1fastxz

iTrader: (16)

Trying to decide if it worth spending the extra money on upgrading to ball bearing
car is a DD street car with with A/C and all.

I know the ball bearings use a lot less oil and spens a lot easier.
Also heard they are more reliable then Journal bearing
But witch bearing would be better cooling?
coming from a journal bearing that was water cooled. Didn't have any issues with them

The upgrade for my APS kit don't have water cooled center section

Car is not a track only car and sees alot of long distance driving and street driving.

Looking to make 1000-1200 rwhp

stevieturbo

Unless you're running a lot of boost and need the faster transient response, then there will be little real benefit over a good oil journal unit.

But if you're happy to spend the money, then there arent any real downsides either.

Kmspeedie

iTrader: (1)

for a street car i assume you want as little lag as possible, and ball bearing will help that tremendously!! Only downside is when a journal bearing turbo goes bad they can be rebuilt easier, where as a ball bearing unit is just kind of done.. but i ran a ball bearing single turbo and looooved how quick it spooled.. worth it to me

stevieturbo

Precision BB's can be rebuilt. Garret can not. Not sure of other brands.

And I think an expectation of it helping "tremendously" is being a little optimistic

etijsma

I would of never gussed the garrett's couldn't be rebuilt. I've only been around journal bearings turbos so im rather uneducated on BB units. What is it about they that they can't? Seems rather dumb.

stevieturbo

Something to do with their bearing cartridge I think. It goes together ok....it just doesnt come apart again.

That's why you see a lot of upgrade or replacement units sold as a centre core with no compressor or turbine covers.

1fastxz

iTrader: (16)

OK cool not planning on running over 22 lb on the set up ever
will be between 14 and 18 lb most of its life.
Have a good oiling system on the car with a scavenging pump that had worked flawless.
Changed out the turbos on a APS twin kit to some 62/66 units
Motor is 403 so don't think I'll have a issued spinning then up.

Kmspeedie

iTrader: (1)

I went from a BB unit to a borg warner journal, i gained about 70 cubic inch and only 5mm on the compressor wheel and of course a lil larger a/r, but to me id pay for a BB upgrade if borg offered it 10/10 times because i do see a tremendous difference especially when were talkin street car. just my opinion though.

stevieturbo

So on a like for like, back to back test. What difference in spool and transient response did you see ?

Kmspeedie

iTrader: (1)

347 bone stock with a 7575 tnetics ball bearing full boost around 3200 rpm

Now
TMS 416 LS3 with custom cam
still a t4 turbo, S480 billet wheel and full boost around 4200rpm

was hoping with staying t4 and a smaller compressor wheel id have right around the same setup full boost wise, around 3-3500 rpm's but it didnt happen..

But now that im makin alot more power the little bit of lag is ok i guess, it does give the tires a sec to hook and it pulls like a freight train.

End of the day though id of bought a BB upgrade if available, and i feel itd drop it to 3700rpm or so for full boost with my exact same setup.

Ive always gone by BB will have a 10-15% better response time when comparing the same turbo

stevieturbo

So no actual valid results for either boost threshold or transient response.

I'd say a 500rpm difference in boost threshold would be optimistic, but if you happened upon a very good combo you may get that lucky.

Obviously for a single application, additional cost is much less so easier to justify, with twins the cost is double.

There would need to be really good evidence of gains for many to warrant the extra cost, and even then it would depend on actual usage of the vehicle.
If there are few on-off-on throttle scenarios etc then if there are gains, the user might never actually see them anyway. eg auto trans. Obviously a manual trans car stands more chance. If drag only use again less potential benefit, for other types or racing perhaps more chance of benefit.

If I'd excess money myself, I'd choose the BB option, but when always on a budget, I havent seen enough evidence that they would offer real benefits to me, and I do see those same on-off-on throttle events whether road racing, track racing etc etc.
I always have power on tap and response is very good.

But I 'm pretty certain there isnt a chance they'll gain me 500rpm in boost threshold.

Kmspeedie

iTrader: (1)

Basically OP, if you have enough $$ and want a spool that will start a couple hundred rpm earlier, go BB.
But journal is just as good to me. I went BB to journal lol and still love it, i thought i wouldnt. But about fixing them. Many local shops familiar with assembling turbos can rebuild Journal turbos, which about a $2-300 fix. Whereas BB units have to be sent to the manufacture like precision where they charge around $700-800.
At the end of the day journal turbos will suit your needs,but BB will give you a slightly faster spool. Then again you have big Cubic inch and small turbos so in your setup itd probly be about a 200rpm difference

1fastxz

iTrader: (16)

cool I ended up ordering a set of PT6766 turbos for my 403. should give me some room down the road when every I build a 4L80 for my car.