kaj

iTrader: (60)

should there be any? one of my HKS 7460s has some. about as much as a JB, i'd say. i push on it and spin the turbine and it doesn't seem to hit the housing.. but it kinda looks like there are some scrapes on the cold side.
the turbo is coming out tonight. i was thinking to sharpie an area on the inlet to see if it gets rubbed off.
the dyno sheet looking NOTHING like the others i've seen.. meaning it seems to make boost pretty slow.
my last turbo lagged really bad and dropped off nearly instantly at the end of a tuning run, right before it blew. maybe i'm just being paranoid. i bought this used and don't always have the best of luck buying used, important parts LOL. the seller swears the turbo is fine, and i really have no reason to not believe him.
i could swear i read BB turbos have very little to no shaft play.
and yes: i could compare my two turbos, but one is not available for quite some time.. so really hoping this one is good.

comments/opinions? thanks in advance, guys.,

94AWDcoupe

iTrader: (125)

bb turbos have just as much play as plain bearing turbos. the term "no shaft play" really just means no abnormal play that would suggest the turbo is on its way out. I am 1000% certain you do not have a turbo problem with your missing power. just because it cant be pinpointed over the net on the forum doesnt mean a problem doesnt exit. there is only so much trouble shooting you can do on paper. it pails in comparison to having a proper mechanic look at it.

kaj

iTrader: (60)

okay, cool. it was my understanding BB turbos have very little to none. i know journal bearings do. i also know what "no shaft play" in for sale ads means.
as for my power issue, it's a mystery. myself, the shop i worked at, my tuner, and a second shop are all at a loss. nobody can find an issue with the engine. but you never know.

LetsGetThisDone

iTrader: (1)

I thought the engine was blowed up?

kaj

iTrader: (60)

Yah. Spun a bearing. Haven't found an oiling issue yet. I did have a mechanical over-rev, though. About a week before the engine quit. 6k in 2nd down to first (very bad timing of a bump on a freeway onramp + me being distracted. 1,000,000:1 odds, but it happened). I'm told it could have been that. I remember hearing what I thought was valvetrain noise after. Maybe it was the bottom end. I opened the valve cover and everything looks perfect. Leakdown shows no bent valves.

FossilAus

Which version of the 7460 is it? The first version had issues with the wastegate flapper arm (which was addressed on the second version), could explain the slower than expected boost threshold?

kaj

iTrader: (60)

It's non-kai, so checking the arm is top on my list.
By slow, I mean 25psi not until around 4k or so. That's nuts.