TEOST 33C - any relation to DI Intake deposits?

[jrustles]

Since AMSOIL published their own comparo of various ASTM tests, some have inevitably noticed ranges of variability in the results of various tested blends.

The issue of DI deposits has gained prominence in recent history, with owners concerned about ways to prevent or minimize the issue. Logically, since intake buildup on DI engines are referred to as "deposits", it is then logical to turn to a deposit test. This is perfectly logical. However, logic (by m atching concepts using the same word of the english language) is not enough. This is where the TEOST camp falls short.

A deposit test is not a deposit test is not a deposit test.

TEOST 33C procedure highlight:
This test is specifically modeled to predict turbine bearing deposits.
Full-composition motor oil is pumped over a heating rod in a laminar fashion, which represents a turbine shaft. The full-composition oil is intentionally reacted with oxygen and a catalyst.


A note regarding the higher TEOST deposit on the high-moly oils in the AMSOIL test:
http://papers.sae.org/2008-01-2480/


DI Intake valve:
Highly turbulent environment in which the valve is mainly 'dry'. When they do, some components of the motor oil encounter the valve (light fractions, polymers, P additives) at higher/inproportional ratios vs the full-compositional, laminar, wet flow over the heated-test rod in 33C.

For example, since it is known that organic moly has a markedly negative effect on the 33C, at least two questions arise; how much of a problem is MoDTC (& other additives that may work in a similar way) for dry DI intake valves? How likely are those components to arrive at, and deposit onto the valves?

 

[Olas]

IMO, highly unlikely.

IVDs on GDIs are PCV and EGR related.

 

[wemay]

Originally Posted By: jrustles
...since it is known that organic moly has a markedly negative effect on the 33C, at least two questions arise; how much of a problem is MoDTC (& other additives that may work in a similar way) for dry DI intake valves? How likely are those components to arrive at, and deposit onto the valves?


A very good question.
Especially in light of at least one GDi mfr recommending (high moly) SOPUS oils - Hyundai. I will add though, there is no rash of high mileage Hyundai GDi equipped vehicles (2010+) having intake valve deposit issues to this point.

 

[Olas]

PCV & EGR are responsible for 99% of intake valve deposits, the other 1% is valve timing IMO.

Additive type will only make a difference if youre burning oil, and PCV should vta to solve the problem.

Or a wet manifold.

 

[Shannow]

Somewhat familiar with the test (and desposits where they shouldn't be)...have never been able to mentally correlate that test with DI intakes.

 

[wemay]

Maybe all of it plays a part in intake-deposit prone applications...

Fuel quality
SAPS
TEOST
Noack
OCI
AW pkg

 

[wemay]

As stated by jrustles, it appears that ILSAC uses the TEOST 33c bench test more so for turbine (turbocharger) consideration.

From:
http://www.gf-5.com/the_story/performance/

Turbocharger Protection
Use of the TEOST 33C deposit bench test is being considered in GF-5 to evaluate Turbocharger Protection.

During this test, problems were observed with oxidative degradation/thermal coking of engine oil in the turbocharger bearing area during hot shut-down. It is necessary to protect the bearing from deposits because deposit build-up in the turbocharger bearing area can lead to loss of engine performance and possibly engine failure.

Turbocharger Protection is important, but there are tradeoffs when it comes to Fuel Economy. The detergent and dispersant components that go the metal surfaces to keep the engine's parts clean and prevent deposit build-up in the turbocharger, compete against the friction modifier components that go to the metal surfaces to reduce friction and improve fuel economy.

It is estimated that 15 to 25% of all Ford, GM and Chrysler engines by Model Year 2011 will have turbochargers.

or

http://www.gf-5.com/uploads/File/ILSAC_GF-5_requirements.pdf

Turbo/High Temperature Deposits
Turbocharger and high temperature deposits can rob an engine of critical lubrication and shorten its life. Lubrizol’s
detergent and antioxidant systems maintain cleanliness of critical turbocharger parts.
When compared to GF-4:
Attribute: Reduces formation of harmful engine
deposits and sludge
Benefit: Protects your engine
Substantiation: Sequence IIIG, Sequence VG and
TEOST 33C tests

 

[wemay]

Having read this, and seeing that only AMSOIL's Synthetic 5W-30 test correlates the intake valve deposits to TEOST scores, has me questioning my previous stance on the subject. This is always a learning experience.

 

[Garak]

Look at it this way. If the manufacturers even knew for sure the best way to deal with this from a lubrication standpoint alone, they'd have come up with such specifications. As it stands, there's a reason that we're seeing more hybrid type fuel injection systems. There is no easy answer.

 

[wemay]

Originally Posted By: Garak
Look at it this way. If the manufacturers even knew for sure the best way to deal with this from a lubrication standpoint alone, they'd have come up with such specifications. As it stands, there's a reason that we're seeing more hybrid type fuel injection systems. There is no easy answer.


No arguing that point. "No easy answer"

 

[jrustles]

Originally Posted By: wemay
Maybe all of it plays a part in intake-deposit prone applications...

Fuel quality
SAPS
TEOST
Noack
OCI
AW pkg


Good call with the ILSAC transcription. Doesn't get any clearer than that.
The low SAPS indeed is another possible key in managing IVDs - particularly for controlling the Phosphorus aspect.


http://saefuel.saejournals.org/content/1/1/1534.abstract
(anyone have an account!?)

It's weird, because in 15 years of opening up Redline filled engines, they have always been exceptionally clean, even the turbos. Needless to say, I wasn't buying that Redline is a deposit forming dirty oil at the time the AMSOIL comparo was published.

It is still curious, the chemical reaction that causes a buildup of carbide in the 33C test.

Originally Posted By: Olas

PCV & EGR are responsible for 99% of intake valve deposits, the other 1% is valve timing IMO.

Additive type will only make a difference if youre burning oil, and PCV should vta to solve the problem.

Or a wet manifold.


I agree that PCV is a significant transporter of contaminants. Most EGR these days is done via valve timing though, how that would affect IVDs is yet to be determined. What do you think?

 

[wokeupdead]

Not being an expert on these, I fully believe the change in valve overlap to effect EGR is greatly responsible for causing the crankcase vapors to turn in to deposits in the intake tract/valves.

The vapors are the base material, and the reversion required to use camshafts as EGR("overlap") cause somewhat higher than optimal temperatures in the runners. Just a theory. Doesn't change the end result. Regular and repeated cleanings of intake.