Ball vs plain bearing turbo

[Z24O]

I have been looking into an upgrade turbo for my RB30.....current T3...my local turbo shop says the ball bearing garretts don't seem to be lasting long on the installs he's done (as little as 3000km),he puts it down to the fact that the ball bearings have no lateral play(unlike the plain/oil bearings) to absorb movement created by the harmonic vibrations of the spinning shaft

he has been in business for a long time and has a respected reputation in my city,he sells 70% plain turbos to his customers,doesn't beleive the ball bearing turbos spool up significantly faster and seem to suffer from premature bearing failure.

Any comments for or against????

Any technical links/info to back up your opinion???

[MatMan]

Yes, I believe your supplier. But, with turbos, you win some, you lose some. When I was working at AlliedSignal/Garrett 6 years ago, they were doing research on air bearings, have they come out with those yet?

 

I have seen deisel applications of Garretts lasting as much as 144K miles, and some gas applications as little as 6K. It's all in how you drive, and how lucky you are to not get an intermetallic inclusion on one of the vanes.

[thehelix112]

The argument makes sense, but you would think that the factory is capable of balancing the rotating mass enough that the bearings don't get worn. Unless your supplier is doing funky stuff like putting bigger compressor wheels on the front and then rebalancing it himself, in which case.....

 

Dave

[MatMan]

The argument makes sense' date=' but you would think that the factory is capable of balancing the rotating mass enough that the bearings don't get worn. Unless your supplier is doing funky stuff like putting bigger compressor wheels on the front and then rebalancing it himself, in which case.....

 

Dave[/quote']

What I remember of the problem was not in the bearings around the shaft which took care of the "wabble" it was in the collar bearings that were supposed to handle creep.

if you follow the right hand rule, when you put a rotaion on an object, there will always be a torque acting perpendicular to that roation.

When the turbo axle is spun, it naturally wants to creep one way. Couple that force with the hot gasses loading the vanes (F=Ma) and you get quite a force on the collar bearings.

[thehelix112]

Are you saying there are two sets of bearings? Ones that the shaft spins on and ones that...?

 

And I'm not getting the creep thing at all. Define `one way' please.

 

Dave

[MatMan]

Are you saying there are two sets of bearings? Ones that the shaft spins on and ones that...?

 

And I'm not getting the creep thing at all. Define `one way' please.

 

Dave

Imagine an axle like that of a 1 ton truck. The axle system is basically a tube within a tube. One end is driven by the differential, the other drives the tire, and by extension, the ground. There are bearings at the hub which allow the axle to spin.

If you had a straight axle, and tried to apply power to it, eventually it would slide away from the differential through the housing tube, and out into the street. At the hub, there is also a collar, which impedes the axle from slipping out. This collar is basically a change in outer dimention of the axle.

The same is true on a turbo, between the exhaust fan and the intake fan there is an axle which rotates within a tube. The air hitting those fans creates a lateral load, or as I called it, creep. Imagine a propeller, when you spin it, it wants to move laterally, depending on which way the propeller forced the air. That lateral force, coupled with the 2 spinning masses (one on either end of the turbo axle) impart a lateral load (creep) on the axle, causing the collar bearing grief.

[260DET]

Just like with anything new, there is always some backlash opinion against the new technology. Personally, the GT28RS is the king, TO3 the s**t

 

On a FJ20.

[yo2001]

BB CHRA is more prone to failure if you are not using an inline oil filter before the turbo. Not real forgiving when it comes to an oil contamination.

 

 

Are you talking about Dual Ball Bearing off Garrett? or any ball bearings? Some IHI OEM turbos are BB front bearing. They seems fine for a very long time.

[thehelix112]

MatMan,

 

You I think are talking about the thrust bearings? The garrett catalogue says the BB cartridges are 10 times more durable than the plain journal ones. That combined with the higher nickel content turbine housings.. no contest IMHO.

 

Friend used to have his T4 go soft every 3 race meetings. 3 seasons on a GT35R and no change. Good enough for me.

 

Dave

[MatMan]

Yes, thehelix. Thank you. If I remember correctly, the thrust bearings were giving up before the ball bearings and their races.

[Z24O]

thanks guys,food for thought,it seems most of you would choose the BB

[thehelix112]

Oh and fwiw I believe all Garret GTs have 360deg thrust bearings which are options on older turbos so they're really essentially the same?

 

Dave

[jeffp]

I am running a gt35R turbo, and one thing I noticed when I first got the engine going was that when the engine would die and it was not at idle, the turbo would still be spinning after the engine stopped. Not a bad thing, but still the turbo was spinning, and there was no oil supply because the engine oil was not being circulated. So in my opinion, make sure the engine is at idle when you shut it off, and at idle long enough so the turbo is not spinning faster then what idle will spin the turbo. That way, the turbo will not sit spinning for to long of a time after there is not an oil supply. make since?

 

I guess one could always go electric oil pump and seperate the turbo oiling from the engine oil pumping completly to insure there is always oil to the bearings when the ignition key is on. Get a line off the oil pan and route it through the electric pump and heck you could even put a delay timer on the electric pump so that even if you turned the key off the timer would keep the pump going for a period of time and then shut down. That would be ideal.

[Z24O]

hey jeff p,

last time i was in a truck turbo supplier i noticed they had an add on device that 't's into the oil line to the turbo, once the oil pressure went above 'x' psi it would compress a spring in the reservoir and fill up with a couple of litres of oil

on engine shutdown the spring would decompress and pump the 2 litres of cool oil through the turbo bearings.......this should solve the problem you mention?

paul

[BLOZ UP]

I am running a gt35R turbo' date=' and one thing I noticed when I first got the engine going was that when the engine would die and it was not at idle, the turbo would still be spinning after the engine stopped. Not a bad thing, but still the turbo was spinning, and there was no oil supply because the engine oil was not being circulated. So in my opinion, make sure the engine is at idle when you shut it off, and at idle long enough so the turbo is not spinning faster then what idle will spin the turbo. That way, the turbo will not sit spinning for to long of a time after there is not an oil supply. make since?

 

I guess one could always go electric oil pump and seperate the turbo oiling from the engine oil pumping completly to insure there is always oil to the bearings when the ignition key is on. Get a line off the oil pan and route it through the electric pump and heck you could even put a delay timer on the electric pump so that even if you turned the key off the timer would keep the pump going for a period of time and then shut down. That would be ideal.[/quote']

 

I doubt that's a problem. There's enough left over pressure and drip for the bearing to be fine for the 3 seconds it's slowly spinning down.

 

However, if you do go WOT under load, then turn it off immediately, that's a problem.

[thehelix112]

My GT35R spins for significantly longer than 3 seconds. More like 30.

 

Dave

[BLOZ UP]

My GT35R spins for significantly longer than 3 seconds. More like 30.

 

Dave

 

30 seconds? when after you're at idle?

 

Still, there's enough oil in the bearings to allow this.

[yo2001]

mine was closer to 1 minutes after shut down. SOmething to do with a big shaft p-trim BB turbo.

[Brad-ManQ45]

It's easy to believe the long time for a BB turbo to finish spinning down - after all, it spins UP quicker...

 

I can still read the advisory info on the back of my '83ZXT's sunvisor recommending idling for 3 minutes before shutting down. Nosw that was in part because the stock turbo was cooled only by oil. Since I now have a water-cooled center section, I only idle for a short time before shutting down unless I had a recent burst of fun...

 

The add-on device is known as an oil accumulator, and anytime the oil pressure drops below a certain point it releases oil into the oiling system.

 

Trying to remember some trade names....

 

AccuSump?