Why might lower Noack Volatility help with DI?

[Ayrton]

I have seen it referenced several times here that an oil with a low Noack Volatility could help keep intake valve deposits to a minimum on direct injected engines.

I fully understand the reason for deposits on intake valves in direct injected engines.

However, I am not sure why a low Noack volatility could help combat this to some degree? Any help? Thanks!

 

[badtlc]

reduce the amount of oil vapor coming back through the PCV.

and it is just a guess. there is no evidence showing lower NOACK will reduce deposits. I don't think it would because an oil catch can doesn't even help fight off intake deposits.

 

[volk06]

All engines burn a little bit of oil, some very little but it still uses some. Lower NOACK, means the oil is less likely to burn off which helps reduce the possibility of deposits.

 

[MolaKule]

Anytime you can reduce oil vapors, which carry some of the same additive and base oil molecules as the formulated oil, you theoretically reduce intake and exhaust vale deposits, and cat contamination.

As badtic has stated, to-date no studies have been brought forth to show a direct cause and effect relationship.

I suspect some mechanical engineer or Tribology PhD candidate somewhere is working on this and or some researches are preparing an SAE paper on this subject.

 

[147_Grain]

.............and oils with higher quality basestocks tend to have lower NOACK values.

 

[Ayrton]

Thanks all! I understand now. Probably not a huge help, but might as well when there are good products with lower NOACK.

Great information. On an opposite note, a dealer told me Top Tier Gasoline are more volatile, therefore they also help keep some deposits away from the intake ports because less unburned fuel finds it way to the ports. Not sure if true?

 

[MolaKule]

Quote:
On an opposite note, a dealer told me Top Tier Gasoline are more volatile, therefore they also help keep some deposits away from the intake ports because less unburned fuel finds it way to the ports. Not sure if true?


Fuel additives to make the fuel burn more efficiently and completely will help but I don't see fuel volatility coming into play.

 

[Ayrton]

Originally Posted By: MolaKule
Quote:
On an opposite note, a dealer told me Top Tier Gasoline are more volatile, therefore they also help keep some deposits away from the intake ports because less unburned fuel finds it way to the ports. Not sure if true?


Fuel additives to make the fuel burn more efficiently and completely will help but I don't see fuel volatility coming into play.


Do the Top Tier gases additives achieve the more efficient and complete burn?

 

[badtlc]

Originally Posted By: Ayrton
Originally Posted By: MolaKule
Quote:
On an opposite note, a dealer told me Top Tier Gasoline are more volatile, therefore they also help keep some deposits away from the intake ports because less unburned fuel finds it way to the ports. Not sure if true?


Fuel additives to make the fuel burn more efficiently and completely will help but I don't see fuel volatility coming into play.


Do the Top Tier gases additives achieve the more efficient and complete burn?


I doubt it, at least not directly. Top Tier is just detergent/cleaning level requirements. They help keep systems clean. I would think octane rating would have more of an impact on quality of burn.

 

[Ayrton]

Originally Posted By: badtlc
Originally Posted By: Ayrton
Originally Posted By: MolaKule
Quote:
On an opposite note, a dealer told me Top Tier Gasoline are more volatile, therefore they also help keep some deposits away from the intake ports because less unburned fuel finds it way to the ports. Not sure if true?


Fuel additives to make the fuel burn more efficiently and completely will help but I don't see fuel volatility coming into play.


Do the Top Tier gases additives achieve the more efficient and complete burn?


I doubt it, at least not directly. Top Tier is just detergent/cleaning level requirements. They help keep systems clean. I would think octane rating would have more of an impact on quality of burn.


That is what I thought. Perhaps, when the dealer asks a customer with intake valve deposits what gas they buy, they say Arco & Costco (what the dealer told me). However, the Arco & Costco buyer I suspect is more likely to be using regular in a car that calls for premium, so that is potentially the reason for their more accelerated issue.