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@nautir8 , Find out about water injection and you will find that it does not work like a jet of water from the garden hose or an inlet manifold gasoline injection valve.

It is more of a water mist that must be permanently available and it requires a larger amount of water.(distilled water is mandatory here)

Whether it makes sense with an engine that draws its own air, I leave out.

If it should bring a good result, I would have already done it on my R8 V8, but I haven't.

Tom
 

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I would be interested to see how clean everything was after a few pulls with water injection
Water and/or meth injection have no effect. There have been long-term tests done and there was no change in buildup. The only way to keep the carbon off the valves is to hit them with detergent fuel. The PCV system also contributes to the process (evaporative volatiles from gas blow by and from the oil itself) as does oil getting past the valve guides over time. So it's not just valve overlap and unburned hydrocarbons.

Toyota uses a throttle body injector to eliminate carbon buildup on their direct-injected engines. If someone were enterprising, you could have one injector bung per bank and run a stand-alone fuel injector controller. It'd take a bit of work but have it run in closed loop so the 02 sensors would adjust air/fuel ratio.

The seals on the injectors are necessary. If you move them even a bit, the teflon seal breaks and they must be replaced. What usually happens is the injectors get stuck in the lower intake manifold and when you pull those up, the injectors come with, necessitating new seals. And at that point you'd want to replace the o-rings which seal the top of the injector inside the fuel rail bungs. It's just a really good idea to plan for their replacement. For higher mile cars, I'd also take a hard look at replacing the injectors themselves. They're problematic. Just take a look at the misfire count for each cylinder with a VCDS or ODIS. That can be very telling if you have one or two injectors which are iffy or on their way out. We're talking in the 60,000 imperial mile range plus.

The flaps can be programmed to stay "shut" via ECU tuning. Keep them enabled for cold start as it's brutal without them. I suspect most of your better tunes already do this as it helps midrange WOT quite a bit.
 

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Good man, you have no idea, I drive without PVC and despite the carbon on the valves. No oil gets into the inlet port via the valve stem seals, there is no oil that can get into the position. Take a close look at the valve drive.

Water and/or meth injection have no effect. There have been long-term tests done and there was no change in buildup. The only way to keep the carbon off the valves is to hit them with detergent fuel. The PCV system also contributes to the process (evaporative volatiles from gas blow by and from the oil itself) as does oil getting past the valve guides over time. So it's not just valve overlap and unburned hydrocarbons.
Tom
 

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Yes well most guys here drive with crankcase ventilation as its part of our mandatory emissions equipment. Place a catch can in that loop and you catch a whole lot of junk. But it's not worth it in my opinion as it doesn't prevent carbon buildup from valve overlap. I use PCV block off plates on another Audi DI engine but you still have the crank breather. While there isn't a ton of buildup inside the intake manifold, some is present and can be seen on the flaps and other components like the MAP sensor, etc...so it does actually get in that way. As for valve guides and seals, I'd be referring to higher mileage cars.

I'm simply saying that by eliminating the flaps, you're still not going to completely eliminate carbon buildup. But by doing so it helps greatly towards that end goal (which is what you're saying). Most of us have known about the valve overlap issue for a long, long time.

Edit, here's a shot of of the lower intake manifold. You can see the flaps and see that they're black. That's due to ingestion of volatiles from the PCV system. Those flaps are actually YELLOW in color. Just to give you an idea! The gunk extends up into the rest of the upper intake manifold a bit but being a simple runner with a bell mouth in an open plenium, not as much to stick to.


Prototype PCV blockoffs for the CFSA motor (not R8 motor).
 

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I know the system very well and have been trying it out for years. I have had PCV from the intake manifold since at least 2015 and have been installing it as shown in the picture for two years. The flaps in the intake manifold have not been installed since 2014.
I did a coal cleaning last winter. I never said that removing (v10 not working) the flaps didn't put coal on the valves, I wrote "less".

Astronomical object Flash photography Science Circle Astronomy



PCV Air Box
Motor vehicle Light Automotive fuel system Black Automotive exterior



Tom
 

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I think things are getting lost in translation. I've had my flaps disabled (except for cold start) for some time. I'm agreeing with you! It's worthwhile eliminating/disabling the flaps from a carbon buildup and performance standpoint.
 

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Then we are of the same opinion and my suggestion to fix the flaps with glue is the solution for very little money.
The intensive coal cleaning for maximum performance then does not have to be carried out once a year, but every 3-4 years. ( like me )

Tom
 

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