Originally Posted by weitek
unabomber i looked at your faq before posting this.
now this may be the wrong place to ask, and if so please excuse my ignorance. my question is if cryo treating is so wonderful why doesnt subaru use this process on the sti gears? as i understand it they are carburized (heat treated) and shot peened, but not cryo treated.
the reason i am skeptical about cryo treating is because a friend of mine had a brand new wrx 5 speed gear set cryo treated and installed by rallispec. he was running utec/pump/injectors/fp green and stock top mount and he destroyed 2nd gear from a roll with only a few thousand miles on the trans.
im just posting this because he was told that by cryo treating the gear set it would hold a substantially higher level of power and that proved to not be the case. it was a huge financial set back for him and almost caused him to have to sell the car. im not an expert and dont claim to be im just going from personal experience and i think these are legitimate concerns.
so what do you guys think?
If I may comment on the matter, cryoing gears will allow them to hold a substantially higher amount of power. However, there is no way to tell if the product has been treated visually (except for maybe some WD40 on the product). I'm not implying that your friend installed gears that weren't actually treated; I'm simply searching for an explanation. Also, cryoing something will not make it indestructable, it will make it stonger. With enough abuse, cryoed products will break just like untreated products; it will just take longer. Bottom line: cryoing a product is not a license to abuse it. I do not know the details of your friend's situation so I will reserve comment. In my humble opinion, $20 for a gear set for a 5spd, and $25 for the forks and shafts is a risk worth taking (with documented benefits) to make a gearset last twice as long.
With regard to shot-peening and carburizing, I would guess that STi does not use cyroing for a couple of reasons. First, it is a more expensive and time consuming process than the other two techniques. Running a small cryo machine is quite expensive (because it uses liquid nitrogen) and the process takes 72 hours. To do all the gear sets that Subaru puts in the STi would take a lot of time and money. The cost benefit gain of cryoing a product for a street car is probably minimal. Secondly, cryoing is a newer and less accessible process than shotpeening and carburizing. Perhaps in 10 years, cryo-treating things will cheaper, more accessible, and commonplace.