bch5428

i had a new (ebay) turbo on my crx for less than 30 miles before critical failure.

(i dont wanna hear about this ebay **** i know its bad, trying to figure out if that is the cause of if it was something else.)

i was boosting 7-9psi with an EVO III 16g knock off turbo, and all spool/turbo related activities stopped immediately. got home, checked the compressor wheel only to pull it out of the housing and there were no fins left on it. the turbine shaft had broke just inside of the compressor housing.

the oil feed/return as well as the coolant lines were run correctly. i did not do anything to this turbo that would be regarded as anything more than functional use. is there a turbo break in period that i dont know about? cheap turbo or not, the only crap ive heard go wrong with ebay turbos was casting issues.

i was seeing very late boost the entire time. im running an e-cut out set up 2.5" DP on a D15b2 with a D16a6 head. 2.5" charge piping, tuned via turboedit. anywho, i couldnt even get the bitch to spool with the e-cut out shut!! but with virtually no exhaust, i still wouldnt see boost until 4700-5000rpm. ~1000rpm later than i expected. there were no exhaust leaks, or boost leaks to my knowledge, i did my best to ensure there were not as i was worried of such a thing.

the engine was at WOT at the time of failure, roughly 4500rpm in 3rd gear. so it probly wasnt making much boost, if any at all. just before i backed off to slow down, the boost gauge dropped to 0. i couldnt hear specific "clank/snap" noises as the car is quite loud with the exhaust switched to open.

there are some issues i have before buying (a much better) turbo and reinstalling.
essentially, what caused this to happen?

was it..
1) surge? ive heard of surge ruining compressor wheels and my bov was adjusted poorly, but if anything it was too lose. i didnt hear anything out of the ordinary, but the car is loud like i said above.

2) did the main shaft over heat causing the break or did it seize after the balance went to all hell? everything spun smoothly by hand with virtually no play. remember it was a brand new turbo.

3) perhaps the turbo wasnt balanced correctly from the get go?

4) is this just another plain and simple example of why not to buy a chinese turbo?


other than my possible reasons for failure, im pretty stumpted. anyone else snapped a mainshaft before? can anyone share some real-life, mainshaft snapping experience and their probable causes? perhaps some educated opinions? ive run short of ideas and dont have much summer left to drive as upstate ny weather totally blows goats.

and finally once again, i dont wanna hear about how bad of a decision it was to buy this turbo, i wanna hear about why it may have broke. aka, i dont want short - "ebay turbos suck, you shouldnt have bought it you loser" answers. i wanna know what typically causes turbos to fail in such a fashion. thanks.

HiProfile

Probably balanced like ****, causing it to bite the bearing surface, causing the shaft to twist & break the cheap shaft material. There is no breakin with a turbo, its just that you have to make sure it's filled with oil before you let the engine fire up the first time. Also, even if you aren't boosting, the turbo will be spinning quite a bit.

My experience with an ebay turbo (guy I know, not mine) got a 57trim t3/t04e. Seals junk after a few K miles, and enough shaft play to scrape the sides of the housings.

You wouldn't try to save a few bills on a crx/civic because every piece of sheetmetal was twisted up, so why cheapout on a turbo? Now you know...

bch5428

awesome, thanks for youre .02.

i bought turbo over a year ago. by the time i was ready to put the thing in had learned a ton more and knew the turbo was junk but was stuck with it. i learned the hardway, but ill never make that mistake again.

oscarmayer

yea balance and/or lack of oil wuch could trash the bearing sand cause it to back and scrape the sides.

bch5428

lack if oil was not the issue, as stated above in my first post.

it didnt have enough play to catch either housing, spun by hand. i realize things change when theyre heated, but geez.

anyone think that the late spool was related to the balance thing or the turbo is just too big? (im almost certain the turbo is NOT too big).