2 stroke oil (2SO) as an additive to diesel fuel

[CardinalSin]

Here's another post where they measured the sound reduction.

6th post down.

"He gave me the green light and said it couldn't hurt anything at a 200:1 ratio so I purchased some Activ T2 yesterday and gave it a crack. I filled the tank and then went home and put the 2stroke oil in, after starting it up it was normal volume for a few seconds and then it went a fair bit quieter.

I don't have a proper SPL meter but I did use a basic one on my phone because I figured it would show if there was an objective difference (even if it wasn't the real dB level), with my driver side window down and the mic pointed out the window it was ~70dB with just diesel and it then went to ~67-68dB with the 2 stroke oil, the Mrs also noted it was quieter without me saying anything."

View topic - Interesting thread about 2 stroke oil in diesel fuel | Australian 4WD Action

[kaanage]

One thing that anyone wanting to try 2-stroke oil in their petrol is that it does slightly reduce the octane rating (see the warning here - Octane & 2-Stroke Oil: Mercury 2.0 Liter | COR Boat Racing), although the very low ratio used is unlikely to have a significant effect.

On the plus side, it almost guarantees a slight cetane improvement in diesels
(a US military study on the relationship between octane and cetane - http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0779512)

[brad]

One thing that anyone wanting to try 2-stroke oil in their petrol is that it does slightly reduce the octane rating (see the warning here - Octane & 2-Stroke Oil: Mercury 2.0 Liter | COR Boat Racing), although the very low ratio used is unlikely to have a significant effect.

Interesting. Keep in mind they are talking Motor Octane Number, not Research Octane Number but 20 points decrease in MON is freaking HUGE and more relevant to real life usage than RON (IMO).

[kaanage]

They are talking about ratios as high as 24:1 which is 20 times what the petrol guys seem to be running in 4 strokes.

I can't see 2 stroke oil dropping MON without affecting RON (it's possible chemically but I think it would be unlikely) but as you said, MON is more likely to be important anyway in real life engine loadings.

[CardinalSin]

Also, Brad is using a fully synthetic oil which only reduced the MON by about 10% of the amount the mineral oil changed it by. When you reduce that by the 1/20th of the quantity it becomes insignificant.

The reduction of the MON by 20 at 1:24 for a mineral 2SO is a surprising result that seems unlikely in theory.

[Amalgam]

Just a follow up on my PULP + 1:600 2SO use.

After 2 tanks of straight PULP my consumption has crept up to 7.2L/100km on the MFD. My route remains the same.

[CardinalSin]

That's still a 4% improvement in economy which might be from cleaner injectors?
You aren't tempted to carry on using it?

[Amalgam]

Just modifying the experiment to see whether the fuel economy improvements are due to the combustion of the 2SO and / or the fuel injector cleaning.

I am also carrying out the same experiment with the Passat.

[CardinalSin]

That's what I should do too but I've been using it for so long it would feel as if I was harming the engine not to add it.
Next time I fill up I'll try to leave it out.

[Amalgam]

Reporting back on the Passat 125TDI.

I am nearing the end of the second tank sans 2SO and I believe that there is more diesel clatter and it seems harder to achieve the same low L/100km on the MDF. My only disclaimer is that current driving is in suburbia not on the highway with the cruise on.

Interesting nonetheless.