White Alligator Racing (WAR) gave its new development of the long established Suzuki Pro Stock Motorcycle (PSM) I4 its debut during the NHRA Nationals at Norwalk, Ohio, June 23-26 2022. The new engine was fitted to the bike of team owner Jerry Savoie for the fourth round of qualifying. At that stage it had only made eighth mile test runs and it ran 7.01 s at 192 mph on this debut quarter mile pass despite a vacuum leak that the team believes cost about 9 bhp. The standard motor was put back in for eliminations and Savoie went to the semi finals.
The Achilles Heel of the 1851 cc naturally aspirated Suzuki I4 is its roller bearing crankshaft, built up from no less than eight steel elements. WAR has replaced this with a one piece billet steel production running in plain (fluid film) big end and main bearings. This has necessitated a switch to con rods having a detachable cap and to a new, higher pressure oil system. Gone is the Suzuki oil pump; in its place is a new pump with twin scavenge sections within a proper dry sump arrangement.
The new dry sump system allows deletion of a vacuum pump while the clearance needed for the rod bolts has necessitated revision to the crankcase and development of a smaller clutch. The bottom end of the engine has consequently undergone significant redesign, which has been done with the assistance of Competition Engine Services. The upshot is a hoped for increase in crankshaft life from 40-45 runs to over 100. Also the stronger bearing assembly should support higher revolutions, potentially increasing output.
WAR owner Jerry Savoie has a new version of the Suzuki PSM I4 [Photo: Dwayne Culpepper]
In addition Savoie told Tim Hailey of Eat My Ink, “With a roller bearing crankshaft, you can’t take them apart in house. So it’s hard to see some things that are going to fail. The cool thing about this particular [new] part is you’ll be able to take the rods off the crankshaft and Magnaflux it, evaluate it, look for cracks or things that may be starting to happen and catch a failure before it actually happens.”
As to its performance on track, Savoie remarked to Hailey, “Man, I’m telling you—this thing is really sweet. It revs different, it’s smooth. It’s comparable to a Hayabusa [which has a plain bearing crank]. Basically, that’s what it feels like. It’s really crispy. It’s just a different ride, and definitely a lot quieter.”