Turbo is still spinning after engine off - GT-R Register - Nissan Skyline and GT-R Drivers Club forum

Want to buy a banner ad? Find out more here.

Go Back   GT-R Register - Nissan Skyline and GT-R Drivers Club forum > General > Nissan Skyline > Tuning: General
Register Garage FAQ Members List Calendar Search Today's Posts Mark Forums Read Insurance


Reply
 
LinkBack Thread Tools Rate Thread Display Modes
Old 14th August 2011, 09:54 PM   #1 (permalink)
MikeyB571 is unaware they can edit their status
GTR.co.uk seasoned Member
 
MikeyB571's Avatar
 
Join Date: Feb 2010
Location: Worcestershire
Posts: 593
Turbo is still spinning after engine off

I am hearing a sound when I turn my engine off that goes on for a few seconds, initially I thought it was an air leak but I now think that it is the front turbo spinning.
Would really appreciate some third party feedback, has anyone else noticed this on their car?
I think that this is happening because of the position the engine is in when it stops, so if piston 1,2, or 3 is in a position where it is just starting the exhaust stroke, then it could be leaking through the barely open exhaust valve and keeping the front turbo spinning for a short while.
It does sound a bit far fetch, but this is the only thing I can come up with.

Ideas anyone, please.
__________________
MikeyB571 is offline   Reply With Quote
Old 14th August 2011, 09:58 PM   #2 (permalink)
mattysupra is gutted he sold his R34 GTR S1
GTROC Member
 
mattysupra's Avatar
 
Join Date: Oct 2008
Location: Solihull
Cars owned: R34 GTR OMORI FACTORY SPEC S1
Posts: 3,585
LOL, its a healthy turbo. Its a good thing

You have uprated turbos to ball bearing i guess?

the reason why you can here the turbo spinning still is because of the revs it spins at and the bearing are in good condition and allowing it to free wheel until, well until it stops.
__________________
mattysupra is offline   Reply With Quote
Old 14th August 2011, 10:05 PM   #3 (permalink)
MikeyB571 is unaware they can edit their status
GTR.co.uk seasoned Member
 
MikeyB571's Avatar
 
Join Date: Feb 2010
Location: Worcestershire
Posts: 593
Quote:
Originally Posted by mattysupra View Post
LOL, its a healthy turbo. Its a good thing

You have uprated turbos to ball bearing i guess?

the reason why you can here the turbo spinning still is because of the revs it spins at and the bearing are in good condition and allowing it to free wheel until, well until it stops.

Awesome, thanks for the advice. I am really relieved.
They are Garret 2860-5's so ball bearing turbos, one less thing to worry about before my session on the rolling road .
__________________
MikeyB571 is offline   Reply With Quote
 
Old 15th August 2011, 03:04 AM   #4 (permalink)
jaycabs is skint for a long time :-#(
Official GTR.co.uk Photographer
 
jaycabs's Avatar
 
Join Date: Nov 2007
Location: https://www.flickr.com/photos/[email protected]/
Cars owned: R32 GTR
Posts: 2,671
lol use to hear that every time .

just think , your turbo's spin up to and over 250,000 rpm depending on what boost your running so it will take time for them to come down and thats exactly why you are ment to give them time to slow down before you turn off the engine

( or just have a turbo timer )
__________________
jaycabs is offline   Reply With Quote
Old 16th August 2011, 12:43 AM   #5 (permalink)
chaz_r33_gtr is mourning the sale of his car
GTROC Member
 
Join Date: Aug 2005
Location: Lancashire
Cars owned: R33 GTR VSpec, (Yamaha R1 - yeah its abike ) Rover216 GTI Beast!
Posts: 818
yup roller bearing turbos do this, normal journal bearing turbos slow down much quicker due to the higher friction on their bearings compared to roller bearing turbos.

Healthy roller bearing turbos will still spin after stopping the engine even if you just leave the car idling and then stop the engine.

Note: The turbo timer is not really to allow the turbos to slow down (due to the point about idling above), its more to allow sufficient oil and water to help cool the turbo core before you switch off after hard driving. (if you dont oil tends to bake on the bearing surfaces, carbonise and wear the bearings much quicker). Turbos that do not have water cooling are particuarily liable to this (your GT2860-5s are oil lubed/cooled and water cooled so dont worry!). I find its much easier to chill out your driving for the last few miles of your journey and let everything cool rather than use a turbo timer.
__________________
chaz_r33_gtr is offline   Reply With Quote
Old 16th August 2011, 01:11 AM   #6 (permalink)
DrGtr is unaware they can edit their status
GTR.co.uk seasoned Member
 
DrGtr's Avatar
 
Join Date: Jul 2009
Location: Cyprus
Posts: 1,773
Quote:
Originally Posted by jaycabs View Post
lol use to hear that every time .

just think , your turbo's spin up to and over 250,000 rpm depending on what boost your running so it will take time for them to come down and thats exactly why you are ment to give them time to slow down before you turn off the engine

( or just have a turbo timer )
250000 rpm?? i think thats too much you are saying i would say close to 100000+/-
__________________
DrGtr is offline   Reply With Quote
Old 16th August 2011, 02:06 AM   #7 (permalink)
jaycabs is skint for a long time :-#(
Official GTR.co.uk Photographer
 
jaycabs's Avatar
 
Join Date: Nov 2007
Location: https://www.flickr.com/photos/[email protected]/
Cars owned: R32 GTR
Posts: 2,671
Quote:
Originally Posted by DrGtr View Post
250000 rpm?? i think thats too much you are saying i would say close to 100000+/-
many different pages on the net say what some turbos can do , some ranging from 100,000 to 150,000 rpm and others like this saying its maximum of 250,000 rpm

Mitsubishi TD025 Specs | eHow.com

varies quite alot on boost pressures though
__________________
jaycabs is offline   Reply With Quote
Old 16th August 2011, 02:10 AM   #8 (permalink)
jaycabs is skint for a long time :-#(
Official GTR.co.uk Photographer
 
jaycabs's Avatar
 
Join Date: Nov 2007
Location: https://www.flickr.com/photos/[email protected]/
Cars owned: R32 GTR
Posts: 2,671
Quote:
Originally Posted by chaz_r33_gtr View Post
yup roller bearing turbos do this, normal journal bearing turbos slow down much quicker due to the higher friction on their bearings compared to roller bearing turbos.

Healthy roller bearing turbos will still spin after stopping the engine even if you just leave the car idling and then stop the engine.

Note: The turbo timer is not really to allow the turbos to slow down (due to the point about idling above), its more to allow sufficient oil and water to help cool the turbo core before you switch off after hard driving. (if you dont oil tends to bake on the bearing surfaces, carbonise and wear the bearings much quicker). Turbos that do not have water cooling are particuarily liable to this (your GT2860-5s are oil lubed/cooled and water cooled so dont worry!). I find its much easier to chill out your driving for the last few miles of your journey and let everything cool rather than use a turbo timer.
i was just being basic about the turbo timer lol

but agreed on chilling the driving down after a spirited drive as i use to do that too when i was driving my R32 at high speeds
__________________
jaycabs is offline   Reply With Quote
Old 16th August 2011, 04:14 AM   #9 (permalink)
GT-R Glenn is aware Veilsides street R32 gtr ran 8.612 @ 172.5 MPH (Radials)
GTR.co.uk seasoned Member
 
GT-R Glenn's Avatar
 
Join Date: Nov 2002
Location: Waiuku NZ
Cars owned: R32GTR /GSXR1300DatsunB310/ R33 / KTM / Gasgas / Type R EG Civic
Posts: 4,429
Actually it IS to let the turbo slow down ....
Or am I to assume its ok to turn off the oil supply to the bearing (s) with the turbo spooled up....if its cold ?

A good plain bearing turbo would seize if it was turning at anything much greater than what speed it runs at at idle, if you turned the oil pressure off to it...

The core cooling down is definatly correct, but the spindle speed is the most important thing prior to turning the engine off.
The ball bearings are just less pedantic about oil supply and more durable when abused ( by being turned off early)
__________________
GT-R Glenn is offline   Reply With Quote
Old 16th August 2011, 07:15 PM   #10 (permalink)
chaz_r33_gtr is mourning the sale of his car
GTROC Member
 
Join Date: Aug 2005
Location: Lancashire
Cars owned: R33 GTR VSpec, (Yamaha R1 - yeah its abike ) Rover216 GTI Beast!
Posts: 818
Quote:
Originally Posted by GT-R Glenn View Post
Actually it IS to let the turbo slow down ....
Or am I to assume its ok to turn off the oil supply to the bearing (s) with the turbo spooled up....if its cold ?

A good plain bearing turbo would seize if it was turning at anything much greater than what speed it runs at at idle, if you turned the oil pressure off to it...

The core cooling down is definatly correct, but the spindle speed is the most important thing prior to turning the engine off.
The ball bearings are just less pedantic about oil supply and more durable when abused ( by being turned off early)
yup agree about the shaft speed when you put it like that. I was thinking that most people dont get the turbos up to 100,000rpm and then just shut the engine off!.. usually there is some slowing down period coast to pits / car park etc and usually by that time the turbos have slowed down a lot!!.

Defo agree that rollerbearings are more tolerant to lack of oil, which is why they take a good few seconds to stop spinning when the engine is stopped whereas plain bearing turbos stop much more rapidly ( presumeably as the shaft touches the plain bearing surface as the oil film its suspended on drains away).
__________________
chaz_r33_gtr is offline   Reply With Quote
Old 16th August 2011, 07:54 PM   #11 (permalink)
MikeyB571 is unaware they can edit their status
GTR.co.uk seasoned Member
 
MikeyB571's Avatar
 
Join Date: Feb 2010
Location: Worcestershire
Posts: 593
What is actually happening is not that the turbos are spinning from a previous boost, I get this spin down even if I just start the car leave it to idle for 20 secs and the stop it. I don't even rev it and when it stops I get the turbos spinning.
I assume they will still spin up slowly on idle.
__________________
MikeyB571 is offline   Reply With Quote
Old 16th August 2011, 08:24 PM   #12 (permalink)
dan-hipgrave is Gtr-less
GTROC Member
 
dan-hipgrave's Avatar
 
Join Date: Nov 2008
Location: Hampshire
Cars owned: R33 GTR v-spec
Posts: 1,589
Yep, turbos will still be spinning on idle so you still get the noise even if you havent boosted the car at all.

I only got the 'spinning down' noise after upgrading to 2860-5's, like others have said above, its because they are roller bearing jobbies.
__________________
dan-hipgrave is offline   Reply With Quote
Old 16th August 2011, 08:25 PM   #13 (permalink)
MikeyB571 is unaware they can edit their status
GTR.co.uk seasoned Member
 
MikeyB571's Avatar
 
Join Date: Feb 2010
Location: Worcestershire
Posts: 593
Quote:
Originally Posted by dan-hipgrave View Post
Yep, turbos will still be spinning on idle so you still get the noise even if you havent boosted the car at all.

I only got the 'spinning down' noise after upgrading to 2860-5's, like others have said above, its because they are roller bearing jobbies.
Well, thats exactly what i've got. Thanks
__________________
MikeyB571 is offline   Reply With Quote
Old 16th August 2011, 09:21 PM   #14 (permalink)
blue34 is in a Fujimura Auto 32GTR
GTROC Member
 
blue34's Avatar
 
Join Date: Jul 2005
Location: Hampshire
Cars owned: R34GTR
Posts: 3,226
my 2835s spin down for about 5-10 seconds... when new or newly refurbished its a nice gentle whoooshhh as they spin down but as they get used and abused they get noisier as they spin down but don't be too alarmed by that.
__________________
blue34 is offline   Reply With Quote
Old 17th August 2011, 10:12 PM   #15 (permalink)
R.I.P.S NZ is down to 7.28 @ 197mph worlds quickest skyline GTR
GTR.co.uk seasoned Member
 
R.I.P.S NZ's Avatar
 
Join Date: May 2004
Location: Rotorua NZ
Cars owned: R32 GTS4
Posts: 6,560
To put your mind at ease watch from 2:25 to 3:00. 35 seconds to stop spinning from idle.

RIPS Drag-R walk round and on road - YouTube
__________________
RIPS is NZDRA Champion 2010/2011/2012, IHRA Champion 2011/2012
Worlds quickest and fastest RB30 6.99 and 192.7mph on the 1/4
CC/D, DD/D and EE/D NZ record holders and multiple track record holders with a street based RB30
Mild to wild RB30s, 7,8,9,10 sec street/drag cars built to order, custom fabrication, worldwide shipping

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
e-mail
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
R.I.P.S NZ is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 On
Pingbacks are On
Refbacks are On



All times are GMT. The time now is 11:20 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
http://www.Tyreforums.com

tyreforums

 

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.