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Old 02-25-2018, 09:01 AM   #1
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Lightbulb Here Are The Pros And Cons Of Direct Injection

https://youtu.be/xrLNDgrIw3U

Well, I guess I'll be looking for the 2.9L 987 instead of the DI 3.4 motor.


Last edited by ekam; 02-25-2018 at 09:04 AM.
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Old 02-25-2018, 09:46 AM   #2
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I have a twin turbo BMW N54 engine in my 535 that needed a ‘walnut blast’ valve cleaning at about 75k miles. It was $400 at an Indy and I had him install a catch can at the same time to limit future buildup. The DI is fantastic in a boosted application w/E85.
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Old 02-25-2018, 09:53 AM   #3
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Quote:
Originally Posted by ekam View Post
https://youtu.be/xrLNDgrIw3U

Well, I guess I'll be looking for the 2.9L 987 instead of the DI 3.4 motor.
Thereís a 2010 base with 91k miles for sale locally, Panama City,FL...my guess is that itíll sell in the $16ís. All Black and looks clean.
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Old 02-25-2018, 10:12 AM   #4
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Good video. I think that most DI owners will simply have to pony up for the cleaning every 50K-75K miles as part of long term maintenance.

For me, it wouldn't necessarily be a fatal flaw that would prevent me from owning a car that I really liked.
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Old 02-25-2018, 10:55 AM   #5
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The fact that it eliminates a self-cleaning system, is ass backwards from an engineering perspective.

It gives you more efficiency and performance ONLY when it's new and both begin to degrade once the system becomes dirty which the manufacturers do not care for, because that means more visits to the dealership.

They made this change to meet emission standards.
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Old 02-25-2018, 11:23 AM   #6
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Thatís why......

....the new trend is to use BOTH DI & Port Injection on the engines.

Each system has pros and cons at different load and throttle settings and putting the port injection back in gives you the valve washing.
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Old 02-25-2018, 12:38 PM   #7
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This is on the 9A1/MA1 motor, they angled the injector so some of the fuel sprays onto the valve.

But you're still screwed if you drive a Panamera or Cayenne.



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Old 02-25-2018, 07:20 PM   #8
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Nice video Eek.. Thanks for posting... Saw some you tube videos on catch cans and was completely lost. This video clears it up.
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Old 02-25-2018, 10:25 PM   #9
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I had a Mini Cooper S with DI loss the motor due to the injector on one of the cylinders being stuck open. Was driving on the freeway in traffic and the motor start running rough. To get to the side of the road safely took a few minutes and that was enough to score the cylinder walls and lose compression. Curious if others have seen this happen with DI Motors?
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Old 02-26-2018, 04:55 AM   #10
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That 9A1 image doesn’t show you the depth. That injector is between the two valves. It is not really washing them. The DI is also at much higher pressure than port injection and fires multiple small pulses. If you are DI only, your detergent gasoline is not helping.

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