NASA 25 Hours of Thunderhill with Pure Performance



Ivan Zwart and his sons Joshua and Daniel all attended competition licensing school together after Daniel built the Zwart’s racecars while working at Bullet Performance. Although he never got his license, he was always deeply fascinated with the strategy of racing and wanted to know what was going on inside the car to make better decisions outside of it. Ivan has been competing for about 10 years in BMWCCA and NASA, in both sprint racing and enduros (which are his obvious favorite).

We asked Ivan about his thought process with respect to pit stops, fueling, driver strategy and what other things he considers during the race to make decisions, how the unplanned issues affected his decision making, and also what he thought about the team’s effort. Here’s what he shared:

In endurance racing the goal is to go fast and not burn fuel, so I keep track of how far we can go wide open, and if we back it off a little how much further can we go. I also track tire wear. We never change a tire unless we are changing a driver since the fuel goes in so fast. I keep notes on our competition too: How far they are going on a stint, who is driving for them and how our times stack up against theirs. This affects who I put in the car later.


The office where drivers will spend long stints during the 25 hours of racing. Ivan takes a number of factors into consideration when determining who should be in the seat.

Well, the crash with the Miata put us behind the 8-ball big time. Once we made the repairs it was just about getting through the night without any more issues. The “dawn patrol” stint as we call it was Greg's. I had told him we might juggle some stuff in the night to try to make some time up. He raced 3 laps before a full course caution, and I had him save as much gas as he could. He was at the back of the field due to where the pace car had picked up the leader, so when it went green I had him duck into the pits for another 10 gallons (which is all we are allowed to put in at a time in EO), which now meant the car had 20 in it. I had him continue his stint until I could get another 10 in the car (the fuel cell holds 27). When he came in we fueled the car and the cell was full all the way up the neck, which meant we had 28 gallons. I put Mickey in, with Brett to follow. Both are cleanup drivers who are very fast and experienced. With the car this full of gas we pushed hard. We increased the stints from 45 minutes to one hour and still had enough fuel in the car to run the last 2 hours without stopping, thus picking up 2 stops.


The maximum amount of fuel that can be added during a stop in the EO class is 10 gallons.

We were about 4 laps down to second when Mickey got in the car and he made up a lap and a half in 2 hours. We put Brett in the car with 3 hours to go and 2 1/2 laps down. He was fast. We put pressure on hard and got on the same lap as second place with an hour and a half to go. The team in second at the time needed to stop and we had enough fuel to finish. Well the pressure worked. Their car blew up and we didn't need to push any more. We were too far back to catch first place which had run perfectly all night, so we put Daniel back in to finish the last hour, and put it into conservation mode to the finish.

The team? They are the best! I have some of the best club racers in the country. They have multiple wins and championships between them. But even better is the fact that we are all friends. They ALL want the best for the team, and everybody checks their egos at the door. If they are due to go into the car and I put someone else in, not a word is said about it. WE go to win, period.


Checking in with timing and scoring.

This race, everybody dug down deep and did the best we could with what we were dealt. Being able to make half of the time back in the last 6 hours was all team effort. I remember looking at T&S early in the morning and we were running 33rd overall and 5th in class with 25 laps down, so to end up where we did was a win as far as I'm concerned.


Despite all the unforseen circumstances the team kept battling. Preparation played a big role, but teamwork and keeping cool when the shit hit the fan made all the difference.

We have great partners, and having AEM on board as a partner was a huge part of the victory. Besides just the tunability of the car, Beau would plug in every stop and give us updates from the logs, which was so critical. I'm sure just him diagnosing the cam sensor alone saved us 10 minutes, which translates to 5 laps.—IZ


The team finished and fought hard the last six hours to move up four spots and be the fastest BMW on the track.


Pure Performance



Leave a Reply

Your email address will not be published. Required fields are marked *