Thoughts on direct injection?

[SwampSurvivor]

Originally Posted By: supton
Lots of debate on it. If you ask me, wait another year or two and the answer will be evident.

From what I read here, it is starting to look good. A number of early cars had problems, but as things have rolled along, the teething pains are coming to an end. And a few models seem to have skipped problems altogether.

But I plan to let others be the early adopters. Another year or two and the answers should be known.



You already have one direct-injected engine in your stable

 

[OneEyeJack]

DI in common use for gasoline engines started about 20 years ago and in the evolution of the gasoline engine that still makes it relatively new technology if you consider that the gasoline engine has been in continuous development for more than a hundred years. When it replaces all other fuel injection systems like fuel injection replaced carburetors in the 80's then it can be considered main stream technology.

DI has had an amazingly good start with few problems if you consider what it takes to make such an idea work. The final solution will only appear when these last few problems get worked out.

The real driving force is market place competition, not rules and regulations. Rules and regulations got it started but bragging rights will finish the job.

 

[edyvw]

I ahve two DI cars, no issues so far at all. Always used Castrol 0W30, M1 or Castrol 0W40. Tried several times Mobil1 ESP 5W30 (Low-SAPS since fits better DI, but US gas not really compatible with Low-SAPS oils).
OCI at 5K.

 

[Vuflanovsky]

I like the idea that this topic has started to morph from "We're all going to die" to an acknowledgement that the carbon deposit issue may not be anywhere near as bad as what that internet engineer told me about carbon deposits being a GIVEN problem with GDI engines and I need to plan and budget for the walnut shell blasting.

I own a DI car with no carbon issues but relatively low miles. Is it too bold to say that the old VW/Audi designs seem to be more prone to coking than newer designs?? Could it be logical that the VW/Audi DI designs of old are not the same as the Asian makers and there are ( gulp ) differences?? I thought that this idea of carbon deposits was sacrosanct because an engineer told me. Funny, I know someone who has the same DI car as myself and now has 95K miles with no issues. Maybe he can use that walnut blasting money for a new dishwasher after all.

 

[Quattro Pete]

Originally Posted By: Vuflanovsky
Is it too bold to say that the old VW/Audi designs seem to be more prone to coking than newer designs??

Can't really tell. The newer designs haven't been around long enough to provide statistically viable data.

Interestingly, VAG has introduced secondary port fuel injection on some of their recent DI engines, but the US isn't one of the countries where they made them available.

 

[Vuflanovsky]

Yeah, probably true. My point was that at least there's an acknowledgement that saying "DI engines are DI engines" might not be an appropriate statement where carbon deposits are concerned...possibly inclusive and independent of the general type of maintenance done.

 

[supton]

Originally Posted By: Miller88
Originally Posted By: supton
Lots of debate on it. If you ask me, wait another year or two and the answer will be evident.

From what I read here, it is starting to look good. A number of early cars had problems, but as things have rolled along, the teething pains are coming to an end. And a few models seem to have skipped problems altogether.

But I plan to let others be the early adopters. Another year or two and the answers should be known.



You already have one direct-injected engine in your stable


You know what is unfortunate? I think the design has finally proven itself. But VW hasn't sold this engine here for several years now, so it is not like I could buy another. [And of course the known weak spots would keep me from buying a used one.]

 

[pitzel]

Originally Posted By: cptbarkey
Originally Posted By: pitzel
Pretty sure the issues with direct injection, namely the gradual occlusion of the intakes, was nailed down to certain users overly-frequently changing oil and using improper (ie: too volatile) lubricants for the job.


elaborate, or stop making up trash like the 40k OCI is okay thread.


I beg your pardon? You're making a pretty serious accusation here, which is certainly against the spirit of BiTOG, if not the explicit rules.

Might I add to my previous posts that the intake occlusion issues almost never turned up in Europe, where the culture is to adhere to manufacturer OCI intervals (not the made-up 3k mile nonsense that much of the industry still pushes here) with the proper oils. Intake occlusion was pretty much a "Made in USA" issue caused by improper maintenance including over-maintenance and substitution of appropriate oil for inappropriate oils in the name of saving a few bucks.

 

[Quattro Pete]

Originally Posted By: pitzel
Might I add to my previous posts that the intake occlusion issues almost never turned up in Europe, where the culture is to adhere to manufacturer OCI intervals (not the made-up 3k mile nonsense that much of the industry still pushes here) with the proper oils. Intake occlusion was pretty much a "Made in USA" issue caused by improper maintenance including over-maintenance and substitution of appropriate oil for inappropriate oils in the name of saving a few bucks.

From what I've read, the primary reason why DI deposit issues are not as prevalent in Europe is due to different ECU programming (air:fuel map) as a result of different emissions requirements. Don't recall the details, but here in the US we are not allowing the engines to lean burn due to NOx emissions requirements. Whereas lean burn results in hotter engine temps that allow these intake deposits to burn off more easily.

 

[cptbarkey]

Originally Posted By: pitzel
Originally Posted By: cptbarkey
Originally Posted By: pitzel
Pretty sure the issues with direct injection, namely the gradual occlusion of the intakes, was nailed down to certain users overly-frequently changing oil and using improper (ie: too volatile) lubricants for the job.


elaborate, or stop making up trash like the 40k OCI is okay thread.


I beg your pardon? You're making a pretty serious accusation here, which is certainly against the spirit of BiTOG, if not the explicit rules.

Might I add to my previous posts that the intake occlusion issues almost never turned up in Europe, where the culture is to adhere to manufacturer OCI intervals (not the made-up 3k mile nonsense that much of the industry still pushes here) with the proper oils. Intake occlusion was pretty much a "Made in USA" issue caused by improper maintenance including over-maintenance and substitution of appropriate oil for inappropriate oils in the name of saving a few bucks.


still waiting on references.

 

[edyvw]

Originally Posted By: cptbarkey
Originally Posted By: pitzel
Originally Posted By: cptbarkey
Originally Posted By: pitzel
Pretty sure the issues with direct injection, namely the gradual occlusion of the intakes, was nailed down to certain users overly-frequently changing oil and using improper (ie: too volatile) lubricants for the job.


elaborate, or stop making up trash like the 40k OCI is okay thread.


I beg your pardon? You're making a pretty serious accusation here, which is certainly against the spirit of BiTOG, if not the explicit rules.

Might I add to my previous posts that the intake occlusion issues almost never turned up in Europe, where the culture is to adhere to manufacturer OCI intervals (not the made-up 3k mile nonsense that much of the industry still pushes here) with the proper oils. Intake occlusion was pretty much a "Made in USA" issue caused by improper maintenance including over-maintenance and substitution of appropriate oil for inappropriate oils in the name of saving a few bucks.


still waiting on references.

No issues in Europe. I was talking to some mechanics over there, and they looked at me with question mark on their face when I mentioned deposits.
There are several variables:
1. ECU programing, leaner burn
2. Low Sulphur gas, which allows usage of Low-SAPS oils.
3. I would add also more demand on cars since highways are much faster, even those that have speed limit.

 

[SwampSurvivor]

I don't think lean burn is allowed here in the US. They have to run richer to keep the catalyst up to temp.

 

[badtlc]

Originally Posted By: Miller88
I don't think lean burn is allowed here in the US. They have to run richer to keep the catalyst up to temp.


DI engines in the USA use an "ultra lean" or stratified burn mode. It actually reduces emissions.

 

[OneEyeJack]

Is the gasoline in Europe better quality than here?

 

[edyvw]

Originally Posted By: OneEyeJack
Is the gasoline in Europe better quality than here?

Yep, much less sulphur!
Cali gas is closest to Euro gas.
When I lived in San Diego, I could not smell gas odor in oil at all. As soon as I moved to CO, odor returned (previously lived in Alabama).

 

[Merkava_4]

Originally Posted By: Quattro Pete
http://auto.howstuffworks.com/positive-crankcase-ventilation-system.htm


Thanks Pete.

 

[Bamaro]

One question for those who say that they have DI with no problems, how do you really know? I think that everybody would agree that clean valves are better than dirty valves. Unless you open up the engine and look, how do you really know? Maybe you are getting 27 MPG instead of 29. Maybe your 0 - 60 is 9 seconds instead of 8. Maybe you are putting out 5% more pollution. All that I am saying is that it is not always easy to see effects like these.

 

[itguy08]

Originally Posted By: Bamaro
One question for those who say that they have DI with no problems, how do you really know? I think that everybody would agree that clean valves are better than dirty valves. Unless you open up the engine and look, how do you really know? Maybe you are getting 27 MPG instead of 29. Maybe your 0 - 60 is 9 seconds instead of 8. Maybe you are putting out 5% more pollution. All that I am saying is that it is not always easy to see effects like these.


Your valves don't care if they are dirty or clean (within reason). Your engine doesn't either as it will adjust the mixture so you are always running well. It's why clean or dirty air filter has negligible effect on MPG.

I've got 88k of MPG data from the Taurus in my signature. It's got no loss of MPG over all this time. It's actually amazingly consistent over that time period. It still runs like a scalded cat too.

I've got close to 20k of MPG data on the F150 in my signature. Pretty consistent there too with more seasonal fluctuations.

If there are "issues" with DI, they sure are not showing up on my vehicles. Always the cheapest swill in the tank, oil changed when the MM says to, and 0 engine issues other than a bum knock sensor in the Taurus.

No reason to be scared if DI is done right.

 

[badtlc]

Originally Posted By: Bamaro
One question for those who say that they have DI with no problems, how do you really know? I think that everybody would agree that clean valves are better than dirty valves. Unless you open up the engine and look, how do you really know? Maybe you are getting 27 MPG instead of 29. Maybe your 0 - 60 is 9 seconds instead of 8. Maybe you are putting out 5% more pollution. All that I am saying is that it is not always easy to see effects like these.


Lots of regular engines have cleanliness problems that aren't causing any easily observable issues without taking the motors apart. Most cars have combustion chamber deposits and build up on piston tops. They assume everything is perfect and it isn't. How is it different?

 

[Quattro Pete]

Originally Posted By: itguy08
Your valves don't care if they are dirty or clean (within reason). Your engine doesn't either as it will adjust the mixture so you are always running well.

Tell it to all those DI owners whose engines run like [censored], their CEL light is on, and they have to go in for periodic cleaning.