the previous owner to help correct the mushiness out back. Finally, some fresh new Koni Yellow dampers and Eibach springs are sitting in my garage. Once I have all three installed with a good track-centric alignment dialed in, I'll head back to SOW's tarmac and determine whether or not more work is needed to scrub away understeer.

Another one of my 128's shortcomings was its pedestrian 280-treadwear Yokohama Apex performance tires. As a buddy pointed out, they're trackrat all-seasons, meaning they're great on the street and have good grip on twisty public roads but fall short up against the demands of track work. They weren't miserable and they did put up a good fight for a solid four to five laps before throwing in the towel. But under track conditions, they only exacerbated understeer and made a lot of noise in the process. I'll definitely need a 200-treadwear extreme performance tire in the near future. Plus, I'm well versed in a variety of tires in this range, as I used to daily drive them all year round on my Mazda 2. (I love living in Southern California.)

I'm still debating whether I want to throw stickier rubber on the factory wheels that came with my 1 Series or splurge on some inexpensive and lighter units, which will also give me the opportunity to go with a wider tire. Though, there are limits here, as there isn't a lot of room in the 128's wheel well for big meats. If I'm adding more camber and not slamming the thing, I should hopefully be in the clear. Basically, I'll replicate what other 1 owners have pulled off without issue, which seems to be a 17X8-17X8.5 wheel with 235/40/17-245/40/17 tires at all four corners.

I'm glad that I was able to set a solid baseline with my 128i. I was bummed that my best lap time wasn't three or four seconds quicker, but hopefully, that'll change after some mild suspension, chassis, and grip remedies. I have a good plan in my head and even recorded some data, which I'll save for a future blog on easy track data analysis.

I'm also quite relieved that I could feel a grippier, more competent chassis screaming to be let out. It's there, it's just being held back by a very street-centric setup. I can also check brakes off of my list, at least for the time being, as I had no issues with them all day long.

There's more to solve, too, such as enthusiasts reporting that BMW programs in some unique methods of detecting overheated brakes, as well as the dreaded e-diff, which is when the rear brakes poorly facsimile what a real limited-slip differential does. I have some electronic coding hijinks to engage in to clear some of this up and will also be in the market for a proper mechanical limited-slip differential. Though, I don't want to do too much at once. Those will probably happen after a couple more track days. Quality differentials are quite expensive, though enthusiasts say it's money incredibly well-spent.

This all brings up an important point: Keep up with maintenance and stay in tune with the Bimmer's overall health. I don't want to have to delegate funds meant for fun over to annoying, costly fixes.

Contact the author here: peter.nelson@recurrent.io