Club G40 Forum
Technical => Engine and Transmission => Topic started by: oilman on June 21, 2013, 09:27:06 am
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The Advantages of Synthetic Oils over Mineral oils
Extended oil drain periods
Better wear protection and therefore extended engine life
Most synthetics give better MPG
They flow better when cold and are more thermally stable when hot
Surface-active meaning a thin layer of oil on the surfaces at all times (in ester based oils)
How Synthetic oils Achieve these Benefits
Stable Basestocks
Synthetic oils are designed from pure, uniform synthetic basestocks, they contain no contaminants or
unstable molecules which are prone to thermal and oxidative break down.
Because of their uniform molecular structure, synthetic lubricants operate with less internal and
external friction than petroleum oils which have a non-uniform molecular structure.
The result is better heat control, and less heat means less stress to the lubricant.
Higher Percentage of Basestock
Synthetic oils contain a higher percentage of lubricant basestock than petroleum oils do.
This is because multi-viscosity oils need a great deal of pour point depressant and viscosity improvers
to operate as a multigrade.
The basestocks actually do most of the lubricating. More basestocks mean a longer oil life.
Additives Used Up More Slowly
Petroleum basestocks are much more prone to oxidation than synthetic oils. Oxidation inhibitors are
needed in greater quantities in petroleum oils as they are used up more quickly.
Synthetic oils do oxidize, but at a much slower rate therefore oxidation inhibiting additives are used up
more slowly.
Synthetic oils provide for better ring seal than petroleum oils do. This minimizes blow-by and reduces
contamination by combustion by-products. As a result, corrosion inhibiting additives have less work to
do and will last much longer in a synthetic oil.
Excellent Heat Tolerance
Synthetics are simply more tolerant to extreme heat than petroleum oils are. When heat builds up
within an engine, petroleum oils quickly begin to burn off. They are more volatile. The lighter
molecules within petroleum oils turn to gas and what's left are the large molecules that are harder to
pump.
Synthetics have far more resistance as they are more thermally stable to begin with and can take
higher temperatures for longer periods without losing viscosity.
Heat Reduction
One of the major factors affecting engine life is component wear and/or failure, which is often the
result of high temperature operation. The uniformly smooth molecular structure of synthetic oils gives
them a much lower coefficient friction (they slip more easily over one another causing less friction)
than petroleum oils.
Less friction means less heat and heat is a major contributor to engine component wear and failure,
synthetic oils significantly reduce these two detrimental effects.
Since each molecule in a synthetic oil is of uniform size, each is equally likely to touch a component
surface at any given time, thus moving a certain amount of heat into the oil stream and away from the
component. This makes synthetic oils far superior heat transfer agents than conventional petroleum
oils.
Greater Film Strength
Petroleum motor oils have very low film strength in comparison to synthetics. The film strength of a
lubricant refers to it's ability to maintain a film of lubricant between two objects when extreme pressure
and heat are applied.
Synthetic oils will typically have a film strength of 5 to 10 times higher than petroleum oils of
comparable viscosity.
Even though heavier weight oils typically have higher film strength than lighter weight oils, an sae 30
or 40 synthetic will typically have a higher film strength than an sae 50 or sae 60 petroleum oil.
A lighter grade synthetic can still maintain proper lubricity and reduce the chance of metal to metal
contact. This means that you can use oils that provide far better fuel efficiency and cold weather
protection without sacrificing engine protection under high temperature, high load conditions.
Obviously, this is a big plus, because you can greatly reduce both cold temperature start-up wear and
high temperature/high load engine wear using a low viscosity oil.
Engine Deposit Reduction
Petroleum oils tend to leave sludge, varnish and deposits behind after thermal and oxidative break
down. They're better than they used to be, but it still occurs.
Deposit build-up leads to a significant reduction in engine performance and engine life as well as
increasing the chance of costly repairs.
Synthetic oils have far superior thermal and oxidative stability and they leave engines virtually varnish,
deposit and sludge-free.
Better Cold Temperature Fluidity
Synthetic oils do not contain the paraffins or other waxes which dramatically thicken petroleum oils
during cold weather. As a result, they tend to flow much better during cold temperature starts and
begin lubricating an engine almost immediately. This leads to significant engine wear reduction, and,
therefore, longer engine life.
Improved Fuel Economy
Because of their uniform molecular structure, synthetic oils are tremendous friction reducers. Less
friction leads to increased fuel economy and improved engine performance.
This means that more energy released from the combustion process can be transferred directly to the
wheels due to the lower friction. Acceleration is more responsive and more powerful, using less fuel in
the process.
In a petroleum oil, lighter molecules tend to boil off easily, leaving behind much heavier molecules
which are difficult to pump. The engine loses more energy pumping these heavy molecules than if it
were pumping lighter ones.
Since synthetic oils have more uniform molecules, fewer of these molecules tend to boil off and when
they do, the molecules which are left are of the same size and pumpability is not affected.
Synthetics are better and in many ways, they are basically better by design as they are created by
chemists in laboratories for a specific purpose, rather than being modified from something that came
out of the ground to be as good as they can for a purpose.
Cheers
Tim
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Thanks for this mate, what oil do you recommend for a g40 then? To cope with the oil fed supercharger stresses too?
ive always used vw approved qauntum 10w40 semi synthetic, and its only £20 for 5 litres
any better price on that? Thanks
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If your budget is £20, then you are looking at a 10w-40 semi as the best option, but I would say it's worth spending a little more and going for a 5w-40 synthetic. Something like the Fuchs Supersyn is just over £20 with your members discount.
http://www.opieoils.co.uk/c-656-5w-40.aspx
Out of those, the best ones are the Fuchs/Silkolene Pro S, Millers CFS/CFS NT, Motul 300V, Redline and Gulf Competition. The Motul 8100 X-Cess, Millers XFS, Fuchs GT1 XTL/Supersyn, Gulf Formula G, Shell Helix and Mobil Super 3000 are good, cheaper alternatives.
Cheers
Tim
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Your saying fully synthetic is better over semi?
Ok thanks for that, and what do you recommend for top of the range?
Car is used for commuting so is driven when not fully warm and the thrashed, track abuse now and again
how often do you recommend changes?
thanks again
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Hi
Yes, a full synthetic is better than a semi and a 5w will give better cold start protection than a 10w, so will help out, especially with the commuting.
How many miles do you cover in a year? What's the standard service interval on those?
Cheers
Tim
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Hi
Yes, a full synthetic is better than a semi and a 5w will give better cold start protection than a 10w, so will help out, especially with the commuting.
How many miles do you cover in a year? What's the standard service interval on those?
Cheers
Tim
every 10k oil filter and oil but i do mine much sooner. 5w 40 fully synthetic? Whats the benifit of 5w 50 over 5 w 40? Fully synthetic
i always worry about full syn as it looks so runny, definitly be ok for the delicate charger bearings?
um probably 15k a year mainly commuting but, track day thrashes and long road trips to switzerland etc, so she does have a hard life
thanks bud
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Hi
There is no advantage in a 50 over a 40, unless the car needs a 50 rather than a 40.
The right grade of synthetic (5w-40 or 10w-40) will give better protection than a mineral based oil. Oil is supposed to be runny, you need it to flow well to lubricate properly. Okay, too thin will lead to reduced protection, but a 5w-40 or 10w-40 will be fine. If you're doing 15k a year, changing a synthetic twice will be fine.
Cheers
Tim
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How do you rate the silkolene 5w40 pro s fully synthetic? Tempted by it with 20 percent off
also any chance of getting some motul rbf race fluid, enough to bleed my entire system through or something just as good with a really high boiling point
many thanks taylor
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Tim,
What oil would you recommend for the standalone oil supply for the supercharger?
Bearing in mind it uses a fuel pump running approx 7psi.
Most people run thin oils like compressor oil and some run 0W10 oils, are these ok to run?
Also operating temps be seem to see 45 degress.
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How do you rate the silkolene 5w40 pro s fully synthetic? Tempted by it with 20 percent off
also any chance of getting some motul rbf race fluid, enough to bleed my entire system through or something just as good with a really high boiling point
many thanks taylor
Hi Taylor
The Pro S is ideal, a really top quality oil.
The RBF is a very good brake fluid, one of the best, quite expensive though, so have a look at the Gulf RF800 if you want to save a bit.
http://www.opieoils.co.uk/p-69355-gulf-competition-rf800-racing-brake-fluid.aspx
Cheers
Tim
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Tim,
What oil would you recommend for the standalone oil supply for the supercharger?
Bearing in mind it uses a fuel pump running approx 7psi.
Most people run thin oils like compressor oil and some run 0W10 oils, are these ok to run?
Also operating temps be seem to see 45 degress.
Do you know what the recommended oil spec is? I don't have it listed.
Cheers
Tim
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It usually runs on just the standard oil spec but cause the pump is designed to pump fuel it needs to be a runny oil.
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Hi
Sorry for the delay with this, I've been having a look around to see what I can see on the specs for the oil.
Based on what I can see, a really good fork oil will be ideal
http://www.opieoils.co.uk/p-852-silkolene-05-synthetic-racing-fork-suspension-fluid.aspx
A few people have used that in similar chargers in the past. Not cheap but very high quality.
Cheers
Tim
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Tim,
Would running redline 10wt oil be ok? Im assuming its very runny.
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Hi
I don't know is the honest answer. When we asked a couple of oil companies before, the fork oil I mentioned above was the only one that came back recommended. The oil tech that analysed the original fluid said it was pretty weird stuff due to the way it behaved, so the only thing I'd suggest other than the original fluid is the Silkolene 05 fork oil.
Cheers
Tim
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Hi
Sorry for the delay with this, I've been having a look around to see what I can see on the specs for the oil.
Based on what I can see, a really good fork oil will be ideal
http://www.opieoils.co.uk/p-852-silkolene-05-synthetic-racing-fork-suspension-fluid.aspx
A few people have used that in similar chargers in the past. Not cheap but very high quality.
Cheers
Tim
What chargers Tim? Is it compatible with the seals?
Cheers
Pete
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The only thing i was worried about was the seals.
If its good for the seals then i might get this.
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Whats the stuff used in the eaton m45? does that eat seals? or is that an extreme pressure oil?
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Is there any evidence that charger seals are degrading because of oil type? Usually blowing from pressure spikes.
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Is there any evidence that charger seals are degrading because of oil type? Usually blowing from pressure spikes.
*opens can of worms quietly*
My question to Opie Oils is, instead of recommending a random oil (which they stock) has any testing been done to warrant the recommendation, if so what?
If is hasn't (which I suspect not) then what basis is the product being recommended on?
Regarding the oil pressure spikes- I've never seen any conclusive evidence (high speed pressure transducer traces pre-chrager) of oil pressure spikes on the rev limiter.
The pressure relief valve is open at this point anyway, any excess pressure (3.5bar +???) is vented to the sump. Oil pressure fluctuates when each lobe forces oil into the gallery, so you have a natural sine wave anyway.
If you're overcoming the PRV (i.e choking the relief) then oil pressure can rise sure and any fluctuations are seen directly on components.
I've not done any testing myself, but I'd have thought rapid speed fluctuations or excessive oil pressure would be more the problem rather than oil pressure fluctuations. Happy to be educated though ;D
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Is there any evidence that charger seals are degrading because of oil type? Usually blowing from pressure spikes.
*opens can of worms quietly*
My question to Opie Oils is, instead of recommending a random oil (which they stock) has any testing been done to warrant the recommendation, if so what?
If is hasn't (which I suspect not) then what basis is the product being recommended on?
Why would I recommend something with no basis at all? That would be stupid and expensive. We had Fuchs test some supercharger oils for us a while ago and they found that the ones used in the VW chargers were very similar to the 05 synthetic fork oil. It was chemical testing, rather than in a supercharger, but that fork oil was the closest thing they have to the original fluid. It's not an exact match, but the properties of the fork oil were close enough to the original stuff to make it fine to use. As it was chemically tested, I can see no reason why it would affect the seals.
Regards
Tim
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Well, you can always send me some for free and i will test it for you on my supercharger.
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Tim- What 'basis' have you used to select an oil for a standalone 7psi oil system using a fuel pump on a Polo G40?
- No question regarding operating pressures/temps
- No question regarding pump/supercharger seals
- 'Testing' of a 'supercharger' oil used a comparison for a system which operates completely differently to a sealed oil system
Testing showed:
"The oil tech that analysed the original fluid said it was pretty weird stuff due to the way it behaved, so the only thing I'd suggest other than the original fluid is the Silkolene 05 fork oil."
It was 'weird stuff...'
You make no mention of the comparison oil?
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The comparison oil was the original oil from the charger. Yes, it was quite odd stuff when compared to some other oils, which is why the fork oil was recommended. The fork oil is very shear stable (needed by the supercharger) and behaves in a very similar way to the original fluid across a range of temperatures.
You seem to think that I'm just recommending anything I can think of that we sell, just to try to make a sale. You're not considering the problems for us if I did that - bills from customers for damage caused, loss of reputation and therefore loss of sales.
Cheers
Tim
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What was the spec of the original oil from the charger?
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Hi
I don't have that to hand right now, but I'm pretty sure it was a Klubersynth product, if that helps.
Cheers
Tim
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So nothing like the oil that is used in a g-lader... ::)
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Pressure spiking was some thing that's been suggested a couple of times (ex CP IIRC) and looked quite a good suggestion taken with hitting the rev. limiter too frequently or for too long. Wouldn't that produce a "hammer effect" in the supply.
Are long term users of standalone systems experiencing much in the way of oil seal failure? or do they see any improvement. It starts to get a bit difficult to quantify when blowing seals is something you try to avoid at the best of times.
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Pressure spiking was some thing that's been suggested a couple of times (ex CP IIRC) and looked quite a good suggestion taken with hitting the rev. limiter too frequently or for too long. Wouldn't that produce a "hammer effect" in the supply.
Are long term users of standalone systems experiencing much in the way of oil seal failure? or do they see any improvement. It starts to get a bit difficult to quantify when blowing seals is something you try to avoid at the best of times.
It only produces a 'hammer effect' if the PRV isn't doing it's job, or you're exceeding the flow of the relief valve. also due to the fact it's not 100% liquid, there's a dampening factor to take into account.
Hitting the rev limiter isn't good for sure, but I've not seen any evidence of this being a result of charger speed fluctuation, or oil pressure fluctuation.
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Doesn't pressure rise with revs and therefore those giving the limiter death are more likely to subject the lader to higher oil pressures. That said pressure is pretty high at cold even at idle
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You do know the G lader doesnt use a sealed oil system, like say and eaton? It uses the engine oil. What supercharger did you test? So the fork oil you recommend is completely wrong
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Sounds like (if any) they tested an Eaton from a modern TFSI lump.
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Doesn't pressure rise with revs and therefore those giving the limiter death are more likely to subject the lader to higher oil pressures.
Pressure rises with pump revs 'til the PRV pops open - whole point of the PRV is to cap peak oil pressure.
Of course there's a limit to what the PRV can flow, but it'd be safe to assume that VW would've ensured it could flow enough to control oil pressure across the standard operating speed range of the engine.
This of course assumes the PRV is operating properly! In my G-lader experience it was always high rpm stints that did my oil seals - and that was with a standalone oil supply in the end.
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In my G-lader experience it was always high rpm stints that did my oil seals - and that was with a standalone oil supply in the end.
800 hours at full chat in proving; just wtf were you doing with your charger Andy? Spend your holidays on the Ring? lol.
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Ok been doing some reading into redline 10wt, which im looking to use, is 27.2 cst @40°C. Think the pump will be able to handle it?
I could go for the 5wt 21.8 cst or the 2wt which is 11 cst but i dont think that 5wt and 2wt are really suitable as its to be used under temps of 71°C (5wt) and 65°C (2wt) whereas i might get close even above that.
Fuel is between 0-5 - 0.74 cst @ 40°C but i think it will be hard to get oil that close.
This is the data from redline:
Phosphorus, avg PPM 2500
Zinc, avg PPM 2400
Vis @ 100°C, cSt 5.2
Vis @ 40°C, cSt 27.2
Viscosity Index 130
CCS Viscosity, Poise, @*C 30@-30°C
Pour Point, °C -54
Pour Point, °F -65
Flash Point, °C 215
Flash Point, °F 420
NOACK Evaporation Loss,
1hr @ 482°F (250°C), % 6
Will it be runny enough?