GDI deposits - a very different perspective

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wemay

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A small reference to BITOG is even given.


http://www.pecj.or.jp/japanese/overseas/conference/pdf/conference12-19.pdf

from 9/2013

Discussed:

Deposits in GDI vs PFI
IVD and CCD deposits
Effects of engine load on deposits
Effects of fuel and deposit formation
Effects of older oil vs fresh oil
Group II vs III vs IV regading fresh oil and used oil(very interesting page 15 of 20)

I just wish i knew how they defined 'used' oil.
 
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Great article. Thanks for posting.

Something that caught my eye was the 7.5w-30 oil used. I don't know why it caught my eye though. I'm assuming it's just equal parts 5w-30 and 10w-30 mixed.
 
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Yeah, it was odd. The kicker for me is how well, used group II performed compared with the higher end III and even how poorly IV did.
 
Interesting. My bet would be that there might be wide variations in GDI results beyond just the same engine with one GDI and one PFI fuel delivery. For example, the older VW/Audi designs versus this Hyundai Theta II in the test or more recent designs by Ford, Toyota, Honda, etc. I don't buy into the idea that all GDI engines are the same as we seem to be into the second generation of these designs and I wouldn't doubt there might be differing results.

I've always heard the quality of the fuel is more important ( all things being equal ) than the oil regarding these deposits but that hasn't stopped me from using lower NOACK GTL oil in my DI car...which might add yet another crinkle in the results concerning the level of deposits here. I would be of the mind that a natural gas base would be cleaner but I wonder how the additives ( as per the article ) might negate the difference.
 
Originally Posted By: wemay
Yeah, it was odd. The kicker for me is how well, used group II performed compared with the higher end III and even how poorly IV did.


As there wasn't a number given (that I noticed) to how "used" the oil was, I concluded that the reason the Group IV "used" performed badly is that PAO does not hold on to its additive package as well as Group II (best if you don't count Group I oils) and Group III (better than Group IV but not as good as Group II) base stock.
 
Caltex Makes lots of GPII oils. So is the article slanted towards their product? or is it actually a non biased report? .
 
Originally Posted By: CT8
Caltex Makes lots of GPII oils. So is the article slanted towards their product? or is it actually a non biased report? .


If true about Caltex, Interesting side note.
 
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DI is adding complications to engines, higher pressure, more price control, more plumbing, more bits and pieces and so on. Now to solve the possible problems of valve deposits there will be more complication added. And who knows what that will lead to. And so on and so on. We could end up with an additive injection system with its own reservoir with attendant pump, plumbing and monitoring system with warning lights to inject additives into the intake manifold. It's scary enough looking under the hood of a new car and it's only going to get worse as legislation continues to engineer our vehicles.
 
So all the "drive it like you stole it" folks driving GDI cars ought to be fine, while the sedate drivers will have issues.

It would be interesting to see what effect turbocharging has on those issues.
 
Originally Posted By: sciphi
So all the "drive it like you stole it" folks driving GDI cars ought to be fine, while the sedate drivers will have issues.

It would be interesting to see what effect turbocharging has on those issues.


+1
 
My understanding:

•Don't baby the throttle
•Use Grp II oil - it remains most consistent throughout OCI
•Don't extend OCI (more often done if using Grp III, IV)
•Keep fresh oil in the sump no matter the Grp.

This is consistent with Hyundai's oil recommendations and counter the, 'i only use synthetic crowd.'
 
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Interesting and thanks for sharing. It looks like keeping fresh group IV oil in there or use oil with low metallic additive content and run the car at higher load is a good idea.

I'll keep my IS250 strictly for freeway duty.
 
these are intriguing results, but the results are far from conclusive. maybe the 7.5W30 is just a typo, or maybe a sign how unprofessional the whole study is.
 
I'd like to see more of these types of studies as I would agree, I don't think it's particularly conclusive. I'd like to see how a GTL oil performs versus a more conventional oil across several engine makes. With GDI ever expanding, this seems like something that SOPUS could use in their marketing if it made a marked difference.
 
Originally Posted By: wemay


This is consistent with Hyundai's oil recommendations and counter the, 'i only use synthetic crowd.'


Yep, their insistence on short OCI's definitely encourages dino use and frequent oil changes. Maybe they are ahead of the crowd on this.
 
Originally Posted By: Throt
Great article. Thanks for posting.

Something that caught my eye was the 7.5w-30 oil used. I don't know why it caught my eye though. I'm assuming it's just equal parts 5w-30 and 10w-30 mixed.


That implies that mixing equal amounts of two different oil viscosities produces the "arithmetic average" viscosity. IIRC it doesn't

Again, IIRC, the relationship is complex and I'm not sure that the result is entirely predictable, but its heavily skewed towards the lower viscosity.
 
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