I've searched for over an hour but I can't find a picture of a new compressor wheel. This compressor wheel is from my S5T2. Does it look bent or are is it actually supposed to be like this?

 

Never seen one bend before, they always break. It's made of cast aluminum, so it's not very malleable. That one looks fine to me.

 

Thanks, I was thinking that the fins looked uniformly bent but I just wanted to confirm before putting it back together.

 

If the fins werent "bent" then how would it scoop air in to compress it? The stock t2 compressor wheel looks just like any other automotive compressor wheel. Whole question is a bit silly.

 

yes the fins can bend before breaking but this one looks fine.

if the top edges of each of the blades are not straight out from the center then you will notice it, that is where you will see a deformed wheel. cause is worn journal bearings which allow the compressor wheel to drag on the compressor housing.

 

Really, you actually think the the fins "have" to be bent exactly like they are?

 

This is what I've seen of fins that get damaged. They break









But if you look at it (yes, this is a hybrid, but same concept) the fins are all laid down. They have to be laid like that in order to move air. It's all due to a bunch of eggheads that sit around thinking about how to make stuff more efficient, and this is the end result.

 

if my card reader wasn't broken i would show you the wheel i was describing. i don't know why your wheels keep getting chewed up by a mouse Agreen but that's not always how they end up.

to me it still looks like debris is somehow getting into your turbo and bouncing around on the compressor wheel face i cannot imagine ANY other reason why it is getting chipped up like that with fresh scratch marks like something was rattling around on the face.

 

The first was due to me not using loctite on the shaft threads. My fault completely.

Each subsequent one had to have been from improper balancing. As I said in that one thread a while back, I'm no stranger to rebuilding things.

I found out that the balancing shop balanced the wheel and shaft separately somehow. So when I got it back, it was assembled, but without any paint/sharpie marks. I would mark the position with a sharpie and assemble the turbo. After a few minutes of running, the compressor wheel would end up hitting the housing and chip the fins off, then that chunk would fly around and chew the wheel up. That's my only theory as of now. I threw compressor surge out the window after putting an unmolested stock S5 turbo on it and it did fine. I even replaced the blowoff valve with a piece of regular pipe and surged it numerous times without issue (since I remembered what you said about surge being BS anyways). The common denominator is either my building skills or the balancing shop. After seeing people with absolutely no experience with anything mechanical rebuild a turbo without a hitch, then I try 4 or 5 times with no luck... something didn't smell right.

 

probably the balancing shop, odd being that they specialize in turbos but have no idea how to properly balance the WHOLE assembly. a big enough chunk coming off could have done the damage.

if the metal is hot i assume it is more prone to bending before breaking but yours was too tight and hit the housing when cold and just shattered. that's my assumption, materials also play a role. i can literally take a stock wheel and bend the blades a bit before they begin to crack, some more brittle alloys might not be as forgiving. the stock hitachi wheels were meant to take a bit of abuse in this environment, they are also quite flimsy looking in comparison to your garrett of unknown origin wheels, yet i can hardly bend them by hand and takes a bit of force even though they are paper thin.

the tolerances in your picture from wheel to housing also look too tight(yet erratic from one to another), the wheel should never come close enough to contacting the housing under load and it looks like yours barely have any clearance. good for efficiency, bad for reliability. but you also notice the thicker the blades are, the worse the result was. the first had the thinnest blades and probably was a true garrett wheel, likely would have been fine had the nut not come off but the tolerance did look a bit too tight.

 

Well, they sort of do and don't specialize in turbos. It was a diesel shop, and it was the only shop in a 100 mile radius that would balance it.

Interesting theory on the tight tolerance between the compressor cover and wheel. I'm going to attempt this madness again at some point, but I'll definitely get some fin-to-cover measurements on my stock turbo before sacrificing it for a hybrid.

The wheel never came in contact with the compressor cover when spinning it with my fingers, not even if I wiggled it around while spinning. Side play was in spec, on the very low end as each turbine shaft was carefully selected and measured meticulously, and assembled with true Garrett bearings that were also carefully measured, even though they were brand new.

See? It had to have been the balance throwing everything off.

I hope Alritzer feels that the original question has been thoroughly answered, as I've successfully derailed yet another thread

 

The original question was answered and I would like to thank everybody for their input.


ash

 

Ash.
I got a turbo for ya..(BNR stage3).
sorry I had to..(shameless FS plug!)