Racing engine oils - "short list"
11-04-2003, 11:17 PM
#1
Burning Brakes
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Racing engine oils - "short list"
Hi,
In the recent thread on "bearing issues" I suggested that we collectively look at the factors involved with these failures. Well again, "oils ain't oils" and in the pursuit of more knowledge and possible corrective action many people mentioned preferred oil brands - this is an area where I and many others may be able to assist a little
We do know that the main components ( rods, mains, valve lifters ) experience temperatures between 200-500F with the piston crown up to around 800F. Some oils relish these temperatures, and high revs., and some have extraordinary loading capacity at the extremes - others do not
For the 928 in normal use the Handbook's recommendations are fine, racing however is another matter
I believe that collectively we can isolate the most important lubricant qualities/factors and produce a "short list" of engine oils that would be the best possible choices for those who wish to race our vehicles
As an example Motul ( a USA Company until 1932 ) produce a number of products and their premium race oil, V300, is made in variety of viscosities. Would their 15w-60 "Le Mans" version be the most suitable for the 928 when in competition? They do recommend a 15w-50 for their non race oils in normal use!
Some Redline and Amsoil products will not be suitable for either long life or for racing and some will be. Some have a good wear and/or cleaning reputation and some don't. ExxonMobil are base oil suppliers to these and many other Companies. Which is their best race oil?
ExxonMobil's Mobil 1 range has a number of formulations as do Castrol's synthetics. Some of Castrol's race oils are still castor oil based
Mobil's new SuperSyn is completely different from the superceded TriSynthentic. Good/bad results from one will be different from the other.
Castrol's SLX is different from the RS range. Some are International blends and others are formulated via Market requirements. Some will be better than others in a race engine. I know that their special race formulations for sponsored race car teams are unavailable over the counter
ExxonMobil are about to or have already released their "Racing" grade M1 in NA as a 10w-30 I believe
Other brands like Shell the "Ferrari" oil, Repsol, FUCHS, Schaeffers etc. will no doubt figure too in any unbiased selection list.
If those persons who commented like "...I only use Amsoil..." in the other thread(s) would respond with the following factual information we could perhaps move forward by assembling the facts without brand hype and religious fervour
Brand ( say, Castrol )
Type ( say, V300 )
Ratings ( such as API's SJ/CH, ACEA's A1/B1, MB229.1, VW505.1, Porsche Approved etc.)
Viscosity ( say, 15w-40 )
Good or bad experience ( loss of oip pressure etc - backed up by factual data )
It is important that the full data is supplied so that the actual formulation and performance of the oil can be determined. Some thousands of engine oils are sold worldwide and this complicates the task
If you are interested, please participate and please note that I am not connected to any Oil Company in any way. I do have access however to persons with an interest in Tribology who may assist too
Oils really ain't oils - they really are very complex chemical formulations! Let us try to make a comprehensive list for selecting a product to use in racing the 928
After all, all the makers have their "approved" or "preferred" oils lists
There is no magic elixer!
Regards
In the recent thread on "bearing issues" I suggested that we collectively look at the factors involved with these failures. Well again, "oils ain't oils" and in the pursuit of more knowledge and possible corrective action many people mentioned preferred oil brands - this is an area where I and many others may be able to assist a little
We do know that the main components ( rods, mains, valve lifters ) experience temperatures between 200-500F with the piston crown up to around 800F. Some oils relish these temperatures, and high revs., and some have extraordinary loading capacity at the extremes - others do not
For the 928 in normal use the Handbook's recommendations are fine, racing however is another matter
I believe that collectively we can isolate the most important lubricant qualities/factors and produce a "short list" of engine oils that would be the best possible choices for those who wish to race our vehicles
As an example Motul ( a USA Company until 1932 ) produce a number of products and their premium race oil, V300, is made in variety of viscosities. Would their 15w-60 "Le Mans" version be the most suitable for the 928 when in competition? They do recommend a 15w-50 for their non race oils in normal use!
Some Redline and Amsoil products will not be suitable for either long life or for racing and some will be. Some have a good wear and/or cleaning reputation and some don't. ExxonMobil are base oil suppliers to these and many other Companies. Which is their best race oil?
ExxonMobil's Mobil 1 range has a number of formulations as do Castrol's synthetics. Some of Castrol's race oils are still castor oil based
Mobil's new SuperSyn is completely different from the superceded TriSynthentic. Good/bad results from one will be different from the other.
Castrol's SLX is different from the RS range. Some are International blends and others are formulated via Market requirements. Some will be better than others in a race engine. I know that their special race formulations for sponsored race car teams are unavailable over the counter
ExxonMobil are about to or have already released their "Racing" grade M1 in NA as a 10w-30 I believe
Other brands like Shell the "Ferrari" oil, Repsol, FUCHS, Schaeffers etc. will no doubt figure too in any unbiased selection list.
If those persons who commented like "...I only use Amsoil..." in the other thread(s) would respond with the following factual information we could perhaps move forward by assembling the facts without brand hype and religious fervour
Brand ( say, Castrol )
Type ( say, V300 )
Ratings ( such as API's SJ/CH, ACEA's A1/B1, MB229.1, VW505.1, Porsche Approved etc.)
Viscosity ( say, 15w-40 )
Good or bad experience ( loss of oip pressure etc - backed up by factual data )
It is important that the full data is supplied so that the actual formulation and performance of the oil can be determined. Some thousands of engine oils are sold worldwide and this complicates the task
If you are interested, please participate and please note that I am not connected to any Oil Company in any way. I do have access however to persons with an interest in Tribology who may assist too
Oils really ain't oils - they really are very complex chemical formulations! Let us try to make a comprehensive list for selecting a product to use in racing the 928
After all, all the makers have their "approved" or "preferred" oils lists
There is no magic elixer!
Regards
11-05-2003, 12:37 AM
#2
Nordschleife Master
Doug,
I appreciate your scientific approach, just can't fulfil the requirements! Here's my data points, toss them if you wish.
Here are oil pressures as I recall them. All in summer conditions with hot engine. Pressures at rpm are in bar.
The bottom line is that the Amsoil racing formula gave noticably higher pressures. Getting 5 bar at 3K even on 90F when beating the car at the track. Under those conditions, the Mobil1 would start to show only 4.5 bar at 5k rpms. Didn't run the dyno oil under those conditions.
My summary is use the regular oil if you don't drive it hard. Use Mobil1 if you're a "boy racer" with occasional straight-line outbursts. Use Amsoil at the track.
Don't have API ratings.
I appreciate your scientific approach, just can't fulfil the requirements! Here's my data points, toss them if you wish.
Here are oil pressures as I recall them. All in summer conditions with hot engine. Pressures at rpm are in bar.
Code:
Oil Visc. Idle 3k 5k Castrol Mineral 20w50 1 3 4.5 Mobil1 15w50 1.5 3.5 5 Amsoil racing 20w50 2 5 5
My summary is use the regular oil if you don't drive it hard. Use Mobil1 if you're a "boy racer" with occasional straight-line outbursts. Use Amsoil at the track.
Don't have API ratings.
Last edited by GlenL; 11-05-2003 at 12:59 AM.
11-05-2003, 02:40 AM
#4
Burning Brakes
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Hi,
GlenL - top stuff, thanks
George 911-V8 - thanks for the comments
Please supply the type and viscosity of the oil if you can
It is very important to "nail" the type and spec. of the oil.
Many Oil Company brands are marketed in 100's of types/viscosities
Regards
GlenL - top stuff, thanks
George 911-V8 - thanks for the comments
Please supply the type and viscosity of the oil if you can
It is very important to "nail" the type and spec. of the oil.
Many Oil Company brands are marketed in 100's of types/viscosities
Regards
11-05-2003, 03:02 PM
#5
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I had similiar results as Glen, the only thing I would add is that
when the Mobil 1 got hot (ie end of an ORR) the pressure at idle
would drop to 1 bar or less. That didn't happen with Amsoil.
when the Mobil 1 got hot (ie end of an ORR) the pressure at idle
would drop to 1 bar or less. That didn't happen with Amsoil.
11-05-2003, 04:23 PM
#6
Race Director
In my 8v 944 motor in my 944-spec car with standard Mobil 1 15w-50 has shown the pressure drop as with Glen & George (Jorj7)
Conditions & Car specs
Racing
Stock oil/water heat exhanger (no ext cooler)
Water Temps in warm but normal range
Air Temps up to 105F
I have not tried other oils in this car at the track (yet)
Also for refernce I experinced 1 #2 rod bearing failure in a 100% stock motor using Mobil 1. Occured during race with 70-80F ambient air temps.
Later analysis of in car video showed momentary low oil pressure (close to zero) in the braking zone of 1 corner on the track (1.5 mile) for 2 lap prior to failuire. Oil pressure was solid at 3+ bar when catastrophic failure occured at full throttle.
Conditions & Car specs
Racing
Stock oil/water heat exhanger (no ext cooler)
Water Temps in warm but normal range
Air Temps up to 105F
I have not tried other oils in this car at the track (yet)
Also for refernce I experinced 1 #2 rod bearing failure in a 100% stock motor using Mobil 1. Occured during race with 70-80F ambient air temps.
Later analysis of in car video showed momentary low oil pressure (close to zero) in the braking zone of 1 corner on the track (1.5 mile) for 2 lap prior to failuire. Oil pressure was solid at 3+ bar when catastrophic failure occured at full throttle.
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11-05-2003, 05:36 PM
#10
Amsoil Racing oil, 20/50.
Pressure at idle is usually 2.5 to 3. 5 immediatley after applying the throttle.
After some canyons and highway stuff, on a hot day, no shifts under 5k, and the oil is at 2.1-2.4 bar. NEVER below 2.0
Pressure at idle is usually 2.5 to 3. 5 immediatley after applying the throttle.
After some canyons and highway stuff, on a hot day, no shifts under 5k, and the oil is at 2.1-2.4 bar. NEVER below 2.0
11-05-2003, 05:54 PM
#11
Race Director
Originally posted by mark kibort
any questions. anyone still running mobil 1 after this thread is pretty silly!
mk
any questions. anyone still running mobil 1 after this thread is pretty silly!
mk
Good thing my next race is not for a nother couple weeks
11-05-2003, 07:13 PM
#12
Rennlist Member
Good topic.
Oil pressure is dependent on engine tols and then oil type.
Here are some items to think about as you look at oil pressure issues.
1 Oil pressure is controlled by clearances (gaps) in the oil path.
2 clearances are - lifter bore to lifter, cam bore to cam, crank journal to crank bearing, thrsut gaps, rod side and radial tols...etc. Older engines with greater wear, will produce lower oil pressures for a given temp.
3 the engine is alum. two different alloys, and as such, has different exp rates...in other words, the gaps get bigger with increasing temps....this is the primary reason why the oil pressure drops as temp increases.
4 Different parts expand to different dims due to heat....BTW, the heads expand the most due to highest temps and the most "gaps"...lifters/cam journals.
Oil pathways
Crank - under 6500, there is no issue with the stock oiling flow pattern as long as there is sufficient oil pressure to provide lubrication to the rod bearing...this is tricky...look at my old testing point #3. I can say that the oiling pattern is not acceptable for 8000 rpm....no actual data on 7200 or 6950 for that matter...etc.
Block - it is darn good oil galley. Tried to reduce flow in one alley, and no noticable difference....
944 check valves - hard to install if the head is on the car...anyone with a success?? They seem to limit flow more than pressure.
I look forward the the analysis and recommendation. For now, I have found that of three oils, redline, mobil 1 and AMsoil, Amsoil produces the highest oil pressure at a given temp...and I have a real temp gauge. Is it the best oil to use....dont know,.....looking forward to finding out if there is something better...maybe the Motul will be the winner??
Marc
DEVEK
Oil pressure is dependent on engine tols and then oil type.
Here are some items to think about as you look at oil pressure issues.
1 Oil pressure is controlled by clearances (gaps) in the oil path.
2 clearances are - lifter bore to lifter, cam bore to cam, crank journal to crank bearing, thrsut gaps, rod side and radial tols...etc. Older engines with greater wear, will produce lower oil pressures for a given temp.
3 the engine is alum. two different alloys, and as such, has different exp rates...in other words, the gaps get bigger with increasing temps....this is the primary reason why the oil pressure drops as temp increases.
4 Different parts expand to different dims due to heat....BTW, the heads expand the most due to highest temps and the most "gaps"...lifters/cam journals.
Oil pathways
Crank - under 6500, there is no issue with the stock oiling flow pattern as long as there is sufficient oil pressure to provide lubrication to the rod bearing...this is tricky...look at my old testing point #3. I can say that the oiling pattern is not acceptable for 8000 rpm....no actual data on 7200 or 6950 for that matter...etc.
Block - it is darn good oil galley. Tried to reduce flow in one alley, and no noticable difference....
944 check valves - hard to install if the head is on the car...anyone with a success?? They seem to limit flow more than pressure.
I look forward the the analysis and recommendation. For now, I have found that of three oils, redline, mobil 1 and AMsoil, Amsoil produces the highest oil pressure at a given temp...and I have a real temp gauge. Is it the best oil to use....dont know,.....looking forward to finding out if there is something better...maybe the Motul will be the winner??
Marc
DEVEK
11-05-2003, 09:09 PM
#13
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Mark , not all of us are running around shifting at 6500 rpm in corners and such.
Mobil is fine for me, has been for 147,000 miles. Dont step on too many toes...there are a lot of "silly " 928 owners out there, K
Me being one
Mobil is fine for me, has been for 147,000 miles. Dont step on too many toes...there are a lot of "silly " 928 owners out there, K
Me being one
Last edited by Tony; 11-06-2003 at 04:56 PM.
11-05-2003, 10:55 PM
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Originally posted by marc@DEVEK
3 the engine is alum. two different alloys, and as such, has different exp rates...in other words, the gaps get bigger with increasing temps....this is the primary reason why the oil pressure drops as temp increases.
3 the engine is alum. two different alloys, and as such, has different exp rates...in other words, the gaps get bigger with increasing temps....this is the primary reason why the oil pressure drops as temp increases.
Originally posted by mark kibort
any questions. anyone still running mobil 1 after this thread is pretty silly!
any questions. anyone still running mobil 1 after this thread is pretty silly!
11-06-2003, 12:19 AM
#15
Burning Brakes
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Hi,
thanks for the collective information to date - from my side, I am en-route to our QLD/NSW 928 Frenzy ( see Asia Pacific events ) and then off to New Zealand to see my sons for 10 days
Please keep the information coming in - already some interesting stuff has been provided. The more data on the brand/type/viscosity and the specs. on the original container we can assemble the better
It may take some time ( a couple of weeks or so at least ) to assemble the data in a meaningful way and to prepare some results if that is want you all want me to do
I would hesitate to say "Mobil 1"!
Is it Mobil 1 15w-50 ( or 10w-30, or 0w-40 etc. ) Tri-synthetic or is it Mobil 1 15w-50 SuperSyn?.
These differences are very very important. It is well known that the older Tri-synthetic blend may have had some in use "problems" - one of these ( grade and spec. dependant ) was at high temperature shear!
Mobil 1 in the correct spec. and viscosity is a truely excellent product for normal use and has countless results worldwide to back it up. I do NOT use this product. And for racing - well the jury, our jury must still be out
Generally, the loss of OP is interesting. Is starvation an issue???
The viscosity ( in this case thinning ) at 150C will be one thing I will investigate. While this High Temperature/High Shear viscosity at 150C is very important, so is the film strength and the oil flow rate. At least one of these is a product of the oil's chemistry and base stock
The actual oil's specification can also give us an idea how the oil will react regarding foaming and its volatility at very high temperatures
Another thing that is often mooted is that say a 50 "mono" grade oil is better for racing than a multi-grade. This answer will be another end result of this thread - with a bit of luck. Most Tribologists for instance believe that the multi-grade is better - I tend to agree with synthetics!
I hope we do not get in to a "brand knocking" session. This will simply do nothing for any of us and I would prefer not to be involved in that case.
A "short list" of likely Racing Oils is surely what we are trying to achieve
Regards
thanks for the collective information to date - from my side, I am en-route to our QLD/NSW 928 Frenzy ( see Asia Pacific events ) and then off to New Zealand to see my sons for 10 days
Please keep the information coming in - already some interesting stuff has been provided. The more data on the brand/type/viscosity and the specs. on the original container we can assemble the better
It may take some time ( a couple of weeks or so at least ) to assemble the data in a meaningful way and to prepare some results if that is want you all want me to do
I would hesitate to say "Mobil 1"!
Is it Mobil 1 15w-50 ( or 10w-30, or 0w-40 etc. ) Tri-synthetic or is it Mobil 1 15w-50 SuperSyn?.
These differences are very very important. It is well known that the older Tri-synthetic blend may have had some in use "problems" - one of these ( grade and spec. dependant ) was at high temperature shear!
Mobil 1 in the correct spec. and viscosity is a truely excellent product for normal use and has countless results worldwide to back it up. I do NOT use this product. And for racing - well the jury, our jury must still be out
Generally, the loss of OP is interesting. Is starvation an issue???
The viscosity ( in this case thinning ) at 150C will be one thing I will investigate. While this High Temperature/High Shear viscosity at 150C is very important, so is the film strength and the oil flow rate. At least one of these is a product of the oil's chemistry and base stock
The actual oil's specification can also give us an idea how the oil will react regarding foaming and its volatility at very high temperatures
Another thing that is often mooted is that say a 50 "mono" grade oil is better for racing than a multi-grade. This answer will be another end result of this thread - with a bit of luck. Most Tribologists for instance believe that the multi-grade is better - I tend to agree with synthetics!
I hope we do not get in to a "brand knocking" session. This will simply do nothing for any of us and I would prefer not to be involved in that case.
A "short list" of likely Racing Oils is surely what we are trying to achieve
Regards