Even modern technology has it's issues.. - ZR-1 Net Registry Forums

todesengel · 01-23-2011

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.

todesengel · 01-23-2011

I forgot to add that after cleaning I picked up 42 hp over the previous dyno.

I am also going to pursue some bio oil to see if it helps combat it, but I would like to know the affect of each step before moving to another.

I am also open to suggestions from any of the more experienced members of the board, or hear their input on whether they agree, or disagree with the steps I am taking.

Locobob · 01-23-2011

Wow, that engine has some serious port volume starting not far above the bowl area.

todesengel · 01-23-2011

Quote:

Originally Posted by Locobob

Wow, that engine has some serious port volume starting not far above the bowl area.

Honestly I do not know a lot about the heads on the b7 rs4, there is not a lot of information out there. I know on the b5 rs4, which came turbo charged, they were designed for velocity over total flow numbers by cosworth. Since this engine came as a free revving n/a I am not sure who designed the heads, or flow number. I do have the cam specs as they were changed.

If the engine ever pops i will have some fun with these heads though, I can promise you that. I may even change it to include 8 secondary injectors, in place of the meth injectors as I will dump the s/c and go turbo.

Hog · 01-24-2011

Your meth injection doesn't clean that crud during "normal" operation? Like if you had some sort of regular WOT operation?

That filth reminds me of the crap that is found in the intake manifolds of 1996-2002 Vortec 305/350 V8 engines. The combo of EGR and PCV really gunk up the intakes.

These "direct injection" engines sure do have good power production, even the domestic manufacturers.

peace
Hog

todesengel · 01-25-2011

Quote:

Originally Posted by Hog

Your meth injection doesn't clean that crud during "normal" operation? Like if you had some sort of regular WOT operation?

That filth reminds me of the crap that is found in the intake manifolds of 1996-2002 Vortec 305/350 V8 engines. The combo of EGR and PCV really gunk up the intakes.

These "direct injection" engines sure do have good power production, even the domestic manufacturers.

peace
Hog

It is set to only activate under boost. I do a lot of highway driving, 900+ miles a trip is nothing unusual

FU · 01-25-2011

This build up has been a problem with direct injection engines. Direct injection is the way to go for better fuel mileage and more H/P. As technology prevails these "problems" will be worked out.

01-23-2011	#1
todesengel Join Date: Apr 2010 Location: O'Fallon, Mo Posts: 738	Even modern technology has it's issues.. 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. Last edited by todesengel; 01-23-2011 at 01:36 PM.

01-23-2011	#2
todesengel Join Date: Apr 2010 Location: O'Fallon, Mo Posts: 738	Re: Even modern technology has it's issues.. I forgot to add that after cleaning I picked up 42 hp over the previous dyno. I am also going to pursue some bio oil to see if it helps combat it, but I would like to know the affect of each step before moving to another. I am also open to suggestions from any of the more experienced members of the board, or hear their input on whether they agree, or disagree with the steps I am taking.

01-23-2011	#3
Locobob Join Date: Jan 2004 Location: Portland, OR Posts: 1,057	Re: Even modern technology has it's issues.. Wow, that engine has some serious port volume starting not far above the bowl area. __________________ Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368

01-24-2011	#5
Hog Join Date: Jul 2010 Location: Woodstock, Ontario, Canada Posts: 1,275	Re: Even modern technology has it's issues.. Your meth injection doesn't clean that crud during "normal" operation? Like if you had some sort of regular WOT operation? That filth reminds me of the crap that is found in the intake manifolds of 1996-2002 Vortec 305/350 V8 engines. The combo of EGR and PCV really gunk up the intakes. These "direct injection" engines sure do have good power production, even the domestic manufacturers. peace Hog

01-25-2011	#7
FU Join Date: Mar 2004 Location: Found Member Posts: 4,346	Re: Even modern technology has it's issues.. This build up has been a problem with direct injection engines. Direct injection is the way to go for better fuel mileage and more H/P. As technology prevails these "problems" will be worked out.