COBB Tuning Blog

Photo Courtesy of GotCone.com

It has been a long, cold, snow-filled winter for most of us and that means few opportunities for motorsports events. However, with the coming of spring means the big thaw and once again, petrol heads are filling parking lots full of cones. That’s right, autocross season is upon us! COBB Tuning hot-shoes Rob Irish (BMW and MINI ECU Guru) and Jon Pomrenke (Subaru ECU and Software Engineer) hit the course recently to clear the cobwebs out of their STU class STI along with long time friend and COBB Tuning customer, John Hale.  After nine months away from racing, Rob’s 2006 STI returned to the 2011 Mineral Wells ProSolo with a 1-2 finish! John Hale contested the event in his own car, a 2005 STU-prepared STI, and finished third behind Jon Pomrenke.

Winter is a time for racers to rebuild and refit. However, sometimes quick rebuilds take a bit longer than expected. The STI was torn down nine months ago for a suspension rebuild but the car was not completed until the Thursday before the Houston event! In that time, the turbo-back exhaust was replaced with a COBB Tuning turbo-back exhaust for better power, sound, and ground clearance. The intake was replaced with the stock airbox at a loss of top-end in exchange for cooler air. Suspension was replaced with all new remote reservoir coilovers to properly control the high spring rates.

Just one weekend prior, Jon and Rob contested the first round in the 2011 Houston National ProSolo Tour (2nd and 4th place finishes) in Jon’s S2000, so while they had a little bit of seat-time to get back into the groove, the STI was still in pieces waiting to be reassembled. With that event behind them, the team quickly completed the STI to make it ready for the Mineral Wells event just a week away. The suspension was installed Monday-Tuesday, alignment done Wednesday, tires mounted Thursday with the race on Saturday and Sunday.

With fresh, unscrubbed tires and untested suspension, both Jon and Rob came out strong Saturday morning to end in 1st and 2nd after the first session. More seat time and a faster course allowed the class to find more time in the afternoon session. Jon managed to hold 1st through afternoon runs, but Rob slipped to 3rd. With more rubber on the course and the cold morning temperatures, they headed out for the final session. The 1st place position was lost and regained repeatedly through the weekend, with the top three drivers all holding 1st place during the final runs of the weekend! Jon fought and held 1st until Rob’s last run, which catapulted Rob from 3rd to 1st.

Jon and Rob use the COBB Tuning AccessPORT to tune their ride. Not only this, but the pair use the map switching capabilities of the AccessPORT to quickly change from a pump gas calibration to a race gas map at the event. They drive to the track on as little pump fuel as possible. Then, they take off the fuel return line and drain the tank trackside. Then they fill up with race gas and switch maps for more horsepower! At the end of the day, they drain the race gas and switch back to pump fuel and the pump fuel map!

Jon and Rob will be looking to continue their winning ways this year with both local and national events being contested. Check out Cobb Tuning.com for more information on the parts they use to take their STI to the top of the class!

1st- Rob Irish
left: 43.669s, .544 R/T, 1.820 60′
right: 43.929s, .567 R/T, 1.873 60′
total: 87.598s

2nd- Jon Pomrenke
left: 43.930s, .534 R/T, 1.795 60′
right: 43.763s, 0.530 R/T, 1.814 60′
total: 87.693s (0.095 from 1st)

3rd- John Hale
left: 43.807s, .582 R/T, 1.811 60′
right: 43.877s, .646 R/T, 1.856 60′
total: 87.784s (0.091 from 2nd)

Rob’s Best Run

Jon’s Best Run

Comments Off

I’ve been known to shave tires for racing. I usually get some puzzled looks when I explain why I just cut off half the tread.

The RA-1 is one of the few tires where the manufacturer openly recommends shaving for better performance. For their next generation, the R-888, Toyo recommended customers go full-tread. I think this article does a good job of explaining the pros and cons: Buffing or shaving grooved tyres used for motor sport.

Photo courtesy of Toyo Tire

Usually it takes some phone calls or face time with the manufacturer’s motorsports guys. Some will say to shave them, others say not to; if you are lucky they may tell you why. Some tires have consistent grip from full-tread to chords, others increase grip as they wear, while others decrease. Tread blocks may add forgiveness to the tire where shaved tires may snap. For the low-horsepower guys, the decreased diameter or Lose Weight Exercise reduction can pay dividends. The high-horsepower guys might like the extra gearing.

With so many factors to consider, it is just another thing to test when trying to turn in a lower time than your competition.

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