What's the difference between normal tubros and DBB, I've tried to research the forums here about dual ball bearings but I haven't found to much.

 

DBB "Dual Ball Bearing" turbos have just that.... ball bearings.

for example the turbo wheels obviously sit on them for turning. The ball bearing design is like 2 cirlces... one bigger and one smaller and small ***** in between to reduce friction when turning.

its the same as a bearing on a skateboard... or suspension system of a skateboard........ theres the truck (axel for skateboards) then the bearing goes on... and the wheel on top of that.

heres a couple of good links that will show you examples.
http://science.howstuffworks.com/bearing1.htm
http://science.howstuffworks.com/bearing3.htm


on turbos... theres dual ball bearing or journal bearing. DBB is usually about 8% faster in spooling (someone can correct me on the number... but its close)..... so a DBB turbo would spool up roughly 300-500rpm quicker than a journal bearing turbo.

on garrett turbos... the "R" at the end of the turbo model number means that its a DBB.
for example.... a GT35R is DBB, but a GT3574 is not.... btw the "74" is the turbine size or "exducer"

on HKS turbos..... the TO4R and TO4E are journal bearing and the TO4Z is DBB

generally the DBB turbos cost just a little more than journal bearing turbos.

- Artin

 

I did a notice link while snooping around that had different dyno graphs with different turbo setups, and I noticed a difference in the spool time with DBB...Turbos.

But your explanation cleared it up so much more. The break down of the different model of tubro's to know which are dual bearing helps a lot to.

Thanks.

 

lurking around the single tubro section for a while will answer alot of questions in the future.... but if you have anymore just PM me

 

Generally DBB turbos cost quite a bit more than journal bearing turbos, like $500 or so.

 

Ball bearings are more robust as well. They can handle thrust and radial loads much better than conventional brass journal bearings.

They have about 6% better turbine efficiency in transient response, but only about 3% in steady state conditions.

The ball bearing cartridges are one of the most expensive parts in the whole turbo.

Kevin

 

To date it's you can't buy just the center section. You must purchase the entire turbo. Which makes it an expensive initial proposition.

 

Thanks for all your input, it's appreciated. Right, no unfortunately I don't have an FD3 at the moment (18 wheeler hit mine 12 - 10 - 06) and I'm looking at purchasing another this year.

Some of the cars i'm interested in come with the single conversion and a dbb turbo, I just want to be as informed about them as I can be.

Although with 7s, it seems there's so much to know, being prep'd for everything is almost impossible unless you acheive the title of Guru j/k... Kudos to those who are there . I'm glad I learned about this community it's really helped me learn a lot.