I have a Holset WH1C (HX35 essentially) 56/60/14 and am looking at upgrading to a 58mm compressor wheel. Does anyone know what diameter the compressor housing needs to be machined to accept this wheel, before I call BAE? I tried a 60mm wheel and cover previously but it surged so bad I sold it. The WH1C doesn't have the MWE (map width enhancement) slot that the HX has, probably another factor in the surging. I figured for $70 and some machining, a 58mm upgrade would be a good experiment.

 

Stock 56mm Wheel

http://baeturbosystems.com/compressorwheelformitsubishitd04hl4350mminducer-5600mmexducer-3-1-1-1-1.aspx

 

58mm Upgrade

http://baeturbosystems.com/compressorwheelformitsubishitd04hl4350mminducer-5600mmexducer-3-1-1-1-1-1-2-1.aspx

CT I've kind of been studying up on turbos and I think your issue is going to be the size of the exhaust turbine. Most of the big name turbo manufactures have a much larger exhaust side. This is what I think is also causing your surging problem. Example I'm looking a buying a super B special and it is a 64/72/14. I think if you want to do that you would need this to keep it from surging.

http://baeturbosystems.com/compressorwheelformitsubishitd04hl4350mminducer-5600mmexducer-1-1-3-1-2-4-1-5.aspx

I concur, my previous setup was definitely pushing more air than the exhaust could handle. Can the exhaust side be machined? I think at that point I'm better off with a new aftermarket unit. I've been putting off buying a turbo, mainly because I don't have $1200-1400, but I don't want to sacrifice spooling, especially with my current torque converter. I'm still debating the super b, but now I'm debating the ATS 3000 because of it's supposed quicker than stock spooling. I almost always keep my RPMs between 1800-2200 and don't race my truck, so I don't need/want top end. But, when I had that 60mm, my truck had a lot more power, so some turbo upgrade is in the future. 

Since you are in ohio there is a guy in Findlay that builds upgraded stock appearing turbos and I've heard good things about them, prices are pretty good too. I'm planning on getting in contact with him this spring/summer to see about getting a 63/65 or 68 hx35 from him, the business is called Tater built turbo chargers. Some of the compressor wheels he will put in the stock housings I don't think are really worth it since the housing would seem to limit the turbo at that point(66mm and 67mm compressors in stock housing) but for a 63mm or smaller compressor I think it may be the way to go.

Oh sweet! Thanks Bryan! I am also in Findlay. I've seen his ads on craigslist but never knew the shop name.

Yes both sides can be machined to your needs. Bob at BAE was telling me that I should just machine my exhaust housing on my he351 and I would have a better performing turbo than a Super B. Not sure if I want to take that on yet. It was a real PITA the last time I took this turbo apart.