JB Red> BB BBK-B (spool difference?)
#18
Evolved Member
iTrader: (125)
No offense...but I'm going to bet they have equipment to measure such a thing much much more sophisticated then you do which proves their information correct, otherwise I doubt they are in the business of publishing false information
now, it maybe for a specific situation hahahahaha
now, it maybe for a specific situation hahahahaha
in the end the reason they say there is a 15% gain is because outside this forum the term spool is used to describe both spool and transient response. when you group the two terms together the statement works.
I could give you a more technical reason why there is no spool gain but dont have the 10 minutes to give you. if you want to go on believing there is a spool gain because garrett said so feel free to do so.
#19
Evolved Member
iTrader: (8)
Then you toss in the common reference of spool and you' e just been fooled.
I dont exactly agree that they are exact. Anytime you remove friction it will increase accell. However it wont be remotely noticable so for arguements sake i will stick with they spool the same.
#21
Evolved Member
iTrader: (8)
Then you toss in the common reference of spool and you' e just been fooled.
I dont exactly agree that they are exact. Anytime you remove friction it will increase accell. However it wont be remotely noticable so for arguements sake i will stick with they spool the same.
#22
Former Sponsor
iTrader: (1)
That Garrett quote to my knowledge was published when their Ballistic line of Ball Bearing CHRA's were first released which means they would have been comparing it to 40 year old journal bearing turbo technology and probably a p-trim or q-trim wheel which would have been larger than the GT30R and 35R's they would have been comparing them too. So that number is skewed by a lot and you'll find if you take a like sized turbo in jb and bb and test them you will never see 15% better initial spool response in real world testing. You might be able to replicate it on a test stand with some "wizardry" but put it on a car and you wouldn't notice.
The reason BB offers better transient response is that it doesn't slow down as much when you let off the throttle it retains more inertia (shaft speed) so that when exhaust is reintroduced at a high rate it doesn't have far to go to reach it's target shaft speed.
-Michael
The reason BB offers better transient response is that it doesn't slow down as much when you let off the throttle it retains more inertia (shaft speed) so that when exhaust is reintroduced at a high rate it doesn't have far to go to reach it's target shaft speed.
-Michael
#23
Evolved Member
iTrader: (50)
Anyways, get a BB, different ball game in around town driving, not even a discussion. Drag racing when the turbo is spooled it stays so for a reasonable amount of time between shifts so you are in boost longer.
Initial spool-up? Not an ounce of change.
#24
Evolved Member
iTrader: (50)
That Garrett quote to my knowledge was published when their Ballistic line of Ball Bearing CHRA's were first released which means they would have been comparing it to 40 year old journal bearing turbo technology and probably a p-trim or q-trim wheel which would have been larger than the GT30R and 35R's they would have been comparing them too. So that number is skewed by a lot and you'll find if you take a like sized turbo in jb and bb and test them you will never see 15% better initial spool response in real world testing. You might be able to replicate it on a test stand with some "wizardry" but put it on a car and you wouldn't notice.
The reason BB offers better transient response is that it doesn't slow down as much when you let off the throttle it retains more inertia (shaft speed) so that when exhaust is reintroduced at a high rate it doesn't have far to go to reach it's target shaft speed.
-Michael
The reason BB offers better transient response is that it doesn't slow down as much when you let off the throttle it retains more inertia (shaft speed) so that when exhaust is reintroduced at a high rate it doesn't have far to go to reach it's target shaft speed.
-Michael
What about the friction a JB provides Vs. a BB? Is there anything in there to hurt spool-up in a 100% completely healthy turbo?
#25
Evolved Member
Thread Starter
iTrader: (1)
Join Date: Mar 2005
Location: Mesoamerica/ SF Bay Area
Posts: 7,905
Likes: 0
Received 5 Likes
on
5 Posts
Probably this is OT, but the question about frictional losses and the lower friction of ball bearings vs. Journal bearings, reminded me about my daughter's roller hockey skates.
The wheels on those skates didnt originally come fitted with ballbearings. So, we used to swap out the OEM wheel bearings for aftermarket, replacement, ceramic ballbearings.
I just remember the night and day difference in how the ballbearings allowed her to sustain her coasting speeds when skating. With the ballbearings she could effortlessly sustain her coasting speed whereas, by comparison, with the non BB wheels she could not sustain speed while coasting. This kinda jives with what FP's Michael stated above.
The wheels on those skates didnt originally come fitted with ballbearings. So, we used to swap out the OEM wheel bearings for aftermarket, replacement, ceramic ballbearings.
I just remember the night and day difference in how the ballbearings allowed her to sustain her coasting speeds when skating. With the ballbearings she could effortlessly sustain her coasting speed whereas, by comparison, with the non BB wheels she could not sustain speed while coasting. This kinda jives with what FP's Michael stated above.
Last edited by sparky; Mar 21, 2013 at 12:36 PM.
#27
Former Sponsor
iTrader: (1)
Probably this is OT, but the question about frictional losses and the lower friction of ball bearings vs. Journal bearings, reminded me about my daughter's roller hockey skates.
The wheels on those skates didnt originally come fitted with ballbearings. So, we used to swap out the OEM wheel bearings for aftermarket, replacement, ceramic ballbearings.
I just remember the night and day difference in how the ballbearings allowed her to sustain her coasting speeds when skating. With the ballbearings she could effortlessly sustain her coasting speed whereas with the non BB wheels she couldn't coast at all.
The wheels on those skates didnt originally come fitted with ballbearings. So, we used to swap out the OEM wheel bearings for aftermarket, replacement, ceramic ballbearings.
I just remember the night and day difference in how the ballbearings allowed her to sustain her coasting speeds when skating. With the ballbearings she could effortlessly sustain her coasting speed whereas with the non BB wheels she couldn't coast at all.
If you were to push your daughter up to 5mph the initial force required would be the same from bearing system to bearing system though. Unless you changed the weight of the person, incline, head wind, etc.... then the intial force would remain constant.
-Michael
#30
Evolved Member
Thread Starter
iTrader: (1)
Join Date: Mar 2005
Location: Mesoamerica/ SF Bay Area
Posts: 7,905
Likes: 0
Received 5 Likes
on
5 Posts
Would the rate of spool be identical on two identically configured turbos differing only in the bearing type? One of the two turbos spinning on journal bearings whereas the other spins on ball bearings.
.
.