A video on direct injection

IDriveACivic

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https://www.youtube.com/watch?v=xrLNDgrIw3U
I came across this informative video on the pros and cons of direct injection engines. As you are all aware, the higher end engine on the new Civic has direct injection and turbocharging. As I gathered from the video, this is not a good combination when we are talking about engine longevity. It is also my understanding that carbon deposit by the intake valve is not necessarily the end of the world, but one would notice reduced performance and efficiency.

I'm not very savvy at all when it comes to the underpinnings of automobiles, so I'm wondering what everyone on this forum thinks about this issue. Obviously, CivicX is not the only vehicle out there that has direct injection and/or turbocharger. What are some things average consumers can do to mitigate the problem of carbon buildup? I read the "Italian tuneup" method is pointless.
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CivicXI

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I know a lot of people are paranoid. But have we actually seen a case of the 1.5T having enough carbon deposits to affect gas mileage/power? I mean the engine's been out 2+ years in over a million cars and I'm sure quite a few people have over 50000 miles on it.

Honda is not stupid, they're not going to risk their reputation on a new engine that is sold globally in their 3 main lines, the Civic, Accord, and CRV. My best guess is that engineers have been pulling tricks from the diesel and DI world using the past 2+ decades of experience to implement things such as exhaust gas re-circulation and valve overlap. I'm willing to bet that all the moisture in recirculated exhaust gases basically steam cleans the intake valves. They also may occasionally leave some un-burnt fuel in the chamber and overlap the intake and exhaust valve enough that it pushes a small amount of fuel back over the intake valve seats to clean it.
 
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IDriveACivic

IDriveACivic

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I know a lot of people are paranoid. But have we actually seen a case of the 1.5T having enough carbon deposits to affect gas mileage/power? I mean the engine's been out 2+ years in over a million cars and I'm sure quite a few people have over 50000 miles on it.

Honda is not stupid, they're not going to risk their reputation on a new engine that is sold globally in their 3 main lines, the Civic, Accord, and CRV. My best guess is that engineers have been pulling tricks from the diesel and DI world using the past 2+ decades of experience to implement things such as exhaust gas re-circulation and valve overlap. I'm willing to bet that all the moisture in recirculated exhaust gases basically steam cleans the intake valves. They also may occasionally leave some un-burnt fuel in the chamber and overlap the intake and exhaust valve enough that it pushes a small amount of fuel back over the intake valve seats to clean it.
Good points! Ultimately time will tell how these engines run in the long-term.

Honda (and other brands like Mazda and Subaru) might partly be forced to go direct engine due to emission standards.
 

CivicXI

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Good points! Ultimately time will tell how these engines run in the long-term.

Honda (and other brands like Mazda and Subaru) might partly be forced to go direct engine due to emission standards.
Mazda is way beyond that. They are dieseling their next gen gasoline engine.
 
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IDriveACivic

IDriveACivic

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Mazda is way beyond that. They are dieseling their next gen gasoline engine.
Ahh the mad scientists of Mazda. SkyActiv-X is still a year away from hitting the market? As a consumer, I'd be wary of new major tech in the first year.
 

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I know a lot of people are paranoid. But have we actually seen a case of the 1.5T having enough carbon deposits to affect gas mileage/power? I mean the engine's been out 2+ years in over a million cars and I'm sure quite a few people have over 50000 miles on it.
We don't.

General comments for this thread: A lot of this is based on experience from automakers who were believed to have rushed their engineering to meet global economy standards. It's believed many of the early DI powertrains were based off port injection designs, instead of building from the ground up.

Modern DI powertrains seem to have gotten a lot better. Others like Honda and <soon to be> Toyota have had much more development time to their advantage.

More in depth-discussion here:
http://www.autonews.com/article/201...ast-honda-and-toyota-prepare-for-turbo-charge
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