GC road racing findings.

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Oct 31, 2003
I got some GC just in time to prep the car for a day at Lime Rock Park on the road course. Didn't do a Patman flush, but did vacuum out the cyl heads and lifter gallery (had the intake off for a lifter swap). Car is an '82 Camaro, with an L98 engine rebuilt in 1998. I usually run Amsoil 10W-30, figured I'd try the GC since it's got more viscosity at the 100degC point. With Amsoil, I see 28-30psi idle and 50-55psi above 3500rpm at operating temps. At op temp, GC pulled at 25psi idle, 55-58psi above 2500rpm on the oil pressure gauge. Great! Drove the car to work 2x last week, drove it to Lime Rock, drove it home from Lime Rock. But...after the race the car sat in the garage all day Sat, and on Sun when I pulled it out for a drive I noticed 50psi idle and pegged the needle (>60psi) anywhere above idle. Even after 30min of driving, temp gauge showing normal 180-185degF coolant temps. Never seen oil pressure that high since the engine went into the car in 1999, and it's been to Memphis, Pocono, Indy Raceway Park, and Lime Rock for racing. I have a Blackstone oil analysis kit on the way, will post their results. The sudden rise in oil pressure suggests the oil got a lot thicker after a hard day on the road course. It didn't turn black, still green, but definitely thicker than prior to the track. Engine parts list and whatnot can be found at: http://www.mycar.net/mafb/registry/detail.cfm?id=276
My initial findings were incorrect. Driving the car around for >30min today, getting the oil warmed up for sampling, the pressure finally dropped off to 28psi idle and 58psi off-idle. My apologies for the unscientific observation earlier. The only conclusion I can reach is the GC's extra 100degC viscosity (compared to my usual Amsoil 10W-30), as well as the cooler ambient air temps, are running up the oil pressure when the oil temp is < operating temp. After waiting over a week for the Blackstone kit to arrive, I hit the local NAPA and bought a pre-paid analysis kit from them. When/if the Blackstone kit arrives, I'll use it for a mid-Winter analysis of the GC. Will post the results of the NAPA lab analysis.
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