940 S turbocharger life expectancy

[XC90Mk1]

Originally Posted by Clan

petrol exhaust temperature can be up to 800C hence glowing manifolds if you are on boost / full power for too long .

Diesels run at much lower temperatures because more of the energy is burnt in the combustion chamber , typicaly 200C when cruising along . A regeneration goes to a maximum of 600C to burn off the particles from the particle filter . the gas does not get that hot in normal use .

200c are you sure about that?

[Clan]

Originally Posted by XC90Mk1

200c are you sure about that?

yes , why don't you monitor your own parameters ? A £5 Bluetooth OBD II sender and "Torque" application on an android device ..

haven't you noticed if you start a diesel and let it idle for 15 mins you can still touch the manifold ?

[Laird Scooby]

Originally Posted by Clan

yes , why don't you monitor your own parameters ? A £5 Bluetooth OBD II sender and "Torque" application on an android device ..

haven't you noticed if you start a diesel and let it idle for 15 mins you can still touch the manifold ?

I couldn't with the last diseasel i owned!

I am curious though, both petrol and diesel burn at about the same adiabatic temperature of 2100C ish so how does the diesel engine manage to reduce this to 200C? Also the auto-ignition point of diesel is higher than petrol so the temperature needs to be higher to start with, hence the higher compression. I did look those temperatures up as well but can't remember what they were now.

Interesting the OBD_II system monitors EGT, never thought they'd do that on a production car.

[indigo]

My first 940 was in poor shape and had been thrashed when it was scrapped at 135k the turbo was shot. I bought my current 940 from a old lady who had It almost her whole life and looked after it well. It had a 165k and after inspecting the turbo its mint. Its all down to servicing!

[tofufi]

Originally Posted by Laird Scooby

I couldn't with the last diseasel i owned!

I am curious though, both petrol and diesel burn at about the same adiabatic temperature of 2100C ish so how does the diesel engine manage to reduce this to 200C? Also the auto-ignition point of diesel is higher than petrol so the temperature needs to be higher to start with, hence the higher compression. I did look those temperatures up as well but can't remember what they were now.

Interesting the OBD_II system monitors EGT, never thought they'd do that on a production car.

I'm no emissions expert, but it's definitely true that diesels have significantly lower EGTs than petrol. Perhaps it's because they normally run very lean, so there's a lot more air to heat throughout the cycle - but that's a total guess

[LPTJoe]

Yup, aside from the Volvo we run two VAG diesels (A Mk4 Golf and a Lupo), they run at a fraction of the temperature of petrol stuff I've had.