A sticky ZP motor oil question.

A sticky ZP motor oil question.

The major antiwear motor oil addditive is an organometallic compound, ZDDP or zinc diakyldithiophosphate that also has anti-oxidant properties. The alkyl branch of the molecule can be modified to change its properties like solubility, active temperature range, and the balance between anti-wear and anti-oxidant properties .
Recently the new ILSAC GF-4 specification requires that the phosphorous levels of the oil must be less than 800 ppm of phosphorus . The reason behind this specification is that the ash forming species of ZDDP , contain phosphorus , zinc and sulpur which are detrimental for catalytic converter performance and other emission control equipment.
According to Mobil, the engine manufacturers are confident that this level of phosphorus will suffice to protect both new and older engines.
Some consumers are concerned about this specification , they are reporting thrust bearing failures in modified performance engines using Mobil 1 5W-20. Exxon - Mobile recommends them, for racing or high performance cars, to move to a Mobile 1 oil with a higher level of phosphorus, however they don't indicate which one.

A question arises :Can we use our favorite racing oil and increase the P level with an ZDDP additive , by-passing the catalytic converter , if the rules allow this:[question]

 

Hi turbocup!!!
I will go beyond your question. It´s a well known problem about Mobil 1 that this oil isn´t working properly in some engines, like VAG group models . What make it undesirable for that engines :confused: ??? will it be improved some way??? will it work properly in a flat six motor for ages???? :[yahoo]
Thinking about all that questions, I won´t recomend it to anyone...
The other question is about the degrees you write down in your post. Isn´t to low a 5w-20 especification???
Cheers!!!
Rain :D

 

PD: I really enjoy to write in english!!! I have to practise to avoid loosing my vocabulary!! :[yahoo] :[yahoo]
Thank you very much!!!
Cheers!!!
Rain

 

Oily Spots

Well, following Porsche recommendations I'm using Mobil 1 0w40 in a Porsche 996 3.4.
Exxon-Mobile claims that his product is fully synthetic. It is a know fact that Mobil 1 contains a polymeric alpha polyolefin base, however it could also contain a Group III Base Oil, but this is only my speculation.
According NPRA ( National Petrochemical & Refiners Association) a Group III base oil is classified as a synthetic oil .
As I'm curious about oil composition I asked Exxon. Yesterday I got this answer.

------------------------------------------------------------------------
Jaime

To meet the demanding requirements of today's specifications (and our customers' expectations) Mobil 1 uses high-performance synthetic fluids, including polyalphaolefins (PAO), along with a proprietary system of additives. In fact, each Mobil 1 viscosity grade uses a specific combination of synthetic fluids and selected additives in order to tailor the viscosity grade to its unique requirement.

Mobil does not disclose specifics regarding our formulation, consumers should focus on product performance not on product formulations.

Thank you for choosing ExxonMobil products.
If you need further assistance, please contact ExxonMobil at 1-800-ASK-MOBIL

-Matt Jacob

 

Oil, have you tried the Silkolene PRO S 5w-40 ? a proper Ester Oil

Although Mobil 1 0w-40 is a good oil a proper synthetic, from a synthetics perspective, esters are better as they are surface-active (electrostatically attracted to metal surfaces) this means that a protective layer is there at all times, even during that crucial start-up period. This helps to protect cams, gears, piston rings and valve train components, where lubrication is “boundary” rather than “hydrodynamic”, i.e. a very thin non-pressure fed film has to hold the surface apart. Even crank bearings benefit at starts, stops or when extreme shock loads upset the “hydrodynamic” film.

Better to use a 5w-10 or better still a 10w-50 to cope with higher temperatures

 

Esters

No I haven't tried Silkolene. Perhaps I should.
Your explanation about the way an ester oil performs looks scientifically sound , it makes me think that perhaps you're a chemist or engineer.
Just a last question , is Silkolene Porsche approved:[question]

Thanks

 

It was till last month :eek:

But since FUCHS bought up the Silkolene, they dropped it from Porsche Approval to focus on their Supersyn Product :[blah]

I still use Silkolene Pro S in my 996 GT3, but will be switching from 5w-40 to 10W-50 for the summer

 

Fuchs

I was too, ( 1 & 1/2 year ago).
Thank you for your answer. It's a pleasure to discuss this theme with a colleague.
The world is small,:eek: incidentally a friend of mine is the director of Fuchs oil division Spain.
I'll ask him.

 

Hi, would Silkolene then be a better oil for our cars?
I am not a Mobil1 fan at all, so which one may I use for a 997 Turbo: 5-40, 10-50 or both?
Thanks a lot

 

Mobil vs Silkolene

Well I've contacted both Exxon and Fuchs.
Mobil 1 is an PAO ( Poly alpha olephin) based oil and Silkolene is an esther based oil. Although both Group IV oils are OK for high perfomance engines, esthers have an better inherent Viscosity Index than PAO oils.

For my concern Exxon have recently reduced the amount of phosphate anti wear additive due to the risk of poisoning the catalytic converters , they wrote to me that this is not a problem:[question].

Silkolene ( now Titan) is not easily found in Spain . Fuchs offer their PRO R SAE 5W-40 and 10W-50 Electrosyntec ( esther based oils) for 4 stroke racing superbikes however I don't know if they can be used in cars.

You can put your questions to:
FUCHS LUBRICANTES S.A. SPAIN

Pol.Ind.San Vicente
08755 Castellbisbal Barcelona, España

automotive-spain@fuchs-oil.com
www.fuchs.es

 

Thanks for your quick response. I have found this english online shop:
http://www.opieoils.co.uk/c-388-silkolene-engine-oil.aspx


They ship to Spain!!

 

Link

Thank you for the link.

It looks like that Silkolene Pro S 5W-40 would be a good choice.

Please note that for racing they recommend Silkolene Pro R 0W-20. It is really a very low viscosity oil . It seems logical , most of the hydrodynamic lubrication drag in a engine is caused by internal oil to oil friction.

Modern fuels contain a significant amount of ethanol. In my opinion , oil drain periods for ester oils should be reduced since acohols could degrade the oil through metal catalysed trans-esterification reactions.

 

Ester based oil drain periods

Good advice, thanks. Will it be safe, lets say 5000km. or 8000km., periods for high speeds runs?

 

Drain intervals

My hypothesis about oil degradation by trans-esterification is based only in "my chemical impressions" it isn't based in scientific tests.
Per ex. checking the viscosity index ( VI )with a high shear viscometer before and after 10 or 20 thousand km.
If the ester oil is good and the engine is new it will withstand a hard work
Porsche recommends an oil change every 20 Th. km. If you want to be conservative, and money is not a problem I would say that draining after 10 to 15 Th. km will suffice.

 

10000km. seems reasonable.

 

FYI, I´ve ended up buying Motul 300V 5w-40 online. As you know is also an ester based oil. Not cheap but doing myself the change will cut some expenses.

 

Oil

I know abouy 1000 times less about oil than you chaps , but I do know that:

The Duckhams Q rally team did not use their own oil.

My car builder recomendeds Valvoline and Silkolene for all race and rally engines. He particularly disaproves of Mobil 1 as a performance oil , and so
does the engine bloke.

That's just their opinion though.

Ralph

 

Eclou, on 6speedonline said this, regarding my Motul 300v 5w-40 question:
"One of the Motul reps was a sponsor at this past track weekend. He told me that in Europe Porsche is going to switch from 0w oils altogether to the 5w oils, and that the rest of the world would follow thereafter"

 

I'm not a chemical engineer but I think many concerns surrounding the quality, positive or adverse effects of motor oil on performance automobile engines can be adequately answered by using a certain brand and viscosity and actually having it lab tested at periodic intervals.

5 years ago, a fellow from Australia named Doug Hillary did just this with his Porsche 928 and posted the results on Rennlist. Since it's not often that you see empirical data on this subject in car forums or just about anywhere else unless you have the testing done yourself, I'm attaching his posts for your information and review.

01-27-2003, 08:52 PM
In response to comments from "Marc@DEVEK" I will commence a programme forthwith to sample the engine oil in my car a MY89 928S4
ExxonMobil have agreed to sample my oil as follows;

1 - new Shell Ultra Synthetic 15w-50 ( SJ/CF-A3 Porsche approved )oil sampled as baseline

2 - current oil in crankcase ( same batch Shell Ultra Synthetic 15w-50 ) will be sampled within the next month @ 7 000-8 000 kms of use
To enable accellerated results I decided to remain with my present Shell oil rather than move to Mobil 1 5w-50 or Mobil Delvac 1 5w-40

3 - samples will then be taken every three months - use factors noted in %, and top ups noted as is normal

4 - oil will be changed @ 20 000 kms ( maximum Porsche recommended ) or as the samples determine - whichever is first

5 - results will be posted here if anybody is interested

Note 1: Analysis will cover contamination, wear metals and viscosity - a "normal" analysis

Note 2: As we do NOT have a wear metal "history" on this engine the most meaningful parts will probably be related to contamination and viscosity

Note 3 : This engine has been well serviced from new and the speedo reads 109000 kms at present
Please comment

Regards
__________________
Doug Hillary
Rennlist Member # 030204-2681/060810-4400
01 Boxster (986) 2.7 Tiptronic
06 Mercedes Benz CLK Kompressor
(MY89 928S4 Auto - sadly sold)


03-05-2003, 02:58 AM
The first oil analysis report has arrived back from ExxonMobil and the results follow below

As stated in an earlier post it will be difficult to meaningfully measure wear metal trends due to;
a ) the the low vehicle use factors and,
b ) not having any reference material available on this subject/engine from Porsche

We will see any "unusual" elemental ( wear metal ) movements as/if they happen between the quarterly samples

Therefore, we can establish an oil change interval by monitoring its condition which is what this programme is all about

Vehicle = MY89 S4
Vehicle Speedo = 110112 kms
Oil distance covered = 6597 kms
Date Oil/Filter last changed = 17/10/02 ( about 5 months ago )
Oil = Shell Helix Ultra 15w-50 ( synthetic )
Oil topup since change = nil
Use = 10% Town, 15% Urban, 75% Highway
Avg Speed = 68 km/h
Avg Fuel economy = 12.1 ltr/100km
Temperatures = Highest 40C, Lowest 14C

Oil condition;

Viscosity - 94 - OK ( 58, much lighter oil though )
Water - 0% - OK ( 0 )
Soot index - 0.01 - OK ( .3 )
TAN - 3.2 - Ok ( NA )
The Total Acid Number ( TAN ) is an increasing measure of how the additive package is surviving
The Total Base Number ( TBN ) is the new oil's acid neutralising factor
Note: The TBN of the new oil is being tested today but is believed to be about 9.
The TAN should never exceed 70% of the TBN ( 6.3 )
( Note some comments are simplified for easy comprehension )

ExxonMobil's overall rating - "Normal" - excellent for continued use

For academic purposes the elemental analysis was;

Iron - 6 ( 19 )
Aluminium - 3 ( 5 )
Chromium - 1 ( 2 )
Copper - 3 ( 99 )
Lead - 4 ( 7 )
Silicon - 22 ( 9 )
Sodium - 5 ( 8 )
All shown as parts per million ( PPM )

We believe the high? silicon reading is due to the block's metallurgy

Figures for Mobil 1 10w-30 in a LS1 GM motor in the USA are shown in brackets. While these cannot be used to compare results it give some perspective to the figures in my 928 engine

I hope this is of interest. It shows so far that the oil has survived 5 months and varied use very well.

If anybody wants the one page doucument faxed to them just provide me your number with Country codes on here


04-30-2003, 07:34 PM
This then is the second report, six months after the oil and filter were changed

Details:
Car - MY89 928S4
Speedo - 111831kms
Oil - Shell Helix Ultra 15w-50 - full synthetic
Oil/filter change date - 10/17/02
Distance since - 8316kms
Oil used - nil
Date of this sample - 4/21/03
Distance since last sample - 1719kms
Use in period - 17% town,31% urban,52% hiway
Avg speed in period - 66 km/h
Fuel economy in period - 12.3ltr-100km
Ambient in period - 34c high to 21c low
Humidity in period - 98% highest</font></li>
Oil Condition - "use" factors;

· Note - last report figures shown thus new/old
Viscosity - 98/94 OK
Water - 0.01%/0.00% OK
Soot Index - 0.00/0.01 OK
TAN - 2.6/3.2 OK - the Max allowed is 8.9

Lab. Report Summary

ExxonMobil's rating - "O-Normal"
Status-Excellent for continued use
Last Report - "O-Normal"
Estimate of distance to oil change - 25000kms
Estimate of total oil life distance - 34000kms

Elemental Analysis;
Iron - 7/6
Aluminium - 2/3
Chromium - &lt;1/1
Copper - 5/3
Lead - 4/4
Silicon - 11/22
Sodium - 2/5

· Note: None of the movements are significant. The silicon level fall is positive
The oil has survived 8316kms (5100lms) and six months very well. Porsche's recommendations look good
Regards

07-17-2003, 07:39 PM
This is the third report on the oil in my car - at nine ( 9) months.
The testing was commenced six months ago to confirm the oil change recommendations from Porsche namely - 20000kms or 12 months for "normal" use
This sample was taken nine months after the oil and filter were changed

Details:

Car - MY89 - 928S4 Auto
Speedo - 114848kms
Oil - Shell Helix Ultra 15w-50 - SJ/CF, A3-96/B3-96 - fully synthetic
Oil/filter change date - 10/17/02
Distance since Oil/filter changed - 11333kms
Oil used since fill - nil
Date of this sample - 7/14/03
Distance since last sample - 3017kms
Use in period - 15% town,25% urban,60% hiway
Avg speed in period - 69 km/h
Fuel economy in period - 11.8ltr-100km
Ambient in period - 26c high to 4c low
Humidity in period - 98% highest
OIl Condition - "use" factors;

Note - last report figures below are shown thus: newest-last-oldest

Viscosity - OK - 98-98-94 ( excellent )
Water - OK - 0.05%-0.01%-0.00% ( excellent )
Soot Index - OK - 0.00-0.00-0.01 ( excellent )
TAN - OK - 4.6-2.6-3.2 ( very good ) the Max allowed is 8.9

Lab. Report Summary

ExxonMobil's rating - "Normal"
Status-Excellent for continued use
Last Report - "Normal"
Estimate of distance remaining to oil change - 3700kms ( 2300 miles ) 3 months
Estimate of distance of oil life left to change - 15000kms ( 9500 miles )
Estimate of total distance to end of oil life - 27000kms ( 16700 miles )

Elemental Analysis;

Iron - 9-7-6 ( excellent )
Aluminium - 3-2-3 ( excellent )
Chromium - 1-<1-1 ( excellent )
Copper - 8-5-3 ( very good )
Lead - 7-4-4 ( very good )
Silicon - 5-11-22 ( excellent )
Sodium - 2-2-5 ( excellent )

Note: None of the elemental movements are significant

The oil has survived for 11333kms (7038 miles) and nine months very well. Porsche's recommendations are looking very very good and with a big margin too!!
Regards


10-09-2003, 07:50 AM
This is the fourth and the final Oil Condition Report concerning the oil in my car - at approx. twelve (12) months and at the oil change point

The Used Oil Analysis ( UOA ) commenced nine months ago - the oil had been in the engine three months then. It was undertaken to confirm Porsche's original oil change recommendations for the 928 - namely, 20000kms or 12 months for "normal" use
The engine oil is now at the maximum time limit set by Porsche, not the distance limit
Used Oil Analysis is used by Equipment Manufacturers, Fleet Managers and Race Teams worldwide. The standardised testing processes compare the original ( virgin ) oil's composition alongside the used oil sample. I have been involved with this process since the late 1960's

The oil and filter were changed at this sampling point even though the ExxonMobil report OK'd the oil for continued use

It was my call to change it out now as it follows Porsche's prescribed maximum time limit

Details:

Car - MY89 - 928S4 Auto
Speedo - 117084kms ( 72709 miles)
Oil - Shell Helix Ultra full synthetic 15w-50 - SJ/CF**, A3-96/B3-96
Oil/filter change date - 10/17/02
Distance since Oil/filter changed - 13569kms (8426 miles)
Oil used since fill - nil ( level only 200ml down = total volume of all samples )
Date of this sample - 10/07/03
Distance since last sample - 2236kms (1388miles)
Use in this period - 16% town,40% urban,44% hiway
Avg speed in this period - 71 km/h ( 44mph)
Fuel economy in this period - 11.7ltr-100km (24 mpg Imp) ( 20 mpg US )
Ambient in this period - 28c high to -2c low
Ambient - annual historical averages - 27.5c max. & 21.5c min.
Ambient - actual in 12 months - max. 40c & min. -2.5c
Humidity in this period - 96% highest
** This oil has a later "rating" than in the 928 S4's Handbook - technology has moved on since 1989. It is not the very latest API oil rating - SL/CF ( and A3/B3 ) - which should perform even better than this oil did over the time and/or distance limits!

Oil Condition - "use" factors;

Note - report figures below are shown thus: now-3-2-1(1=first sample)

Viscosity OK - 98-98-98-94 ( excellent )
Water OK - 0.06%-0.05%-0.01%-0.00%
Soot Index OK - 0.00-0.00-0.00-0.01
TAN OK - 3.8-4.6-2.6-3.2 ( excellent ) the Max allowed is 8.9

Lab. Report Summary

ExxonMobil's rating now - "Normal"
Status-Excellent for continued use
Last Report - "Normal"

Estimated oil's lifespan left until change required - 24500kms ( 15200 miles )
Estimated total of oil's lifespan - 38000kms ( 23500 miles )

Elemental ( & wear metal ) Analysis;

Industry "acceptable" rates (range rounded) - not 928 specific - shown as ((?))
My engine's averages are shown as [?]

Iron 10-9-7-6 ( excellent ) ((30-100)) [ 8 ]
Aluminium 4-3-2-3 ( excellent ) ((5-30)) [ 3 ]
Chromium 1-1-<1-1 ( excellent ) ((1-30)) [ 1 ]
Copper 4-8-5-3 ( excellent ) ((10-30)) [ 5 ]
Lead 7-7-4-4 ( excellent ) ((40-100)) [ 5.5 ]
Silicon 5-5-11-22 ( excellent ) ((10-30)) [ 10.75 ]
Sodium 6-2-2-5 ( excellent ) ((8-10)) [ 3.75 ]

Note:

None of the elemental "movements" have ever been significant. All are at or well below Industry acceptable figures. This indicates that rings, pistons, bores, cams, bearings and other major components are wearing at a very low rate

Oil Condition Summary:

The oil itself has survived for 13569kms ( nearly 8500 miles) and nearly twelve (12) months very very well. The oil's degradation has been very low and its ability to fight acidic corrosion is better than many new cheaper oils. It's viscosity has remained exceptionally close to the original new "virgin" oil - virtually no thicker or thinner than at the start 12 months ago
On the oil's condition readings alone, it could have been left in for another extended period of use. This is but one advantage of a good quality synthetic lubricant

UOA Test Results Summary:

Porsche's Handbook recommendations for normal use are hereby confirmed by the UOA and with a big margin too!! Newer specification oils either mineral or synthetic, will extend the margin still further
Like everything else, time has "moved on" and so has the quality of the oils we can readily purchase today. There has been about five quality upgrades since 1989 alone!!

As a result of the UOAs, the engine has now been put on to Mobil's Delvac 1 5w-40, a lighter viscosity Heavy Duty commercial diesel oil. This oil is the very latest rated diesel oil - API CI/SL - it also exceeds ACEA's A3 and B3 ( E3,4,5 & B4) and is suitable for high performance petrol engine vehicles too. It will stay on this oil as I have good access to this product - it is also used in my heavy and light trucks - and in my other cars too

It will be argued by some ( and indeed already has been here ) that my car gets an "easy life" - I accept that I am probably rated as a smooth and sensible Driver. I was in volved Prototype Vehicle Development including Test Driving many years ago and by experience/knowledge do not abuse my vehicles - but I always know their limits!
I would say that my car is treated close to the way the average 928 owner treats their vehicle.

According to our "Landsharkoz" information, the ownership profile of the 928 is 95% male and aged in the 45-50 range. 57% are self employed and own two or three other cars.
I'm about an "average" owner/user then, just a bit older and I own more cars! And I drive about 40000 miles per annum

I hope this is of interest

DIESEL ENGINE OIL ANALYSES

11-25-2003, 12:29 AM
This Oil Condition Report ( Used Oil Analysis - UOA ) relates to the current oil in my car and may be of interest to those who have followed the previous four reports
As noted the oil has covered 5435kms ( 3375 miles )

The oil and filter were NOT changed at this sampling point as the ExxonMobil report OK'd the oil for continued use and it will be changed at Porsche's prescribed maximum time limit

The car is now on Mobil's Delvac 1 5w-40, a Heavy Duty commercial diesel engine oil. This oil is the very latest rated diesel engine oil - API CI-4/SL - it also exceeds ACEA's A3 and B3 ( E3,4,5 & B4) and is suitable for high performance petrol engine vehicles
It has a lighter viscosity than the previous Shell Helix Ultra which was a 15w-50 grade

Details:
· Car - MY89 - 928S4 Auto
Speedo - 122519kms ( 76090 miles)
Oil - Mobil Delvac 1 - 5w-40 full synthetic - API rated as "CI-4/SL" **
Oil/filter change date - 10/07/03 ( OEM "MANN" filter used )
Distance since Oil/filter changed - 5435kms (3375 miles)
Oil used since fill - nil ( still at "FULL" mark )
Date of this sample - 11/19/03
Distance since last sample - ( first sample of this oil )
Use in this period - 4% town, 15% urban, 81% hiway
Avg speed in period - 85 km/h ( 53 mph)
Fuel economy in period - 10.9ltr-100km (25.9 mpg Imp) ( 22 mpg US approx )
Ambient in this period - 34c high to 2c lo
Humidity in this period - 94% highest

** This "mixed fleet" oil far exceeds Porsche's original recommendations for the S4 but meets the original viscosity requirements
Oil Condition - "use" factors;
· UOA report figures:

Viscosity OK - 88 ( excellent )
Water OK - 0.3%
Soot Index OK - 0.00
TAN OK - 2.8 ( excellent ) Max allowed = 8.9
Lab. Report Summary
· ExxonMobil's rating now - "Normal"
Status-Excellent for continued use
Last Report - "Normal"

Elemental ( & wear metal ) Analysis;
· This UOA results appear first and my engine's averages from the first four UOA's are shown as [?]
The Oil Industry "acceptable" wear metal rates (range rounded) and not 928 specific - are shown as ((?))

Iron 5 ( excellent ) [ 8 ] (( >100 ))
Aluminium 2 ( excellent ) [ 3 ] (( >30 ))
Chromium <1 ( excellent ) [ 1 ] (( >30 ))
Copper 1 ( excellent ) [ 5 ] (( >50 ))
Lead 3 ( excellent ) [ 5.5 ] (( >100 ))
Silicon 2 ( excellent ) [ 10.75 ] (( >30 ))
Sodium 1 ( excellent ) [ 3.75 ] (( >10 ))
Note:
None of the elemental wear rates are significant. All are below the previous averages and well below Industry acceptable figures.
This indicates that rings, pistons, bores, cams, bearings and other major components are wearing at a very very low rate

This is another "technical analysis" of why the 928 engine is so durable in normal use and when using the Porsche recommended ( or better ) lubricants changed at Porsche recommended servicing intervals

Oil Condition Summary:

The oil was used for 5435kms ( 3375 miles) in about one month. During this time the car was driven above 160km/h ( 100 mph ) for extended periods in 33+C temperatures

This very high quality oil will be changed according to Porsche's distance/time recommendations or earlier if a UOA determines this - which is most unlikely!

Regards


03-12-2004, 03:21 AM
This Oil Condition Report ( Used Oil Analysis - UOA ) relates to the current oil in my car and may be of interest to those who have followed the previous five reports over the last year or so

The oil and filter were NOT changed at this point as ExxonMobil's Lab. report OK'd the oil for continued use. It will be changed at Porsche's prescribed maximum time limit

Mobil's Delvac 1 5w-40, a synthetic commercial HDEO ( heavy duty engine oil ) with both diesel/petrol ratings is being used and this is the second UOA on this lubricant
This is the latest API rated "mixed fleet" diesel engine oil - CI-4/SL - and it also exceeds ACEA's A3 and B3 ( E3,4,5 & B4).
It is suitable for high performance petrol engine vehicles and meets the car's viscosity requirements

Details:

Car - MY89 - 928S4 Auto
Speedo - 125214kms ( 77758 miles)
Oil - Mobil Delvac 1 - 5w-40 full synthetic - API rated as "CI-4/SL" **
Oil/filter change date - 10/07/03 ( OEM "MANN" filter used )
Distance since oil/filter changed - 8130kms ( 5049 miles) Time since oil/filter changed - six months ( approx )
Oil used since oil/filter change - nil ( still at "FULL" mark )
Date of this sample - 3/9/04
Distance since last UOA - 2695kms ( 1674 miles ) Time since last UOA - three months
Use in this period (approx ) - 10% town, 30% urban, 60% hiway
Avg speed in period - 61km/h ( 38 mph)
Fuel economy in period - 12.2ltr-100km (23 mpg Imp) ( 19.5 mpg US approx )
Ambient in this period - 40c high to 18c low
Humidity in this period - 98% highest

** This oil far exceeds Porsche's original API rating recommendations for the S4 but meets the original viscosity requirements

Oil Condition - "use" factors;

Note - UOA report figures:
Viscosity OK - 86 ( excellent )
Water OK - 0.7%
Soot Index OK - 0.01 TAN OK - 3.5 ( excellent ) Max allowed = 8.9

Lab. Report Summary

ExxonMobil's rating now - "Normal"
Status-Excellent for continued use
Last Report - "Normal"

Elemental ( & wear metal ) Analysis;
Detail of the Elemental columns are:
Col 1 = this UOA ( my comments in brackets )
Col 2 = averages of all six UOA's
Col 3 = Oil Industry's "acceptable" max. wear rates (rounded) & not 928 specific
· Iron 7 ( excellent ) [ 7.33 ] (( >100 ))
Aluminium 4 ( excellent ) [ 3 ] (( >30 ))
Chromium 1 ( excellent ) [ <1 ] (( >30 ))
Copper 2 ( excellent ) [ 3.83 ] (( >50 ))
Lead 5 ( excellent ) [ 5 ] (( >100 ))
Silicon 6 ( excellent ) [ 8.5 ] (( >30 ))
Sodium 1 ( excellent ) [ 3.83 ] (( >10 ))
Note:

None of the elemental wear rates are really significant. All are around the previous averages and well below the Oil Industry's maximum acceptable figures. This indicates that rings, pistons, bores, cams, bearings and other major components are wearing at a very very low rate
This is another "technical analysis" of why the 928 engine is so durable in normal use when using the Porsche recommended ( or better ) lubricants that are changed at Porsche's recommended servicing intervals

Oil Condition Summary:

The oil has been used for 8130kms ( 5049 miles) in about six months. During this time the car was driven above 160km/h ( 100 mph ) for extended periods in 33+C temperatures

This very high quality oil will be changed according to Porsche's distance/time recommendations or earlier if the June UOA determines this - which is most unlikely!

Regards

05-18-2004, 07:48 AM
This Oil Condition Report (Used Oil Analysis - UOA), the seventh, relates to the current engine oil in my car. It may be of interest to those who have followed the previous six reports over the past almost two years

The oil and filter were NOT changed at this point as ExxonMobil's Lab. report OK'd the oil for continued use. It will be changed at Porsche's prescribed maximum time limit

Mobil's Delvac 1 5w-40, a commercial HDEO (heavy duty engine oil) with both diesel/petrol ratings is used, this is the third UOA on this lubricant
This, the latest API rated "mixed fleet" diesel engine oil - CI-4/SL - also exceeds ACEA's A3 and B3 ( E3,4,5 & B4). It is suitable for high performance petrol engine vehicles and meets the car's viscosity needs and exceeds the quality requirements stated in the Owners Handbook

Details:

Car - MY89 - 928S4 Auto
Speedo - 133675 kms (83012 miles)
Oil - Mobil Delvac 1 - 5w-40 full synthetic - API rated as "CI-4/SL"
Oil/filter change date - 10/07/03 (OEM "MANN" filter used )
Distance since oil/filter changed - 16591 kms (10303 miles) Time since oil/filter changed - eight months ( approx )
Oil used since oil/filter change - nil (still at/near "FULL" mark )
Date of this sample - 5/13/04
Distance since last UOA - 8461 kms (5255 miles)
Time since last UOA - approx. three months
Use in this period (approx) - 5% town, 10% urban, 85% hiway
Avg speed in period - 80km/h (50 mph)
Fuel economy in period - 11.1ltr-100km (25.4 mpg Imp)(21.2 mpg US approx)
Ambient in this period - from 40c high to -5C low Humidity in this period - 98% highest

Oil Condition - "use" factors;

Note - UOA report figures:
Viscosity OK - 93 (excellent)
Water OK - 0.06%
Soot Index OK -0.00
TAN OK - 4.6 (excellent) - Start 1.00 & Max allowed 8.9

Lab. Report Summary

ExxonMobil's rating now - "Normal"
Status-Excellent for continued use
Last Report - "Normal"

Elemental (& wear metal) Analysis;

Detail of the Elemental columns are:
Col 1 = this UOA results (my comments are in brackets)
Col 2 = averages of all six UOA's
Col 3 = Oil Industry's "acceptable" max. wear rates (rounded) & not 928 specific

Iron 9 ( excellent ) [ 8 ] (( >100 ))
Aluminium 5 ( excellent ) [ 3 ] (( >30 ))
Chromium 1 ( excellent ) [ <1 ] (( >30 ))
Copper 5 ( excellent ) [ 5 ] (( >50 ))
Lead 8 ( excellent ) [ 8 ] (( >100 ))
Silicon 6 ( excellent ) [ 6 ] (( >30 ))
Sodium 8 ( excellent ) [ 8 ] (( >10 ))

Note:
The elemental wear rates are very low. All are around the previous averages and well below Industry acceptable figures. This indicates that rings, pistons, bores, cams, bearings and other major components are wearing at a very very low rate
This is another "technical analysis" of why the 928 engine is so durable in normal use when using the Porsche recommended (or better) lubricants that are changed at Porsche's recommended servicing intervals

Oil Condition Summary:

The lighter 5w-40 viscosity oil has now been used for 16591kms (10303 miles) - over about eight months. During this time the car was driven above 160km/h (100 mph) for extended periods in 33+C and below freezing temperatures

This very high quality oil has contributed to the overall lowering wear rate trends and has caused the wear trend averages to fall accordingly
The oil will be changed according to Porsche's time - maximum 12 months use - recommendation, as the maximum distance allowed will not be reached!

RENNLIST members now have a very good baseline of UOAs from which to measure their own car's wear rate trends from. This will also assist those persons who race our engines. A number of Labs. in NA do UOAs - but it is always better to use one that is well known

Regards


08-26-2004, 05:44 AM
This Oil Condition Report (Used Oil Analysis - UOA) is the eighth and final. It may be of interest to those who have followed the previous seven reports over the past almost two years
The oil and filter were NOT changed at this point as ExxonMobil's Lab. report OK'd the oil for continued use. It will be changed about one month from now at Porsche's prescribed maximum time limit of twelve months or sooner if the distance covered exceeds 12k miles

This is the fourth UOA on Mobil's Delvac 1 5w-40, a fully synthetic commercial "mixed fleet" HDEO (heavy duty engine oil). This oil has both the highest diesel/petrol ratings and is the latest API "CI-4/SL" rated "mixed fleet" diesel engine oil. It also exceeds ACEA's A3 and B3 ( E3, 4, 5 & B4) ratings. It is suitable for high performance petrol engine vehicles and meets the 928's viscosity and quality requirements stated in the Owners Handbook

Details:

Car - MY89 - 928S4 Auto
Speedo - 84557 miles (136163kms)
Oil - Mobil Delvac 1 - 5w-40 full synthetic - API rated as "CI-4/SL"
Oil/filter change date - 09/20/03 (OEM "MANN" filter used )
Distance since oil/filter changed - 11848 miles (19079kms)
Time since oil/filter changed - eleven+ months
Oil used since oil/filter change - nil (still near "FULL" mark)
Date of this sample - 8/23/04
Distance since last UOA - 1545 mile(2488kms)
Time since last UOA - approx. four months
Use in this period (approx) - 10% town, 13% urban, 77% hiway
Avg speed in period - 44 mph (70km/h)
Fuel economy in period - 20mpg US (11.8ltr/100km) (24 mpg Imp)
Ambient in this period - from 35c high to -3c low Humidity in this period - 88% (highest)

Oil Condition - "use" factors;

Viscosity OK - 92 (excellent)
Water OK - 0.0%
Soot Index OK - 0.00
TAN OK - 3.7. (excellent) - Start 1.00 & Max allowed 8.9

Lab. Report Summary

ExxonMobil's rating now - "Normal"
Status-Excellent for continued use
Last Report - "Normal"


Elemental (& wear metal) Analysis;

Detail of the Elemental columns are:
Col 1 = this UOA (my comments in brackets)
Col 2 = averages of all eight UOA's
Col 3 = Oil Industry's "acceptable" max. wear rates (rounded) & not 928 specific

Iron 10 ( excellent ) [8] (( >100 ))
Aluminium 6 ( excellent ) [4] (( >30 ))
Chromium 1 ( excellent ) [<1 ] (( >30 ))
Copper 4 ( excellent ) [4] (( >50 ))
Lead 11 ( excellent ) [6] (( >100 ))
Silicon 5 ( excellent ) [8] (( >30 ))
Sodium 6 ( excellent ) [4] (( >10 ))

Note:
The elemental/wear metal rates are very low. All are around the previous averages and well below the Auto Industry's "acceptable" figures. This indicates that the rings, pistons, bores, cams, bearings and other major components are wearing at a very very low rate indeed
This is another "technical analysis" of why the 928 engine is so durable in normal use when using the Porsche recommended (or better) lubricants that are changed at Porsche's recommended servicing intervals

Oil Condition Summary:

The lighter 5w-40 viscosity oil has now been used for almost 12000 miles (19079kms) over about eleven months. During this time the car was driven above 100mph(160km/h) for some long periods in 30+C and at below freezing temperatures
This very high quality oil has contributed to the overall lowering wear rate trends and has caused the wear trend averages to fall accordingly
The oil will be changed in September according to Porsche's time - maximum 12 months use - recommendation, but the maximum distance may still be reached!

RENNLIST's 928 owners now have a very good baseline of UOAs from which to measure their own engine's wear and oil degradation rate trends. This will also assist those persons who race our engines.
A number of Labs. in NA do UOAs - but it is always better to use one that is well known

Regards


04-05-2005, 05:19 AM
This is the result of the ninth Used Oil Analysis (UOA) of the engine oil(s) in my ‘89 S4

The oil and filter were NOT changed at this sampling point, after 3464 miles (5587kms) and six month's use. Exxon-Mobil's Laboratory OK'd the oil for continued use and it will now be changed at Porsche's prescribed maximum limit of 12000 miles (20000kms) or 12 months - whichever is reached first

I use Mobil's Delvac 1 5w-40 Heavy Duty (HDEO) commercial diesel "mixed fleet" oil and it has the API's CH-4/SJ quality rating (now updated - but I am still using the older version). It far exceeds the ACEA's A3/B3-04 requirements. It has ACEA's E3, E4, E5 & B4 Certification for severe diesel engine standards of high turbo-charger boost pressures, deposit control, heavy piston and bearing loads, elevated heat and extended oil drain intervals. Being dual rated (diesel/petrol) it is most suitable for use in high performance petrol engines
Although NOT Porsche Approved it FAR exceeds Porsche's original quality recommendations for the 928 and their current Approval regime. It's viscosity is recommended in the 928 S4 Porsche Owner's Handbook. (In North America I believe that this oil is also sold as Mobil 1 SUV 5w-40)

Using higher viscosity oils than are absolutely necessary to meet the expected ambient range in your area should be avoided in any 928 engine

Details:

Car - MY89 - 928S4 Auto
Speedo - 88602 miles (142677 kms) now
Oil - Mobil's Delvac 1 5w-40 fully synthetic HDEO - API quality rated as "CH-4/SJ"
Oil & filter change date - 14/09/04 (OEM "MANN" filter used)
Distance since Oil & filter changed - 3464 miles (5587 kms)
Oil used since 14/09/04 - nil (still at "FULL" mark)
Date of this sample - 25/3/2005
Distance since last sample - 3464 miles (5587kms)
Use in this period - 9% town, 12% urban, 79% highway
Avg speed in period - 42 mph (68 km/h)
Fuel economy in period - 12.1 ltrs/100km
Ambient in this period - 42C high to 18C low Humidity in this period - 93% (highest)

Oil Condition - "use" factors;

Viscosity OK - 88 (excellent)
Water OK - 0.09%
Soot Index OK - 0.00
TAN OK - 2.6 (excellent) the Max allowed is 8.9

Lab. UOA Report Summary;

ExxonMobil's rating now "Normal"
Translated status "Excellent - suitable for continued use"
Last Report "Normal"

Elemental (& wear metal) Analysis;

Details of the following columns;

Col 1- this UOA results in ppm (my comments are in brackets)
Col 2 - [?] rounded average of all nine UOA results

Iron 6 (excellent) [8]
Aluminium 4 (excellent) [<4]
Chromium 1 (excellent) [<1]
Copper 2 (excellent) [4]
Lead 4 (excellent) [6]
Silicon 3 (excellent) [7]
Sodium 4 (excellent) [4]
Tin 4 (excellent) [4]

NOTE 1: General summary

The results are typical of the previous eight UOAs and therefore normal. All of this UOA's elemental wear metal readings are at or below the previous averages for this engine and well below Industry acceptable limits. One Techron Concentrate fuel treatment has occurred since the oil change last September but no evidence of this appears in this UOA

The series of nine (9) UOAs indicate that the rings, pistons, bores, cams, cam, rod and crank bearings, thrust washers and other major components are wearing at a very very low rate indeed

The testing to date justifies using the Porsche recommended (or better) oils and following their recommended servicing intervals despite what some so called Porsche "experts" may say in promoting shorter oil change intervals

NOTE 2: Engine oil performance observations (Shell Helix Ultra /Delvac 1)

It is interesting to note the following issues now that over 25000 miles (40000kms) have been spanned by the nine UOA's covering two different viscosity synthetic lubricants

A - Oil viscosity

The first four UOAs (one year - 8.5k miles, 13.6k kms) embraced using Shell Helix Ultra, a Group 3 synthetic 15w-50 top quality oil. No oil was consumed during this period

The last five UOAs (18 months - 15.9k miles, 25.6k kms) concerned Mobil's Delvac 1 5w-40, a Group 5 synthetic oil of a somewhat lighter viscosity. No oil has been consumed during the total test period

Both oil viscosities were originally recommended by Porsche for this car but 5w-40 is the current recommendation!

B - Fuel economy and speed
During the heavier viscosity oil (Shell Helix Ultra) test period the fuel economy was measured at 12.2ltrs/100kms and the average speed was 69 km/h

During the lighter oil's (Delvac 1) test period (to date) the fuel economy was consistently better. The car was definitely driven a little harder during the last year and a half as well.
This means at over 100mph for very long periods and at between 30-40C temperatures

C - Wear metals

The lighter viscosity oil has certainly produced a downward trend in engine wear rates. This is a sign that even while the car was probably driven harder in the last 20 months the oil offered greater wear protection generally. This may have been during the warmup phase. It is easy to rightly conclude that the engine was better off because of the change to Delvac 1 5w-40

It should be noted that wear metals will increase in volume (in ppm) as time goes by until drained with the oil - they are too small to be filtered out

NOTE 3: Current oil condition summary

The oil has performed very well indeed and for those persons using Delvac 1 5w-40 in their 928 you have plenty of reasons to feel confident that you "caught the right tram"! The oil's viscosity is at near new and its ability to combat deposits and acids remain very high indeed

The oil (it will be staying on Delvac 1) and filter (MANN) will be changed in September according to Porsche's maximum time recommendation but it is still likely that the maximum distance will be covered first!
It is worth noting that by tracking both the oil's condition and the rate of wear metal(s) uptake the following data emerges;

a) the premium synthetic oil will last for at least two (2) years and probably three (3).
The Sodium "action" limit would be reached theoretically at around 90 000kms

b) the highest wear metal uptake is Lead. Using this factor, the oil would last theoretically up to 100 000kms before the "action" limit is reached

c) the MANN oil filter will last for at least two years or 50 000kms

I do not advocate going beyond 12 months without changing the engine oil and filter in a 928

I hope this is of value to some Rennlist people. There are now nine Used Oil Analysis results published here that can be "trended" and used to monitor engine wear rates and the condition of the oil

Regards

09-22-2005, 09:27 PM
This is the result of the tenth Used Oil Analysis (UOA) of the engine oil in my ‘89 S4, and it will be the last provided by me

The oil and filter were changed at this sampling point, after 5016 miles (8078kms) over twelve months. Exxon-Mobil's Laboratory OK'd the oil for continued use

I use Mobil's Delvac 1 5w-40 Heavy Duty (HDEO) commercial diesel "mixed fleet" oil and it has the API's CH-4/SJ quality rating (whilst it has now been updated I am still using the older version). It far exceeds the ACEA's A3/B3-04 requirements. It has ACEA's E3, E4, E5 & B4 Certification for severe diesel engine standards of high turbo-charger boost pressures, deposit control, heavy piston and bearing loads, elevated heat and extended oil drain intervals. Being dual rated (diesel/petrol) it is most suitable for use in high performance petrol engines
Although NOT Porsche Approved it FAR exceeds Porsche's original quality recommendations for the 928 and their current Approval regime as well
This oil is now officially recommended for the 928 by Mobil in the US and is also marketed there as M1 T&SUV 5w-40

Using higher viscosity oils than are absolutely necessary to meet the expected ambient range in your area should be avoided in any 928 engine

Details:
Car - MY89 - 928S4 Auto
Speedo - 90150 miles (145168 kms) now
Oil - Mobil's Delvac 1 5w-40 fully synthetic HDEO - API rated as "CH-4/SJ"
Oil & filter change date - 14/09/04 (OEM "MANN" filter used)
Distance since Oil & filter changed - 5016 miles (8078 kms)
Oil used since 14/09/04 - nil (still at "FULL" mark)
Date of this sample - 16/9/2005
Distance since last sample - 1547 miles (2491kms)
Use in this period - 5% town, 12% urban, 83% highway
Avg speed in period - 42 mph (68 km/h with highest speed of 220km/h)
Fuel economy in period - 12.1 ltrs/100km
Ambient in this period - +42C high to -2C low
Humidity in this period - 98% (highest)

Oil Condition;

Viscosity OK - 89 (excellent) [90]< Average of all at Oil change
Water OK - 0.08%
Soot Index OK - 0.00
Sodium OK - 3
TAN OK - 3 (excellent - lowest is best, max allowed is 9)

Lab. UOA Report Summary;

ExxonMobil's rating now "Normal"
Translated status "Excellent - suitable for continued use"
Last Report "Normal"

Elemental (& wear metal) Analysis;
Details of the following columns;
Col 1- this UOA result in ppm (my comments are in brackets)
Col 2 - [?] rounded average of all UOA results at oil change

Iron 14 (excellent) [11]
Aluminium 5 (excellent) [5]
Chromium 1 (excellent) [1]
Copper 3 (excellent) [4]
Lead 5 (excellent) [8]
Silicon 4 (excellent) [5]
Sodium 3 (excellent) [5]
Tin <1 (excellent) [NA]

SPECIAL NOTE: The averaged figures are a good baseline for any 928 owner to use!

NOTE 1: General summary

The UOA result is typical of the previous nine UOAs and is therefore normal. Although iron is a little higher, this UOA's other elemental wear metal readings are at or below the previous averages for this engine and well below Industry acceptable limits. One Techron Concentrate fuel treatment has occurred since the oil change in September 2004 but no evidence of this appears in this UOA

The series of ten (10) UOAs indicate that the rings, pistons, bores, cams, cam, rod and crank bearings, crankshaft thrust washers and other major components are wearing at a very very low rate indeed

The testing to date justifies using the Porsche recommended (or better) oils and following their recommended servicing intervals despite what some so called Porsche "experts" may say in promoting shorter oil change intervals

NOTE 2: Engine oil performance observations (Delvac 1 5w-40)

It is interesting to note the following issues now that about 26000 miles (42000kms) have been spanned by the ten UOA's covering two different viscosity synthetic lubricants

A - Oil viscosity

A 5w-40 viscosity (the current recommendation) seems ideal for year round use in a 928!

B - Wear metals

The 5w-40 viscosity oil has certainly produced a downward trend in engine wear rates
It should be noted that wear metals will increase in volume (in ppm) as time goes by until drained with the oil - they are simply too small to be filtered out

NOTE 3: Current oil condition summary

The oil has performed very well and for those persons using Delvac 1 5w-40 in their 928 you have plenty of reasons to feel confident that you "caught the right tram"! The oil's viscosity is at near new and its ability to combat deposits and acids remain very high indeed

The oil (Delvac 1) and filter (MANN) were changed when the sample was taken
It is worth noting that by tracking both the oil's condition and the rate of wear metal(s) uptake the following data emerges;

a) the premium synthetic oil will last for at least two (2) years and probably three (3).
b) The Sodium "action" limit would be reached theoretically at around 90000kms
c) wear metal uptake rates indicate that the oil would last theoretically up to 80 000kms before any "action" limit is reached
d) the MANN oil filter will last for at least two years or 50 000kms

Even now with substantive "clinical" evidence to the contrary I do not advocate going beyond 12 months without changing the engine oil in a 928

I hope this is of value to some Rennlist people out there - there are now ten Used Oil Analysis results published that can be "trended" and used to monitor engine wear rates and the condition of the oil in their own car


08-17-2006, 11:38 PM
This is a Used Oil Analysis (UOA) of the engine oil in my ‘89 S4
It is No 11 and it will help enable others to compare their own UOAs for trending purposes

The oil and filter were changed near this sampling point after 3131 miles (5042kms) over eleven months. Exxon-Mobil's Laboratory OK'd the oil for continued use

I use Mobil's Delvac 1 5w-40 Heavy Duty (HDEO) commercial diesel "mixed fleet" oil

Details:
Car - MY89 - 928S4 Auto
Speedo - 93280 miles (150210kms) now
Oil - Mobil's Delvac 1 5w-40 fully synthetic HDEO - API rated as "CH-4/SJ"
Oil & filter change date - 16/09/05 (OEM "MANN" filter used)
Distance since Oil & filter changed - 5016 miles (8078 kms)
Oil used since 16/09/05 - nil (still at "FULL" mark)
Date of this sample -11/08/2006
Distance since last sample - 3131 miles (5042kms)
Use in this period - 8% town, 22% urban, 70% highway
Avg speed in period - 38 mph (61 km/h with a highest speed of 220km/h)
Fuel economy in period - 12.1 ltrs/100km
Ambient in this period - +42C high to 0C low
Humidity in this period - 98% (highest)

Oil Condition;

Viscosity OK - 84 (excellent) [88]< Average of Del 1 at OC (Virgin oil is 92)
Water content OK - 0.00% (0.06%)< Average of Del 1 at OC
Sodium content OK - 4 [5]< Average of Del 1 at OC
TAN OK - 2.7 (excellent - lowest is best, max allowed is 9)

Lab. UOA Report Summary;

ExxonMobil's rating now "Normal"
Translated status "Suitable for continued use"
Last Report "Normal"

Elemental (& wear metal) Analysis (in parts per million - "ppm");
Details of the following columns;
Column 1- current UOA result (my comments follow in brackets)
Column 2 - [?] rounded average of all UOA results at oil change

Iron 9 (excellent) [11]
Aluminium 4 (excellent) [5]
Chromium 1 (excellent) [1]
Copper 1 (excellent) [4]
Lead 3 (excellent) [6]
Silicon 5 (excellent) [5]
Sodium 4 (excellent) [5]
Tin <1? (excellent) [NA]

SPECIAL NOTE: The averaged figures are a good baseline for any 928 owner to use and apply to a non tracked road use vehicle!

NOTE 1: General summary

This UOA result is typical of all of the previous UOAs. Although iron is a little higher, the other elemental wear metal readings are at or below the previous averages for this engine and well below acceptable Industry limits

The full series of UOAs (taken at various distances) indicate that the rings, pistons, bores, cams, cam, rod and crank bearings, crankshaft thrust washers and other major components are wearing at a very low rate indeed

The oil testing done to date justifies using Porsche Approved and Listed (or better) oils at the Listed viscosity. It confirms that following their recommended servicing intervals is cost effective

NOTE 2: Oil performance observations (Delvac 1 5w-40)

A - Oil viscosity
A 5w-40 viscosity (the current recommendation) oil seems ideal for year round use in a 928!
Delvac 1 5w-40 has retained its viscosity very well indeed

B - Wear metals
Porsche's recommended 5w-40 viscosity oil has maintained the lower trend in engine wear rates
It should be noted that wear metals will increase in volume (in ppm) as time goes by until eventually drained with the oil - they are simply too small to be filtered out. The averages shown above are only from those samples taken at the oil change point for this very reason

NOTE 3: Current oil condition summary

Delvac 1 5w-40 has again performed very well and using in a 928 gives plenty of reasons to feel confident that we "caught the right tram"! The oil still has near new viscosity and its ability to combat deposits and acids remain very high indeed

The oil and filter (MANN) were changed shortly after the sample was taken

It is worth noting that by tracking both the oil's condition and the rate of wear metal(s) uptake the following data emerges;

a) the premium synthetic oil will last for at least two (2) years and probably three (3).
b) The Sodium "action" limit would be reached theoretically at around 90k kms
c) wear metal uptake rates indicate that the oil would theoretically last up to around 80k kms before any "action" limit is reached
d) the MANN oil filter will easily last for at least two years or 50k kms
I do not advocate going beyond 12 months in any 928 without changing the engine oil/filter

I hope this is of value to those RENNLIST people who want to maintain a condition history and "keep an eye" on thrust bearing and other wear/failure points in the 928 family of engines


06-18-2007, 05:15 AM
This is a Used Oil Analysis (UOA) of Mobil's Delvac 1 5w-40 Heavy Duty (HDEO) commercial diesel "mixed fleet" oil used in my ‘89 S4 over the last several years
It is UOA Report No 12 and it will help to enable others to compare their own UOAs for trending purposes. This is the final UOA from me on this vehicle as I have replaced it with a Boxster. The 928's new owner will be encouraged to carry on the practice

Details:
Car - MY89 - 928S4 Auto
Speedo - 96984 miles (156174 kms) now
Oil - Mobil's Delvac 1 5w-40 fully synthetic HDEO - API rated as "CI-4/SL"
Oil & filter change date - 11 Aug 06 (OEM "MANN" filter used)
Distance since Oil & filter changed - 3703 miles (5964 kms)
Oil used since 11 Aug 06 - nil (still at "FULL" mark)
Date of this sample - 9 June 07
Distance since last sample - 3703 miles (5964 kms)
Use in this period - 10% town, 20% urban, 70% highway
Avg speed in period - 50 mph (80 km/h with a highest speed of 220km/h)
Fuel economy in period - 12.1 ltrs/100km
Ambient in this period - +42C high to 5C low
Humidity in this period - 98% (highest)

Oil Condition after 10months use; OK for continued use

Viscosity OK - 84 (excellent) [88] Average of all at Oil change (Virgin oil is 92)
Water OK - 0.00%?
Sodium OK
TAN OK - 3 (excellent - lowest is best, max allowed is 9)

Lab. UOA Report Summary;

ExxonMobil's rating is "Normal"
Translated status "Excellent - suitable for continued use"
Last Report "Normal"

Elemental (& wear metal) Analysis (in parts per million - "ppm");
Details of the following columns;
Column 1- current UOA result (my comments are in brackets)
Column 2 - [?] rounded average of all UOA results at oil change

Iron 7 (excellent) [11]
Aluminium 3 (excellent) [5]
Chromium 1 (excellent) [1]
Copper 2 (excellent) [3]
Lead 3 (excellent) [7]
Silicon 4 (excellent) [5]
Sodium 4 (excellent) [5]
SPECIAL NOTE: The averaged figures are a good baseline for any 928 owner of a non tracked road use vehicle to use for comparison purposes

NOTE 1: General summary

This UOA result is typical of all of the previous UOAs. All lemental wear metal readings are at or below the previous averages for this engine and well below Industry acceptable limits

The full series of twelve UOAs taken at various distances, indicate that the rings, pistons, bores, cams, cam, rod and crank bearings, crankshaft thrust washers and other major components are all wearing at a very low rate indeed

The oil testing done to date justifies using Porsche Approved and Listed (or better) oils at the Listed viscosity. It confirms that following their recommended servicing intervals is cost effective

NOTE 2: Oil performance observations (Delvac 1 5w-40)

A - Oil viscosity
A 5w-40 viscosity (the current recommendation) oil seems ideal for year round use in a 928!

B - Wear metals
The Porsche recommended 5w-40 viscosity oil has maintained the lower trend in engine wear rates
It should be noted that wear metals will increase in volume (in ppm) until eventually drained with the oil - they are simply too small to be filtered out. The averages shown above are only from those samples taken at the oil change point for this very reason

NOTE 3: Current oil condition summary

Delvac 1 5w-40 has again performed very well and using in a 928 gives plenty of reasons to feel confident that we "caught the right tram"with this lubricant! The oil still has near new viscosity and its ability to combat deposits and acids remain very high indeed

It is worth noting that by tracking both the oil's condition and the rate of wear metal(s) uptake the following data emerges;

a) the premium synthetic oil will last for at least two (2) years and probably three (3).
b) The Sodium "action" limit would be reached theoretically at around 90k kms
c) wear metal uptake rates indicate that the oil would theoretically last up to around 80k kms before any "action" limit is reached
d) the MANN oil filter will easily last for at least two years or 50k kms

I do not advocate going beyond 12 months without changing the engine oil/filter in a normally used 928

I hope this is of value to those Rennlist people who want to maintain a condition history and also "keep an eye" on thrust bearing and other wear/failure points in the 928 family of engines

Regards

 

Testing oils

That's right, I agree with you, however too much data make me feel dizzy.
They should have tested too , the oil viscosity, before and after,under high shear stress, p.ex using a tapered bearing viscometer.
Lab testing of acidity, metal content, sooth etc. is ok but in my opinion can't evaluate the real behavior of the oil in a high speed engine.