Gasoline Octane & Performance

[Locozodiac]

Have been reading several engine tech manuals in which it's specified that high octane unleaded gasolines performs and cleans the engine better as having better gas cleaners compared to lesser octane unleaded gasolines.

Ok for this point, was wondering if using unleaded premium 95 octane gasolines compared to same 90 octane would make a difference in speed/engine performance. Don't know if it's my idea but when using 95 octane compared to 90 feel the sib/engine performing much better, with instant punch on the throttle. What are your thoughts about this issue ?

We only have 90/95/97/98 unleaded pure gasolines, with no alcohol mix whatsoever.

Happy Boating

[codprawn]

Our minimum is 95 but there are different ways of measuring it. To think in WW2 Britain had 150 octane!!!

Most engines will only benefit if they are tuned for it. Altering timing and mixture etc. Some modern computer controlled engines haver a sensor which will allow you to take advantage of better fuel.

Having said that most engines will benefit a little in smoothness etc if your wallet will stand it.

Just remember that fresh low octane is better than stale high octane!!!

[Polwart]

loco - I think you would need to try it to see in your engine, but I doubt it will make a huge difference. as cod says there are differences in how octane is measured in the US and Europe so be cautious when comparing people's claims.

[Bigmuz7]

I'm not really sure why its sold in the UK as I have never found any difference in any car engines i've tried with the higher octane stuff. I can imagine it giving a small 2 stroke a little edge though, .. maybe my strimmer is crying out for super unleaded and I've denied the little fella all these years

[Nos4r2]

I notice the difference on the bikes between unleaded and super-but all 3 are carbed. Saying that, it makes as much difference if I stick a tablespoon of tcw3 in the tanks

[Rigaud]

Stock setup theirs zero benefit and pretty much all engines are sold to run on low octane fuel. Engines especially 2 stroke with high compression heads, big bore carbs or throttle bodies, ect.. than you would pretty much have no choice but to use higher octane fuel.

Just keep your set up properly tune all the time and you'll have no issues.

Been there done that.

Cheers

[Locozodiac]

Originally Posted by Polwart

loco - I think you would need to try it to see in your engine, but I doubt it will make a huge difference. as cod says there are differences in how octane is measured in the US and Europe so be cautious when comparing people's claims.

Pol, to compare will need to have 2 tanks available, one with 90, other with 95, get a gps and on very calm waters full throttle same given distances with both gasolines to compare: same or better performance. The 90-95 price difference is not a big pocket issue, the largest engine used is a 30 HP, can have a full day divertimento with just 3-95 gas/gal/oil for about $ 15.00. So will stick with 95 octane for the moment. Thanks for all inputs fellow boaters.

Happy Boating

[jambo]

I read the same at begining of the summer and checked with my mariner dealer who advised there was no benefit in running the higher stuff, the most important thing was the oil!

[Locozodiac]

Originally Posted by jambo

I read the same at begining of the summer and checked with my mariner dealer who advised there was no benefit in running the higher stuff, the most important thing was the oil!

Maybe run the slight higher gasoline because of having better cleaning components as advertized by gasoline stations, but who really knows. Other issue, would both gasolines form the same amount of carbon builup inside engine ?

[jambo]

Originally Posted by Locozodiac

Maybe run the slight higher gasoline because of having better cleaning components as advertized by gasoline stations, but who really knows. Other issue, would both gasolines form the same amount of carbon builup inside engine ?

One of the things he did tell me to stay clear off was the supermarket fuel as it has to much sulphur in it and tends to go off quicker especially in deck tanks.
J