I just spent three hours on my new AVO 420. Cut screws that entered the housings causing turbulence, blended the back side of wastegate port into the nozzle area, especially the back wall where the exhaust needs to pass over the port during spoolup. Found a HUGH burr in there! Gasket matched both cover's nozzle, and bell mouthed the compressor inlet. Did a major clean-up job on the inside of the compressor cover.....rough, rough, rough sand casting.
And last, flared out the inside of turbine housing just after the turbine wheel, heading into the DP. I also used indicating tape to verify proper puck sealing...it was perfect. I found a few loose boltz on my new turbo, but I was going to take them off ayway.
I used a $7000 stereo micro-scope, and air-turbine, and electric handheld engines to do the work. I have a glass bead and shell blaster at work, and a large ultrasonic cleaner to help remove all the crap out when done. This is around turbo #10 for me. I only do it for myself. Send yours to J@ Crucial. He taught me everything I know.
There is SOOOOOO much to do, even to a brand new turbo! I recommend this service, and you would too if you ever saw the inside of a turbo. Don't forget to send your gaskets to Jeremy to get your covers ported to match!!
I would never attempt this, unless I owned a Dental Lab full of neat stuff for working on little car parts like this....clean environment, well lighted, suction, proper tools, etc.
Last edited by turbo2nr; 01-25-2007 at 02:11 PM..