We tried it on a set of bevel gears in the (Lola/Hewland) transaxles on the Indycars at Rahal. But, it was only one set. We finally lifed them out at 3.5k miles which is over 55% longer than we usually left them in regardless of what they looked like or measured. Replacing them was a two guys, torches, fans, dial indicators, and about 5 hours kind of job. And $4k a set (maybe $6K?) if I recall correctly. The cryo was done to finished sets straight from Lola. This was in '01 or '02. They've served as paperweights ever since.
Apparently a lot of NESCAR engine builder are doing it and are gaining up to 2% HP.
These days Superfinishing seems to be the go.
was the replacement cost of a complete unit if you did run them too long excessive (within the realms of "it's racing, of course it's excessive") compared to the servicing every 2k cost.We didn't do another set, unfortunately, to prove it out fully. Most teams went with Hewland's recommended 2k mile lifespan. Early on, you might only get 1K miles. They had to be set up perfectly in the middle of the spec range and then broken in just so. That would get you to 2k miles. Because of the amount of time it took to install another set, nobody really wanted to take a chance on pushing them.
The set I have (the cryo'ed ones) started in a racecar, then into the test car, back to the racecars, and back to the test car before we called 'time'. I don't recall ever trying cryo on other parts but dog rings would have been interesting test subjects.
Goes back to that diminishing returns curve, dunnit.... When racing on the dyno or in the real world every bit counts so small gains matter, often those small gains will also cost the most.
Yes! I just logged back in to post it ... I was going back to bed when it popped back into my head. It used to be used to polish combustion chambers/ports in 4 stroke heads, polish ports in 2 stroke barrels, and many other things where manual polishing was typically done. I remember it was even used by pro Jet Ski competitors to polish the impeller housings of the drive jet. One negative I recall was if a given 4 stroke cylinder head didn't have much material around the ports in the casting the abrasive media paste could actually perforate the casting and wreck the head (or whatever item was being honed). May be why the process seemed to fall out of favor as the 90s rolled in.Extrude honing?