Journal Bearing vs Ball Bearing - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Insert BS here A place to discuss anything you want

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 03-28-2008, 11:13 AM   #1
Elite Member
Thread Starter
iTrader: (9)
 
Saml01's Avatar
 
Join Date: Jul 2007
Location: NYC
Posts: 5,730
Total Cats: 2
Default Journal Bearing vs Ball Bearing

I am a bit confused. So journal bearing turbos have only one bearing in a grove while ball bearing turbos have packed bearings surrounding a shaft?

Why don't turbos just use the same type of bearings that engines use? Which aren't really bearings at all, the crank and rods are separated by a film of oil.
Saml01 is offline   Reply With Quote
Old 03-28-2008, 11:26 AM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

Quote:
Originally Posted by Saml01 View Post
Why don't turbos just use the same type of bearings that engines use? Which aren't really bearings at all, the crank and rods are separated by a film of oil.
that's what a journal bearing is...its a brass sleeve with holes in it...


BB turbos spin for about 37 minutes after you shut the car off, journal bearings...maybe .5sec.

Braineack is online now   Reply With Quote
Old 03-28-2008, 11:27 AM   #3
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,796
Total Cats: 248
Default

Quote:
Originally Posted by Saml01 View Post
I am a bit confused. So journal bearing turbos have only one bearing in a grove while ball bearing turbos have packed bearings surrounding a shaft?

Why don't turbos just use the same type of bearings that engines use? Which aren't really bearings at all, the crank and rods are separated by a film of oil.
I hate quoting Wikipedia but it will be fine for this discussion, as I don't think bearings is a highly debatable subject.

Quote:
A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can handle.
Our engine uses journal bearings/fluid bearings.
patsmx5 is offline   Reply With Quote
Old 03-28-2008, 11:33 AM   #4
Elite Member
Thread Starter
iTrader: (9)
 
Saml01's Avatar
 
Join Date: Jul 2007
Location: NYC
Posts: 5,730
Total Cats: 2
Default

Quote:
Originally Posted by Braineack View Post
that's what a journal bearing is...its a brass sleeve with holes in it...


BB turbos spin for about 37 minutes after you shut the car off, journal bearings...maybe .5sec.

OHHHHHH.

Well that clears everything up.

Thanks Pat, Fluid Bearings explains everything as well.

I was confused this whole time.

This also explains why oil pressure is so important to journal bearing turbos.

You guys are great.
Saml01 is offline   Reply With Quote
Old 03-28-2008, 09:58 PM   #5
Senior Member
 
Join Date: Mar 2006
Posts: 1,379
Total Cats: 1
Default

Quote:
Originally Posted by Braineack View Post
that's what a journal bearing is...its a brass sleeve with holes in it...


BB turbos spin for about 37 minutes after you shut the car off, journal bearings...maybe .5sec.

This graph shows how BB turbos are superior, but not that superior! Once under boost, the bearing matters naught. Thanks, I'll take the cheap *** rebuildable at home sleeve bearing unit. After 2 seconds, it's all about the $1,000 I saved.

Mark
Markp is offline   Reply With Quote
Old 03-28-2008, 11:01 PM   #6
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Quote:
Originally Posted by Markp View Post
This graph shows how BB turbos are superior, but not that superior! Once under boost, the bearing matters naught. Thanks, I'll take the cheap *** rebuildable at home sleeve bearing unit. After 2 seconds, it's all about the $1,000 I saved.

Mark
point two?
y8s is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
Odd Steering issue interestedofold Suspension, Brakes, Drivetrain 5 09-29-2015 02:42 PM
Another Alternator thread ihiryu General Miata Chat 9 09-28-2015 11:22 AM
Auto Engine into Manual Car Wino General Miata Chat 0 09-23-2015 09:35 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 07:10 PM.