Apologies if there’s already a thread for this. When I first got my car and learned about the carbon buildup issue, the first thing I thought was, “Well, is there something that can be done to reduce or eliminate it from happening in the future?”. Aside from a few snake-oil tricks I’ve read about, I have yet to hear an actual professional opinion on the matter.
Some theories I’ve read:
Vent the crankcase to the atmosphere instead of back into the intake, using an oil separator to prevent oil from getting everywhere under your hood. Obviously this could create an emissions compliance problem.
Coat the valves in something so carbon can’t stick as easily.
Drive the motor hard regularly, as gentle driving allows carbon to build up faster.
Is there any truth to any of the above theories? I have no idea. But it sucks to have a known problem like this, and no way to reduce or eliminate it. Or is this just something we all need to learn to accept - that each and every one of us needs a $1k cleaning performed annually?
I wouldn’t say annually is required, the guidance I previously heard was once every 20-25k miles or every 2 years depending on how anally clean you want it.
I’ve also heard IM spacers help a a bit, but I doubt that they would reduce it dramatically. Then there is always water or meth injection, but then you introduce more maintenance and additional failure points, in exchange for some other beits as well though.
nothing works but manual cleaning. Do it every 2 years. Forget about it otherwise…it’s not a big deal. Forum people will make you think it’s the end of the world.
Reality?
It doesn’t impact your acceleration much, other than top top top end. Ripping through the gears right to redline from 0 to 110 mph? It might cost you a tenth or two in the 1/4 mile. That’s it. Ripping through the gears onto the highway? you’ll never notice it.
People are just loopy and panic about this shit.
My car set the stock RS4 1/4 mile record with 30,000 miles of carbon buildup. My car got cleaned, and went no faster. Mistro’s RS4…same deal. We did back to back weeks at the dragstrip. Same conditions, same everything. Nominal change if any at all.
As for having carbon in there? It’s not ideal. As I said clean it every couple of years. I’m due to do mine. Some ships do it for $500-600 now. That’s peanuts on these cars which were $70,000 when they were new. If someone can’t afford $500-600 every 2 years they bought the wrong cars. Your air conditioner will cost triple that.
Carbon is a hard thing to really wrap a labile on. Depending on your driving your envirement and maintanence carbon build up will come at different stages for some.
You suggestion of number 1. The cars come with an oil separator but many have seen it dosent do enough and getting an oil separator that does more work causes idle and other issues. Still keeping oil out of the intake track will help.
2 to coat the valves is a great idea. but the down side is anything that will stick to the valves will also be sticky itself and act as a magnet.
3 not letting your car idle for long times and getting some good fresh air past the valves is also a good way to keep the carbon at bay. The intake spacers are good for helping this as they drastically drop the intake temps and help reduce hot oil mist that slowly attaches itself to spots on the intake and intake valves.
Depending on your driving style and over all car conditions its good to check on the carbon build up every two years or so. The new Audi cars have an external injector that sprays to help clean the valves. So audi has seen that over time if left unchecked carbon can do some serious damage. And so have many Audi car owners that have never looked at or serviced there cars for carbon.
My findings have always gone like this.
Intake spacers help in dropping the intake temps.
Having a good clean air filter helps in keeping the air flow faster and more dense.
even a catback exhaust or catless exhaust helps. As a good exhaust system actually pulls air past the valves harder than the piston pull on its own.
Checking the oil separator and PCV system regularly like every oil change regularly is a big help as well.
Make sure your valve covers dont leak and that they are sealed properly. A leaky valve cover reduces the flow in the PCV system. Lower slower flow allows build up.
Keep on top of overall maintantence for hoses and other motor hardware
Ill see if I can do a write up. Its difficult enough that pictures would probably be needed. Basically what your doing is testing to see that the system isnt leaking pressure.
