Finding a turbine wheel
 

I am in the process of rebuilding my HT18 (it was making some scary noises) and I sent my turbine and compressor wheels away to be balanced. Now I knew there was a chipped fin on the turbine wheel and the wheel had started to wear into the first cup thing at the back of the center housing (sorry I don't know the offical term) but I didn't think it would be too bad. The place I sent it to get balanced said it was toast, and that I could run it but it would not be long before it would take out the bearings again.

In any case, it looks like I need a new turbine wheel. I know I could probably just buy another used turbo but I've ported the WG and and replaced all the bearings and seals so I'd kinda like to hang on to this one. So I have a couple questions...

1) Should I look for a new wheel or will a used one be fine?

2) How much is $ a new wheel and where can I find one?

3) Are there turbine wheels from other brands(Garrett) that will work?

Thanks,
Devan

a used wheel is cheapest option. but most t3/t4 "standard shaft" wheels will work, the problem is it wont be plug and play.. you will need to get the turbine housing milled for it (~$100 at most turbo shops)

the factory wheel dimensions are about 2.5" inducer, 2.1" exducer. a garrett or turbonetics stage 3 wheel is slightly bigger and would be a nice upgrade

http://www.turbocharged.com/catalog/twheel.html

Having recently gone through the process of having my own ht18 built I can tell you these things.

A good shop will take a used shaft and measure the run out, grind the bearing journals to make them smooth again (foreign particle matter will score these on nearly all used turbos you buy), and blast (not sure on the medium) the wheel itself to take it back to raw metal. They will then reassemble with a step gap piston ring and bearings that are undersize on the inside to take up the slack of the machine bearing surface.

Past that you can use an original centre housing (from either a HT18S-2S or a HT18S-BM) and have that drilled and tapped for the set screws to hold the 360 degree thrust bearing/washer to the CHRA. If you use the HT18S-BM CHRA you'll change the turbo to be oil cooled only and look a lot neater.

You can then get a T04B backing plate bolted to the front of your mazda CHRA (the bolt holes are slightly different so the shop will have to file the mazda CHRA by a few parts of a mm). Then you get to the choice of dynamic or carbon front seals. My turbo uses carbon. Carbon seals better but causes drag. Dynamic seals poorer but has less drag and is the current standard for what turbos use.

I managed to find a good used turbine wheel from a guy locally.