Direct Injection causes power loss overtime?

[bmorecam]

Very interesting article that I found on direct injection recently published on dailytech.

Check it out. http://www.dailytech.com/Direct+Inje...ticle21962.htm

For the lazy ones..

Reduced performance is blamed on carbon deposits

The promise of direct injection is very appealing to drivers and to the automakers that are always looking for an edge in performance and fuel economy. While most people that have vehicles that use direct injection have cited no issues, there are some that are having lots of problems with the technology.

Auto Observer reports that the issue is the tendency of direct injected or DI engines to build up a layer of carbon or soot around the intake valves that can over time significantly affect the performance and economy of the engines. The soot is able to build up in a DI engine because unlike a port injected engine there is no constant spray of fuel that can keep the deposits washed away.

Some engines are more trouble plagued thanks to the direct injection than others. The technology is used in multiple vehicles from different automotive firms including Audi, VW, BMW, Ford and others.

Volkswagen filed a patent application in 2002 that described the issue with DI engines, "Gasoline engines with direct injection of the fuel into the combustion chamber…suffer especially from the problem of the formation of carbon deposits…especially in the neck region of the intake valves." The application also noted that these carbon build-ups "have extremely negative effects" on the performance of the engine.

The patent app was intended to propose a new catalytic surface to the engine that would prevent the buildup of carbon. One automotive enthusiast found out the hard way how much carbon build-up can affect performance. Constantine Boyadjiev purchased a slightly used 2008 Audi RS 4 and later found that carbon build-up is a big issue with the vehicles.

Boyadijev said, "The loss of performance became very noticeable over time." Boyadijev took his RS 4 to a dyno to help document the problem. He reports that when the RS 4 has 15,000 miles on the clock it produced 324 all-wheel horsepower. At 20,000 miles, the same dyno showed 317 AWHP, and at another 5,000 miles, the car produced 305 AWHP.

That is hardly a direct conclusion that carbon build up is the cause of the shrinking power numbers. Anyone familiar with a dynamometer knows that there are a number of things that can affect how much power is read on a dyno including the gear the car is tested in, the heat and humidity on the day of testing, the fuel grade and quality, and even how snugly the car is strapped to the dyno rollers. There is also going to be a normal variance on each run of the dyno.


Boyadjiev said that he paid $1,200 to have the engine cleaned of carbon deposits and when the car went back to the same dyno it put down an extra 41 AWHP. Different engine designs are also having less of an issue with carbon build up so some of the issue lies with the engineers that design the motors.

Some owners of the Cadillac CTS with a direct injected 3.6-liter V6 have also complained of problems with carbon deposits. However, GM is quick to combat these claims. “We maintain great engine function and performance in our all our DI engines through an optimization strategy with our valve events,” said Ameer Haider, GM’s assistant chief engineer for V6 engines. “Our intake-cam timing, injector targeting and timing of the injection events are optimized to avoid direct fuel contact on the intake valves. This strategy keeps smoke and soot formation to an absolute minimum, which in turn prevents excessive deposit formation.”

Direct injection is used in all classes of vehicles today ranging from lowly subcompacts like the Hyundai Accent to compact sedans like the Ford Focus to midsize sedans like the Hyundai Sonata to full size pickups like the Ford F-150 with EcoBoost. Only time will tell if these vastly different vehicles using direct injection will develop issues with carbon buildup down the road.

[rtcat600man]

Interesting, I will have to check with a few buddies on this one.

[PoorMansCamaro]

Um, isn't that what catch can is for? Or am I missing something?

[rtcat600man]

Originally Posted by PoorMansCamaro

Um, isn't that what catch can is for? Or am I missing something?

Good Point...........

[KMPrenger]

So would a catch can help prevent this type of build up? (Obviously I'm not smart enough in this area to know the answer lol).

I'm running a catch can, and I know it is catching oil so I'm good to go there, and I know the function of the catch can...just curious if the catch can IS a good answer for the issue described in the OP.

Hopefully, with how GM described the engineering in the LLT this problem really is kept to a minimum.

[bmorecam]

An oil catch can is used in turbo applications, or high-performance race applications where excessive blow-by (leakage past the piston rings) of air and fuel vapor occurs. This creates a positive pressure in the crankcase. Engine manufactures have placed a valve on the engine block which releases this pressure. This valve is known as a PCV (Positive Crankcase Ventilation) valve. During engine operation, blow-by gases, as well as oil mist from the rotating components of the engine, pass through the PCV valve and are routed back into the intake for the engine to burn off. However, some of the oil mist and other products settle along the engine intake and over time form a "gunk." The oil catch can collects the oil mist and condenses the fuel vapors while allowing "cleaner" gases to be passed back into the intake. Typically the blow-by gasses are passed through a wire mesh, which give the vapor droplets something to adhere to. Since the oil catch cans condense the vapor portion of the gasses, they will need to be drained periodically of all the oil, fuel and other contaminants.

Read more: http://wiki.answers.com/Q/What_is_an...#ixzz1RQguGi59

Now I know what my next mod is just to be safe. This should of been my 1st mod especially running e85 and now this. Something that catches my mind on what GM said: “We maintain great engine function and performance in our all our DI engines through an optimization strategy with our valve events,” said Ameer Haider, GM’s assistant chief engineer for V6 engines. “Our intake-cam timing, injector targeting and timing of the injection events are optimized to avoid direct fuel contact on the intake valves. This strategy keeps smoke and soot formation to an absolute minimum, which in turn prevents excessive deposit formation.” you guys do know the the tune changes valve timing and injector events right? I was going to get a catch can soon but it look like its going to be asap.

[blackknight]

Interesting read, my dad has a 2011 Buick Enclave and it has the DI 3.6L V6 (same engine as the LS Camaro, but slightly changed?)

I noticed a lot of carbon build up on his exhaust tips. And now im wondering if I should install a catch can on his car!

[Kid]

So basically all of the additives that you would use to clean deposits from your engine will be usless. Most go in your tank, so they will never contact your valves, only clean your injectors. Guess I'll be getting a catch can as well.

[dthomp2366]

Us cobalt guys use some stuff called Seafoam or similar products to clean valve deposits due to DI

[Kid]

Ahhh...forgot about that stuff. That would solve the problem as it's pulled through the intake. Of course, it smokes like the car in your sig till it clears out...and not the tires.lol

[dthomp2366]

LOL yup but want to make sure it doesnt get to any sensors or seals.

[Kid]

I assume on the 3.6, you could use the oil return in the center of the intake to draw the Seafoam in. You have to cut the line anyway to install a catch can, so it should be a no brainer.

[dthomp2366]

Thats where I plan to do it to my brother's Camaro when he gets some miles on it.

[rolnslo]

http://www.seafoamsales.com/sea-foam-spray.html

From their site, it looks like you can easily get the Seafoam into the intake manifold. I guess this is something that should be done periodically, especially if you aren't running a catch can at all or only running it on one side not both.