DI engines and coaking

[cchase]

Originally Posted By: Rand
Originally Posted By: cchase
Originally Posted By: d00df00d
I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.


Sorry, but I know someone with a 2009 MY vehicle who uses 93 octane and changes oil religiously who had to have the engine de-carboned at 30,000 miles.


what kind of car.. without the type of car your post isnt very useful or informative.


For the record, there was no specific information I was trying to get across, it was just an experience. The vehicle was a 2009 Mini Clubman S. Vehicle was a lease car with oil changed at the proper intervals. FWIW I made a thread when the engine was rebuilt.

 

[Garak]

Originally Posted By: dparm
Garak, which FSI motor was it?


Oh, geeze, you're putting me on the spot. I can't recall off the top of my head. I'll have to see if I can find the issue in my collection (I never, ever throw out magazines, so I'm guaranteed to have it, somewhere). I'm thinking it was in an A4, but possibly an A6, for as much as that narrows it down - not much.

I do recall that I had looked at the article specifically back just after the time that Doug Hillary mentioned that there had been some engineering speculation that the deposits seemed to be lesser when an approved oil was used (obviously) and when drivers went the full OCI, rather than changing early.

C&D is known to follow the OEM recommendations to the letter in their long term tests. Doug had mentioned the matter of not going for early oil changes, and I recalled that an issue of the magazine around that time had completed a long term test of about 30,000 miles, and I knew that Audi did dyno and performance tests at the beginning and end of long term tests. At the end of the test, C&D noted an increase in power, as one expects with a "normal" engine breaking in.

Update - okay, this was bugging me so I checked online. The online version doesn't have all the dyno and performance charts that the print version does, but the link is here. I stand corrected. It was a 40,000 mile test. 0-60 mph times remained the same, and top gear passing times improved. If I find the magazine, I can let you know more. It was a 2009 A4 with the 2.0TFSI.

 

[SteveSRT8]

http://www.caranddriver.com/reviews/2009-audi-a4-20t-audi-a4-test


Here's the test data

 

[PZR2874]

Ludicrous....

 

[dparm]

I'm not sure if the 2.0TFSI has been revised or was just a better design from the start, but the older FSI motors definitely had issues.

As with any technology, these kinks take time to work out and it sounds like the second and third-gen DI setups are getting much better.



Switching gears a bit, why is Pennzoil claiming that VIIs can create problems with buildup?

 

[Quattro Pete]

Originally Posted By: dparm

Switching gears a bit, why is Pennzoil claiming that VIIs can create problems with buildup?

It was generally thought that VIIs contribute to higher volatility which in turn contributes to more deposits. Alas, as you noted, the RS4 guys did not notice a correlation there. Maybe Pennzoil did some tests that showed otherwise.

Supposedly low SAPs also help reduce deposits.