Water Injection to combat carbon build up

[androidmarrs]

Was just having a thought about the carbon issues with the RS4's and I remembered looking into water mist injection when I had my S3.

Does any know if fitting water mist injection to the V8 RS4 would help to try and combat the build up of carbon that we see around the valves and inlet manifold?

Has anyone ever tried this?

Cheers

[JCviggen]

I think it would probably cause more issues than you would solve. Your S3 was turbocharged, the RS4 isn't. Most of the time the water injection would not be working anyway (and I suspect you'd have to inject methanol f you want a decent cleaning effect) and its not as easy to trigger as with a turbocharged car where you use a boost switch.
It might lose you power rather than gain anything.

[adsgreen]

Also depends on where the nozzles are.
If near the top of the manifold (near the throttle body) then the mist won't be as effective. It's a n/a manifold so inside it has an air chamber and trumpets. The water will most likely collect there or form larger droplets.
You ready need to fit injectors in place of the core plugs.

[androidmarrs]

Ok I see the problem, where there is no boost to activate the water mist.
Is it possible to remove the EGR valve or will the car then fail an MOT on emisions?

[adsgreen]

No EGR valve to remove. It's internal so EGR is by valve overlap - exhaust valve held open and exhaust gases pulled back in along with fresh charge. Probably the main cause of carbon - exhaust crap gets its way into the intake manifold.

The only way that could be cured is by carefully changing the valve timing do that when EGR was active there was no overlap. But I don't have any specs to what the valve timing is under various operating conditions.

[androidmarrs]

Ok, I'm starting to understand now. I did not realize it was to do with the timing. Was think about buying a gasket set and doing a carbon clean myself any pointers if i was to undertake this?

[sakimano]

someone asked about using a meth injection system and including some kind of cleaner in the mixture. Something that made it's way through the intake tract to wash the valves.

I believe that is what JHM is doing with the carbonator which will add a ninth injector and spray fuel like a port injection fuel stratified injection frankenstein.

[adsgreen]

I still don't see how this will work.
Normal non direct injection has the injection very close to the valves and as such the fuel is sprayed directly onto them under pressure. A mist from one injector will do very little. The fuel from an injector only remains as a mist for a short time - boiling point is approx 95c and many parts outside the engine chambers are cooler than that so it'll condense on contact.
Then you have the prob of where to put the injector... If its only one then probably in the intake after the tb and maf... But then the air goes into the intake manifold airbox which then needs to find its way up into the intake trumpets that are angled down. Sure some will but some won't and it could easily collect in the manifold.
Not sure I would want fuel collecting above the engine like that.
This is before you get onto the problems of adjusting the engine map to account for varying fuel differences.

I don't see it working well for the same reason as water/meth doesn't.

But if carbon is not a problem why bother?

[Stoffle32]

guys in SA have been using water/meth for awhile in the Rs4, comes in around 5000 rpm, use it mostly for heat and the keep the intake temps down because of the warm climate, but no problems have been brought up as of yet, think its been about 2 years since the first one was installed... obviously a remap is in order for this setup...

[MortenJuul]

I am running Water / Meth on my RS4 - Works perfect!!

Using "Devils Own" stage 2 (NA) System - hooked up to the voltage on the MAF - Running a DO7 (375ml/min) nozzel after the Throttle Body

Using 50/50 Water / Sunoco Meth (25liter = 14L meth / 11L Wather due to the mass volume)

I only kick it in at 4 / 4.5V (full gas) -

Using the headlight washer "container" (will change this since the engine / Carbon disk heats this to 65C and looses some of the "cooling" idea)

At trackdays I am able to lover my oil temp by 20 - 25C (from 142 > 120C) by switching it on!!

I also have a custom REVO map that runs more advanced timing, since the W/M delays the detonation - You want max explosion on 4degrees piston

This gives you A LOT of tourqe (the expansion of water / meth is much more powerfull than gasolin (my Shell VPOWER RON/MON 99 becomes 116 octane with my aprox 1:20 mixture)

NOTE! - Because this is AFTER the TB, you have vaccum!! - You need a check valve or solenoid valve to close the meth "line" - else it will "sipp" - This CAN be quite dramatic (white smoke and loads of "pops" )

You also need to look at the air/fuel ratio (must be around 1:12) - I am running catless and Miltek, so already needed to adjust this before (due to the flow) , but the meth can mess up the mix - You can log this with VCDS lamba values

Let me know it you need more info -

1. it cleans
2. it cools
3. it raises the octane to run advanced timing

[Timster]

Rule 1.

FON.

[sakimano]

Skeptical African kid is skeptical of Devils Own salesman...

[MortenJuul]

Here is my nozzle placement

[androidmarrs]

how much meth/water does it tend to use and a daily use basis?

[MortenJuul]

Not much - this only kicks in at 4.5v (0-5v maf sensor) - i also have a switch to turn the system off - I use it at trackdays - here I use 8 - 10 liters for at full Day (1:10) - I had my intake cleaned in march and this mounted at the same time - I am having some internal engine pictures taken soon (bhoroscope through the sparkplug holes - Will post the "before" pics later