How the Mods on My BMW 128i Helped Me Set a Personal Best Lap Time

Some minor adjustments and determination made this track session a rousing success.

byPeter Nelson| PUBLISHED Nov 1, 2022 3:38 PM
How the Mods on My BMW 128i Helped Me Set a Personal Best Lap Time
Peter Nelson
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It was ungodly hot outside the last time I visited Willow Springs International Raceway's Streets of Willow circuit with my 2011 BMW 128i. I also foolishly forgot to swap in track-centric brake pads. During a recent visit, however, the weather was much more pleasant and my braking system was in tip-top shape with fresh Castrol SRF fluid, Hawk HP+ pads, and BimmerWorld stainless-steel braided brake lines. Plus some wheel studs. With a little gumption, improved braking performance, and conditions in my favor, I set a new personal best lap time by a longshot behind the wheel of my beloved 1 Series.

Better Prep

The only part of the weekend that wasn't in my favor was the counter-clockwise (CCW) direction that we were running in. CCW is fun, but I much prefer clockwise (CW) as I'm far more familiar with exactly where to brake and turn in, and have a generally good idea of what kind of speed to maintain. In the past, my CW lap times have always been around two seconds faster than my CCW lap times.

Though, after a very successful visit to Buttonwillow a few months back, I've accumulated a bit more seat time, my brake system is in much fresher shape, and the weather was much nicer. Instead of 105 degrees and barely any breeze, it was a refreshing 84 degrees, tops, with a nice breeze.

Plus, Lotus Club of SoCal ran the event, and they do such an excellent job—the price is a little higher than other companies, but they keep run groups very small and make sessions much longer. My buddy Rob and I got so much track time before lunchtime with very little traffic, it was probably one of the top-three track days I've ever attended.

Refining My Approach

Here's an annotated Google Earth view of the track. You can also a track illustration at RaceOptimal.com which you might find a little easier to follow. Google

I knew my brakes could stand up to some abuse, so I focused on maximizing the amount of speed I could carry in certain sectors, as well as what the line ought to look like.

At first, I was keeping it in third gear a bit too much where second gear would've been much wiser, even if it meant banging the rev limiter a tad. To be well-protected, the 128's N52 inline-six was topped off with fresh 5W-40 full synthetic. I realized that if I downshifted to second in two key areas—Turns 1-4 and 10-12—I'd have better acceleration onto each of the long straights that followed.

I did alright at my line around Streets CCW initially, but following a few Lotus Elises and Exiges for a couple of laps quickly showed me where I was messing up. Well, when I could—they're right at home on its tight, technical tarmac, whereas my hefty, 3,300-pound Bimmer is a bit less turn-on-a-dime. I still don't have the bowl (Turn 6) down very well, but I was doing much better at it than the last time I'd ran CCW, which was when the 128i was basically stock.

Trying out different lines and braking zones was also easy to do via my APEX Pro Digital Driving Coach, which uses a system of lights to key you in on where you're maintaining the most ideal cornering speed. Then, reviewing its data in the APEX Pro app drove it all home, including giving me every tiny bit of detail on each lap, including taking a quick look at each friction circle. I should write a separate blog on track data analysis someday … stay tuned.

Finally, the Accelera tires, for how not-ideal they are (they barely grip any better than a 300TW, non-track-oriented tire) still proved to be one of the best purchases ever for learning the chassis. They're super communicative and predictable, and even when I upped the intensity past the point of a good lap, they never got too greasy. I look forward to replacing them with much better rubber in a few months and potentially seeing a big drop in time.

Success

Peter Nelson

All of this amounted to a best lap of 1:32.38, which is more than six seconds faster than what I was able to do when the car was stock. To me, it's a big improvement, especially considering I haven't messed with damper tuning or rolled on top-performance rubber in perfect track weather just yet. My times were also consistently between a mid-1:34 and low-1:33 if I didn't need to give a point-by.

Perhaps my two-second deficit between Streets of Willow CCW and CW would apply, too. I'd be elated if I could lay down a high-1:28 running CW before Spring.

Another big plus is Rob also set a personal best with a low-1:29 behind the wheel of his E92 M3. He let me take it out for a few laps later in the day, and man, I'd really love my own someday. That engine is just heavenly, and even though people say the E92 doesn't have the most ideal stock brakes, they were immensely better than my 128's. Because of this, I'm definitely looking into some substantially upgraded stopping power sooner than later. I wish stock M3 brakes fit under my 17-inch wheels—despite being single-piston, they'd slow down my 3,300-pound coupe more adequately than they do bolted up to something that weighs at least 350 pounds more.