Advanced Driving Hub

chriskay wrote:Let's put an end to all the scientific hocus pocus: look at the question...when is it too much?. The answer is simple; when Silk says it is.

It took you long enough.

trashbat wrote:

michael769 wrote:The biggest issue that the moment is inlet valve carbon build up on direct injection vehicles. Both car manufactures and the oil companies are working to try to find a solution to the problem.

The problem of course is because of a lack of a wash effect from the fuel. Unless you could produce an oil that has no vapour, and even then you have exhaust gas recirculation to contend with, then neither fuel additive nor oil improvement will resolve anything. Some manufacturers have resolved it by reintroducing port injection for the purposes of cleaning.

I know plenty about this

That frightens me, takes me back to my youth and having to decoke stuff. There was I praising modern cars too.
Thing is, old style decoke was easy, modern engines much harder.

This is relevant to additives nonsense...

Do people find that more modern engines are becoming particularly fuel sensitive as they're mapped more precisely to certain fuels?

Just because I notice our Yeti will run, albeit with slightly less power and a much rougher idle, and is more lethargic in terms of being revved, whenever we put Sainsbury's diesel in it. However, putting Tesco diesel in results in a smoother idle, but the engine is very rough when being revved. When we put Shell diesel in it, it runs very smoothly and will happily rev to the red line without any weird behaviours such as flat torque spots etc. We've never put BP diesel in it but I suspect BP would give a better behaving engine.

Would the weird behaviours be attributed to the car being particularly fuel sensitive or just simply a bad batch of diesel?

WhoseGeneration wrote:

trashbat wrote:

michael769 wrote:The biggest issue that the moment is inlet valve carbon build up on direct injection vehicles. Both car manufactures and the oil companies are working to try to find a solution to the problem.

The problem of course is because of a lack of a wash effect from the fuel. Unless you could produce an oil that has no vapour, and even then you have exhaust gas recirculation to contend with, then neither fuel additive nor oil improvement will resolve anything. Some manufacturers have resolved it by reintroducing port injection for the purposes of cleaning.

I know plenty about this

That frightens me, takes me back to my youth and having to decoke stuff. There was I praising modern cars too.
Thing is, old style decoke was easy, modern engines much harder.

Terraclean appears to be the simple solution - no experience I hasten to add!

superplum wrote:Terraclean appears to be the simple solution - no experience I hasten to add!

For direct injection petrols, I have my doubts.

In fact I have my doubts more generally.

It's been a long time and there's not been any non-anecdotal evidence of it working, AFAIK.