UA-44735833-1
Nissan Qashqai Owners Club UK Homepage
Forum Home Forum Home > Qashqai Care and Technical Information > Diesel Heads > 1.5 diesel
  New Posts New Posts RSS Feed - turbo boost
  FAQ FAQ  Forum Search   Register Register  Login Login

Nissan Qashqai Club


turbo boost

 Post Reply Post Reply
Author
Message
chrisw99 View Drop Down
Tekna
Tekna


Joined: 16áJaná2013
Location: Cheshire
Status: Offline
Points: 893
Post Options Post Options   Thanks (0) Thanks(0)   Quote chrisw99 Quote  Post ReplyReply Direct Link To This Post Topic: turbo boost
    Posted: 22áJaná2013 at 2:12pm
Having only ever driven petrol engines for 25+ years, this is my first ever experience of diesel/turbo.
 
The first thing I am finding is that I am changing gears up more quickly. Say I'm turning right at a crossroads, in the petrol I would probably have turned right before I change from 1st to 2nd.  Now I find in the 1.5 dci I am changing into second shortly after accelerating, so I'm ready to go from 2nd to 3rd by the time I would be changing up to 2nd in the old days!
 
All good stuff, it's putting the fun back into driving again.
 
One thing that intrigues me reading through a lot of the threads on here is this turbo boost, or the turbo kicking in
 
My question ... how would I know when this happens, that it is happening when it's supposed to, etc?  Is it just something you "feel"? 
 
If pulling away on a straight, at what RPM point do most shift their gears, and at what points should the turbo kick in?  Or would it not during normal acceleration, is it more of a kick when needed (overtaking?)
 
Thanks in advance for educating a diesel noob..
 
Back to Top
Craigfishin View Drop Down
Admin Group
Admin Group
Avatar
Prestige Detailing

Joined: 31áJaná2010
Location: bucks
Status: Offline
Points: 22590
Post Options Post Options   Thanks (0) Thanks(0)   Quote Craigfishin Quote  Post ReplyReply Direct Link To This Post Posted: 22áJaná2013 at 2:43pm
1st in a diesel is just to get you moving really so yes its a lot different to petrol 

its not a kick as such you feel unless you floor it then you will feel the slight lag before the turbo kicks in and away you go  , you can hear the turbo whistle if you have a window open
2010 1.5dci Tekna in Nightshade,2013 1.5dci Tekna arctic white with stone leather interior, 2016 1.2 auto in nightshade ,detailer at prestige car detailing
Back to Top
chrisw99 View Drop Down
Tekna
Tekna


Joined: 16áJaná2013
Location: Cheshire
Status: Offline
Points: 893
Post Options Post Options   Thanks (0) Thanks(0)   Quote chrisw99 Quote  Post ReplyReply Direct Link To This Post Posted: 13áMayá2013 at 10:52am
Now it's got warmer and the window has been down, I've been hearing this whistle a lot more.  I know it's normal as I hear it on most other Qashqai's that drive past me, and the occasional Renault etc
 
Just wondering what causes it?
 
It doesn't seem to match the same time as the turbo spool up sound (the woo wooo spooky ghost noise you get around 1.5k revs that goes higher with revs and lower when you take your foot off), unless that isn't the turbo spool and something else?
Back to Top
chrisw99 View Drop Down
Tekna
Tekna


Joined: 16áJaná2013
Location: Cheshire
Status: Offline
Points: 893
Post Options Post Options   Thanks (0) Thanks(0)   Quote chrisw99 Quote  Post ReplyReply Direct Link To This Post Posted: 13áMayá2013 at 11:56am
Just asked the know-it-all guy at work, we all have one who seems to know everything even though he's usually wrong!
 
Anyway, he says the whistle we all know and love is pressurised air escaping - exactly the same as the old kettles to let you know they've boiled, which is true I suppose, it does sound exactly like that.  Which is why you get it usually only at low revs, low speed, it's when the pressure has built but turbo hasn't really been needed so it has to let off a bit of steam (literally). 
 
You don't really hear it at all at higher speeds/revs, that's when the turbo does actually spring into life and you hear the telltale woo wooo wooooo noise of it spooling up.
 
I wonder why they they make it whistle so much when it lets off the pressurised air, surely these days they could make it do that silently!
Back to Top
hundleton1 View Drop Down
Tekna
Tekna


Joined: 04áMayá2011
Location: Milford haven
Status: Offline
Points: 33
Post Options Post Options   Thanks (0) Thanks(0)   Quote hundleton1 Quote  Post ReplyReply Direct Link To This Post Posted: 01áAugá2013 at 8:50am
The whistle you hear is the turbo spinning and the noise from it rotation at such a fast speed, your man at work is slightly wrong.

What he is refers to is called dump noise and its not normally noticeable on a diesel as its runs a far lower boost than a Petrol and does not have a dump valve to release air into the air

Your turbo will start to give you noticeable power at 2500rpm onwards. Its spinning all the time but below that its not really making enough boost to make any benefit that why you get the lag you can get when flooring it at low rpm.



Edited by hundleton1 - 01áAugá2013 at 8:52am
Back to Top
chrisw99 View Drop Down
Tekna
Tekna


Joined: 16áJaná2013
Location: Cheshire
Status: Offline
Points: 893
Post Options Post Options   Thanks (0) Thanks(0)   Quote chrisw99 Quote  Post ReplyReply Direct Link To This Post Posted: 01áAugá2013 at 9:21am
Thanks for the explanation - so if the high pitched whistle heard from outside is the turbo spinning, what is the woo woo whine you hear from inside at 1600 -1800 rpm that is also usually attributed to turbo spool, and happens at different times to the whistle?
 
Is that because a turbo has two things that spin - the compressor and the turbine?
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.078 seconds.