GC 0W30

[Coheed]

ZDDP creates a thin metal film over metal parts. You can actually see it fill in microscopic cracks and imperfections in the metal.

That being said, many engines are actually designed these days with this in mind. Flat tappets and bucket-shim followers experience a lot of wear. Especially when valve spring pressures are high. This is where the ZDDP comes in handy. Also, in regards to bearing wear, just hope that the oil film retention is there. Because if it breaks down, the ZDDP film will be all that's left.

But the FA20 was designed with roller rockers. Newer tech. Also, the bearings are designed to be narrow but with a larger journal surface area than the older EJ. This is likely in response to their goals with design.

Is ZDDP absolutely necessary? No, not really. But high pressure additives only cut friction while the oil film strength is high. ZDDP cuts friction when that film strength breaks. Like on a cold start, or if oil temps get too hot and pressure drops too low. Some would argue the effects are minimal, but the flat tappet guys can tell you otherwise. It's not all about reducing friction, but preventing it as well.

[serialk11r]

Molakule writes that EP additives bond with the metal surface itself and allow shearing (instead of gouging) under high pressure, and I think in that thread he says it's primarily a transmission/diff thing. Engine oil is usually antiwear and friction modifier additives, but not dedicated extreme pressure.

But you might be right, I think most moly used is soluble moly and so it doesn't form a protective film. But using colloidal MoS2 would achieve the same protective film effect yea? Also I think it's mentioned that friction modifier additives become plastic under high pressure, which sounds like they don't get squeezed out.

And about the preventing boundary lubrication thing, I think race engines using thinner oils gives the answer for that. The lower viscosity oil creates lower energy losses overall even if at times the lower viscosity means hydrodynamic lubrication fails.

I think I'll continue searching for a straight answer from an expert on this...to me it seems like the lower viscosity is good as long as you have a lot of antiwear additives and good thermal management. Afterall, allowing a 40 weight oil to exceed operating temp by 50C makes it more useless than a 20 weight at correct temperature.

[Coheed]

Originally Posted by serialk11r

I think I'll continue searching for a straight answer from an expert on this...to me it seems like the lower viscosity is good as long as you have a lot of antiwear additives and good thermal management. Afterall, allowing a 40 weight oil to exceed operating temp by 50C makes it more useless than a 20 weight at correct temperature.

Very true. And considering engines running over 10k rpm have problems shattering oil pump gears when too thick of an oil is used makes even a stronger case against going too thick.

I've only built street engines, modified for track use. Never a standalone racing engine. So I'm not familiar with their oiling techniques. But I do agree, running a lower weight with a proper oil cooler setup will be ideal!

[serialk11r]

Originally Posted by Coheed

Very true. And considering engines running over 10k rpm have problems shattering oil pump gears when too thick of an oil is used makes even a stronger case against going too thick.

I've only built street engines, modified for track use. Never a standalone racing engine. So I'm not familiar with their oiling techniques. But I do agree, running a lower weight with a proper oil cooler setup will be ideal!

Oh really? I thought shattering oil pumps was due to the "centrifugal forces"...I suppose much higher loads on the vanes doesn't help in that respect though.

If the oil cooler in question is a water to oil heat exchanger, you also get the benefit of quicker oil warm up and thus lower wear, longer oil life (boils off condensation and fuel faster) and better mpg on the street! Makes you wonder why they don't equip more cars with it, or at least just have some finned coolant pipes run through the sump.

[Coheed]

Originally Posted by serialk11r

Oh really? I thought shattering oil pumps was due to the "centrifugal forces"...I suppose much higher loads on the vanes doesn't help in that respect though.

If the oil cooler in question is a water to oil heat exchanger, you also get the benefit of quicker oil warm up and thus lower wear, longer oil life (boils off condensation and fuel faster) and better mpg on the street! Makes you wonder why they don't equip more cars with it, or at least just have some finned coolant pipes run through the sump.

Actually, what I find interesting is the SR20s I'm familiar with have a oil passage run right by the coolant chambers in the block as the oil makes its way to the oil squirters. So not only did they have a water/oil cooler, but they utilized the actual block to provide cooling where possible.

[rice_classic]

Originally Posted by serialk11r

I think he brings up VI because a lot of wear happens when the oil is cold

That's exactly why he brought it up and exactly why it's important.

But my argument is that a higher VI =/= better oil. You saw this when 2 oils had the same identical cold start viscosity but had negligible differences in viscosity when hot. However, that negligible difference of hot-viscosity had a major affect on the Viscosity Index, as much as 20 points! Also that oil with the 20 point lower VI had identical protection when cold and a higher HTHS rating when hot and that's why VI isn't that important.

And

When looking for the best protection under abusive conditions, VI isn't important. The best racing oils available to humans have very low VI numbers. And what we were discussing when he brought up VI was best protection under tracking conditions, and VI is a pointless thing to pay attention to for that specific conversation. Example, look at the oil used in the NASCAR engines or the ALMS cars.

And

Take into account time of the year. During the winter, VI bares a much greater importance to the consumer for judging overall protection because of how much colder the oil is at startup but the cold start viscosity still needs to be considered because like proven above, simply looking at VI doesn't tell the whole story.


Cheers.

[Gords_zenith]

Hate to revive an old thread, but I thought I would share my experience (200 km on oil now) so far with castrol syntec 0W-30 "European formula" it says on the bottle so I'm assuming its the same as the German Castrol everyone is talking about. Anyways, I use 94 octane fuel, and completely stock car with 25000km. And from what I can tell, the engine seems way peppy'er than with stock oil. It's rpm idle dip also seems to have subsided. I will update when hotter temps start coming. As I was getting a power loss last year during the super hot spells with stock oil. So we'll see. And by power loss it's my butt dyno and sounds like it pulls timing. I have the dash command so now I can see if it does pull timing based on oil temp and pressure. My .02

[bluesubie]

Originally Posted by Gords_zenith

Hate to revive an old thread, but I thought I would share my experience (200 km on oil now) so far with castrol syntec 0W-30 "European formula" it says on the bottle so I'm assuming its the same as the German Castrol everyone is talking about. Anyways, I use 94 octane fuel, and completely stock car with 25000km. And from what I can tell, the engine seems way peppy'er than with stock oil. It's rpm idle dip also seems to have subsided. I will update when hotter temps start coming. As I was getting a power loss last year during the super hot spells with stock oil. So we'll see. And by power loss it's my butt dyno and sounds like it pulls timing. I have the dash command so now I can see if it does pull timing based on oil temp and pressure. My .02

Interesting that the engine seems way peppier since you jumped from a 20 weight oil to a nearly 40 weight oil. I would think that the increased drag from a thicker oil would be less peppier.

-Dennis

[Gords_zenith]

Originally Posted by bluesubie

Interesting that the engine seems way peppier since you jumped from a 20 weight oil to a nearly 40 weight oil. I would think that the increased drag from a thicker oil would be less peppier.

-Dennis

Ya I know it's seems counter intuitive, but it almost seems like the torque hits harder when I mat the throttle, maybe it's the cams phasing changing faster due to the heavier weight oil-I don't know for sure though. I can't really explain it, but my ears and butt suggest that it's peppier. I'm going to a dyno tomorrow so we'll see what kind of power I'm making with this oil and 94 octane and a new stock air filter.

[Gords_zenith]

Also, I have another theory, what if the heavier oil quieted down the piston slap-thus the knock sensor allowing more timing? Cuz my fuel mileage also increased a little bit an extra 60 km between fills.

[Laika]

At 200km, it's not enough to give much info, especially qualitative information. Any oil will feel better than something that has several thousand miles on it.

I tried GC 0W30, then amsoil SS, then regular Eneos, then Sustina. All for 4k miles except only 2k on the Sustina so far. The Sustina is my favorite (subjective testing so far).

[Gords_zenith]

Originally Posted by Laika

I tried GC 0W30, then amsoil SS, then regular Eneos, then Sustina. All for 4k miles except only 2k on the Sustina so far. The Sustina is my favorite (subjective testing so far).

Hmm good point. I will keep that in mind about the mileage as I have now about 600km on GC. So we'll see.

[Coheed]

I'm using the GC 0w30 as well and don't have any idle dip issues, even with AC going. Engine runs smooth. I'm not really sure how much of this is attributed to the weight of the oil. But I am a bit harder on my car than most, and I do see track days without swapping oil out.

[Hanakuso]

FYI Autozone is having a $29 sale on 5 bottles + Fram filter. There's an option to go with Mobil 1 filter for $4, which I did for my GF's Jetta since I prefer the OEM filters

Not sure if this is a nationwide sale but all 3 local stores had this deal here in SoCal