Member Since: 05 May 2016
Location: hertfordshire
Posts: 250
i never go above 2000-2500rpm untill my engine has warmed up - oil reached optimum viscosity and temperature.
i would also always let the engine idle for at least 30 seconds before i turn it off on whatever journey and where i have done 100-200plus miles, i would let the engine sit idleing for around 5 mins - this has been out of habit amd what i have been tought.
18th Nov 2021 8:16 am
sasdiscos
Member Since: 22 Feb 2013
Location: Northants
Posts: 889
Turbos can run from 300 to 500 and anything up to 1200 deg c. Do you think 30 seconds is going to do anything to cool down a turbo?
Any modern engine will run under many conditions and take a lot of abuse.
Apart from a land rover engine!
Steve.You remind me of a younger me, not much younger mind...perhaps even a little older!
18th Nov 2021 8:21 pm
will.i.am
Member Since: 05 May 2016
Location: hertfordshire
Posts: 250
Better than stopping and turning it off straight off........
Older journal bearing turbos it was a lot more critical to let them spool and cool down. They could damage the bearings if shut off with the turbine doing anything other than idle speed due to oil pressure disappearing. These style of turbos also relied on the oil flow for cooling of the core. If shut of while hot these could cook the oil and cause coking within the bearing core.
Newer ball bearing turbos don't require anything near the oil flow to stay lubricated as ball bearings don't require all that much oil to stay lubricated - its much less than you would think. So shutting them down while the turbo is spinning is no where as detrimental to the bearings as a journal bearing. And due to the lack of oil flow most of these are also water cooled which should keep the core cooler and reduce the chance of oil coking in the bearing.
So I'm not saying you dont need to let the turbo's spool down and cool - its still good practice to do this, but its no where near as critical as it once was.
19th Nov 2021 5:12 am
Sidewaysste
Member Since: 10 Oct 2021
Location: Pinxton Nottinghamshire
Posts: 25
Has nobody mentioned the difference between sleeve and rollerball bearing chras?
A sleeve bearing turbo required oil pressure to prevent metal to metal contact in much the same way as the shells in an engine. Turbos take a period of time to decelerate and at full boost will be spinning somewhere in the region of 180,000 to a quarter of a million rpm.
The idea behind the idle period before shutdown was to allow the turbos to return to idle speed and from that to 0 rpm would be a much shorter space of time so the amount of time without adequate bearing lubrication and support would be reduced to a minimum.
Nearly all modern turbos use roller ball bearings which operate on a completely different principle, yes they require oil but not a a high pressure, they can run quite happily with little to no oil pressure so long as there is still some oil and they're not running dry. hence it isn't critical to allow the misnamed cooldown period. That and they tend to be water-cooled which prevents hotspotting.
11th Jan 2022 6:35 pm
forest66
Member Since: 04 Jan 2021
Location: Lymington
Posts: 85
back in my ren 5 turbo days we let it tick over if its been a hard run and you come to quick stop, it went that if you shut off quickly the oil would stop and the turbo will spin on and heat the shaft up and trash the bronze bearings and shaft ,
i used to work for uk turbos building them and fitting them back in the late 90s,
the boss drummed in to us all the importance of the 30 second rule at start up, and stop, this was for the higher revving petrol engines with bronze bushes, and his shoddy turbos built with used parts at times
derv motors there wasnt any real need back then they were lower revving , in fact i dont remember seeing a blued shaft on a derv turbo,
modern oil pumps are very good , but it cant hurt to do if you want modern dervs are higher revving than they used to be.
the 30 sec rule is what you want to do if you want to try it,
tick over for 30 sec at start up same at stop and job is a goodun that is all you need to do
i dont bother with it these days no need imo on modern turbos, unless its being shagged about maybe, , i dont race around in my d3 it does tick over before use and when i pull up which is plenty good enough i plod mostly like the lord of the manor!
11th Jan 2022 9:31 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5052
I was in Toyota dealership a few days ago when the service manager showed me a turbo from a car that was not producing even scintilla of boost.
It looked fine, very little end float, and was surprisingly clean too. It was only when I spun the impeller I then noticed the turbine was stationary. Snapped shaft, although the turbine did move freely even if it was independent of the impeller. yµ (idµ - eAµ) ψ=mψ
11th Jan 2022 9:53 pm
Justme
Member Since: 09 Aug 2015
Location: Pwllheli North Wales
Posts: 104
robpenrose wrote:
So how do modern turbos and stop start work then? Do they have something in place to protect turbos?
NJSSAm I Gammon or Woke ? - I neither know nor care.
2016 Discovery 4 Landmark
2011 Mercedes Benz SL350 (R230)
1973 MG B GT V8 - 3.9L John Eales engine, 5 speed R380 gearbox, since 1975.
1959 MGA roadster - 1.9L Peter Burgess Engine - 5 speed gearbox
Past LRs - Multiple FFRs, Discos & a Series I - some petrol, some diesel,
none Electric or H2 fuel cell - yet.
There are 10 types of people in this world: Those who understand binary, and those who don’t.
12th Jan 2022 8:21 am
Justme
Member Since: 09 Aug 2015
Location: Pwllheli North Wales
Posts: 104
No idea but I know some cars do have them.
Or was it an elec coolant pump in addition to the main pump that cooled the turbo my old astra J ecoflex had?
Some EVs certainly have electric pumps to lubricate transmissions & to replace the vacuum servos we see on ICE vehicles.
I'm not aware of any JLR ICE vehicle with an electric oil pump, but I stand to be corrected.
NJSS
12th Jan 2022 10:45 am
Justme
Member Since: 09 Aug 2015
Location: Pwllheli North Wales
Posts: 104
NJSS wrote:
Quote:
Electric oil pumps to the turbo.
Which LRs have such electric pumps please?
NJSS
I never said any Landrovers did.
Was not aware that we cant talk about other cars in here
12th Jan 2022 11:01 am
Dondiddy
Member Since: 26 Dec 2019
Location: Hamilton
Posts: 309
Does that mean that I can`t mention that my Volvo XC60 T8 has an electric oil pump as the ICE is constantly stopping and starting during normal running as it switches between the ICE and battery power?
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