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Dyno sheet for Constantine Boyadjiev's Audi RS 4  (Source: AutoObserver)
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.

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By czarchazm on 6/21/2011 7:01:04 PM , Rating: 3
Lexus uses a technique that indirectly addresses this issue. They have two sets of injectors. One set is for idle in order to reduce noise. The second is direct injection for performance and economy.

Though I have no research to reference, I suspect that this idle sequence with the low pressure injectors would provide enough detergent-laden gasoline to keep the valves clean.

As a side note, it wasn't until recently that gasoline had decent detergents in them to address the carbon deposit issues.

RE: Lexus
By Alexvrb on 6/21/2011 7:21:58 PM , Rating: 2
Actually the detergency of gasoline varies. If you're always putting the cheapest gasoline you can find, don't be surprised if it only barely meets government mandated minimum detergency (and maybe even has some undesireable components tagging along). Personally I try to use Top Tier gasoline whenever possible. If you can't, a periodic cleaning works. It doesn't cost $1200 unless you're a freak and want to rip your heads off just to clean the valves. You can do an inductive cleaning for much less periodically. Maybe more often if you've got an Audi/VW DI setup that is really prone to carbon. Sounds like the GM, Ford, Toyota, etc. approaches don't build carbon nearly as rapidly.

Anyway, regarding Lexus using a second set of injectors, they probably do this mostly to make the engine idle as smoothly and quietly as possible. Keep in mind that most cars on the road ONLY inject fuel prior to the intake valves (100% of the fuel, not a little bit of fuel at idle), and they can still build carbon up over time on the intake valves. However, this doesn't preclude Lexus et al from using careful valve timing, which I am sure they do.

Basically, just because one overly-aggressive DI engine design in certain Audi/VW models causes excessive/rapid carbon buildup, doesn't mean that gasoline DI across the board is prone to this. In fact most engines probably aren't having any more issues than non-DI setups, and it's a good idea to decarbon any gasoline engine once in a blue moon anyway. Granted, it may be a little more difficult in some cases, but it's far from impossible and it doesn't require you to yank the heads.

RE: Lexus
By undummy on 6/21/2011 8:29:28 PM , Rating: 4
Its not only a Vw/Audi issue.

Ford/GM/BMW/Mazda have the same problem but most of their owners might not notice it as much as 'performanced minded' Vw/Audi owners.

Ford also has patented a DI reversion cleaning of the intake valve on the DI engines. Like VVT replacing EGR, Ford is using VVT to allow a timed fuel/air mixture to rinse the intake valve as needed.

IMO, Toyota/Lexus twin injection is the best solution as DI isn't optimum at all rpms/load. IDI has its benefits. And, the combination of the two would be best.

RE: Lexus
By toyotabedzrock on 6/22/2011 12:23:07 AM , Rating: 2
I think more conservative valve timing and elimination of the EGR would prevent all these problems.

RE: Lexus
By heffeque on 6/22/2011 8:52:14 AM , Rating: 1
So basically VW says... "ok, our DI engines have problems", and GM says... "no, our customers are wrong, our DI engines don't have problems, it's all in your head".

And people wonder why american cars are less and less popular.

RE: Lexus
By Spuke on 6/22/2011 2:12:01 PM , Rating: 2
And people wonder why american cars are less and less popular.
That's because they're actually right for once. My Solstice and every single Solstice/Sky owners cars makes the same hp since day one. I wouldn't be so quick to blame every automakers DI engines because of some POS Audi. They've been sliding down the reliability mountain for quite some time. Besides dyno readings are notoriously inaccurate and easy to fudge. One day can't be compared to the next on the same dyno let alone two different dyno's. This well known in the car enthusiast community and if the Audi owner doesn't know this then he's an idiot and is clueless about what actually is wrong with his car.

RE: Lexus
By undummy on 6/22/2011 5:27:28 PM , Rating: 3
Sorry, but the GM turbo DI's have buildup issues too. They're just lucky that it starts at the TB and less downstream, meaning that you'll see it a little later on the odometer reading. You ever wonder why the Cruze 1.4T didn't get DI?

Not sure how you can claim that every single Solstice/Sky owner makes the same power. I know of a bunch of the 2.0 Turbo DI turning into oil burners with the power/MPG loss to go along with it.

RE: Lexus
By tastyratz on 6/22/2011 8:49:28 AM , Rating: 3
Shane: FYI A modern dynometer does SAE correction. This corrects for elevation, air temp, etc. for repeatable results. There are other engine conditions, tire air pressure, and strap torques that can influence results yes but not that much. If you look at the dyno there is an sae correction factor of 0, meaning the conditions were the same as sae baseline.

Others including OP:

Reversion happens slightly on valve overlap normally, but Counting on it wont do well for the back of the valves.

The problem has to be analyzed first. What causes carbon buildup? Oil on the valve stem getting hot and burning off. Some valve seals work better than others but then you risk galling if you seal TOO much oil.

I personally can think of a few different solutions:
2 piece valve guides with a secondary seal in the center or even the bottom. Prevent less oil consumption
or even better: a lubricated cleaning solution with a pinhole draw perforated near the bottom of the valve guide. This could easily use oil pressure on a bladder to force fluid through at set intervals and channels are just cast into the head like any others. People might object to an additional fluid but if it is considered part of normal service and changed infrequently (think 30k or maybe at oil changes) then it might be fine. mild brushes could be pressed onto the bottom of the stem to agitate the surface.


Dual injection is only SO elegant because it adds a large level of complexity to the fuel system as DI vs non DI have VERY different fuel pressures. Idle piston speeds aren't fast enough for optimal mixture with single point injection but more complicated routines should make DI idle very well. It might have been around for diesel for awhile, but it has only recently become practical in normal gasoline engines. With some more engineering and development time it should progress nicely and quickly.

Water injection systems work well to steam valve faces and the combustion chamber but not the backs of valves as much. It also would not work for cold environments so alcohol would be required.

RE: Lexus
By Bagom on 6/22/2011 9:40:28 PM , Rating: 2
Well Lexus also has issues with carbon build up. I have an IS250 and I have taken it in twice b/c the engine would lose RPM for a split second. Like it was about to stall. A bunch of other Lexus IS owners seem to have issue. At first they tried to sell me on a top end engine clean. After I mentioned that other IS owners have the same issue the took the car for a day to "fix". Engine has not shuttered since I got it back.

RE: Lexus
By MattL on 6/23/2011 11:11:34 AM , Rating: 3
The Lexus IS 250 uses what Toyota refers to as D-4 Direct Injection. This sprays fuel directly into the combustion chamber. The IS 350 and IS F use D-4S which uses two separate injection systems that work together to operate in the following way:

Cold Operation - Direct and Port
Cold Idle Warm-up - Port
Normal Idle - Direct
Part-Throttle Application - Direct and Port
Full-Throttle Application - Direct

The dual injection setup on the IS 350 and IS 4 have the secondary bonus of utilizing the port-injectors to wash deposits from the intake valves.

The TSB referring to the Lexus IS 250 uses a General Motors-branded engine cleaning solution that soaks the valves/stems, and in some cases the pistons too. This cleaning is generally good for 10,000+ miles.

This is the very reason we researched and published the article. It seems early adopters are paying for this newer technology in gasoline engines - in more ways than one.


RE: Lexus
By YashBudini on 6/21/2011 8:34:29 PM , Rating: 2
Basically, just because one overly-aggressive DI engine design in certain Audi/VW models causes excessive/rapid carbon buildup, doesn't mean that gasoline DI across the board is prone to this.

Wow, you single handedly took the wind out of all the sails of the extremists that lurk here.

Nice work.

RE: Lexus
By Reclaimer77 on 6/21/2011 9:54:22 PM , Rating: 2
I don't know why people still buy VW's and Audi's. The amount of empirical evidence that they do NOT care about vehicle reliability is damning enough.

I agree that one car having DI carbon problems doesn't damn the technology. Because of the fact that the cars in question are Audi/VW. I'm honestly not surprised one bit.

The only brand I can think of worst than the A4 in overall reliability is a Saab 9-5 after GM took over.

RE: Lexus
By YashBudini on 6/21/2011 10:14:48 PM , Rating: 2
My 84 GTI had a reputation for replacing certain "parts" on a regular basis, far far too often than just about any other brand. Some might suggest they did it for money, but I see no financial upside to this problem.

Pehaps if gas was more consistent in quality and formula across the world they would not be in this mess. I wonder what the story is with DI cars in Europe?

I miss the steering feel and the shifter from my GTI, not much else.

RE: Lexus
By bigdawg1988 on 6/22/2011 3:02:40 PM , Rating: 2
but I see no financial upside to this problem

Perhaps the fact that many automakers make most of their profit from selling replacement parts would be the upside? The markup on replacement parts was ridiculous, especially in the eighties.

RE: Lexus
By RussianSensation on 6/22/2011 12:28:41 AM , Rating: 2
My 2008 A4 now has 40,000 miles with 0 issues (not even a burnt lightbulb). On the other hand, my company Dodge Charger that I use has needed its transmission and breaks replaced at only 50,000 miles. My friend's brand new X6M's right rear view mirror needed to be replaced after just 1,600 miles (in case you are wondering that repair cost $2,000, although under warranty, for the part to be shipped from Germany). Of course all this is anecdotal evidence, but so is your statement about because it has no empirical evidence to support it.

RE: Lexus
By Reclaimer77 on 6/22/2011 1:31:00 AM , Rating: 5
I was expecting someone to post something like this "my such and such has such amount of miles". 40k? I would certainly HOPE it's having no problems yet. It's barely broken in.

but so is your statement about because it has no empirical evidence to support it.

While the VW brand reliability has improved, Audi has "spotty reliability" and drags down the company's overall score. Too, "If the new (VW) Jetta sedan , with its low-grade interior and mediocre fuel economy, is an indication of where Volkswagen is headed, it's going in the wrong direction."

VW has slipped in the European JD Powers initial quality ratings to 34 out of 37 manufacturers. More empirical evidence you'll probably dismiss. Pick pretty much any year you want, you'll find similar results; Audi and VW near the bottom in initial quality and reliability.

RE: Lexus
By Reclaimer77 on 6/22/2011 2:25:38 PM , Rating: 3
Well? I'm waiting.

RE: Lexus
By DigitalFreak on 6/22/2011 8:43:38 AM , Rating: 3
Chrysler isn't exactly known for quality. :0)

RE: Lexus
By Spuke on 6/22/2011 2:13:56 PM , Rating: 2
Chrysler isn't exactly known for quality. :0)
Yet they're higher than VW.

RE: Lexus
By radium69 on 6/22/2011 6:10:28 PM , Rating: 2
My Japanese Nissan Almera (or pulsar) still has it's original engine and it makes greater output then it's factory specifications. After 13 years!

For example, the car was build in 1998. It is absolutely fun to drive. And as far as I know, reliable.

I bought it with 85.000km and it is now at 140.000km

already drove 55.000km with it , problem free. Only regular maintenance. Also a new set of brake pads (which imo, is regular maintenance to me)

I dyno'd it when I bought it. After 12 years it still had 138BHP (oem 143BHP)
It was running a bit lean so I gave it a little bit more fuel. After that the engine was running at 145BHP (+2 over oem). Ignition was at 15. Ignition at 17 , BHP went from 146 to 148 (on ron95)

After that I changed the breathing of the car (CAI and the whole exhaust including manifold)

It's again been dynod this year (13 year old car) and it saw a nice 155BHP. And 120WHP (first dyno showed 100WHP)

I wonder where the reliability is from newer cars. Almost makes me want to keep my Nissan till its totally broken.

RE: Lexus
By cjc1103 on 6/23/2011 11:09:02 PM , Rating: 2
I see, you mod your car with aftermarket performance parts, and it now produces more power! Congratulations!

RE: Lexus
By Manch on 6/22/2011 8:52:01 AM , Rating: 2
I would take comparing a personal vehicle to a company or fleet vehicle with a grain of salt. People tend to flog the crap out of company/fleet vehicles, since they aren't paying for it/own it themselves. If you're the only driver of that Charger then, I guess that would make it a better comparison. Plus it is a Dodge. There quality isnt exactly top notch. Brakes @ 50K isnt bad. At that point they should be replaced anyways.

RE: Lexus
By Bad-Karma on 6/22/2011 3:37:37 AM , Rating: 2
Funny you should mention the Audis. Last I visited my in-laws in New Jersey & NYC, you see Mercedes all over the used car lots and Audis everywhere on the road.

Must be the in thing.....for the moment

RE: Lexus
By undummy on 6/22/2011 12:29:17 AM , Rating: 2
The lurking extremists?

It currently is an across the board issue, even with IDI and carb'd engine. Intake valve/stem cleanliness has been an issue for decades. For IDI engines, a simple bottle of FI cleaner added during the fuel fillup is all that was needed. Stepping up to a toptier fuel was also a great preventative. But, DI eliminates these two simple fixes.

I still haven't found a DI gasoline fueled engine WITHOUT the issue. If anyone knows of a currently available DI vehicle without the issue, please let us know. It would be a vehicle that could be added to the 'buy list'.

RE: Lexus
By Alexvrb on 6/22/2011 6:55:23 PM , Rating: 2
You say that it has been a problem for engines for decades, FI, carb'd, all of em. Then you say that you haven't found a DI gas engine without the issue. So... you agree with me that a proper DI design is no more prone to issues than many typical gasoline engines?

Yeah, you can't just dump cleaner in the gas tank to clean the intake valves on a DI gas motor. So what? Follow the route the air takes on the way to the intake valves. Insert cleaning product of choice (seafoam is always popular), usually via a vacuum line. If you can't perform the service, have a dealer/shop do it for you every 50 or 100k. It's a good idea to clean out non-DI engines too.

RE: Lexus
By Master Blaster on 6/21/2011 11:05:51 PM , Rating: 2
Sounds like some kind of active mixing in the combustion chamber would help keep DI clean. A little Google-Fu reveals intake valves that create a vortex in the combustion chamber:

That's why I'm getting a F-150 5.0
By Pneumothorax on 6/21/2011 7:28:11 PM , Rating: 2
No eco-crap-boost for me with our next truck purchase. The fuel economy difference between the 5.0 vs. the eco-boost engine will quickly be erased with the expensive bills that will come after the warranty is gone. BTW we have a 98 F-150 with 175,000 miles with basic maintenance. I'd be surprised to see an eco-boosted F-150 go that long without a major issue.

RE: That's why I'm getting a F-150 5.0
By russki on 6/21/2011 7:46:33 PM , Rating: 1
That's fine. The fact that diesel engines have been direct injected for decades and have no such valve carbon buildup problems suggests the problem is elsewhere.

RE: That's why I'm getting a F-150 5.0
By undummy on 6/21/2011 8:15:57 PM , Rating: 3
Diesels have had the issues for years. TDI intakes can get constipated with sludge. I've pulled plenty of intakes off for sludge cleaning.

Diesels aren't in volume enough for the majority to care about. And, many diesel owners mod to make up for shortcomings.

Gasoline DI issues are common and will become more common as more vehicles are equipped with it.

RE: That's why I'm getting a F-150 5.0
By heffeque on 6/22/2011 9:08:26 AM , Rating: 1
"Diesels aren't in volume enough for the majority to care about. And, many diesel owners mod to make up for shortcomings."

That's pretty laughable taking into consideration that more than half of the cars sold in some countries in Europe are diesel.

Heck, you even have diesel sports cars over there. That would be seen as ridiculous over here, that's for sure.

Check out the Scirocco TSI 265... it's a diesel that can do more than 150 mph without a fuss (0-62 in 5.8 seconds).

By undummy on 6/22/2011 5:17:26 PM , Rating: 2
US market comparison vs. who/where are reporting these issues?

Laughable? Yeah, assuming different markets with different fuel qualities, maintenance intervals, oil types, and emissions requirements, are equivalent to US market.

The issue is here in the USA and diesel passenger vehicle sales are a drop in the bucket. TDI and ???

Many technicians will be making their RV/boat payments because of these poorly engineered DI gasoline engines. Please avoid toptier fuel, avoid FI cleaners, avoid a PCV catch can mod, avoid oil change intervals with quality oils, avoid...... I need a new fishing boat.

RE: That's why I'm getting a F-150 5.0
By Bad-Karma on 6/22/2011 3:34:43 AM , Rating: 3
I've got an 03 F550 with an international T444E. Originally it was a 7.3L PSD but we tore it down and rebuilt it using IH parts/specs and used an IH chipped ECM. Then modded up from there.

When I first took the Ford PSD injectors out at ~30,000 miles they already showed some moderate carbon build up. I replaced them with triple stage injectors for added performance, but at the same time I also added both a Propane injector and a water & methanol injection systems.

Now I can't say for 100% sure, but I think the steam generated with the water/methanol may be keeping the entire cylinder assembly clean. I've done a partial tear down on the engine every 25,000 miles for inspection, with 245,000 on the odometer everything in each cylinder looks almost like new.

Other than the usual ring wear and a little bit of pitting, there is no trace of carbon.

By Manch on 6/22/2011 9:01:30 AM , Rating: 2
yup, water/meth is great for preventing carbon buildup. I dont have it on my current setup but it's on my list. I just use sea foam every now and then to get rid of the carbon buildup on my 3V mustang. Makes taking the spark plugs out less painful. I'd hate to break a damn plug off.

By Spuke on 6/22/2011 2:33:40 PM , Rating: 2
My engine has no carbon build up on the valves.

RE: That's why I'm getting a F-150 5.0
By dcollins on 6/21/2011 9:05:15 PM , Rating: 3
I don't think that 175K is a particularly impressive number. My Dad's 1987 Toyota Pickup has 495,000 miles, all on a single engine. The only significant maintenance has been two timing chain replacements.

My 1999 Miata has almost 150K, with no major problems, at least not with the engine. My buddy's Civic has over 200K, again without major problems. I could go on, but you get the point: 175K miles is fairly common for a well maintained engine. Only time will tell whether a blown V6 like the EcoBoost in the F-150 can last that long but it would not surprise me in the least.

RE: That's why I'm getting a F-150 5.0
By Pneumothorax on 6/21/2011 10:56:38 PM , Rating: 2
You do realize that all the vehicles you bring up are all naturally aspirated? Much simpler than a DI/Turbo engine.

By robertisaar on 6/22/2011 11:53:44 AM , Rating: 2
naturally aspirated vs forced induction has nothing to do with direct injection.

RE: That's why I'm getting a F-150 5.0
By Manch on 6/22/2011 8:56:30 AM , Rating: 2
Yeah, I'd get the 5.0 over the ecoboost. Check the Forums, they have dyno comparisons out already. RWHP is very similar. So if you have to choose between the two, while the ecoboost is impressive, the 5.0 is definitley better in my opnion, but that's because I'd slap a blower on it!

RE: That's why I'm getting a F-150 5.0
By B-Unit on 6/22/2011 11:35:47 AM , Rating: 2
LOL so for the same power, you would rather have less MPG?

As part of their launch marketing, Ford did something a little bit special with a 3.5L EcoBoost engine. Follow the story on YouTube.

There is no doubt in my mind the new EcoBoost F-150 are good for every bit of 150,000, and based on the teardown, I'm pretty confident in 300,000+. IF I get into the market for a pickup in the next couple years, it WILL be an EcoBoost F-150.

RE: That's why I'm getting a F-150 5.0
By Manch on 6/22/2011 1:56:16 PM , Rating: 2
Yes, 1MPG is not a concern to me. YOU can buy an EcoBoost. For me it WILL be the 5.0 bc if you re-read my last post, you'll see that I said I would slap a blower on it.

By Pneumothorax on 6/23/2011 5:26:05 PM , Rating: 2
Yup, that would be a beastly combo. The Coyote engine is top-notch. Gives a M3 a run for the money.

Not Methanol! Ethanol
By shabodah on 6/22/2011 10:02:15 AM , Rating: 2
Funny how people are quick to mention water/alcohol injection, but don't mention Ethanol.

Ethanol fueled engines have significantly reduced carbon build-up. There are a lot of upsides about E85 that are completely ignored, if not being slandered by the oil companies in the first place.

RE: Not Methanol! Ethanol
By Manch on 6/22/2011 10:31:08 AM , Rating: 2
Well I guess the guy who had his car dynod could switch if his car is compatible but he'll make less horspower, which is the issue he's having so it really doesnt help him.

There are a lot of downsides to ethanol also:
It's heavily subsidized
It takes more energy to make it than it produces
It's corrosive to most cars fuel systems
Less energy dense than gasoline
Raises food prices

Granted I'm talking about corn, since that's how most of it's made. Switch grass and other methods are promising though.

It is funny though how nobody will never mention the negatives of the product their advocating!

RE: Not Methanol! Ethanol
By shabodah on 6/22/2011 11:37:00 AM , Rating: 1
Well, seeing as the oil industry and the American Government, which is pretty much run by people who are in the oil industry's pocket, are the ones who feeding you that misinformation.

E85 makes more power when used as a fuel in the same engine than gasoline does. It gets worse fuel economy, but that's not what was in question here. Because it makes more power in the same size engine, it allows a smaller engine to make the same power as a larger one, giving better powertrain packaging which can help increase fuel economy.

Oil is the most subsidized industry in the world. The US government gave the oil industry 40 Billion Dollars in tax brakes for the first quarter of 2011.

While when using corn, it is very debatable what the net energy equation is, chemistry is much like anything else affected by physics. If someone could come up with a fuel that took less energy to produce than it makes, they'd have a perpetual motion device. It's not possible. The oil industry is using very old research to support their case here.

Engines produced in the last two decades do not have issues with corrosion when running E85. The corrosive qualities of E85 are not really an issue in 2011, the data used is far past obsolete for the studies quoted for most those arguements.

When there are fewer BTUs per gallon in Ethanol, the BTU to used energy conversion rate is higher. There is far more to how converting a fuel into motion is done than a simple statement of BTUs.

The If all the Farmland in the American State of Iowa was used to grow food crops, it could produce enough to feed 6 billion people. Yes, the games that have been played in the market, especially with corn have made food prices go up, but, corn is the worst-case-scenario for a crop. It doesn't matter if you're making food, feeding cattle, or making fuel, there is hardly anything you can grow that is a less efficient use of farmland than corn. Furthermore, it is harder on the soil that just about every other crop.
Regardless of fuels, as a people, the American population is far too dependant on corn and beef production. Neither are an important part of any animal's diet, either.

I find it funny how lobbying has ruined everyone's perception on reality.

RE: Not Methanol! Ethanol
By B-Unit on 6/22/2011 12:50:08 PM , Rating: 2
Please explain how less energy per volume equals more power in the same engine? This seems rather impossible.

RE: Not Methanol! Ethanol
By Manch on 6/22/2011 2:24:02 PM , Rating: 2
In the same engine, it will not do anyting for you, and will hurt your mileage and your hp/tq.

If your engine is setup for it tho, since ethanol has a higher octane rating 105-108 it's very resistant to knock. Therefore you can run even higher compression/advance the timing compared to a gasoline engine. The caveat is you will need a bigger fuel pump and larger injectors bc you will use it up quicker than you would regular gasoline.

RE: Not Methanol! Ethanol
By Manch on 6/22/2011 2:15:44 PM , Rating: 2
Well, going thru my owners manual it says in bold to not use E85 because it's corosive to my fuel system. E85 compatible cars use stainless steel fuel systems. If your car is labeled "FlexFuel" or whatever the moniker is then sure go ahead and use it if you like.

e85 has a higher octane rating so you can use higher compression/more timing and burn leaner and get more HP/TQ than you can with gas if you set the car up to do so, but you're burning a lot more of it because it's less energy dense. In a stock engine it will not make much difference, and will oten times make less. It's like putting premium in a car that's tuned for regular, does nothing but waste your money.

There's a big difference between a tax break, and subsidies taking money out of my pocket to give to someoen else aka wealth redistribution

The energy is already stored in the oil(hydrocarbons). The corn has to be converted to ethanol. So no, it does not take more energy to make gas than it produces. Distillation is nowhere near as energy consuming as converting corn to ethanol.

What does Americas consumption of beef and corn have to do with this?

Not everyone that dislikes corn ethanol is conspiring with big oil and the G-men.

RE: Not Methanol! Ethanol
By shabodah on 6/23/2011 9:59:24 AM , Rating: 2
What does consumption of beef and corn have to do with corn ethanol?!?!? Everything.

We grow 99% of the corn in the US for cattle/livestock foodstuffs, 1% for human consumption.

I'm against corn ethanol myself, or I wouldn't be pointing this out. Ethanol is a good energy alternative, corn ethanol isn't.

Recent research has found that E50 (50/50 gas/ethanol) delivers better power density and fuel quality than any other combination, when an engine is purposely built to run on it. That is because it has 98% of the detonation resistance of pure ethanol, and 85% of the power density, which allows it to run in much higher compression engines, which helps reduce the difference in fuel economy greatly. Also, the ability to resist detonation is what allows it to be run much leaner than gasoline, which also makes up for the economy difference. GM is reporting almost no fuel economy loss in their new flex-fuel Buick Regal versus using gasoline. Technology is not standing still as the oil companies keep trying to make us believe (and they've had the car companies help with that, too).

Here's another link to more current info:

RE: Not Methanol! Ethanol
By FITCamaro on 6/22/2011 2:20:26 PM , Rating: 2
The only benefits of it are rarely cared about by the masses.

Ability to run higher compression and the cooling effect aren't really cared about by people who need a sensor to tell them to check their tire pressure.

RE: Not Methanol! Ethanol
By RU482 on 6/22/2011 7:33:36 PM , Rating: 2
any thoughts on running your tank empty, then running a few gallons of E-85 down to an excersize in cleaning the fuel system?

VW's FSI carbon issue
By cmosentine on 6/21/2011 10:17:15 PM , Rating: 3
I own a 2008 Jetta Wolfsberg with a 2.0 FSI engine. I can tell you MANY members on the VWvortex forums have issues with carbon build up with major buildup occurring by 50K miles. Check out some of the threads and pictures.

On the FSI engine, there are two main causes of these deposits. The biggest culprit is the PCV system which dumps crankcase vapors laden with oil directly into the intake. When this vapor hits the HOT intake valves if burns onto them leading to the buildup. The second issue is an apparent valve seal design which allows very small amounts of oil to weep down the valve shaft.

I plan of pulling my intake manifold at 50K and blasting the valves with walnut shells. As for Seafoam, it really does not touch this stuff. Owners who have preformed a valve cleaning by hand report taking around 1 hour per cylinder to scrape the stuff off.

Lexus has the best system as the port injectors dump gas onto the valves thereby cleaning them.

RE: VW's FSI carbon issue
By YashBudini on 6/21/2011 10:40:01 PM , Rating: 2
I wonder if Mobil 1 would reduce this problem.

RE: VW's FSI carbon issue
By flyingrooster on 6/22/2011 1:23:34 AM , Rating: 2
All of the VW FSI engines require synthetic oil. FWIW, Mobil 1 is really overrated.

RE: VW's FSI carbon issue
By Manch on 6/22/2011 9:14:33 AM , Rating: 2
AMS OIL is pretty good

RE: VW's FSI carbon issue
By Integral9 on 6/23/2011 8:49:56 AM , Rating: 2
I'm not really a fan of Mobil-1 either, but if they have a product that satisfies the VW spec for that engine, you should be ok.

fwiw: I always put Castrol Syntec 5w40 in my '97 Audi 1.8T (AEB) and the turbo is still pulling strong with over 100,000 miles on it.

RE: VW's FSI carbon issue
By Alexvrb on 6/22/2011 7:09:14 PM , Rating: 2
Well when you use seafoam or similar to clean an engine, if its really bad, you use most of the can and then stall the motor out. Do this after you get the engine good and hot! Let the seafoam soak for a while, and then fire it up and take it for a spin. YMMV, and I'm not convinced I'd do this on an all-aluminum 4 banger.

Although I guess you could just kill the ignition while pulling seafoam in, rather than stalling the motor. That would require a second person or a long hose. Might not get as much seafoam soaking in there either, but should still get the job done better than just burning through a can of seafoam without letting it soak at all.

Oh, and I've noticed that instead of a traditional PCV valve, some engines use an air oil seperator (AOS). I wonder if something like this would be a better at keeping oil out of the intake, while still letting the crankcase vent. On second thought, oldschool performance setups have it right, just vent that crap into the atmosphere and forget about it. :P

Methanol Injection
By abscode on 6/21/2011 6:47:23 PM , Rating: 2
Seems I should stop putting off the install of that methanol injection kit, just in case.

RE: Methanol Injection
By bildan on 6/21/2011 7:58:39 PM , Rating: 2
Methanol+water injection will indeed remove and prevent carbon buildups.

Way, way back, I modified a 1972 Datsun 240Z adding a turbo charger and water-alcohol injection. The valves and spark plugs were always so clean they looked new.

In my garage I have a modified windshield washer reservoir with pump which I can plug into the cigarette lighter socket. To clean an engine, I run tubing with a tiny spray head to the air intake. Then I drive up a steep hill at full throttle with the pump delivering a fine spray of a 50-50 mixture of methanol and water to the intake. 1 -2 minutes of this and the carbon is gone.

RE: Methanol Injection
By YashBudini on 6/21/2011 11:04:15 PM , Rating: 2
Given that water turns to steam in the combustion chamber I whether you could have obtained the same "clean" results even without the methanol.

a 50-50 mixture of methanol

What affect does this have on gaskets? Hoses?

RE: Methanol Injection
By Manch on 6/22/2011 9:06:16 AM , Rating: 2
Shouldnt hurt it, and I've never had any issues with it. Water/meth is a very reliable long as you dont run out. Newer kits have sensors to pull timing if the tank gets low to prevent issues.

RE: Methanol Injection
By Burned on 6/27/2011 11:05:13 AM , Rating: 2
RE: Methanol Injection
By Bad-Karma on 6/22/2011 3:50:01 AM , Rating: 2
I've got a 28gal tank under the truck for water/meth. The injector is just below the turbo at the Y pipe. Mine is set to run proportionally to the boost pressure. I use it anytime I've got the 5ft wheel, long trips or in the mountains , or just want to scare the pants off a guy at the spotlight. I don't know about you but when I punch the throttle I start feeling pretty sorry for anyone behind me. I've left 2ft wide soot stripes on cars before.

But I'm with you on the steam keeping everything clean. My engine is at 245,00 and the internals still look almost new.

By slap_ on 6/21/2011 7:05:02 PM , Rating: 2
The carbon buildup is partially caused by the EGR. I know that some people have used a product called Seafoam to clean their intakes of buildup.

By Alexvrb on 6/21/2011 7:35:27 PM , Rating: 2
EGR in a typical semi-modern non-DI engine doesn't cause any significant increase in carbon buildup. In fact some engines don't even use dedicated EGR valves. They perform the same functionality using VVT by pulling in enough exhaust gases via the exhaust valves (during the intake stroke).

A traditional EGR valve setup might affect DI engines significantly more. However if it does, I don't see any reason why they couldn't do what I mentioned above and use the exhaust valves to do the job (and skip the intake valves altogether). That would solve that problem, I'd think.

Anyway, the benefits of EGR are there for gasoline engines, even if you need to approach EGR differently for different engine types. I'm not quite as sold on EGR for diesels, but that also comes down to implementation. Nothing I've seen is worse than the EGR system on Ford's previous 6.0L diesel.

By GreenEnvt on 6/21/2011 8:10:15 PM , Rating: 2
Seafoam rocks. Ran a can through my motorcycle this spring, after I forgot to put in fuel stabilizer in the fall. Cleaned up the rough running and sputtering by halfway through the tank.

By FITCamaro on 6/22/2011 2:41:26 PM , Rating: 2
Works on pretty much any engine. Cars, trucks, motorcycles, boats, lawnmowers, etc.

By undummy on 6/21/2011 8:39:21 PM , Rating: 2
PCV is another culprit(if not the major cause). I don't see EGR as the major cause. Poor fuel quality and lame oil performance, along with EGR/PCV, are all culprits adding to the issue.

By Manch on 6/22/2011 9:12:27 AM , Rating: 2
Yup, just pop off a vacuum line and feed it slowly while the engine is running. Once it's all in their, just rev the eninge up and down till the smoke out of the exhaust clears. I do this before I remove the plugs on my car. 3V mustangs are notorious for carbon buildup around the sparkplug. If you dont clean before you attempt to remove the plugs, you're almost guaranteed to snap a plug off.

Can anybody answer this question.
By YashBudini on 6/22/2011 12:00:25 AM , Rating: 2
I've never heard of diesel engine suffering from pre-ignition. Now if that's true and if it's because of the method and timing of the delivery of the fuel then the question becomes are DI gas engines also immune to pre-ignition?

Keep in mind, it's just a question.

If the answer is yes then there goes the need for any knock-sensors?

By undummy on 6/22/2011 12:05:50 AM , Rating: 2
Diesels can pre-ignite.

DI gasoline engines are not immune to pre-ignition. Knock sensors will still be needed.

By kleinma on 6/22/2011 1:06:24 AM , Rating: 2
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.

I would say tire quality would be a big factor as well. If they weren't the same each time on the dyno, that would affect the result.

RE: also
By Bad-Karma on 6/22/2011 3:58:50 AM , Rating: 2
As the Dyno "wheel" actually raises up and lifts the vehicle, tire quality is pretty negligible to the test. Plus your axle is chained into place against the wheel. If your tires still can't get traction at that point then you've got bigger issues to deal with.

A good dyno shop will ensure that the tires are properly inflated to make the run but not much beyond that.

only $1200 for a valve job on an v8 audi!?!?!
By Integral9 on 6/22/2011 10:22:47 AM , Rating: 2
if that guy's mechanic is a qualified audi mechanic, i gotta get his number.

By Fost04mach on 6/22/2011 5:50:18 PM , Rating: 2
They probably did it the redneck method, how they clean the clogged tdi intakes, with a propane torch and an air compressor :)

Patent water
By 0ldman on 6/22/2011 11:10:13 AM , Rating: 2
Seriously, a small scale water injection system somewhere in the intake.

Old school mechanic trick. Get it good and hot, idled up to around 1500-1700 RPM, almost choke it down dripping water into the intake.

Anyone that has ever worked on a car with a blown headgasket already knows what I'm talking about.

Simple solution
By FITCamaro on 6/22/2011 1:34:38 PM , Rating: 2
Use a simple bottle of engine cleaner a couple times a year and don't buy cheap gas.

Seafoam is about $10-15 and does wonders. You can pour it in the gas tank to clean out the fuel system and run it through the intake to clean out your intake and injectors. It will also clean the valves.

Just need a dropper to run it through the intake. But from what I hear they now make a spray that you can spray directly into the throttle body instead of needing the dropper.

My solution is better
By Fost04mach on 6/22/2011 5:47:54 PM , Rating: 2
Kind of how they made the urea injection on diesels; they should do something similar with the DI engines, a separate tank, filled with Seafoam, every x number of miles open the thing and let it rip. They could even sell it as a Prius deterrent system, putting an ugly-sensor on the back bumper, and when it senses a Prius, let the smoke show begin.

By RU482 on 6/22/2011 7:29:36 PM , Rating: 2
I was just thinking about this today. Hyundai claims the Sonata gets a class leading 35MPG. New. I wonder what that number will look like after 50,000 miles....or 100,000 miles. throw this issue into the mix, and I bet its less than 30MPG running the same test.

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