Carbon deposits
 

Mark, my Z4 has the 1M engine.
Yesterday I cleaned the carbon deposits from the intake valves. They were in tragic condition with only 60k km on the clock.
What is the mileage of your 1M ?

I am thinking water injection kit for M5 and Z4 now...

This issue seems to be the dirty secret of all direct injection cars.

I wont have to worry about it alex its only done 13,000:thumbs:
Thinking about adding an oil catch can

This is part of the reason I have always only run my performance cars on Shell Optimax / V-Power Nitro + (or what-ever they call it in your part of the world).

Not only is it supposed to be a minimum of 98 RON (their COSHH data sheet quotes 98.7 RON), the additives they use keep the intake plenum / combustion chambers much cleaner than other fuels.

I don't think water injection is the answer on an atmo car as it will only work if the charge temps are sufficiently high (i.e. on a turbo car) to create the correct atomisation, otherwise all you will do is induce a misfire (fire and water don't mix LOL) AND reduce power. In the Cossies we use both charge temp and boost level parameters as trigger points for the water injection to prevent a significant loss in performance. This is because injecting water into the combustion process WILL cause a reduction in power, but if injected within the correct parameters will mean that the loss will just be less than if the ECU saw charge temps that would result in ignition and/or boost being pulled out of the engine to prevent det that high charge temps would see. So is just a way of managing the charge temps when the intercooler / charge-cooler cannot keep these within the ideal performance range.

The trigger points we use are 42°C AND 7psi. So the ECU has to see above both those figures before it triggers the relay to fire up the water injection pump. Any less than this temp and the water fails to atomize properly, any higher and the charge temps tend to take more time to drop back into the optimal sub 40°C zone. Obviously the boost parameters are so that the water isn't being injected into the engine when it doesn't need it (heat soak situations for example, where the engine bay / intake plenum can see 70°C temps when the car is restarted after a short period following sustained high load usage.

Obviously this is where just water is used, drag cars use methanol / toluene mixed with the water, which not only have cooling properties, but can help with the combustion process. Unfortunately, these are highly corrosive to aluminium and are not the sort of things I would be running on a road car (although it seems to be the norm in the USA, but I have no idea on the mix levels).

Mike did you read my post?

Nothing of what you wrote relates. :whistle:
The z4 35is has the N54T engine.
It is direct injected and twin turbo... Same engine with the 1M.
The fuel never sees the valves. So even though I run BP ultimate fuel (anyhow the car wants 98 octane or more) plays no role.

It is not a dirty secret, it is a well known issue with DI engines.

MC

For some reason, I got into my head you were talking about your Z3 track car LOL :whistle:.

At least you now have some target values to work with that were obtained from the factory Ford works teams :).

WMI will help with keeping the valves clean.