As the title states, I am thinking about powdercoating my rear knuckles, I'm a little concerned about the rubber bushing, does anyone know if there is a group N or other replacment?
not sure if there's a group n or not but whiteline makes a rear trailing arm bushing http://turninconcepts.com/product_info.php?cPath=1_9_7_480_490_1330&products_id=1032
Rallispec sells individual Group N bushings for the GC and GD chassis. http://www.rallispec.com/prod_chart_stibush1.htm
I seem to remember that the GrpN parts need to be pressed in, whereas there is a SuperProPoly version that just needs greasing before they slip right in. I had the poly ones on my old RS. There's one set that goes at the front in the trailing arm, and another set that go into the knuckle on the hub.
^ Along those lines. STi Group N bushings are made just like factory bushings, and need to be installed as such. Some of the bushings have a metal sleeve, which is great fun to get out. Some poly bushings need to be pressed in too. If I were to do it all over again, I would have used all the Group N bushings instead of Energy Suspension and Super Pro. Poly bushings need to be maintained otherwise they will destroy themselves, espeacially if you drive the car in MN winters.
Harlow, let me know if you need help pressing those in and out. I did them on my Evo back when... Easy to do.
I have the trailing arm bushings if you want any, along with lateral link bushings too. Frankly, my step up is pillow ball bearing connections, so I have little use for them. They've just been sitting in a box for a few years now. I actually kind of advise just stepping to the bearing type ones. They're $100 on eBay for the pair. The lateral links are just $200 and adjustable. They kind of make rubber or poly upgrades pointless. Frankly, NVH is a mute point too, nothing worth complaining about, and bearing connections are the end solution, a solid connection. The only time you'd want to stay with the Group N bushings is if you are forced to for auto-x or something where they specifically require the bushing to be of the same type, but you're free to up the firmness. Otherwise the Godspeed and whatever branded endlinks and trailing arms on eBay are pretty much a no-brainer.