Gentlemen, start your engines: The latenight horse race between Columbia TriStar’s new syndie strip “Vibe” and Buena Vista Television’s “Keenen Ivory Wayans” begins Aug. 4.According to station sources, Col TriStar had been considering launching its high-profile new production from Quincy Jones and David Salzman in late July. Buena Vista settled on Aug. 4 as the premiere date for the Wayans show several weeks ago. “After listening to our network of stations and advertisers, we believe Aug. 4 is the best date to launch this show,” said Barry Thurston, president of Col TriStar Television Distribution. In addition to avoiding the crush of fall season premieres in September, the early launch gives both shows a better shot at reaching their target audience of teens and young adults. On the production front, Buena Vista confirmed the Wayans show will tape at Hollywood Center Studios, where run-throughs will begin in mid-July. “Vibe” is setting up shop at CBS Television City. Col TriStar also named former “Tonight Show” scribe T. Sean Shannon as “Vibe ‘s” head writer; Bill Royce has been tapped as executive in charge of talent. Royce previously has worked as a booker for “The Tonight Show,” CNN’s “Larry King Live” and NBC’s “Today.” Annette Grundy, a veteran of talkers “Jerry Springer” and “Jenny Jones,” will serve as senior producer along with Salzman.