chizz95

Sc300 na-t just under 500 miles since build.turbo was bought from wicked cas but said only had under 100 miles on it,t57 1.15 hot .60 cold .


Car was running 6psi off wg spring,stock hg fuel etc...


Trying to figure out what caused the turbo to blow apart (compressor fins broke off hitting housing also the nut on comp side shaft sheared off) so this doesn't happen to the next one in about a wk.

One main thing I feel could have contributed to failure was I had a greddy knockoff bov and it was recircd,since I am learning as I go I thought it was working but the whole time the bov wasn't opening and later I found out the noise was compressor surge the whole time.

So I heard comp surge is bad for the turbos bearings,and roughly 450 miles of DD maybe that had a lot to do with it.

Since then I threw away the "greddy" bov and now have a Xspower rfl billet not recircd and when I come out of boost I can hear semi flutter but mainly pssshhhhh like a bov should sound like.


Now,today I ripped off the junk turbo,the broken comp fins were sitting in the maf housing,along with the sheared off nut off the shaft,also the intercooler pipe attached to the turbo had oil in it??


I took off the oil feed line to see if the turbo was getting adequate oil and it was ..but I ran the car for 30 seconds today to see what the flow was for the oil feed and it was drip..drip..drip.. it wasn't a steady flow ??

I drilled and tapped the union bolt shouldn't that feed line be speewing out oil? or at idle is it low pressure,and flows better the higher the rpm climbs?


I'm just trying to figure out what caused this turbo to fail so violently so it doesn't happen to my next one next wk.(t70 .84 hot .70 cold) Much better size then the last one..


Any help much appreciated guys ,Thanks-chad

93MSB

iTrader: (8)

it should be shooting a stream of oil from the union bolt. The 2JZ oil pumps dont mess around, at idle mine can put out close to 80psi on a cold start with new oil. It definitly should not be just dripping

what size AN line did you use for the feed? was the turbo ball bearing? were you using an oil restrictor on the line?

Ali SC3

iTrader: (10)

that sucks, yes compressor surge can destroy turbos, but never really at such low boost like 6 psi. I think you have a combo of problems, including that and the oil situation. also that turbo is a little small i bet it was spinning like mad.
when I cracked my oil line (by accident) while trying to wrench on the downpipe, it was idling and it covered about 1/4 of the engine bay in oil in like 5 seconds, so it should be a very steady stream.

Just get the is300 union bolt from toyota (98 vvti na mk4 supra) and call it a day. maybe you are using too thin of a line or a restrictor. unless you are on BB, you should not be using a restrictor.
for most journal bearings in that turbo size range i would go IS300 union bolt and a 3an line direct to the turbo (no restrictor).

chizz95

1) Im using a 4an feed and a 10an drain
2) the turbo is journal bearing NOT BB
3) I was using a restrictor that bolted onto the turbo VERY small hole not even 1/8th hole

I need to take out the union bolt and see if some thread sealant got in the feed clogging it..

So future reference 3-4an feed, NO oil restrictor,and the new bov (no more comp surge) ..should help me out..thanks guys

5sp_jzz30

iTrader: (2)

-10an drain might be too small. when i do turbo rebuild i recommend a bigger than stock oil drain lines even for t25 turbos. get a -12an drain line. its 3/4 inch OD and a bit more than 1/2 inch ID, which in most cases is borderline adequate.

dont use a restrictor on a non ball bearing turbo. most journal bearing turbos have a restrictor cast right into the bearing housing. simply connect your oil feed line.

one more thing....NEVER, BUT NEVER, remove your oil feed line when engine is running to check for flow. always remove the oil drain line and check for flow. also dont actually run the engine. disable the ignition and fuel injector system and crank the car to see steady oil flow. when you remove the oil feed line and crank the engine, you are still pumping air through the turbo, which makes it spin. since you are not feeding any oil to the turbo but still spinning it, you cause a dry start condition. this burns up our oil seal in minutes.

compressor surge killed your turbo. boost pressure doesnt have much to do with how long your setup lasted. boost or manifold pressure is resistance to flow, so if you have a better flowing intake system and head you can flow more air at lower "boost" levels. stress on the turbo is dependent more on the rpm of the shaft rather than how much "boost" you run.

good luck with your next setup.

99SC42

iTrader: (44)

^+1 great post , i always ran -10 for the Return and -4 on the feed.

Ali SC3

iTrader: (10)

yeah if you are using a 4an line and you have no oil flow, there is a major problem, i would not run the new turbo till you get it solved.

cartmill

iTrader: (3)

a -10AN drain did not cause that problem.

99SC42

iTrader: (44)

yeah i know i was just saying that i ran -10 return and -4 feed but i am thnking about going to -12AN on my new setup.

SC300_704

iTrader: (5)

might just be me but i had to use an oil restrictor on mines b/c one time i took my car to a race shop and they told me the same thing, don't use oil restrictor on journal bearing turbos. i listened to them and a few weeks later my turbo seals blows on me. now with the new turbo and a oil restrictor, haven't had the seals blown yet. btw i'm running -4 an feed and -10 an drain lines.

broda805

iTrader: (6)

new turbo? garrett? rebuild and balanced? china made?,

on journal bearings you shouldn't have to need a restrictor with a 3-4an line but you do need a free flowing oil drain thats straight down as possible and least amount of bends as possible, its just a gravity drain and if it gets backed up it will flow out the of the seals

spoolxexo

iTrader: (4)

No restrictor on Journal bearings ever.

I had a TD05 20G on a built 4g63 that made 85psi oil pressure, and it loved life.

Lesson learned, right?

5sp_jzz30

iTrader: (2)

95% of the time, turbo failures are attributed to error in installation or error on the part of the end user. when properly installed and maintained turbos are very resilient.

i have a feeling your turbo had an issue prior to blowing up. i have cut up a few journal bearing turbo center sections and you can clearly see a portion that is the same size as a oil feed line, or very close, and then it gets restricted down to about 0.065 inch right in the bearing housing.

another issue with turbo installs can arise right in the beginning. if the turbo does not get proper lubrication right away, the turbine seal can become damaged due to excessive hear of friction. once the seal is overheated it warps out of shape and doesnt seal properly. high oil pressure can actually put the last nail in your turbos hypothetical coffin.

Ali SC3

iTrader: (10)

I know ill probably get flamed but I feel like a 4an line is overkill.
people with 4an report seal issues on journal bearings and you need a restrictor for BB.
With my 3an line on my journal, it runs perfect, and for a BB you would still need a restrictor. 4an flows a huge amount of oil most journal bearings do not really need that much.

Lexsingle

From your description of things, sounds like the turbo was starving for oil. Especially if you were able to take it off and all it does it drip drip drip and you ran it for 30 sec, 30 sec if done correctly should have emptied at least 3/4 - 1 1/2 quarts of oil. As when I run quick test for oil feed started idle for 5 sec the quart of oil bottle I'm using to catch it is probably quarter full or more already. And sounds like on top of it the surging didn't help, though it wouldn't have mattered since it wasn't getting any oil barely, surprised it lasted that long. Get the oil feed problem fixed and cleaned up and you'll be set to go.