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Lubricating a modded car, some good advice!


oilman

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Geez i'm just glad i've got a stock car:D it takes away the need to fully understand!

 

as long as i'm running stock I think i'll continue with the 5000km, regular 10-40W oil changes. Its cost effective, and at a sooner than recommended interval and easy to keep track of on my 'still counting in km' odo!

 

Interesting stuff though. What about oil filters? if using synthetics could say extend a supra's oil change interval to say 10K miles (is this reasonable?) then is it ok filter wise over this period?

 

I spose what i'm saying is does using a synthetic oil mean less particulates in the oil for the same mileage. ie a synthetic oil and 10K miles filter will see the same level of particulates as 5K of regular/petroleum oil?

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What's the make up of Valvoline's Syn-Power? I have used this in everything from the lawn mower to Cosworth F1 engines. just curious. Also, what about Neo "synthetic" oils, I use this in the odd bits of true exotic race engines I get the pleasure of working on. I also run it in F3 engines for the reduced parasitic drag, although idle oil pressure goes to hell. it's dear enough, i hope it's REALLY good stuff!

 

My only practical experience of how some oils REALLY seem better than others came 18 months ago, with my current race car. When it was built it was designed to fight weight in every practical area, and as such runs a transaxle that is seeing double the torque Hewland specced it for. It used to push the crown wheel out of mesh with the pinion under peak torque, with horrible wear patterns and reduced life (6 races on average). I tried Motul Gear 300, and the CWP does a seasons racing now without too bad a wear pattern. I was impressed and use it in all "worthwhile" diffs and suitable gearboxes. It certainly seemed to be better than generic, but top brand EP gear oils.

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Originally posted by oilman

How did you know I have a Rotary?

 

Cheers

Simon

 

perhaps my sig should be "if it's not a rota its not a mota"!

 

I didn't actually, I have a 13B

 

Your input would be greatly appreciated on the FDUK (3rd gen Rx-7) forum, I have pm'd the address. hope to see you there if you have the time :)

 

Dave

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Originally posted by Chris Wilson

What's the make up of Valvoline's Syn-Power? I have used this in everything from the lawn mower to Cosworth F1 engines. just curious. Also, what about Neo "synthetic" oils, I use this in the odd bits of true exotic race engines I get the pleasure of working on. I also run it in F3 engines for the reduced parasitic drag, although idle oil pressure goes to hell. it's dear enough, i hope it's REALLY good stuff!

 

My only practical experience of how some oils REALLY seem better than others came 18 months ago, with my current race car. When it was built it was designed to fight weight in every practical area, and as such runs a transaxle that is seeing double the torque Hewland specced it for. It used to push the crown wheel out of mesh with the pinion under peak torque, with horrible wear patterns and reduced life (6 races on average). I tried Motul Gear 300, and the CWP does a seasons racing now without too bad a wear pattern. I was impressed and use it in all "worthwhile" diffs and suitable gearboxes. It certainly seemed to be better than generic, but top brand EP gear oils.

 

I'm not sure of the make-up of Valvoline as we've seen chemical tests on a number of their products but possibly not the one you use. They in general are not true synthetics and therefore would need changing on a more frequent basis. TBH

 

Motul is good stuff particularly the 300v products which are ester based and comparable with the Silkolene Competition products for performance. I'm not surprised that you like it.

 

Cheers

Simon

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Ok, to elaborate on the argument.

 

The whole point about good true synthetics is the "shear stability" and the use of VI Improvers or lack of in some cases.

 

Here's some more reading that explains this in great detail.

 

TRUE SYNTHETICS ARE MORE “SHEAR STABLE”

 

SAE has a test called HT/HS (High Temperature/High Shear) ASTM D4683 at 150 degC.

 

The higher the HT/HS number the better because this indicates less shearing. Petroleum oils tend to have low HT/HS numbers which barely meet the standards set by SAE. Because petroleum oils are made with light weight basestocks to begin with, they tend to burn off easily in high temperature conditions which causes deposit formation and oil consumption.

 

As a result of excessive oil burning and susceptibility to shearing (as well as other factors) petroleum oils must be changed more frequently than synthetics.

 

Not all multi-viscosity oils shear back so easily. True synthetic oils (PAO’s and Esters) contain basically no waxy contamination to cause crystallization and oil thickening at cold temperatures. In addition, synthetic basestocks do not thin out very much as temperatures increase. So, pour point depressants are unnecessary and higher viscosity basestock fluids can be used which will still meet the "W" requirements for pumpability.

 

Hence, little or no VI improver additive would need to be used to meet the sae 30, 40 or 50 classification while still meeting 0W or 5W requirements.

 

The end result is that very little shearing occurs within true synthetic oils because they are not "propped up" with viscosity index improvers. There simply is no place to shear back to. In fact, this is easy to prove by just comparing synthetic and petroleum oils of the same grade.

 

Synthetics will generally have significantly higher HT/HS numbers. Of course, the obvious result is that your oil remains "in grade" for a much longer period of time for better engine protection and longer oil life.

 

What are VI Improvers?

 

As a lubricant basestock is subjected to increasing temperatures it tends to lose its viscosity. In other words, it thins out. This leads to decreased engine protection and a higher likelihood of metal to metal contact. Therefore, if this viscosity loss can be minimized, the probability of unnecessary engine wear will be reduced.

 

VI improvers are polymers that expand and contract with changes in temperature. At low temperatures they are very compact and affect the viscosity of a lubricant very little. But, at high temperatures these polymers "expand" into much larger long-chain polymers which significantly increase the viscosity of their host lubricant.

 

So, as the basestock loses viscosity with increases in temperature, VI improvers “fight back” against the viscosity drop by increasing their size. The higher the molecular weight of the polymers used, the better the power of "thickening" within the lubricant. Unfortunately, an increase in molecular weight also leads to an inherent instability of the polymers themselves. They become much more prone to shearing within an engine.

 

As these polymers are sheared back to lower molecular weight molecules, their effectiveness as a VI improver decreases. Unfortunately, because petroleum basestocks are so prone to viscosity loss at high temperatures, high molecular weight polymers must be used. Since these polymers are more prone to shearing than lower molecular weight polymers, petroleum oils tend to shear back very quickly.

 

In other words, they lose their ability to maintain their viscosity at high temperatures.

 

Synthetic basestocks, on the other hand, are much less prone to viscosity loss at high temperatures. Therefore, lower molecular weight polymers may be used as VI improvers.

 

These polymers are less prone to shearing, so they are effective for a much longer period of time than the VI improvers used in petroleum oils. In other words, synthetic oils do not quickly lose their ability to maintain viscosity at high temperatures as petroleum oils do.

 

In fact, some synthetic basestocks are so stable at high temperatures they need NO VI improvers at all. Obviously, these basestocks will maintain their high temperature viscosities for a very long time since there are no VI improvers to break down.

 

Hope this helps to explain the differences.

 

Cheers

Simon

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Just a quick note.

 

I had a long conversation with Simon yesterday. What a great guy. Very helpful and informative.

 

I ordered some Silkolene Pro S from him at 4pm yesterday, and it arrived first thing this morning. Fantastic servce.

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ok 'if' i can stretch the synthetic to 10K km's then the costs stack up like this......

 

Synthetic - £10 Filter

..................£36 oil (x3 changes from 20L)

..................£46 Total

 

Regular......£20 (x2) Filters

..................£26 (no idea but must be a minimum of this for 12L's)

..................£46

 

 

when you factor in the nuisance factors of actually doing the change, its starting to turn into a no brainer even for the stock cars amongst us (assuming synthetic for 10K km IS in fact better than regular 10-40W for x2 5k km? AND the oil filter can stretch to the extended interval)

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Thought that this might clear up some of the old chestnuts about synthetic oils.

 

The Myths regarding Synthetic Oils

 

The benefits of Synthetic motor oils have been much debated over the last 10 years and misinformation is rife, particularly on the internet.

 

There are many so-called experts out there who should know better but hopefully this post will shed some light on some of the most common myths.

 

What are Synthetic Oils?

 

Synthetic Oils are fuel efficient, more fluid and resistant to thermal breakdown, they are constructed in laboratories using basestocks and special additive packages. They are specially formulated to meet and perform to standards set by API and ACEA as required by OEM’s.

 

Synthetic motor oils damage seals.

 

This is untrue. Why would lubricant manufacturers build products that are incompatible with seals. The composition of seals present problems that all types of oils must overcome.

At the end of the day, it is the additive pack in the oil that counts. Additives are added control the swelling, shrinking and hardening of seals.

 

Synthetics are too thin.

 

This is untrue. In order for an oil to be classified in any SAE grade (0W-40, 5w-40,10W-40 etc) it has to meet guidelines with regard to viscosity or thickness.

 

For example, any oil with a viscosity of 10W-40 has to operate at -25 degrees centigrade and 100 degrees centigrade to pass these tests or it cannot be rated as a 10W-40.

 

Synthetics mean higher oil usage.

 

This is untrue. Synthetic motor oils are intended for use in mechanically sound engines, that don't leak oil. In these engines oil consumption will actually be lower because of the lower volatility of Synthetics. They also have better sealing capabilities between piston rings and cylinder walls. Synthetics also have better oxidation stability. (They resist reacting with oxygen at high temperatures)

 

Synthetic Oils are not compatible with other oils.

 

This is untrue. The synthesized hydrocarbons, polyalphaolefins, diesters and other materials from high quality basestocks are fully compatible with other oils.

 

It is best to stick to the same oil for topping up that you have in the engine. It is best not to mix oils, as additives are blended for specific oils. When different oils are mixed additive pack balances can be upset so for the best performance, it’s better not to mix them.

 

Synthetic Oils produce sludge.

 

This is untrue. It is a fact that they are more sludge resistant than other oils as they are better at resisting high temperatures and oxidation. Because Synthetic oils have higher flash points, they withstand evaporation better leaving less deposits.

 

Synthetic oils can't be used with catalytic converters.

 

This is untrue. There is no difference between synthetic and other oils with regards to the components. Neither will damage catalytic converters.

 

Synthetic oils can void warranties.

 

This is untrue. No major manufacturers specifically ban the use of synthetic oils. More and more new performance cars are factory filled with Synthetic oils.

 

Vehicle warranties are based upon the use of oils meeting specific API Service Classifications and recommended viscosities.

 

Synthetic oils will last forever.

 

This is untrue. There are some people that believe that synthetic basestocks themselves can be used forever. However, it is a well known fact that eventually the additives will break down and cause the oil to degrade. The additives in the oil are effectively “used up” by moisture, fuel dilution and acids. Regularly topping up the oil will help but sensible oil change periods are recommended.

 

Synthetic oils will protect an engine for far longer periods than non-synthetics.

 

Synthetic oils are too expensive.

 

This is untrue. It has been proven through testing that Synthetic oils do have longer drain periods and provide better fuel economy. Add this to reduced engine wear and better reliability then do the maths. They are in reality better value for money than other oils.

 

Cheers

Simon

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