KryptoniK

good points, I'm no expert on this but here is what I'm thinking...

with the supercharger installed, install a catch can for that blow-by and maybe it would equalize the cyclone operation with the added pressure...

R1ce

I posted this on the other forum, but figured I'd see if I can get any bites on this here:

I spent a lot of time looking into better PCV systems on my previous turbo cars to keep oil from getting into the combustion chamber. You can log the difference in knock voltage pretty easily when oil gets in there. Seems to me like there are two major items that could help prevent the oil buildup on the valves, and both options have many other benefits.

1 - A crankcase evacuation pump. This would eliminate the need for using the intake tract as a vacuum source. While these are mostly for drag racing applications, they do make a street version. This would be a belt driven unit requiring about 1HP to drive. The electric units either overheat too quickly or do not supply enough vacuum for any real benefit. With forced induction the benefits are much greater, as it prevents pressure from building up in the crankcase. Other benefits include no oil leaking out of seals, and a slight/modest HP increase. I haven't used one yet. Now just add a supercharger on the RS4....
http://www.dragstuff.com/techarticles/vacuum-pumps.html

2 - Methanol injection. I know that others have thought about this too. Methanol has some great cleaning characteristics aside from the obvious power bump from the added octane, and a cooler charge temperature. You would need a new tune to really take advantage of it, but you'd get a lot more out of your dollar with a custom methanol tune than just an OTS chip IMO.

With these two items, I'm willing to bet that the valves would stay very clean indefinitely.

Thoughts/comments?

MrBucket

Talk to richib86 about the methanol injection. He would know.

greatwhiteshark

Seems VW's gone ahead and filed a patent to get rid of this 'phenomenon':

From RS246:

Acknowledgement of the Valve Deposit issue in a VW patent

Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components. Carbon deposits form especially in the neck region of intake valves. A more exact analysis of how these carbon deposits form leads to the following result: Oil and fuel constituents first form a sticky coating on the components. These constituents are chiefly long-chain and branched-chain hydrocarbons, i.e., the low-volatility components of oil and fuel. Aromatic compounds adhere especially well. This sticky base coating serves as a base for the deposition of soot particles. This results in a porous surface, in which oil and fuel particles in turn become embedded. This process is a circular process, by which the coating thickness of the carbon deposits continuously increases. Especially in the area of the intake valves, the deposits originate from blowby gases and from internal and external exhaust gas recirculation, and in this process, the blowby gasses and the recirculated exhaust gas come into direct contact with the intake valve.

Especially in the area of the neck of the intake valves, excessive carbon deposits have extremely negative effects for the following reasons: In the case of Otto direct injectors, the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result. Under certain circumstances, however, ignition failures can lead to irreversible damage of a catalytic converter installed in the exhaust gas tract for purifying the exhaust gas. Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures. This in turn could irreversibly damage the catalytic converter. There is the potential for small particles to break away from the coating of carbon deposits in the neck region of the intake valve and get into the catalytic converter. These hot particles may then cause secondary reaction and corresponding local damage of the catalytic converter. For example, a hole may be burned in the structure of the catalytic converter.

Globular deposits are found especially on the valve stem downstream from a partition plate in the intake port. Due to the dripping of high-boiling hydrocarbons from the partition plate towards the valve neck or valve stem, globular carbon deposits eventually form there by the sequence of events explained above. These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle.

A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible.

greatwhiteshark

Patent link: http://www.google.com/patents?id=fLI...d=1_1#PPA13,M1