I heard this from a friend, but I never heard of it from anyone else, or read it on the forum anywhere. Wanted to see if it's true. The explanation I was given was a) due to the extreme heat generated by rotaries, and b) due to the oil blowby, ball bearing turbos tend to have high failure rates on rotaries, and we all know how expensive ball bearing turbos are to rebuild... Any comments/experience, etc?

Thanks
~Ramy

 

All the GT35/40/42 are daul BB..

 

Thank you for pointing out the obvious In fact, by definition, all GT series turbos are ball bearing

 

The RX-6B from Apexi is and they use it on their FD.

 

its not that they dont last, its if you shoot a seal out of the motor, have fun trying to get it rebuilt. you might as well replace it

 

It's the "R" that designates whether it's a BB center.

 

I'm looking forward to hearing some comments as well. In the process of getting a GT turbo so I'd like to know if theres any validity behind these claims.

P.S. Ramy, I PM'd you. You probably already know what about .

 

I guess I'm in deep trouble then

 

Well that goes for any turbo. Not BB specific.

I thought the GT were BB, and the R was dual ball bearing?

Yea that's what I thought too... Not that you're in trouble, but that just MAYBE ppl like yourself and Steve etc know what they're doing, w/ all the ball bearing turbos being installed on FD's. But again, someone on the forum (I'll leave 'em unmentioned for now) was drilling into my friend's head that BB turbos have short livespans on FDs.

 

Not that I think...

 

the only thing different that i can think of versus running ball bearings on a piston engine is the lack of an engine head to cool off the exhaust gasses on the rotary... so it gets hotter. but if journal bearings are ok, then ball bearings, which are superior, should do fine if not better.

maybe the bearing races get hot and expand beyond specs or something?

however, i'd bet that the only reason mazda/hitachi used journal bearings is cost.

 

It doesn't make sense that a ball bearing type turbo would be any worse than the alternatives (needle & roller). Ball bearing are designed to take axial and radial thrust in 900 degree C jet engines. Unless companies use poor quality ball bearings in there turbos, and good quality bearings in there other non-ball type turbos. Then there is no basis for the claim. It is more likey that there are other factors causing "your friend" to have this hate for the BB turbo.

 

Limpmode, my friend has nothing against him; someone on the forum kept tellin him they're bad, have short lifespan, etc etc.

Oh and I PMed ya

Farhan, I know, I know. Only DAYS left...promise

~Ramy

 

hey dude, i think your friend is full of ****.

 

BB turbos require a little better "care and feeding" than journals, especially in the cleanliness and supply rate/pressure of oil departments. If you botch that they won't last long on anything, and given their lack of repair options its easy to scare people away from them.

 

On an FD ball bearing turbo application it is best to have both oil and water cooling of the turbo.

Also, rebuilds on BB turbos are quite a bit more expensive, almost as much as the cost of the turbo, as alluded to earlier in the thread.

Ramy, your friend is misinformed. Perhaps if only oil cooled they won't last.

 

I very much agree

 

The ball-bearing, oil-cooled, non-water-cooled RX6 turbo has proven itself to last on the rotary.

-Max

 

Hooray Ball Bearing!

 

The hotside on that one is smaller than a gorilla's ********, it doesn't count

 

https://www.rx7club.com/showthread.p...earing+failure

 

http://www.wavsite.com/sounds/18252/fletch12.wav

 

CMonakar, thanks for the link. Looks like the failures were related to human error, not poor quality or reliability.

 

The Garrett GT series turbos will die prematurely if not water cooled as well as some other bb turbos. I find it amazing seeing some people being too lazy to run water lines to a turbo that aleady has provisions for them.

 

I've seen them fail within hours without water hooked up to them. Garrett will not warranty those failures either. That failure was on a EVO, I will not install any that way.