25 hours of Thunderhill

25 hours of 69

For many people across the USA, the days after Thanksgiving means one thing. To them, it’s the start of the Christmas season. The beginning of holiday shopping, pumpkin spice lattes, and the best home cooked meals you can’t wait to dive into.

However, for a small select few group of individuals and teams, it’s a time for something completely different. It’s a time to see what you are made of, a time to put it all out on the table. A time where you know if the past year of planning, testing, and preparation are about to reward you greatly or tear you down completely. It’s the time where you hope to be able to stand up on a Sunday at noon and can say proudly “I survived the 25.”

For those lucky few (some call them crazy or stupid) the weekend after the Thanksgiving Holiday is what you might call a different type of holiday.

For the past 15 years, the 1st weekend of December is when some of the worlds best pro and amateur drivers descend upon a small city in Northern California known as Willows. Just on the outskirts of this quaint little city lies a little well-known road course titled merely “Thunderhill.” Now what makes Thunderhill so unique, well it’s probably the fact that this venue host the longest and most extreme endurance race in all of North America. For 25 hours straight; teams, coaches, drivers, and fans endure the rain, cold, dark, lack of sleep and more to try and make a name for themselves, and this year CorkSport did just that. Made History…

While attending the 25 Hours of Thunderhill is nothing new for CorkSport as we have spent the past several years supporting Mazda North America and their racing efforts with logistics, crew, and parts. This year was the first year where we entered a new team ourselves and brought our car, crew, trailer, and everything else you need to try and survive 25 hours of racing.

Sadly MNAO did not attend this year so it was up to us to make sure that the brand and name would make a forceful showing at the event and that is precisely what we did.

To start this whole thing off, we brought out our 2016 Mazda 3 GT. You guys are more than familiar with this car as Co-owner, and founder of CS Derrick Ambrose has been piloting this ride for two race seasons now in SCCA racing. We spent several weeks leading up to the event preparing the CorkSport Mazda3 for this daunting task.

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We got extra safety equipment installed, upgraded our data acquisition package, optimized and engine tune for the  2.5L engine, and even installed some upgrade prototype pieces to have the car suited for the race.

Some of the CS goodies that were on the car during the run where our SRI, Cat-back exhaust, RMM, sway bar, and some prototype pieces like our aluminum skid tray and upgraded transmission engine mount. We needed the best parts we could get in there if we wanted to be competitive and make history.

No one has ever raced the 3rd generation Mazda 3 for this long in any endurance race. This car started off just like any other Mazda 3 and still retained a full OEM chassis, transmission, and engine. The engine internals where untouched and the transmission received a CorkSport LSD.

The team showed up on a brisk and cold Thursday morning, and we went to work. We immediately set up and got the drivers briefed. We got some practice in on Thursday followed with some qualifying on Friday all to be prepared to push this car to the limit for 25 hours. The team grabbed the pole position, and we were 1.5 seconds ahead of the next car which was fantastic. It showed we had the pace and ultimately the faster car. Fast forward to Saturday, and the flag drops green.

We had a great start and excellent drivers in the car. We struggled a bit through the night with consuming tires at a rate faster than we had anticipated and also had a few issues with how quickly we could get fuel into the car, despite the problems the team and the car pushed through the night. With just a brake change and tweak to the exhaust through the night, we maintained a good pace that ultimately got unwound due to the fuel issue mentioned above.
There was a Miata in our class that could get better fuel economy and tire consumption and slowly crawled there way up to lead during the night.

As the sunlight begins to break through, we are in a healthy 2nd place but a bit far off the leader, however, it does not worry us too much as we still have a shot at a win. Things were looking good till right about hour 22. One of our driver’s radio’s in and let us know he lost 4th gear (that’s not good). None the less we keep pushing knowing we have a spare transmission should we need to swap.

Now at hour 23 we get another message. “I lost 2nd gear” The transmission has now lost two gears, and we get a bit nervous. The car is still going and driving strong but our lap times do suffer from not being able to use all of the gears. After a quick powwow with the team, the decision is made to leave the car out on track and finish the race between 3rd and 5th gear.

With only 2.5 hours to go swapping out the transmission did not make sense as we were very secured in 2nd place. So we did just that and pushed on through, and you know what happened? We did it. While we didn’t get the P1 spot like we had wanted we did what no other SKYACTIV-G Mazda3 had done before.

We survived the 25. We proved the chassis and the platform, we pushed harder, longer, and further than absolutely anyone else has. The car was relatively unscathed, and minus the transmission, the vehicle performed excellently. All of the CorkSport parts did precisely what they needed to and outperformed all expectations.

We took the 3rd gen platform and solidified it as a competitive car and chassis that can be used and used well at all levels of motorsports.

So, what happens next?

The Mazda 3 made it back home and now lay dormant inside of HQ. We will be spending the next few weeks going through a ton of data and running through the car with a fine tooth comb.

We’ll take the transmission apart and see what her demise was. We’ll likely strip the SKYACTIV 2.5L down as well to check out what two years of racing looks like on her. The oil is already out of the car and on its way to the lab so be sure to stick around and see what we find out there.

Now one of the great things about this is what our success brings to the community. Everything we learned here can and will be applied to all of our parts and products moving forward. When we win, you guys all win. So, celebrate our accolades with us and wish us luck as we begin to prepare for the 2018 race season.

Do we tackle the 25 hours again next year? Do we show up with a turbocharger and more aero? And do we fight our ways to a P1 finish? You better believe I am going to try.

CorkSport

2 Replies to “25 hours of Thunderhill”

  1. Awesome and great job! I am extremely curious what the engine internals look like! On my daily driven 2.5L skyactiv I have a 93 tune and E85 tune w/rev limiter @7000 for the summer, intake, exhaust, and cams on the way, so I am curious about the longevity of the internals. I have an automatic trans so that’s cause for concern too.

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