V IMPORTANT - RECOMMENDED S6 ENGINE OILS!!!!!!!!!!
Discussion
Just looking through car documentation, handbook etc, I noticed that the Handbook recommends 0W - 40 fully synthetic for 6000 miles and on (carlube RRR).
I then looked at recent service by TMS and they used castrol formula RS.
I phoned the dealer but could only talk to lady on service reception and she said that they used Castrol RS 10W-60 on all tvr servicing.
Surely with the speed6 a better cold start lower viscosity oil would be better, as recommended.
I did notice the oil P went up after the service, not a bad thing in theory, but pressure is measured on resistance and not flow, and surely a good oil flow is most important with these engines.
As someone else said in another thread you lose out at both ends of the scale with 10w-60. not as good for cold start and higher viscosity means higher temps and ultimately higher engine wear
Any thoughts welcome
>>> Edited by nickfb1 on Wednesday 27th April 18:58
>>> Edited by nickfb1 on Wednesday 27th April 18:58
I then looked at recent service by TMS and they used castrol formula RS.
I phoned the dealer but could only talk to lady on service reception and she said that they used Castrol RS 10W-60 on all tvr servicing.
Surely with the speed6 a better cold start lower viscosity oil would be better, as recommended.
I did notice the oil P went up after the service, not a bad thing in theory, but pressure is measured on resistance and not flow, and surely a good oil flow is most important with these engines.
As someone else said in another thread you lose out at both ends of the scale with 10w-60. not as good for cold start and higher viscosity means higher temps and ultimately higher engine wear
Any thoughts welcome
>>> Edited by nickfb1 on Wednesday 27th April 18:58
>>> Edited by nickfb1 on Wednesday 27th April 18:58
I have heard of this as well. I have always used 0W40, however I have head that oils with a thicker viscosity have been recommended as the engine tends to 'use' less. I believe that this is due to the fact that less slips into the combustion chamber and is burnt. I cant remember what the conclusion of previous threads about this was, but as my own (amateur) reckoning I would agree with you.
I have had Castrol RS10W60 in the Tuscan for the past 3 years & 15K miles ie since TMS had approval from the factory to use.It gives better oil pressure & better oil consumption. The only problem is finding it without going to a TVR dealer.
>> Edited by NCE 61 on Thursday 28th April 11:18
>> Edited by NCE 61 on Thursday 28th April 11:18
nickfb1 said:
As someone else said in another thread you lose out at both ends of the scale with 10w-60. not as good for cold start and higher viscosity means higher temps and ultimately higher engine wear
Any thoughts
Sorry but someone is talking absolute rubbish!
10w-60 is quite possibly the best weight oil you could ask for in a sports car imo.
There seems to be a big confusion as to the viscosity changing, it doesn't!
0w-40 is something I'd never use and is typically only recommended for cars with very tight tolerences (Not my Cerb!).
Let me find the link on Oil viscosity etc as it might make things clearer
. Duncan
DuncanM said:
nickfb1 said:
As someone else said in another thread you lose out at both ends of the scale with 10w-60. not as good for cold start and higher viscosity means higher temps and ultimately higher engine wear
Any thoughts
Sorry but someone is talking absolute rubbish!
10w-60 is quite possibly the best weight oil you could ask for in a sports car imo.
There seems to be a big confusion as to the viscosity changing, it doesn't!
Let me find the link on Oil viscosity etc as it might make things clearer
Duncan
With reference to viscosities
Castrol RS 0w-40
@40degC = 73.5cst
@100degC = 12.90cst
Castrol RS 10w-60
@40degC = 159cst
@100degC = 22.70cst
temperature does change the oils viscosity surely
>> Edited by nickfb1 on Thursday 28th April 11:42
Sorry Nick, my mistake!
What I meant was that people seem to think that the 60 in 10w-60 is a bad thing but it isn't it's a good thing surely?
10w-60 means a good pour rate at cold start and excellent protection at high temps.
If people want to use 0w-40 then that's fair enough but where did people get the idea that an oil having a high viscosity at high temp was a bad thing?
Duncan
What I meant was that people seem to think that the 60 in 10w-60 is a bad thing but it isn't it's a good thing surely?
10w-60 means a good pour rate at cold start and excellent protection at high temps.
If people want to use 0w-40 then that's fair enough but where did people get the idea that an oil having a high viscosity at high temp was a bad thing?
Duncan
I agree, I thought 10w-60 meant the engine oil will remain stable and won't break down or burn at really high temperatures, at the expense of very cold starting viscosity. Maybe it's more suitable for highly tweaked turbos but TVRs seem to run pretty hot to me. The handbook says don't go over 7000 rpm til you have 80 degrees C oil. My chargecooled Lotus Esprit used to settle at 60 degrees. A track thrash has got to see oil temps over 100. So we need an oil that doesn't break down at high temps I reckon.
Also, I thought people made a fuss when mobil 1 went from 5w50 to 0w40 because it meant it wasn't as good at high temps. So much so they had to reintroduce mobil 1 'motorsport' for all the tuned cosworths etc out there which could no longer run the 0w40.
10w 60 is the highest I've heard of! It sounds like top stuff to me! If the above figures are correct, look how much more viscosity you get at 100degrees than the 0w40.
>> Edited by the pits on Thursday 28th April 13:08
Also, I thought people made a fuss when mobil 1 went from 5w50 to 0w40 because it meant it wasn't as good at high temps. So much so they had to reintroduce mobil 1 'motorsport' for all the tuned cosworths etc out there which could no longer run the 0w40.
10w 60 is the highest I've heard of! It sounds like top stuff to me! If the above figures are correct, look how much more viscosity you get at 100degrees than the 0w40.
>> Edited by the pits on Thursday 28th April 13:08
Castrol Magantex is reccomended now as it sticks to the followers more than any other oil thereby reducing wear on them when folks leave them ideal for more than a week at a time. No oil in the head for a couple of seconds on start up is not good! :-( Use the beast as much as poss. :-)
There are a few important points being missed here and expalining is not easy. 10w-60 is not the best grade IMHO, too thick and too much oil drag loses power, generates heat and increases fuel consumption.
misconceptions are rife about oils and I can honestly say there are too few experts on the internet and plenty of pub talk!
If you think a 0w is too thin then think about this!
0w-40 is the same viscosity as 5w-40, 10w-40 and 15w-40 when hot (100degC) 14cst and of course ALL oils are thicker when cold.
WHAT? You don't believe me! The rantings of a mad man!
AFRAID NOT.................READ ON:
Viscosity at 40degC........Viscosity at 100degC
15w-40.......110cst.............14cst
10w-40.......100cst.............14cst
5w-40.........90cst............ 14cst
0w-40.........80cst............ 14cst
There may be a variance depending on the particular oil of around 5cst @ 40degC and 1cst @ 100degC but in essence what I'm saying is that oil is much thicker when cold than when hot and therfore it's the thinning (min to 14cst) that's the key here. Again the second number not the "W" number!
At lower temps as long as you have oil pressure flow is more important to engine wear than anything else!
Hence if you need an sae 40, 5w-40 is better than 15w-40 all round as it affords the same hot protection but gets round the engine quicker when cold as it's not so thick.
Yes that's right a 10w-60 is in fact as follows:
@100degC 24cst
@40degC 100cst (4 times thicker)
@ -30degC 7000cst!
Anyone got it yet?
Cheers
Simon (Guy's Brother)
misconceptions are rife about oils and I can honestly say there are too few experts on the internet and plenty of pub talk!
If you think a 0w is too thin then think about this!
0w-40 is the same viscosity as 5w-40, 10w-40 and 15w-40 when hot (100degC) 14cst and of course ALL oils are thicker when cold.
WHAT? You don't believe me! The rantings of a mad man!
AFRAID NOT.................READ ON:
Viscosity at 40degC........Viscosity at 100degC
15w-40.......110cst.............14cst
10w-40.......100cst.............14cst
5w-40.........90cst............ 14cst
0w-40.........80cst............ 14cst
There may be a variance depending on the particular oil of around 5cst @ 40degC and 1cst @ 100degC but in essence what I'm saying is that oil is much thicker when cold than when hot and therfore it's the thinning (min to 14cst) that's the key here. Again the second number not the "W" number!
At lower temps as long as you have oil pressure flow is more important to engine wear than anything else!
Hence if you need an sae 40, 5w-40 is better than 15w-40 all round as it affords the same hot protection but gets round the engine quicker when cold as it's not so thick.
Yes that's right a 10w-60 is in fact as follows:
@100degC 24cst
@40degC 100cst (4 times thicker)
@ -30degC 7000cst!
Anyone got it yet?
Cheers
Simon (Guy's Brother)
opieoilman said:
There are a few important points being missed here and expalining is not easy. 10w-60 is not the best grade IMHO, too thick and too much oil drag loses power, generates heat and increases fuel consumption.
misconceptions are rife about oils and I can honestly say there are too few experts on the internet and plenty of pub talk!
If you think a 0w is too thin then think about this!
0w-40 is the same viscosity as 5w-40, 10w-40 and 15w-40 when hot (100degC) 14cst and of course ALL oils are thicker when cold.
WHAT? You don't believe me! The rantings of a mad man!
AFRAID NOT.................READ ON:
Viscosity at 40degC........Viscosity at 100degC
15w-40.......110cst.............14cst
10w-40.......100cst.............14cst
5w-40.........90cst............ 14cst
0w-40.........80cst............ 14cst
There may be a variance depending on the particular oil of around 5cst @ 40degC and 1cst @ 100degC but in essence what I'm saying is that oil is much thicker when cold than when hot and therfore it's the thinning (min to 14cst) that's the key here. Again the second number not the "W" number!
At lower temps as long as you have oil pressure flow is more important to engine wear than anything else!
Hence if you need an sae 40, 5w-40 is better than 15w-40 all round as it affords the same hot protection but gets round the engine quicker when cold as it's not so thick.
Yes that's right a 10w-60 is in fact as follows:
@100degC 24cst
@40degC 100cst (4 times thicker)
@ -30degC 7000cst!
Anyone got it yet?
Cheers
Simon (Guy's Brother)
I've got it, loud and clear in fact.
Are you now going to tell me that 10w-60 is too thick for a big V8 that generates a lot of heat?
Are you going to tell me that in racing they typically use a 40 or do they use 50 and 60 weight oils?
Thicker is better at high temps and I don't care what you say to the contrary.
plus, a 10w-60 has the advantage of having a more than acceptable flow at start up too has it not?
Or are you saying that 10w is way too thick but 5w is ok?
Strange that you seem to know what you're talking about but also seem to rubbish an excellent weight oil!?
Edited to add:
If you're going to use stats then let's have the cst for -30deg for the other oils please?
Here is a proper usage of stats.
Viscosity at 40degC........Viscosity at 100degC
15w-40.......110cst.............14cst
10w-40.......100cst.............14cst
5w-40.........90cst.............14cst
0w-40.........80cst.............14cst
10w-60.......100cst.............24cst
Now, from the above I gather you will agree that 10w-60 is just as good as 10w-40 at 40degC in terms of flow and is thicker by a whopping 10cst at 100degC?
The above tell me that 10w-60 is a Great oil for big loose engines like mine and I want you to please explain why you don't believe this to be the case?
Yours
Still Confused
Duncan
>> Edited by DuncanM on Saturday 30th April 23:24
>> Edited by DuncanM on Saturday 30th April 23:25
DuncanM said:
Are you now going to tell me that 10w-60 is too thick for a big V8 that generates a lot of heat?
No. he's saying that it will generate even more heat.
DuncanM said:
Are you going to tell me that in racing they typically use a 40 or do they use 50 and 60 weight oils?
No, but you don't have the clearances that race engines have.
DuncanM said:
Thicker is better at high temps and I don't care what you say to the contrary.
I gathered that but others may listen.
DuncanM said:
plus, a 10w-60 has the advantage of having a more than acceptable flow at start up too has it not?
Apparantly not.
DuncanM said:
Or are you saying that 10w is way too thick but 5w is ok?
No, just that 5 is more suitable for performance, warm up and engine life.
DuncanM said:
10w-60 is a Great oil for big loose engines like mine and I want you to please explain why you don't believe this to be the case?
opieoilman said:
There are a few important points being missed here and explaining is not easy. 10w-60 is not the best grade IMHO, too thick and too much oil drag loses power, generates heat and increases fuel consumption. Hence if you need an sae 40, 5w-40 is better than 15w-40 all round as it affords the same hot protection but gets round the engine quicker when cold as it's not so thick.
Jonathan
There are some very important things to bear in mind here and they are as follows.
Unless you are getting high oil consumption or low oil pressure there are no benefits to using a 10w-60 because...........Thinner is in fact better.
Thinner oils dissapate heat better.
There is less oil drag and therefore in most cases this translates to marginally higher BHP at the wheels.
Thicker oils are more likely to cause cavitation.
Thicker oils are slower to release air.
Thinner oils give better fuel consumption returns.
So you see it's not a case of "can I use it" but more a case of are there any benefits?
If you are worried about an sae 40 or 50 being "too thin" then look at the oil temperatures you are running and bear in mind that a an average 5w-40 is in fact thicker at 110degC (12.00cst) than a 15w-50 is at 140degC (8.00cst).
You could be dragging a heavier oil round your engine than is needed and there are no benefits to this.
The next most important thing is shear stability.
An oils viscosity will decrease as the engine temperature rises. Viscosity Index Improvers are added to reduce this thinning. They are a key addative in the production of multigrade oils.
VI Improvers are heat sensitive long chain, high molecular weight polymers that increase the relative viscosity of the oil at high temperatures. They work like springs, coiled at low temperatures and uncoiling at high temperatures. This makes the molecules larger (at high temps) which increases internal resistance within the thinning oil. They in effect "fight back" against the viscosity loss in the oil.
"Shearing"
The long chain molecules in VI Improvers are prone to "shearing" with use which reduces their ability to prevent the oil from losing viscosity. This "shearing" occurs when shear stress ruptures the long chain molecules and converts them to shorter, lower weight molecules. The shorter, lower weight molecules offer less resistance to flow and their ability to maintain viscosity is reduced.
This shearing not only reduces the viscosity of the oil but can cause piston ring sticking (due to deposits), increased oil consumption and increased engine wear.
Like basestock quality, VI Improvers also vary in quality. The best quality ones are normally found in synthetic oils (Group IV - PAO / Group V - Esters) and it is important to understand that the less of these in the oil the better the oil will stay in grade.
Which oils require more VI Improvers?
There are two scenarios where large amounts of these polymers are required as a rule.
Firstly in "wide viscosity" multigrades. By this I mean that the difference between the lower "W" number and the higher number is large for example 5w-50 (diff 45) and 10w-60 (diff 50) are what is termed as "wide viscosity" oils.
Narrow viscosity oils like 0w-30 (diff 30) or 5w-40 (diff 35) require far less VI Improvers and therefore are less prone to "shearing".
Secondly, mineral and hydrocracked (petroleum synthetic oils) require more VI Improvers than proper PAO/Ester (Group IV or V) synthetic oils as they are less thermally stable to begin with and this is due to the non-uniform molecules in petroleum oils as opposed to the uniformity of synthetics built in laboratories by chemists.
It is a fact that some synthetics require little or no VI Improvers to work as a multigrade due to their superior thermal stability.
How to identify a good "shear stable" oil.
API and ACEA both conduct tests called HTHS (High Temperature/ High Shear) and all oils carrying these specifications are tested and scored.
For all oils, these test results are available however, they are often ommitted from the oils technical data sheet! Oil Companies have a tendency to publish the figures that they want you to see and therefore you often need to dig further or ask for certain information when comparing the performance of various oils.
High-Temperature/High-Shear
This test is a simulation of the shearing effects that would occur within an engine. In fact, it's actually designed to simulate motor oil viscosity in operating crankshaft bearings.
Under high stress conditions where shearing can occur, the VI Improvers (polymers) break down. As they do, the viscosity of the oil decreases. This is what the High Temperature/High Shear test checks for.
The HT/HS test is measured in Centipoise (cP) as the Cold Crank Simulator test is. However, in this case, because you're hoping for the least loss of viscosity with an increase in heat and stress, you want the cP value to remain high.
Each SAE multi-viscosity grade has a specific lower limit for the HT/HS cP value. If a multi-viscosity oil cannot achieve a cP value above that limit, it cannot be classified under that viscosity grade. For instance, according to the SAE specifications, an oil must achieve an HT/HS cP value of 3.7 or higher in order to be classified at the 15w40 viscosity grade.
The thinner the oil the lower the number.
Comparisons of HTHS numbers.
Here for comparison sake are a few numbers that we have compiled from data sheets and requests to the oil companies concerned. These are well known oils and considered to be "quality" synthetics so these comparisons are relevant.
Silkolene PRO S 5w-40
HTHS 4.07
Motul 300V 5w-40
HTHS 4.51
Silkolene PRO S 10w-50
HTHS 5.11
Motul 300V 10w-40
HTHS 4.19
Silkolene PRO R 15w-50
HTHS 5.23
Motul 300V 15w-50
HTHS 5.33
Mobil 1 Motorsport 15w-50
HTHS 5.11
Castrol RS 10w-60
HTHS 3.70
Sorry this is long but you wanted an explanation. Even in a big V8 I would use a 15w-50 or 10w-50 tops viscosity wise and depending on oil temps I would even consider a lower viscosity oil. A good 5w-40 can withstand bulk oil temps of 120degC.
Cheers
Simon
Unless you are getting high oil consumption or low oil pressure there are no benefits to using a 10w-60 because...........Thinner is in fact better.
Thinner oils dissapate heat better.
There is less oil drag and therefore in most cases this translates to marginally higher BHP at the wheels.
Thicker oils are more likely to cause cavitation.
Thicker oils are slower to release air.
Thinner oils give better fuel consumption returns.
So you see it's not a case of "can I use it" but more a case of are there any benefits?
If you are worried about an sae 40 or 50 being "too thin" then look at the oil temperatures you are running and bear in mind that a an average 5w-40 is in fact thicker at 110degC (12.00cst) than a 15w-50 is at 140degC (8.00cst).
You could be dragging a heavier oil round your engine than is needed and there are no benefits to this.
The next most important thing is shear stability.
An oils viscosity will decrease as the engine temperature rises. Viscosity Index Improvers are added to reduce this thinning. They are a key addative in the production of multigrade oils.
VI Improvers are heat sensitive long chain, high molecular weight polymers that increase the relative viscosity of the oil at high temperatures. They work like springs, coiled at low temperatures and uncoiling at high temperatures. This makes the molecules larger (at high temps) which increases internal resistance within the thinning oil. They in effect "fight back" against the viscosity loss in the oil.
"Shearing"
The long chain molecules in VI Improvers are prone to "shearing" with use which reduces their ability to prevent the oil from losing viscosity. This "shearing" occurs when shear stress ruptures the long chain molecules and converts them to shorter, lower weight molecules. The shorter, lower weight molecules offer less resistance to flow and their ability to maintain viscosity is reduced.
This shearing not only reduces the viscosity of the oil but can cause piston ring sticking (due to deposits), increased oil consumption and increased engine wear.
Like basestock quality, VI Improvers also vary in quality. The best quality ones are normally found in synthetic oils (Group IV - PAO / Group V - Esters) and it is important to understand that the less of these in the oil the better the oil will stay in grade.
Which oils require more VI Improvers?
There are two scenarios where large amounts of these polymers are required as a rule.
Firstly in "wide viscosity" multigrades. By this I mean that the difference between the lower "W" number and the higher number is large for example 5w-50 (diff 45) and 10w-60 (diff 50) are what is termed as "wide viscosity" oils.
Narrow viscosity oils like 0w-30 (diff 30) or 5w-40 (diff 35) require far less VI Improvers and therefore are less prone to "shearing".
Secondly, mineral and hydrocracked (petroleum synthetic oils) require more VI Improvers than proper PAO/Ester (Group IV or V) synthetic oils as they are less thermally stable to begin with and this is due to the non-uniform molecules in petroleum oils as opposed to the uniformity of synthetics built in laboratories by chemists.
It is a fact that some synthetics require little or no VI Improvers to work as a multigrade due to their superior thermal stability.
How to identify a good "shear stable" oil.
API and ACEA both conduct tests called HTHS (High Temperature/ High Shear) and all oils carrying these specifications are tested and scored.
For all oils, these test results are available however, they are often ommitted from the oils technical data sheet! Oil Companies have a tendency to publish the figures that they want you to see and therefore you often need to dig further or ask for certain information when comparing the performance of various oils.
High-Temperature/High-Shear
This test is a simulation of the shearing effects that would occur within an engine. In fact, it's actually designed to simulate motor oil viscosity in operating crankshaft bearings.
Under high stress conditions where shearing can occur, the VI Improvers (polymers) break down. As they do, the viscosity of the oil decreases. This is what the High Temperature/High Shear test checks for.
The HT/HS test is measured in Centipoise (cP) as the Cold Crank Simulator test is. However, in this case, because you're hoping for the least loss of viscosity with an increase in heat and stress, you want the cP value to remain high.
Each SAE multi-viscosity grade has a specific lower limit for the HT/HS cP value. If a multi-viscosity oil cannot achieve a cP value above that limit, it cannot be classified under that viscosity grade. For instance, according to the SAE specifications, an oil must achieve an HT/HS cP value of 3.7 or higher in order to be classified at the 15w40 viscosity grade.
The thinner the oil the lower the number.
Comparisons of HTHS numbers.
Here for comparison sake are a few numbers that we have compiled from data sheets and requests to the oil companies concerned. These are well known oils and considered to be "quality" synthetics so these comparisons are relevant.
Silkolene PRO S 5w-40
HTHS 4.07
Motul 300V 5w-40
HTHS 4.51
Silkolene PRO S 10w-50
HTHS 5.11
Motul 300V 10w-40
HTHS 4.19
Silkolene PRO R 15w-50
HTHS 5.23
Motul 300V 15w-50
HTHS 5.33
Mobil 1 Motorsport 15w-50
HTHS 5.11
Castrol RS 10w-60
HTHS 3.70
Sorry this is long but you wanted an explanation. Even in a big V8 I would use a 15w-50 or 10w-50 tops viscosity wise and depending on oil temps I would even consider a lower viscosity oil. A good 5w-40 can withstand bulk oil temps of 120degC.
Cheers
Simon
opieoilman said:
Sorry this is long but you wanted an explanation. Even in a big V8 I would use a 15w-50 or 10w-50 tops viscosity wise and depending on oil temps I would even consider a lower viscosity oil. A good 5w-40 can withstand bulk oil temps of 120degC.
Cheers
Simon
Don't apologise because that's one of the best most informational posts I have read and I thank you
. Now that you have explained the reasons for not recommending the 10w60 grade oils (wide viscosity VI issues) etc I can understand a lot better.
What was confusing me is that Guy has continually recommended 10w50 oils for Speed6/V8 use and yet 10w60 is way too thick
. I currently use a 20w50 in my Cerbera but am very interested in the 10w50 that you are recommending and may well change at my next service
. Would you admit that your first posts statistics were somewhat misleading and didn't really show 10w60 in that bad a light?
Thanks again
Yours enlightened
Duncan
Guy put this pretty well to me when I spoke to him about oil for the Cerb. Put simply increased pressure is present when there is resistance to flow. Reduced flow can mean that insufficient oil is getting where you want it to go. Increased oil pressure may give you a bigger number on the gauge, but it doesn't mean your engine is any better protected, if anything it can be the reverse. Well that's my simplistic view anyway.
Cheers,
Steve.
Cheers,
Steve.
Guy is my brother and I can assure you that he does know his stuff but I have a few years on him experience wise.
The problem here is explaining things.
These issues are deeply technical and it's difficult for us to know the level of knowledge that the average reader has and therefore at what level to pitch the information.
Yes we could write a book everytime but then no one would read it so we try to compress the info into a readable yet informative post and it's not an easy thing to do!
Hope it's all clear now and you can always email us or call if you wish to discuss things as our 2 finger typing is not quick.
If you want to meet us in person then catch up with us at one of the shows this year!
Cheers
Simon
The problem here is explaining things.
These issues are deeply technical and it's difficult for us to know the level of knowledge that the average reader has and therefore at what level to pitch the information.
Yes we could write a book everytime but then no one would read it so we try to compress the info into a readable yet informative post and it's not an easy thing to do!
Hope it's all clear now and you can always email us or call if you wish to discuss things as our 2 finger typing is not quick.
If you want to meet us in person then catch up with us at one of the shows this year!
Cheers
Simon
opieoilman said:
Sorry this is long but you wanted an explanation. Even in a big V8 I would use a 15w-50 or 10w-50 tops viscosity wise and depending on oil temps I would even consider a lower viscosity oil. A good 5w-40 can withstand bulk oil temps of 120degC.
Cheers
Simon
Nice posting Simon, nothing like a bit of theory and fact coupled with experience on this type of critical thread.
I guesss that'll be why TVR Power in Coventry, who have done just about every Speed 6 rebuild use 5w-40 then. Had my first 1,000 service with them about 10 days ago and the mineral oil was drained, well about 8 of the 12 litres, and a semi-synthetic 5w-40 was used.
Dom stressed the importance of not using a fully synthetic oil such as Mobil 1 in a Speed 6 unless you're using it exclusively for track stuff, i.e. high revs and high temperatures. Does that tally with your experience Simon?
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