Hi guys. so! first things first. I am wanting to build a more substantial differential for the skyline, before I can start I need to know what sort of treatment the current gears have been through. I plan to get the crown and pinion tempered to be the strongest it can be at running temperature; and reduce friction as much as I can without affecting the integrity of the gears themselves. my question is pretty strait forward to anyone who knows the answers haha, as standard does anyone know what sort of heat treatment and coating process the crown wheel and pinion go through. anyone who has done a diff build your input on what you have had results from would be greatly appreciated also. my current plan is get the gears tempered then superfinished then possibly diamond coated but this process is untested and could cause issues with having such a hard coating with a softer metal as a base, so looking at other options to improve the friction coefficient and wear properties. Thanks in advance,
The only thing I can think of here that I've seen previously are Cryo treatment or shot peening. With regards to effectiveness, I don't have any experience of either unfortunately, but gives you a start point at least
this is what I read also. but as far as cryotreating goes then it makes the metal more durable at lower temps but not much change in metal properties for operating temps. then shot peening surely cant be as effective as a high polished finish on the teeth themselves? it was more what sort of treatment they have fro standard I was interested in
Basically, it's unessecary. Spend you time and effort elsewhere to reap rewards. Literally I can count on one hand the ammount of skylines and silvias I know of that need anything other than a stock diff. You need a hell a lot of power to upset a Nissan diff that is in good working order
Well I have a Nismo 2 way that destroyed it crown wheel and pinion, 4.1 ratio and figured if I'm making the effort of setting and shimming the diff more accurately to try stop it happening again, while they are out I could get them treated. Once they're in I don't want to have to be taking it out again haha For the sake of the price of another diff it would be nice to have one that I don't have to worry about.
Diff failures are rare on healthy diffs. Your gonna need 5-600+ bhp and similar lb/ft figures to really start breaking them at any regular interval. Mbautomotives vr38det s15 is on a stock 4.1 skyline diff. And he will tell you of many many cars built and tuned running big power on stock diffs. I would say don't sweat it too much. Get the lash set correctly in your new diff and you should be grand.
