The problems with GDI

[burbguy82]

Solving Gasoline Direct Injection Issues: The facts and fictions of GDI - Engine Builder Magazine

Learn about the challenges and solutions related to Gasoline Direct Injection (GDI) in engines. Issues, design flaws, and potential fixes.

www.enginebuildermag.com

Interested to know the mode of some on this forum on this topic. Some find there to be no issues with these designs, while other hate them. Do some here have some real world usage data or experiences with DI? Can you substantiate some of these issues, or write them off as just a nothing burger? Are there any mechanics who in the past 10 years or so observed issues that did not exist before the industry's change to this new "better" system?

 

[buster]

“You’re not seeing this carbon buildup on race engines as much because they’re essentially wide open all the time,” Dickmeyer says. “The port velocity through the engine through the intake port and through the exhaust port is so fast that a lot of this stuff just doesn’t have the time to occur. It’s really the worst on a production vehicle where it sees a lot of throttle and idle time.”

Hmm so driving it harder helps?



"These valves are running hot, so when oil droplets come through the intake port and pass through the cylinder head they’ll stick to the backside of the intake valve. That starts to build up layers and it’s not just a layer of ash or goo, it almost turns into something like a lava rock and it will be surrounded with a greasy slime, which makes it worse and traps dirt.”

These droplets of oil and small amounts of dust and dirt make their way through the intake ports, which are coated with sticky oil and creates a plaque layer that builds up thicker and thicker and thicker."

GM 3.6 V6 with 42k

 

[ARCOgraphite]

Wondering aloud if the old solution using A.I.R pump or reed valve carrying PCV directly into the exhaust just post-cat might help.
You will still have E/I valve overlap at certain cam phasing but that can be mostly tuned out at low speed - if they were not also trying to achieve EGR through VVTi cam position at low speed. - Arco

 

[bullwinkle]

GDI engines really, REALLY need a factory catch can...

 

[IndyIan]

Interesting stuff!
So far we have remained GDI free but it seems some of the manufacturers are getting it figured out.

 

[Bailes1992]

Where I've been able to, whenever we've bought a petrol powered car, if there was a port injected model I've always made sure we purchase that instead

 

[buster]

GDI engines really, REALLY need a factory catch can...

The GM LGX 3.6 has one and it still has carbon buildup. Even those with catch cans end up with it.

 

[Triple_Se7en]

The problems are lazy, broke vehicle owners who won't do the necessary maintenance and won't take unpopular steps to reduce the carbon / soot buildup.
Mid/premium fuel, 12k intake spray cleanings, shortened OCIs and Dexos 1 Gen 3 oils are just 4 of numerous, unpopular ways to help keep the engines cleaner.
Do a Google Search on this subject and find more ways. But if you just want to look at your GDI / TGDI outside in the backyard and continue to sit on your hands, then expect conditions to worsen over time.

 

[buster]

"Restore & Protect can help clean intake valves. It is our highest-performing product in the Valvoline portfolio. While other Valvoline products focus on wear prevention, Restore & Protect couples wear protection while actively helping restore engine cleanliness and protect against future damage by dissolving engine-killing deposits, and meets the demanding requirements of turbo-charged and gasoline direct injected engines. This engine oil meets or exceeds all requirements of ILSAC GF-6A, API SP, API SN with SN PLUS, API SN, Resource Conserving, and all preceding API and ILSAC gasoline categories."

 

[burbguy82]

Mid/premium fuel, 12k intake spray cleanings, shortened OCIs and Dexos 1 Gen 3 oils are just 4 of numerous, unpopular ways to help keep the engines cleaner.

All correct, but is all that nessessary? Previous ICE did not require any of those things.

Seems like these were designed to increase the fleet MPG by a small amount, but add tons of cost to the consumer.

 

[burbguy82]

The GM LGX 3.6 has one and it still has carbon buildup. Even those with catch cans end up with it.

wonder how?

 

[ecotourist]

The problems are lazy, broke vehicle owners who won't do the necessary maintenance and won't take unpopular steps to reduce the carbon / soot buildup.
Mid/premium fuel, 12k intake spray cleanings, shortened OCIs and Dexos 1 Gen 3 oils are just 4 of numerous, unpopular ways to help keep the engines cleaner.
Do a Google Search on this subject and find more ways. But if you just want to look at your GDI / TGDI outside in the backyard and continue to sit on your hands, then expect conditions to worsen over time.

I understand using better oil but why shortened oil change intervals? I would have expected a small early "flash off" from fresh oil. Is that offset by fuel in old oil, or what?

I don't know which would be better for the GDI intake valves - longer or shorter oil change intervals. And why?

Fortunately I've avoided GDI thus far and hope to keep it that way.

 

[BMWTurboDzl]

Solving Gasoline Direct Injection Issues: The facts and fictions of GDI - Engine Builder Magazine

Learn about the challenges and solutions related to Gasoline Direct Injection (GDI) in engines. Issues, design flaws, and potential fixes.

www.enginebuildermag.com

Yet 7 yrs after this article was printed.........GDI engines are doing just fine.

 

[demarpaint]

EFI should have been left alone, it worked fine.

 

[nascarnation]

EFI should have been left alone, it worked fine.

My 2004 GM 3.6 had 260hp and averaged about 18 mpg. My 2023 with DI has 310hp and averages 23 mpg. I realize there have been other improvements but the DI along with added compression it allows is the big one.

 

[nascarnation]

Yet 7 yrs after this article was printed.........GDI engines are doing just fine.

It reminds me of when America's highway shoulders were lined with broken cars due to the Fram (edit - MOD).

 

[demarpaint]

My 2004 GM 3.6 had 260hp and averaged about 18 mpg. My 2023 with DI has 310hp and averages 23 mpg. I realize there have been other improvements but the DI along with added compression it allows is the big one.

As you mentioned there were other improvements along the way. My bet is the numbers might be a little closer with those improvements minus the DI. The 3.6L Pentastar makes HP 305 HP in the RAM 1500 w/o DI. My bet is similar HP and mpg for your 2023 example.

 

[WobblyElvis]

I'm on my second GDI car. I change oil maybe every 6,000 miles using store brand synthetic. I never use any fuel additive or spray cleaner. Regular gas. No catch can. First car, a 2008 Cadillac CTS with 3.6 V6 producing 304 hp. went over 250,000 miles trouble free until scrapped due to rust. I now have a 2016 Elantra [heaven help me] with GDI and 140,000 miles. Again, no special treatment. It burns some oil but is trouble free. I have nothing against GDI.

 

[Sayjac]

Agree with mentioned article publication age notation. While I won't link to it, I found a more recent yt video by "Engineering Explained" with 'imo' very useful information. A google search of 'three problems with GDI" first vid choice should be it. Own a couple GDI now, pay most attention to using oil certs/approvals type recommended in that vid. Beyond that nothing special.

I would add, 'seems' that combining smaller 4 cylinder turbo engines combined with gdi, presents the biggest challenge. Neither of those a type engine I own.

 

[pbm]

Yet 7 yrs after this article was printed.........GDI engines are doing just fine.

Tell that to the Equinox owner mentioned in the article.