Turbo Diesels?

[MrFlibbles]

Owning a car with a turbocharged petrol engine, i understand the importance of letting the turbo cool before turning off the engine.

However, is this the same for TDi engines? You never hear diesels owners saying "I'll be in in a sec, just got to let it idle for a bit!"

And the same for lorry drivers, they just switch straight off, and they must have massive turbos.

So, do diesels turbos run cooler, if so why? And if not, then why do people switch the engine straight off?

[wheeljack888]

Diesels do run at lower exhaust temperatures (roughly 100-200 deg C cooler) than petrols, a side effect of its better thermal efficiency. But any turbo engined car should sit at idle for a few secs to make sure oil pressure is still being fed to the turbo bearing whilst the turbo's decelerating.

[chuntington101]

most turn their engines off straqight away coz they have NO idea of what is under the bonnet, let allown that they are doing damage when they do this. same goes for the stupid short runs they take to the shop!

you have to remember 99.9% of car uses dont have any understanding of cars.

Chris.

[stevieturbo]

That whole thing is blown out of proportion.
Oils of yesterday were not as good as today, so that alone reduces teh chances of the oil baking inside the turbo on switch off. Also combined with water cooled housings, it really isnt a major worry.

[flooritforever]

What also isn't mentioned is that you shouldn't really use the turbo before the engine has warmed up and the oil is nice and warm and flowing properly. This is particularly true if your turbo has an oil bearing.

I'm suprised that manufacturers don't make a point of telling people this, especially with turbo diesels, as diesel oil is thick and heavy when cold, and AFAIK most turbo diesels have oil bearing turbos.

[stesrg]

Hi as i have had a variery of turbo diesels cars and vans, i have never had a problem and i thrash them, and switch off ign after stopping even on a motorway blast, never worried about such thing

Steve,,,

[agent006]

flooritforever said:

What also isn't mentioned is that you shouldn't really use the turbo before the engine has warmed up

That's the trouble, on my Skoda 2.0 diesel, the turbo is working from 1500 rpm and on full boost at about 1800. It's almost impossible to not use it.

[Tony427]

In the early 90's I had an Audi 100 Turbo running at 20psi boost. It came with an auxiliary fan that used to push cold air over the turbo when stationary and when switching the engine off to stop excessive localised turbo temperatures.

I used to thrape the thing through the country lanes around Melton Mowbray and Grantham where I lived and never let it idle down or cool down after a thrash.

I started getting a bit fed up of being kept awake in the early hours after coming in from a fast late night drive because the auxiuliary fan was still running on the turbo so I disconnected it.

I ran that car for 169,000 very hard miles and it ran perfectly, didnt miss a beat, and used hardly any oil with absolutely no turbo smoke..

All my mates used to deride me for not letting the Turbo spool down as they told me it would be running on dry bearings, but I have to say that it didnt do my Audi any harm.

My advice is just switch off, we have better things to do with our time than to sit in a car waiting for it to spool down ...........

Cheers,

Tony

[flooritforever]

agent006 said:

flooritforever said: What also isn't mentioned is that you shouldn't really use the turbo before the engine has warmed up That's the trouble, on my Skoda 2.0 diesel, the turbo is working from 1500 rpm and on full boost at about 1800. It's almost impossible to not use it.

Well, at least it means you don't have to wait an age before your engine actually has some power. My thing is terrible in that respect. Easy to give the engine a gentle warm up, a bugger to make it get a move on. If the engine could talk, as you go up through the revs it would be saying something like this:

750-1949 rpm: Ugh.
1950-2499: Alright I'm getting there.
2500-3499: Boost me, baby!
3500-3999: *puff* *pant* do I have to?
4000-redline: *GASP* For Gods sake *GASP* change gear!