Even modern technology has it's issues..

[todesengel]

My Audi rs4 has a fsi setup (fuel is injected directly into the combustion chamber), it is a fairly technologically impressive powerplant, all the way around. 4.2l, high revving engine that lays down 420 hp in stock form. Of course mine is not stock, it is boosted, but that is irrelevant to this posting.

Dyno'd the car, and it was down almost 40 whp, after 11k miles. No codes, no running issues, just down in the upper rpm ranges. Time for some investigating, so off comes the s/c/intake.....







It appears, even with the advanced cyclonic pcv system (pictures below) that the direct injection system really contributes to buildup on the valves, with nothing injected there to clean them. The buildup is more a gummy tar substance, than the typical hard carbon deposits ordinarily found on most conventional tpi/tbi setups.

Here is the cyclonic pcv system:



Although well designed, there is no way to remove all vapor from the air stream when routing back into the intake.

Here is a pictures of the valves after chemical treating, and before final cleaning (this is a long drawn out process that takes about 14 hours to complete. the entire front of the car has to be disassembled in order to gain access to remove s/c and intake.



I have taken two steps to combat this deficiency, and reduce the chances of the mass gathering of crud on the valves:

1) I have routed my pcv directly to my exhaust via a check valve setup AFTER my cats. This will allow it to burn in the exhaust rather than accumulate in a non vacuum assisted catch can.

2) The meth injection system is now set to dispense for a brief time everytime the car ignition is turned off. the car will remain running for 30 seconds after key switch off, and attempt to clean the valves. There are 8 meth inectors perfectly aligned to spray each valve chamber. The beauty of the meth injector placement is it will also allow me to gain visual access to the valves (via borescope) without removing the intake/ supercharger. I am going to inspect them at 5k mile intervals.

I know that this has nothing to do with the zr-1, but wanted to show people that even with technology, and improvements in power plants, and fuel delivery systems there are often trade-off's. Sometimes you create other issues by attempting to solve another.

BTW, this is not a issue isolated to my vehicle. This is common, at least for audis all over the world. Audi refuses to acknowledge an issue with the setup, and will do nothing unless codes are thrown, then they attempt a chemical clean through the tb. of course my car, even with the low miles is far out of warranty since it has been heavily modified.