I bought a Kinugawa TD06SL2R-25G and blew it up in 4 months and about 5k miles running 30-32 psi. I know the bigger wheels are harder on thrust bearings. They claim that the thrust system is larger and upgraded over the factory 16G.
My question is: If I clip the turbine wheel 15* and lower the back pressure on the turbine wheel, will it help or will it make such a small difference that I am wishful thinking and blowing another one in 4-5 months?
I am also wondering if I should allow more oil flow on the "feed from head" setup or maybe switch to "feed from OFH"

Looking for advise from people that "know" not taking guesses. TIA

 

If you are restricting oil from the head that is the problem. It is already a marginal feed for any larger journal bearing turbos. Only use a restricted feed on OFH and that is if it smokes or uses oil.

 

I have never had a turbo fail from oil loss. I always feed from head.

Its always the turbo shop shifting blame and grabbing straws to not warranty a turbo. You can follow shops advice to a T and there will still be turbo failures.

DO NOT CLIP TURBINE

 

Why not?

Soooooo, I think I am going to feed from OFH so if it does fail, I know thats not the oil flow. (even thought it didn't look starved or cooked)

I wonder how the MHI TD05HR/25G compressor wheel guys are doing?

 

I don't think Mitsubishi made any bigger reverse rotation compressor wheels. All of them are made by other people.

 

the 25g wheel is a big wheel. mating it to a 6SL2 wheel is not a good idea. mating it to a 5h wheel is a horrible idea. clipping makes wheels smaller. that compressor needs a larger turbine wheel not smaller. a 20g wheel works waaay better matched to a big 6h turbine than it does mated to 6Sl2 and 5h wheels. why the heck anyone mates a 25g to anything smaller than 6h wheel is beyond me.

 

I was talking about the factory turbo with a Kinugawa 25g compressor kit on it.

 

I agree with the part where the 25g compressor wheel would be better mated to a larger 6H turbine wheel.

Can you elaborate more on the clip being a bad idea?
I figured more flow with less pressure would make a smaller thrust load.

 

It would but the turbine wheel provides the power to turn the compressor wheel. Get too large a difference and the turbine wheel runs into backpressure issues well before the compressor wheel is maxxed out and you cant make any more power. A much bigger compressor wheel should be matched to a properly sized turbine wheel. Clipping the stock wheel makes it flow a little more but reduces its ability to drive the compressor wheel.

 

x2 , in a nutshell

 

larger wheels allow turbo to operate at lower shaft speeds. clipping the wheel makes it less efficient.

 

So, what does this have to do with the thrust system in my turbo?

 

If there is a huge pressure differential and the Turbo is spinning at higher shaft speeds it places tremendous loads on the thrust bearing.

 

does the turbine wheel generate a thrust load? i always likened it to a paddle wheel.

 

The exhaust sweeps like a paddle wheel, but is ultimately forced perpendicular to its entry.

That suggests to me there is thrust load, but the vector I have no clue.