Cox Wins Summer Thunder Series Feature at Cottage Grove Cottage Grove Speedway, Summer Thunder Series Justyn Cox. (Photo Courtesy of Tina Gargurevich) COTTAGE GROVE, Or. (August 4, 2017) — Justyn Cox won the Summer Thunder Series feature Friday night at Cottage Grove Speedway. Jason Solwold, Logan Forler, Chase Goetz, and Kyle Miller rounded out the top five.