GC 0W30

[gmookher]

There are oils with VI up in the 200 range, thats what the engineers who built our stuff based it all on, just FYI

Using 0w-20 castrol edge is indeed being done by guys on this forum, but they are settling for 168 VI when they could have 200+
GC is the holy grail for alotta motors, but IMHO, not this one. I would mix in 50/50 GC in the summer to my stock oil; which is darn good
The subaru branded SM formulation is excellent, same as Idemitsu branded 0w-20 I buy by the 5 litlre jug
see below, Easy to see why I like the SM oil over SN, tho the SN may be half a MPG better for economy, the SM afforded better protection. The SN cert oil is being driven by emission and EPA.

[finch1750]

Originally Posted by brillo

what oil is GC?

Castrol Syntec 0W-30 aka German Castrol. It says made in Germany on the back, not all 0W-30 Castrol is I think.

[serialk11r]

Originally Posted by gmookher

There are oils with VI up in the 200 range, thats what the engineers who built our stuff based it all on, just FYI

Using 0w-20 castrol edge is indeed being done by guys on this forum, but they are settling for 168 VI when they could have 200+
GC is the holy grail for alotta motors, but IMHO, not this one. I would mix in 50/50 GC in the summer to my stock oil; which is darn good
The subaru branded SM formulation is excellent, same as Idemitsu branded 0w-20 I buy by the 5 litlre jug
see below, Easy to see why I like the SM oil over SN, tho the SN may be half a MPG better for economy, the SM afforded better protection. The SN cert oil is being driven by emission and EPA.

Interestingly enough, the SN oils have lower viscosity, but their TBN is higher, and I imagine there are across the board additive changes.

On BITOG some people recommend mixing in the 221 VI Toyota oil (seems different from the one on this chart? maybe measured different?) to improve VI.

As I understand it, friction is lowest under hydrodynamic lubrication when the film is nearing "mixed lubrication" (maybe I remember incorrectly though), so higher viscosity oil will lower friction if the low viscosity oil gets squeezed out. However as far as wear goes, the moly and ZDDP additives prevent too much scuffing from happening if the oil film does get thin, so it's not a big deal?

The viscosity of oils at high temperature is very similar, but the HTHS goes up a little. From what I read it seems like it's more important to keep oil temperature in the correct range than try to use a heavier oil that thins out from overheating anyways. A 50 weight oil isn't going to do much good if your oil temperature is 50C too high, and it will ruin performance and efficiency at low temperature.

[rice_classic]

Originally Posted by gmookher

thats what the engineers who built our stuff based it all on, just FYI

DISCLAIMER: for the folks playing along at home here's a couple fun links:
http://en.wikipedia.org/wiki/Viscosity_index

Viscosity Index Calculator:
http://www.widman.biz/English/Calculators/VI.html


Base it all on? That's a highly subjective statement GM. It also misses the point for the overall topic at hand because we've primarily been talking about oils at operating temp and even track duty and in the seam of that conversation VI means very little. VI=the measurement of the difference between cSt at 40c and cSt at 100C. (of course you already know this)

And just to argue on why VI isn't that important even in the vein of simply a daily driver application is because the cSt measurement isn't measured like dB. The difference between 8.0 and 8.5 cSt at 100c is extremely small and that's according to BITOG (which you know so well). So let's look at how important VI is when comparing 2 theoretical oils:

OIL A:
40C cst = 38.5
100C cst = 8.0
VI = 187

OIL B:
40C cst = 38.5 (same as A)
100C cst = 8.5 (only .5 higher)
VI = 207 (that's a 20 pt diff VI!!!)

So a .5 diff of cSt at 100C (almost negligible) creates a 20pt difference of VI... This should illustrate the importance or lack of importance VI has to someone making their decision about oil regarding their application.

Also, please note in my comparison above that you quoted beginning this VI discussion; I want to bring something to light and complete a couple comparisons.

Comparing say the Mobile 1 vs the Amsoil and we'll use the VI number now.

Mobile 1 0w-20
Viscosity, @ 100ºC, cSt 8.7
Viscosity, @ 40ºC, cSt 44.8
HTHS Viscosity, mPa•s @ 150ºC 2.7
VI = 173

Amsoil Signature Series 0w-20
Kinematic Viscosity @ 100°C, cSt 8.3
Viscosity, @ 40ºC, cSt 44.2
HTHS Viscosity, cP 2.8
VI = 166

You see the Mobile 1 and the Amsoil have darn near identical performance at startup (only a .6 difference at 40C) but the Mobile 1 has a larger gap in viscosity between cold and hot thus the higher VI. However the Amsoil not only falls withing the acceptable range of cST at operating temp but since it's slightly lower it will be slightly more efficient and it out performs the Mobile 1 at startup (but by a negligible margin). The way the 40C cSt reading affects the VI is signficantly less than how the 100C cSt measurement affects it. That is why Mobil 1 has a higher VI. The biggest bombshell, even thought it's not as thick at 100C the Amsoil still has a higher HTHS rating.


GM, in looking at the chart, which I see you pulled from Primus' post at BITOG, you will notice there is no HTHS rating. This is a value that is important to me and like was said above, the higher the 100c KI cSt reading, most likely the higher the HTHS rating but that's not always the case.

Also regarding protection from "running your car hard"; this assuming you're doing at operating temperature, you make the comment that you prefer the SM over the SN... This I can get behind because in that chart the SM's have a higher cSt @ 100C then their counterparts.

I can't find the HTHS rating info on the Subaru oil (the Indemitsu stuff) anywhere.

I'm glad this all got going again.. makes me feel better about both the factory fill and the Amsoil I bought.

[gmookher]

fwiw, niether Mobil1, nor amsoil, ever see any car in my garage.

this FA20 will get a heaithy mix of lubro moly for track mixed in for days and OE(idemitsu) for DD. a top quality 0w-20 will be plenty of protection at the track. theres a reason I run an oil cooler...

None of the acceptable oils vary much in HTHS, unless you knock up an SAE grade, most of these will have hths in the upper 2.x

[siXXtoes]

Great info, but i am still a little lost. I understand cold start up and operating temp with oil numbers. Based on those numbers in the cart, and i know there is no "best oil", but rank those oils from better to not so better.

I currently run mobil 1 5w30 an am looking to use GC. I live in Sand Diego and run my car hard, just not track hard.

[Coheed]

0w20 is for emissions. Enough said.

GC 0w30 is a great oil, and should hold up to minor track assaults. NA form. Once boosted, I would recommend this only for the street, and a 40 weight for the track.

The engineers built the car to meet the demands of the mileage and emissions requirements, and thus the lighter oil is used. Ford, honda, chrysler, have all been doing this for years. If you look at how the engines are built, you can see that.

Just because the factory fill is 0w20 and is recommended, does NOT mean it is suitable for sustained track abuse.

[serialk11r]

Originally Posted by Coheed

0w20 is for emissions. Enough said.

Just because the factory fill is 0w20 and is recommended, does NOT mean it is suitable for sustained track abuse.

Emissions is pretty different from fuel consumption first of all.

Second of all, what does "suitable" mean? Wasn't 30 weight oil considered "light" sometime ago? Modern oils have plenty of additives to prevent wear, and it's not entirely clear at what point the loads on the bearings make higher viscosity oil a good idea.

What evidence do you have suggesting that 30 is best for "hard driving" and 40 is best for the track in all cases? For boosted applications the thing that matters most is NOACK volatility by the way, which is the reason heavier oils are spec'ed for turboed cars.

[Coheed]

Originally Posted by serialk11r

Emissions is pretty different from fuel consumption first of all.

Second of all, what does "suitable" mean? Wasn't 30 weight oil considered "light" sometime ago? Modern oils have plenty of additives to prevent wear, and it's not entirely clear at what point the loads on the bearings make higher viscosity oil a good idea.

What evidence do you have suggesting that 30 is best for "hard driving" and 40 is best for the track in all cases? For boosted applications the thing that matters most is NOACK volatility by the way, which is the reason heavier oils are spec'ed for turboed cars.

True, Fuel consumption is looked at when considering such a light grade of oil. But it all comes down to emissions. More fuel used means a higher CO2 output. Yes, the US does care about carbon emissions.

And newer oils have plenty of high pressure additives to prevent wear. But ZDDP levels are not where they need to be. Why? Emissions. Zinc kills cats, so it makes sense why most new oils are under 800ppm. And it also makes sense why flat tappet engines see so many failures using newer oils.

Maintaining good oil pressure is absolutely important. Monitoring the oil pressure via a gauge is important. I don't trust the subaru pump is suited to keep oil pressure #s where I like to see them on the track.

The only evidence I have is my experience. As a track junkie, and engine builder for the last 12 years. I can see a direct relationship between the weight/brand oil used and the wear it sees on the track. But I do admit, I'm not really familiar with the FA20 when it comes to track abuse. I've yet to take this car to the track. But Miller Motorsports is only an hour drive away, and it will see some time there next year for sure.

I'm by no means an oil expert. Frankly I don't care to read whats on the internet. I've done my own UOAs and I know what works. If you really truly believe that the 0w20 is fantastic oil, it's your decision to use it.

[gmookher]

Not wanting to argue, or be condescending,

I dont want y'all to miss my point or get it twisted, this will be my final post in this thread, dont think I can add much more value, but the truth is you need to know all the facts:

I do agree with the posters above, but adding in some real engineering, real world track experience, and a light chemistry background changes things alot- heres why-

if you compare VI on say any of the factory oil in the chart I posted above, and say take Adeka Sakura-Lube with its VI over 200 and track that(its factory toyota, as good oil as idemitsu and eneos from japan in 0w20,) versus, say the guy who finds a deal on amazon or wally mart on Castrol Edge SN 0W-20 with it's low 162 VI is about the least attractive 0W-20 oil grade I know of, tracking that and tracking any of the factory are big differences despite same hths. Thats one of my points. I suggest not going below 180 on VI.

In that case, running a 0w-30 with a 180 VI and higher HTHS becomes reasonable for track use, since its got more ZDDP and higher hths, right? One would assume so at first glance. Its done often. Even then, I'd be cautious about selecting an 0w30 with the lowest possible cSt at 100c hence my suggestion for Lubro if you feel you must go thicker thinking its more protection. Its not.

To better understand why and how high pressure hydraulically activated cam systems are pressure critical indeed, one needs to appreciate understanding laminar flo characteristics of a fluid, Thicker fluid with too much pressure is NOT your friend in truth, if that pressure is at the cost of decreased laminar flo. Flo isnt always measured in classical settings using a PSI gauge.

As far as that is concerned, and you should be concerned here as well, so long as you run a quality factory grade protection packed OE oil, its actually not terrible at all since you stay in the correct pressure ranges. Admittedly, if my car sees track time, its oil intervals are shorter than my other cars, so theres that too. Since you said it yourself, using higher ZDDP oils in a ceramic cat like the factory one is not gonna be friendly. So there are good reasons to NOT run a thicker oil too that you should be aware of.

take into consideration the fact that lubrication occurs because of flow and not viscosity then you technically want as much oil flow as you can while maintaining necessary pressure. a standard rule is 10psi for every 1,000 rpms of engine rotation. Our pump produces this without issue with OE weight oil with cst between 6.x and 8.x @100, thats a fact.

Pressure is the best way to evaluate whether or not the oil you are using is to thin or thick for your application. Since oil thins as it warms you would get to a point in oil temperature where you wouldn't be producing enough pressure to flow oil into critical locations. If that occurs then you need to switch to a higher viscosity oil. I dont see that as problem, our cars run great under load in high pressure. It seems the issue is with oil flow at lower RPMs. I dont think a thicker fluid is the correct solution.

While running a higher viscosity oil seems obvious for the novice, one justification for using thicker oil is an owner sits in traffic and sees their oil temperatures go above normal. Their solution is to run a thicker oil for better protection. okay. Now, the First problem is when you increase viscosity you decrease flow. As a result the oil is incapable of carrying heat away from the motor to the coolers. And if youre tracking this thing you really should consider a cooler. Every car I track gets one, but thats me. and most guys at the track too. (the strategy shifts from trying a fluid that may perform 'better hotter' thinking to simply using the correct oil, and managing thermal dynamics-"keeping it cool is smarter than running it thicker" becomes he name of the game)

The result of the wisdom of higher viscosity is your oil ACTUALLY runs hotter than it would have with the thinner viscosity. Not so smart if I may observe so. Second is that when sitting in traffic you don't require the kind of protection you do at 9,000 rpms. At idle your load is maybe 20% and your RPM's are between 850 and 1,500. In this situation there's very little chance of long term damage. But the flo isnt gonna be right at low rpms with the higher viscosity fluid either! Now, if you are running very high temperatures and your flo or pressure isn't as high as it should be at idle as it is at 9,000 rpms then you have a good chance of long term damage from using a higher viscosity oil at idle.

Other aspects play into the capability of a lubricant including the oil's base stock and additive packages. The oil's base stock plays into the lubricant's properties in terms of how it handles changes in viscosity and how well it can hold it. Group III base stocks are mineral oil based and require viscosity modifiers to make the oil a multi-viscosity lubricant. Group IV and V are true synthetics which don't require viscosity modifiers and there is little viscosity change over the life of the oil. Technically if you could remove the contaminants and recharge the additives in the oil a synthetic could be ran forever.

you should use the next thinnest choice for what you think you should be running. If you think you should run a 50w oil then run a 40w and so on. Also, be sure you are using a 0w oil as this will give you the best startup protection. 90% of engine damage happens during cold starts. This is the reason I use the oil I do because I daily drive my BRZ and I have a lot of starts and stops. Using a thicker oil here is less than prudent unless youre trailering your car to the track, and only using it as a track car, and thats my final answer.

Everyone isn't going to agree with my take on oils. I've been told I'm wrong because the other forums say to use a thicker oil, and all these guys at the track do it too, and they are fine.

It sucks being scientific sometimes. I'm simply going by the readouts I see on my gauges and how the car reacts. I do alot of data logging as I do testing, so these are the numbers I watch. People can choose what oil they want. I take pride in trying to dispense some knowledge, and run a top notch 0w20 with no issues on the track. I'll have more hard data in the coming months. I take fluid mechanics and fluid dynamics seriously. More damage is done running the wrong oil in the right weight, and even more damage can occur running the wrong weight. Thicker could be hurting your motor. I wouldnt mix in much more than half a fill of the GC 0w-30 or preferably the Lubro 0w30 if you really want to. I will do so only under triple digit track temps, and only for track use. For anyone DD their car, I'd stick with a factory oil subaru SM>toyota SN.
YMMV, thanks for reading and good luck!

[rice_classic]

Originally Posted by gmookher

Not wanting to argue, or be condescending,

And don't unsubscribe yet, I'm not done with you!

So everything you said in that post, is a reiteration of what's been said earlier and pretty much is the consensus.

1: 10 PSI / 1000 rpms Check
2: Proper pressure at target temp Check
3: importance of HTHS Check
4: Protection comes from flow Check

What I'm struggling to comprehend is your love affair with VI and why you think VI even matters when we're talking about track usage or maximizing "operating temp" protection.

VI is nothing more than a calculation of the delta between 40c cSt (cold start) and 100c cSt (operating temp). That's it. It's an inconsequential piece of data for targeting optimal operating temp protection. VI is only important when trying to optimize protection for ALL ranges and conditions of driving, such as Daily Driving... but that is not the conversation at hand.

So when when I'm looking for the maximum protection at 100C or 150C why do I care so much about the cSt at startup? (rhetorical, because I don't). Like when I used to race with a straight 30w oil.. Where's the VI on that?!

When I'm looking for the optimal oil at 100-150C of operating temp the only things I should be looking at (as a regular consumer) is:
1: Synthetic
2: cSt at temp
3: HTHS rating
4: ZDDP (depending on type of engine and level of abuse)

VI is a none issue, in this case, and this case is the conversation at hand.
So GM, in summary I am saying, and I'm if you disagree then I will agree to disagree and leave it at that but:

1: When discussing protection from startup temp to operating temp and everything in between, VI calculation matters.

but

2: When discussing optimizing protection only at operating temp and extreme operating temp, VI calculation doesn't matter. What does matter are only the functions of the oil at that temp and in that situation.

[serialk11r]

I think he brings up VI because a lot of wear happens when the oil is cold and not flowing well, which is a very very common situation on the street (in fact, it can take up to 30 minutes for oil to reach operating temperature on the street in some cases!). If the car is driven on the street, this situation will happen. If the car is started cold at all, it will happen. Since the oil flow is comparatively much much poorer when oil is cold and started, it makes sense to consider the balance between wear when the engine is cold and wear when the engine is under a lot of stress.

I don't have much experience with this but I always notice this loud grinding noise when the engine is cold and I'm at lower rpm. Can't avoid it because well, gotta accelerate from a stop right? After the coolant hits 80C or whatever, the noise is usually still there for a little bit. I have this feeling that the bearings are taking much more damage when that sound is there than when I'm revving the engine up.

Coheed thanks for your explanation. Always helps to have some sense of data. ZDDP has been cut down in the newer oils resumably to help the cats out, but I wonder if this just makes the brand of oil and their particular formulations even more important. I think one of the industry experts on BITOG said that ZDDP is actually not the best AW additive, it's just been popular in the past because it's cheap. I don't remember the specifics but I think the sophisticated moly compounds nowadays are more effective, and some oils have a lot of it (like Toyota OEM 0w-20).

I went and read some more stuff yesterday, and I came across a thread discussing F1 cars. Supposedly they run very light oils to reduce losses. Now I think this is an interesting point because while the bearing surface speeds are very high on an F1 car, the load to speed ratio is also much higher since the reciprocating components are moving so quickly. That suggests that the oil film is actually doing just fine, because if it weren't, the losses would be higher due to less efficient boundary lubrication. One person claimed that they run heavier oil when not racing however for reduced wear, although that person seemed like one of the countless others spewing out things they weren't sure about. Of course F1 cars have very different oil formulations and much more thought put into the oiling systems, but I think it's worth thinking about.

Just going off all the internet things I've read I'm leaning towards the lighter oil camp, but I'm not completely convinced of either side's argument.

[Coheed]

Originally Posted by serialk11r

Coheed thanks for your explanation. Always helps to have some sense of data. ZDDP has been cut down in the newer oils resumably to help the cats out, but I wonder if this just makes the brand of oil and their particular formulations even more important. I think one of the industry experts on BITOG said that ZDDP is actually not the best AW additive, it's just been popular in the past because it's cheap. I don't remember the specifics but I think the sophisticated moly compounds nowadays are more effective, and some oils have a lot of it (like Toyota OEM 0w-20).

ZDDP helps with startup protection. The zinc lightly coats metal surfaces and provides a slick coating that resists wear. Moly additives are high pressure additives, but they don't provide startup protection. And Moly can't sufficiently cut friction in some engines.

HDEO oils always have a lot of ZDDP in them. Not only are the emissions standards set lower for these engines, you see a lot of these engines lasting a long time. Sometimes under extremely abusive conditions. Turbochargers, heat, heavy loads etc.

The zinc level is absolutely critical in these situations. That's why racing oils and HDEO oils have copious amounts of the stuff to prevent wear.

Motorcycles are the same way. High ZDDP and low moly. They use less moly because of the wet clutch some of them use. And High ZDDP because they have no cats.

I am looking at what the engineers design as far as oil, and the protection it has to offer. Not necessarily the engine's manufacturer that has to hit certain emissions targets. Remember, Subaru wants to hit a 60k mile engine life. That's setting the bar really low.

I've used Rotella 5w40 in my turbo track cars in the past. From straight fresh builds. I've seen very good bearing and break-in wear rates using this oil. Compared to Mobil 1 0w40, the wear was not even close! I was very disappointed in the Mobil oils I've used in the past.

[serialk11r]

Originally Posted by Coheed

ZDDP helps with startup protection. The zinc lightly coats metal surfaces and provides a slick coating that resists wear. Moly additives are high pressure additives, but they don't provide startup protection. And Moly can't sufficiently cut friction in some engines.

HDEO oils always have a lot of ZDDP in them. Not only are the emissions standards set lower for these engines, you see a lot of these engines lasting a long time. Sometimes under extremely abusive conditions. Turbochargers, heat, heavy loads etc.

The zinc level is absolutely critical in these situations. That's why racing oils and HDEO oils have copious amounts of the stuff to prevent wear.

Motorcycles are the same way. High ZDDP and low moly. They use less moly because of the wet clutch some of them use. And High ZDDP because they have no cats.

http://www.bobistheoilguy.com/forums...&Number=729029

He seems to suggest the organic moly compounds have friction modification as well as antiwear properties. Motorcycles have wet clutches so they don't use the usual friction modifiers because they would stick to the clutch and cause it to slip. I thought motorcycle engines need rebuilding quite often though? Maybe it's the short skirts?

The dry moly compounds have a coefficient of friction in the 0.05 range I believe, which is decently low, certainly lower than the 0.1-0.2 he cites. Teflon is the lowest at 0.01 and hydrodynamic lubrication can be as low as 0.001.

Anyways I just get the impression that organic moly is superior to ZDDP.