Doug Hillary

Hi,

some several months ago the issue of engine oils suitable for racing was covered on here and I prepared a list - but no feed back has ever been posted

In short I had suggested:

1 - "Poor performance" by certain oils were almost certainly due to an incorrect oil choice and mis-application
(The obsolete Mobil 1 TriSynthetic 0w-30 had a HTHS* vis. of about 2.6? - Porsche's HTHS minimum vis. is 3.5)
Mobil 1 SuperSyn is now again at the forefront of synthetic oil technology unlike the obsolete TriSynthetic formulation

NOTE 1: "HTHS" is High Temperature High Shear and is a test of the oil's viscosity measured at 150C. It is generally accepted as the test of the oil's film strength when under load and heat. This is a very gruelling test and indicates if the oil may "shear" and loose viscosity temporarily or permanently or alternatively gain viscosity through oxidation etc.
NOTE 2: Mobil's new "Mobil 1R 0w-30" specific racing oil does NOT meet Porsche's standards of viscosity of 11cSt @ 100C (10.3) and HTHS vis. of 3.5 (2.99). By all accounts it is performing very well in NASCAR vehicles and in other racing applications which may be due to its extremely advanced chemistry!

2 - Oil Brands are less important than using the correct oil specifications

3 - That oil specifications applicable and critical to "sports" use were;

a) A synthetic oil with A3/B3 ACEA specification be considered
b) The oil's viscosity should be around 5w>-40> but importantly note; c, d, below)
c) While Porsche's minimum HTHS vis. is 3.5, a HTHS vis. above 4 should be used
d) Using a HTHS vis. that was too high (5>) would sap power and perhaps hinder oil flow and cooling
e) Any oil with a HTHS vis. below 3.5 may well be a contributing cause of bearing failure in 928 engines when racing
f) After the correct HTHS vis.,oils with less than 12% evaporation during the high temperature (250C) NOACK test are probably best used in a 928 when racing

4 - That oil pressure (restriction to flow) was too often the only parameter considered rather than the combination of pressure and flow (volume)

5 - Oil flow is a constant (regardless of pressure) due to the positive displacement of the oil pump and even though pressure may be lower with certain oils at certain times, flow may be higher (oil not by passing full circulation) within the engine and therefore assist component cooling whilst still maintaining the critical film strength (HTHS above 4) needed

6 - Taking oil samples after racing use (distance/time) and conducting Used Oil Analysis (UOA) trending may provide valuable data when compared to those trends published here by me

Is there any feedback available so that we can all learn a little more???

Regards

ErnestSw

G'day Doug,
I'd be surprised if you received any significant response to your post, ie. response containing informed opinion or hard data. I'm unaware of anyone else in the 928 community with the knowledge and resources that you have regarding oils. I'm also unaware of any 928 racers who are prepared to take a rigorous approach to oil issues. Most "failure analysis" seems to involve speculation and assumptions.

shaaark89

doug,
i'm getting ready to do an oil change on my racecar. it runs amsoil race oil 20w-50 with external oil cooler, accusump and remote oil filter. i can send a sample for analysis if you'd like. i've used blackstone labs before to assess some potential issues in my street car, but if you have suggestions, i'm game. car has 10 track days on the current oil.
btw, with the setup i have there are about 16 quarts of oil in the system.

2V4V

Doug,

As Ernest mentioned, I don't know how many folks have easy access to enough data to make this a worthwhile (scientifically anywho) discussion.
I know that I do not have a quality data-set other than empirical.

Personally, when confronted with science that either I can't afford to perform, or that no one (who's not BS'ing) can explain - like why cryo-treating works - I look for the best empirical dataset I can find.

If I am going to abuse a car or bike, I run Motul. I know that it works very well in lots of European race cars of similar ilk. I know that I have seen Motul products in apps that make any Porsche look like a Tecumseh powered go-kart. Holds up just fine in 150+ HP/L motorcyles at 12K+ RPMS, as well as much higher specific-output gasoline and Nitro-burning force-fed drag bikes. I have also seen over 300K miles on more than a few unopened engines using Mobil 1.

There's my empirical evidence. I have NOT done a thorough analysis of the oil's properties vis-a-vis every other hipo-lube out there. Maybe somebody's got better stuff out there. Any more light you can shed is *always* welcome. The last bunch of data that you posted was good to read. I'm always open to more...

Greg

Doug Hillary

Hi,
Ernest - good to hear from you and I agree! Sad, but this does appear to be the situation - very little hard data is available

Greg - thank you, and as you comment Motul is a good and reliable product (in the right specification of course)

Tom - Blackstone Labs are excellent - if you send a sample to them request a "TBN" as well. Subject to the UOA of course the oil may still be in a usable state - the data will be valuable to us all

Regards

Old & New

Doug,

Any caveats regarding supercharged applications?

Doug Hillary

Hi,
Old & New - depending on the construction of the SC, its application, location, pipework, boost & output etc, the lubricant principles still remain the same. The type of drive and the bearings used may be the greatest factors of all

MB in their factory SC installations endorse the same engine oil as the non SC engines. The same applies to the Holden-GM V6 factory installations available here in OZ

Usually SC installations are less problematic than turbo chargers as they are more able to be fed lubricant in the ideal operating temperature range and without the tendency for coking as in some TC installations. TC's due to their heat and operational factors, bearing type(s) and location can lead to rapid oil degradation and severe combustion system/piston/ring deposits

There are a number of lubricants that perform better in these circumstances and these have additive packages more aligned to the application

Usually piston and ring problems will emerge when using an unsuitable lubricant. The heavy diesel engine makers have learned a lot here in recent years due to continuous boost (30psi+) and very high compression pressures. Their lubricants are especially tailored for these conditions

Usually a 5w-40 HDEO "mixed fleet" CI-4/SL synthetic lubricant will perform better than most straight petrol engine only oils in these applications. This is due to their additive package and oil Group 4 or 5 chemistry that does not contain Viscosity Index Improvers (VIIs). They are not "friction modified" either and tolerate high compression pressures very well and resist combustion system deposits

Contact me direct if you wish with further details

Regards

Lagavulin

Doug, thanks for sharing!

mark kibort

I run amzoil 20-50.

3 full seasons, running as fast time as anyone could expect out of a 5 liter.
3 pro 1hour races, lots of club races and always beating the snot out of it during the race!!
No accusump
No oil cooler,
no baffle
All stock!! 335 rear wheel hp in its best dyno run and 1:40.2 at laguna Seca.

proof enough!!??????
(still knocking on wood)

Jim bailey - 928 International

Mr Kibort .." All stock!! " Right a pre-prodution prototype built on an 86 chassis months before production started tested in Italy by Porsche shipped to Holberts Race shop ; then it sets records on the salt flats .........stock ?? the camshafts have weird numbers that is a fact , the engine puts out somewhat high power levels than most . The original brains had external ports for chip changes that is a fact . I think we do not know what may have been done to that engine .

Doug Hillary

Hi,
Lagavulin - thanks!

Mark - you've done very well, keep it up! It would be nice to know your oil temps and pressure
As a matter of interest the lubricant you use has a HTHS vis. of about 5.1> about the same as Mobil's new M1 SuperSyn 15w-50. Castrol's R 10w-60 is up around 5.8 - probably a little too high for most users. Motul run a V300 in that viscosity too for use in distance events or when significant fuel dilution may occur

Did you manage to get an oil sample taken and analysed recently?

Hi Jim - the modifications you mention sure would be worth knowing, keep smiling!!

Regards

mark kibort

Temps in my old part euro 5 liter were in a heated battle, in the 280f range, but generally most of the time in the 260f range.
pressure always at 5 bar + and about 3.5 to 4 bar at idle.

The Holbert car runs 4 at idle and +5bar as soon as the rpms are above 1500. the needle never dips. ive had the camera on the guage during high g turns, and it doesnt move. if you actually time turns , especially like tracks as Laguna or Sears Point, you never really are in a high G loading period for more than a second or two. even the high speed hairpin at Thunderhill is only about 3-4 seconds. (and I know it doesnt take much more than that to kill a bearing under oil starvation)

I would love to have someone take a look at my oil after speedGT or some period of racing. the filter is clean. (took it apart) magnet never has even a hint of material. (except an occasional cam sprocket tooth) and it aways looks clean on changes.

mk

mark kibort

Hey Jim,

it wasnt too far off the stock mark. It currently has stock fuel and spark brains. (from 928 intl) yes, the cams are a mystery, but the shape of the dyno runs looks to be S4. i do have dyno runs with only the cat replaced with a bypass tube, and no other changes, and it put down 285hp. (not too far off stock s4s) keep in mind, this is a realitively new engine , with only 18k orignial miles too.

after a set of equal length headers, it got 305rwhp. after we did the air box mods and removed both MAF screens, we were up to 335rwhp.
Now, last dyno run was 317-320hp. I have a feeling its less now, but we will see.

Ive heard of stock S4s with stage 2 headers making 300plus hp.

Point is, the car has no oiling issues and im not using the Accusump.
could it be oil, driving style , tracks etc?

MK



But your right, it may not be bone stock, but I hardly think they did anythin fancy with the crank, oil pan or anything else.

Carl Fausett

I like the ASTM tests here:

http://www.bestsynthetic.com/comptest.shtml

I know they are pitching their own product, but I am familiar with AMSOILs
reputatiuon among racers and that counts for a lot. And I like the level playing field of the ASTM tests.

BTW - in a different thread about Crankcase ventilation, several mentioned the failure of their Mobil 1 when the temps got high. I just wanted to share my experience of idling on grid on a 110 degree day and waiting to get on the track. There was an accident, so we were stuck on the grid waiting for the clean-up to finish. It was a toss-up whether to turn off the motor and bake - or idle the motor and let the fans run. I tried both. (It was a lo-o-o-o-ng wait) During this wait I had ample to time to watch my gauges - oil pressure holding steady at 40-50 psi at idle, 80 psi during a blip; oil temp and water temp climb and climb - just could not get enough air thru the radiator by fans alone. At one point (do not remember the temp number) my oil pressure just crapped out - it went from 40 psi at idle to like 10! I pulled off the grid and surrendered the race. Theraml Viscosity Break Down?

I do not use Mobil 1 in my race car anymore.

mark kibort

classic. thats what im talking about. seems like mobil one is just not cut out for racing. had the same thing happen with my old 79, and never used mobil one in my 84 , 84 part euro 5 liter or the ole Holbert car. pressure is 4bar, idle, regardless of temps outside. and aways 5 bar+ racing, and through the turns. not so for the mobil one in my 79, and other cars Ive heard.

this weekend's race, there was a vet with mobil one 410hp vet engine. he showed me his oil and it looked like he was panning for gold!!! wasnt magnetic, so who knows what i was . copper, nickel??? lots of shinney stuff. When asked what oil he used, he said mobil one!!! he said he just replaced the bearings and was this normal for break in/seating of the bearings???

the guy had 2 accusumps!!!!

Amzoil all the way!

MK