Originally posted by ToolManTimTaylor
HX = Adjustable wastegate Hy = NON adjustable wastgate hardline. and there is an HX~35 avail with 12 14 ( I think I saw a 16) housings.
Well, that is true but not the entire story! The HX also is a 12cm Turbine housing and the HY is a 9cm turbine housing. The HY's are only on Automatic transmission 2001 trucks. I guess someone @ DC thought it would be better to have the smaller turbine housing unit on the auto's because it spools up so much faster than the 12cm housing unit. Also something to do with letting have both manual and auto ETC motors have 235 HP for 2001.
This is all very true until you start bombing. After you turn up the boost over the stock 20, then the 9cm housing starts to make too much exhaust manifold back pressure, I. E. Drive pressure. It probably will never make over 30 psi no matter what you do and the excessive backpressure drives egt's up in a big hurry. Check out earlier posts over the last year on HY's and you will find alot of guys have swapped in the HX units for the HY's. One caveat here is that you have to change the entire turbo, the center sections and turbine housing mounts are mutually exclussive to the two but they are a direct unit swap.
Todd