The stock rotor weighed in at 9.7728 lbs, or 4,432.87 grams.
After the machine work, our two rotors came in at 9.1350 lbs and 9.1352 lbs, or 4,143.57 and 4,143.68 grams respectively. We were very happy with a 0.638lb (289 gram) weight reduction per rotor and the identical weights of the rotors down to the gram. This totaled a significant 1.28lb (578 gram) reduction in rotational mass from our engine, before even more weight was removed from the counter weights when we have the entire assembly balanced.
For comparisons sake, a forged B16 Honda piston with a 81mm (3.19”) bore typically weighs around 270 grams, a forged LS1 piston with a 96mm (3.89”) weighs 430 grams. We essentially lost two pistons worth of weight from our 13B engine, but that’s from rotors that weigh as much as the total piston weight of over (TWO) LS1 V8 engines!
Our finished rotor was now ready to be sent off to CTP Cryogenics to be thermally treated and WPC for their Metal Surface Treatment.
CTP Cryogenics is located in Southern California and have been in the business since 1983. The cryogenic process involves slowly brings down the temperature to -300*F for hours to alter the crystalline structure of the metal, transforming it to a more uniform and durable construct. These changes become permanent as the temperature is gradually brought back up to room temperature or beyond. The total process takes a total of 2.5 days to complete.