Saps and their affect on direct injection

[Orangepeel]

Hello everyone first time poster long time lurker. How do saps effect di engines. I understand low sap leads to less carbon build up. Is there merit to that statement? I assume there is?
Companies like amsoil have ls ms and fs oils. Is an ms vs an ls a discernible enough difference in carbon build up to justify one over the other? Thanks for having me!

 

[OVERKILL]

It depends on the application (I know, I know).

Most early DI engines only had DI, so there was nothing to keep the intake valves clean. This is where the focus on IVD started, because they were requiring periodic walnut blasting of the valves to clean them off. Work was put into determining how changing the oil chemistry could reduce the rate of build-up (it's still going to happen, just slower).

The more prominent issue with DI was when it was applied to smaller displacement turbocharged engines that were then "lugged" due to programming, which resulted in LSPI. The Euro marques hadn't had much issue with this, as their programming wasn't catering toward that sort of operating profile. This is where the focus on changing the amount of calcium in the additive package to mitigate LSPI happened.

Many recent DI implementations now use hybrid injection, that is, there's port injection alongside the DI. Toyota, FCA, Ford, I'm sure there are others. This prevents IVD's because of course the valves are being wash with the fuel mist like they are in standard port-injection only applications.

So, does your application have DI only, or is it a hybrid setup?

 

[SubieRubyRoo]

So, @OVERKILL if you remember my catch can analysis thread, a higher percentage of the add pack was carried away in the PCV system, but I don’t believe that the PCV distributes equally to all runners in most manifolds (Subaru EJs were essentially plumbed to a single cylinder runner). This makes me think IVDs are more driven by what gets past the valve stems, and why oils with AN/polar ester content seem to have cleaner valves overall.

Even when in vapor form, it seems there are some cleaning benefits IIRC (@Tom NJ had some great info on that!) from those components.

As a side note, I do think it’s quite odd that so much of the add pack goes into the combustion chamber and thru the exhaust; to me this means there has to be SIGNIFICANT oil combustion to poison the cats, but also a good sign for engines that are increasing- they have a little time to get aggressive with things like HPL EC and oil before they hopefully kill the cat and anger PETA.

There’s been a real positive addition to the knowledge base here over the past three years thanks to a certain member.

 

[buster]

https://bobistheoilguy.com/forums/threads/can-i-have-too-much-or-too-little-ash-in-my-oil.367503/

 

[buster]

So, @OVERKILL This makes me think IVDs are more driven by what gets past the valve stems, and why oils with AN/polar ester content seem to have cleaner valves overall.

There may be something to this. Valvoline Modern Engine I believe contained some unique ester. Had a very unique smell and was significantly more expensive than any oil on the shelf at that time (which is why it was discontinued). I have wondered if this was their approach at keeping IVD's down a bit. IVDs are mostly a degradation of the base oil. So again, first and foremost with any oil you want the highest oxidation resistance possible. This is why oils like Mobil 1 EP exceed the Seq IIIH by 20x and (30x) for the 0w40. If you keep an oil from oxidizing, you won't have anything to really clean. However, this is where solvency comes into play (from what I've read). Oils with higher solvency can also breakdown varnish and carbon better.

My guess is if you're trying to build a bulletproof oil you want all of the above. But I would say that super high level of detergents would be last on my last among all of those attributes.

I also assume that is why HPL says on their website that "select" esters can help mitigate IVDs. This can only be done via the solvency properties they offer.

 

[SubieRubyRoo]

There may be something to this. Valvoline Modern Engine I believe contained some unique ester. Had a very unique smell and was significantly more expensive than any oil on the shelf at that time (which is why it was discontinued). I have wondered if this was their approach at keeping IVD's down a bit. IVDs are mostly a degradation of the base oil. So again, first and foremost with any oil you want the highest oxidation resistance possible. This is why oils like Mobil 1 EP exceed the Seq IIIH by 20x and (30x) for the 0w40. If you keep an oil from oxidizing, you won't have anything to really clean. However, this is where solvency comes into play (from what I've read). Oils with higher solvency can also breakdown varnish and carbon better.

My guess is if you're trying to build a bulletproof oil you want all of the above. But I would say that super high level of detergents would be last on my last among all of those attributes.

I also assume that is why HPL says on their website that "select" esters can help mitigate IVDs. This can only be done via the solvency properties they offer.

So that’s the thing… I was talking with Dave quite extensively and mentioned how he said (I thought!) their oils oxidatively thicken over time. He quickly corrected me and said it is NOT oxidation that thickens their oil… all oils not present with a diluent will thicken over time from use, and that is all their oil does… oxidation should remain low, and hence easier to keep the engine clean.

 

[DirectRejection]

Thank you VERY much, @buster
@SubieRubyRoo @OVERKILL

So it's not oxidative--the thickening I am seeing in my particular greatly extended UOAs.

Of course that "Law of Diminishing Returns" SonofJoe mentions does come into play re viscosity.

I try to get out, and they pull me back in.

Motor Oil.
It's an obsession.

 

[Orangepeel]

Engine in question would be a 1.8 tsi

 

[TiGeo]

Engine in question would be a 1.8 tsi

Gen 3 ea888? No issue running a full saps oil w/r to build up.

 

[Orangepeel]

Gen 3 ea888? No issue running a full saps oil w/r to build up.

Yes.

 

[TiGeo]

Yes.

That engine loves some good old-fashioned VW502 00 xW40. Use with confidence. My 1.8 at >2x stock power and almost 100K is humming right along. When I had the valves cleaned while they were in there for the water pump they looked fine...that was around 75K.

 

[buster]

"It usually works like this... Piston deposits can arise from three distinct sources. 1) Decomposition of the VII polymer. The more polymer you have in your oil, the more deposits you tend to get. Synthetic oils tend to contain less VII polymer but you need to be careful how you interpret this. A synthetic 10W30 will contain less VII than a mineral 10W30 but a wide cross-grade synthetic 0W40 may well contain more VII than a narrow cross-grade mineral 10W30. 2) Oxidation of the oil. Unless you're still using an oil based on Group I stocks, you generally don't need to worry about this unless you're into extended OCIs. If you are into extended OCIs, synthetics oxidise less than minerals and will generate less deposits 3) Burnt oil. This could be due to worn valve seals or worn rings. However nowadays, the most likely source of burnt oil is light base stock, stripped out of the crankcase by hot blow-by & recycled through the PCV system. If you want to minimise burnt oil related deposits, use a low Noack oil. Synthetics tend to have lower Noacks than minerals but again you need to be aware of the wide cross-grade vs narrow cross-grade thing. Other things to bear in mind are that in terms of additives, polymeric ashless dispersants counter piston deposits, overbased metallic detergents do not. Heavy oils (or light oils that contain a reasonable amount of very heavy base stock) are way better at preventing piston deposits than light oils. Hope that helps..."

-SonofJoe