Porsche power reigned in the opening practice session at Canadian Tire Motorsports Park with the No. 912 and No. 911 Porsche 911 RSRs going 1-2.

Corvette leads the championship, BMW won the last race, Ford was on pole, but it’s Porsche at the front at CTMP.

Laurens Vanthoor turned the fastest time of the session in the IMSA WeatherTech SportsCar Championship GTLM class at 1:15.151, ahead of teammate Patrick Pilet in the 911.

Winners of the previous race, the No. 25 BMW M6 GTLM car slotted in third, beating out the sister No. 24 BMW and the pair of Corvette C7.Rs.

The ultra-competitive GTLM class saw the championship leading No. 3 Corvette, driven by Antonio Garcia and Jan Magnussen, finish the session just sixth on the timesheets.

Continuing with the two-by-two results of the day, the pair of Ford GTs wound up seventh and eighth in the class, with only 1.132 seconds separating the entire GTLM field.

Elsewhere, the Taylor brothers found themselves back on top in Prototype after snapping their win streak to open the season last week in Watkins Glen. The No. 38 Prototype Challenge car, however, kept theirs up, finishing the session first in class.

Also staying on top is the No. 93 Acura NSX, the winners of the two previous races in GTD, topping the class standings in practice here at Canadian Tire Motorsports Park.

#WeatherTechChampionship – FP1 results #Mobil1SCGP: #911RSR No 912 P1, No 911 P2 in #GTLM. Best #911GT3R in #GTD No 54 P9. @Porsche @IMSA pic.twitter.com/boCMqHfG0c

— Porsche Motorsport (@PorscheRaces) July 7, 2017

The end of practice means it’s time for more practice. Both Corvettes below 1:15.8. FP2 at 3:55p ET #Corvette #C7R #Mobil1SCGP @TeamChevy pic.twitter.com/Pws1HtSXNQ

— Corvette Racing (@CorvetteRacing) July 7, 2017

Some minor adjustments for both cars. @muellerdirk is ready to take his first laps in #66FordGT #FordIMSA #Mobil1SCGP #TeamGanassi #FordGT pic.twitter.com/TGZFgafdQt

— CGR SportsCar (@CGRsportscar) July 7, 2017

//imsa.alkamelsystems.com/Results/17_2017/14_Canadian%20Tire%20Motorsport%20Park/01_IMSA%20WeatherTech%20SportsCar%20Championship/201707071120_Practice%201/05_Results%20by%20Class.PDF