Does alkylate fuel burn cleaner?

[The_Eric]

Hey guys - been using some aspen branded alkylate fuel in the chainsaw while doing tree work for the neighbors.. Using Ipone 2T Samari racing oil I have left over at 32(ish):1

Have pulled the plug a couple of times over the course of cutting trees - about a gallon and a half of fuel mix used and man is that piston top clean! Literally spotless. I did a piston and jug before undertaking this work and it looks exactly like it did when I put it together.

Anyway, is this an artifact of the fuel or oil? Both?

 

[RDMgr]

An alkylated fuel appears to be naphtha, possibly a blend of light and heavy naphtha. Naphtha is produced in the distillation of crude oil process just like gasoline. Naphtha is more volatile than gasoline. Another potential benefit of naphtha is that the range of its carbon chain lengths may be tighter and better controlled or less random than those of gasoline. This may contribute to fewer deposits and a more consistent burn. Pump gasoline is a more complex mixture than alkylated fuel. It contains a lot of compounds other than gasoline such as ethanol and aromatics like toluene and xylene.

 

[CDX825]

Stihl had a video about their motomix that claimed it burned cleaner than regualr gas because it doesn't have all the nasty junk in it that regular gas does.

 

[slybunda]

Isnt that the same as fgas?

 

[The_Eric]

Not sure what fgas is?

Anyway, I think it may be more of a function of the oil than the fuel... I borrowed a bigger saw from from friend to cut up the rest of a large ash - but before I could, it needed a top end. So it too was starting off fresh. Anyway, I got curious and pulled its plug to take a look and it's piston had some deposits, but after considerably less use - only a couple of tanks of gas. Ive been running sthil motomix fuel with a little extra sthil oil and also some alkylate fuel with citgo sea and snow oil at 32:1

I'll see if I can snap a pic later

 

[Cujet]

100LL avgas is mostly "aviation alkylate". It does a great job of producing high levels of carbon deposits in aircraft engines, but seems to be quite clean in small engines. Possibly the oil you chose is also a factor?

 

[MolaKule]

The base distillates for Avgas is an alkylate, which is a mixture of various isomers of isooctanes, including 2,2,4-Trimethylpentane and 2-methylpentane, of which 2,2,4-Trimethylpentane is the main isomer for higher octane gasolines.

The technical specification for 100LL includes 0.56 grams of Pb/Liter (Page 5 of 6, Item 7) so I seriously doubt it is 100LL avgas.

https://www.warteraviation.com/wp-content/uploads/2018/04/AVGAS-100LL-Technical-specification.pdf

I suspect the aspen branded alkylate fuel is simply a series of iso-octanes without any lead. I further suspect some toluene is added to increase the spark-knock rating.

 

[Cujet]

The base distillates for Avgas is an alkylate, which is a mixture of various isomers of isooctanes, including 2,2,4-Trimethylpentane and 2-methylpentane, of which 2,2,4-Trimethylpentane is the main isomer for higher octane gasolines.

The technical specification for 100LL includes 0.56 grams of Pb/Liter (Page 5 of 6, Item 7) so I seriously doubt it is 100LL avgas.

https://www.warteraviation.com/wp-content/uploads/2018/04/AVGAS-100LL-Technical-specification.pdf

I suspect the aspen branded alkylate fuel is simply a series of iso-octanes without any lead. I further suspect some toluene is added to increase the spark-knock rating.

Swift fuels markets an unleaded 94 octane Avgas. As I understand it, the fuel is much like 100LL without the lead. While it is not dyed blue, it does smell similar (to me) and feel (dry) like regular 100LL. While I would never throw a sumped sample of Swift 94 on the ground, "if" that were to happen, the Swift 94 would evaporate at exactly the same rate as 100LL.

Anyway, some testing seems to show that Swift 94 burns clean and leaves fewer deposits in aircraft engines.

https://www.cityofwatsonville.org/DocumentCenter/View/15730/UL94--presentation-updated

Parked next to the Swift fuel pump (the round tank to the left). I purchase the swift fuel for a Rotax powered plane, not my Cessna.