Turbo's
I can't resist chiming in here. In my opinion an HX40 on an engine in the 450-500+ Hp range is on borrowed time. I've managed to Huff 2 HX40's. I know there are a lot of guys out there running HX40's at over 500 HP and they are holding together for them (for the time being). My experience has not been a pleasant one when it comes to HX40's. The 2 HX40's that were briefly on my truck were always cooled down properly and not barked, but still failed. Go figure? Don't get me wrong the HX40 is a great turbo for the lower HP crowd but above 450-500 HP reliability becomes an issue.
I'm currently running a B1B by KwikKurt. It has the standard housing's as the B1 but with a smaller turbine wheel. It works real well for towing, spools about the same as a HX40 but has a little more mid range and top end. I decided to try the B1B because of it's known durability.
Dyno Comparison PDR HX50 vs B1B
PDR HX50 dyno results = 550. 2 HP and 1062 ft-lb. OAT 58 degree's.
B1B dyno results = 542 HP and 1135 ft-lb. OAT 81 degree's.
The dyno runs were made on the same dyno 3 months apart. The only thing that was changed on the truck during that time was turbo's and ambient air temp, no changes in the level of fueling.
The PDR HX50 definitely has the best top end EGT relief, but I didn't like to tow our 5th wheel with it due to its late spooling.
The B1B on the other hand makes all most the same horsepower with more torque and works well for all around use and towing with the trade off being higher egt's on the very top-end.
So if you are at 450+ hp and want to stay with a single turbo and into balls to wall sled pulling or drag racing and don't tow I'd chose the PDR HX50. If you tow and get into an occasional street race or dyno competition and need some utility out of your turbo get the B1B. JMO
BTW... I heard a rumor that PDR is now selling the B1 line-up of turbo's?