since about may, i have been running 30-31 on my stock evo 9 turbo. some time in June, i bought a TME exhaust blade and shaft, and swapped it in place of the stock steel exhaust blade. about 3 weeks later, the turbo blew. you can see pictures below.

the exhaust blade disappeared. the turbo didn't howl or whistle at any point. the compressor wheel did not have a single scratch.

so luckily, i still had my old blade and the tme cartridge. swapped back my old blade and the internals from the tme. next day i was back on the road and the car ran great. did about 50 passes on the track, with a best of 11.9.

well, yesterday, it blew again. now it howls and there is a lot of lateral shaft play. i suspect that the thrust ring broke in half again.

the question is, is ~31psi really too much for these turbos? i am thinking of buying this aftermarket rebuild kit that has a thicker thrust ring. any other suggestions?

 

Did you have the turbo rebalanced with the new wheel or did you just assemble it yourself. If you did not have it balanced I would not expect it to last long even at stock boost levels. At 30+psi the wheels could have been spinning at 100,000+ RPM. At those speeds even a small amount of imbalance would produce significant loads and would destroy the turbo in short time.

-Paul

 

no, i didn't. however, you dont need balancing for the internals of these turbos, since they are balanced seperatley from the factory. this is what BOTH mike at blouch turbo said and forced performance said. and no, they dont spin at 100k rpm. more like 40-50k rpm.

btw, when i bought my used evo 9 turbo back in june, the guy sent it to me with all bent up exhaust blades. so i used the compressor and exhaust wheel from my evo 8. that lasted me almost a year on stock boost without any failure.

 

You need to balance the turbo cartridge when ever you replace a wheel or wheels. If you read on Forced Performance's site part of a rebuild is balancing, and on Blouch's site they have a picture of the shaft with wheel on it being balanced. When you start spinning something at over 50,000 rpm you have to have it damn near perfectly balnced or it will come apart.

 

Not sure about the balancing part, but yes it should be able to handle 30 psi+. I had a friend that was running 35 on his Evo8 turbo with meth. He still uses his VIII turbo when his bigger ones blow up.

 

this is incorrect information. turbos at even very low pressure ratios spin WAY faster then 50k rpm. at peak flow rates and boost pressures they are in excess of 150,000 rpm. look at any compressor map, the lines are labeled with the rpm they spin at.

 

^ youve blown up 3, do you think they can handle 30 psi?

Scorke

 

it would be great if you can post up such a graph, especially for the mitsu turbo.

 

sense we are not allowed to post pictures of turbo maps, here is a link to a mitsu big 16G: http://www.stealth316.com/images/td06-16g-raw.gif

the numbers on the right are rpm.... they range from 55k at 3 psi to 130k at 27psi where the turbo becomes inefficient....

 

link didn't work...

and why are we not allowed to post the pictures of turbo maps?

 

not sure why we can't post the maps. i've done it before in the past but they just get taken down right away. i think it has to do with pictures that could be copy protected by someone (even though they are not marked).

here is the image again. i put it in my photobucket:
http://i2.photobucket.com/albums/y34...06-16g-raw.gif

 

it should last but remember its a 16g it can only do so much

 

I personally think the damage was a result of an installation error.

 

the turbo pictured suffered thrust bearing failure. likely from BOV not venting enough pressure or not venting it fast enough. The bearing collar is broke in half from the heat. then when there is too thrust play the turbine wheel hits the exhaust housing at very high rpm and causes it to shear off the shaft.

 

Turbos can boost whatever psi but if you are out of the efficiency range of the turbo it is just blowing hot air that isn't usable for HP. You can change that range slighty with tuning and proper supporting mods but not like changing to a new turbo would.