Toluene as octane booster

[codprawn]

Originally Posted by Cookee

To my knowledge every outboard sold in the UK does not need high octane fuel, they will all run on standard unleaded - unless you know better?

Mercury 300xs and the Verado 350 - to be fair high octane in the US is almost the same as our normal fuel. 96 octane against our 95 but as it is a little higher super unleaded would prob be the stuff to use.

[v666]

Do any outboards have an ecu that can adjust the engine to make use of the higher octane fuel?

If not, why would anyone bother to use higher octane fuel that you will never have any benefit from.

Tim

[Cookee]

Originally Posted by codprawn

Mercury 300xs and the Verado 350 - to be fair high octane in the US is almost the same as our normal fuel. 96 octane against our 95 but as it is a little higher super unleaded would prob be the stuff to use.

Sorry to disagree, for a start the Verado 350 isn't here yet and the 300xs is fine on standard UK fuel ........... and when the Verado 350 does get here it will be set up for UK fuel. I have never seen super or high octane fuel on a fuel barge either, so it would mean either jerry cans or getting the boat out of the water to fuel it up, neither of which is always practical.

I would advise anyone thinking of adding this to think very carefully about every aspect of it from tank to fuel pipes, effects on your motor and of course yourselves not to mention pollution!

[codprawn]

Well if the 300xs is fine on normal fuel there is no point. Having said that Toluene could be very useful for replacing the lost aromatics on fuel that has been lying in a tank for a while without being used.

Toluene has worse press than it deserves - it is already in petrol and is far safer than benzene.

[Lugnut]

Originally Posted by v666

Do any outboards have an ecu that can adjust the engine to make use of the higher octane fuel?

If not, why would anyone bother to use higher octane fuel that you will never have any benefit from.

Tim

Without having a scantoool to monitor the engine diagnositics, it's hard to tell whether their would be a benefit other than cleaning out the fuel system.

General motors (and many other car mfr's) use a "knock" sensor to monitor detonation. It's a band pass microphone that looks for resonant tones that indicate when teh fuel/air mix is not behaving and lets the ECM know when that happens. The ECM in turn reduces spark advance to eliminate the knock(which lowers power, blows head gaskets, hammers bearings, etc...). However, the spark timing values come from a fixed table and the ECM will not increase spark timing on it's own beyond the values in the table.

If todays marine motors use a knock sensor...

And...

If you have a boat with a few more people on it than normal, or a higher pitch prop that loads the engine enough to drop RPM's then I would bet that SOME detonation is occuring and spark advance is being pulled out...

It would be worth testing with Xylene or Toluene to see whther there was an improvement in performance under heavy load conditions.

Chuck

[v666]

Fair point.

Reading the above makes sense. It does though appear increasing the octane will only have a very small effect on power, by allowing the engine to reach the maximum HP it can by preventing knock.

Originally Posted by codprawn

Having said that Toluene could be very useful for replacing the lost aromatics on fuel that has been lying in a tank for a while without being used.

Out of interest are there any figures to show the degradation of petrol over time, would be useful to know.

Tim

[codprawn]

i doubt there are any figures because it all depends on how it's stored. A full jerry can with a good seal in a cool place will probably last years.

On the other hand a big tank with only a small amount of fuel in a warm place and a poor seal will go off very quickly. The Toluene and the Benzine will be the first to go. That's why super unleaded goes off faster.

petrol stations in Oz were doctoring fuel with up to 50% toluene with no probs so 15% should be quite safe. Super unleaded contains 16% anyway.

[Chris]

Originally Posted by codprawn

i doubt there are any figures because it all depends on how it's stored. A full jerry can with a good seal in a cool place will probably last years.

On the other hand a big tank with only a small amount of fuel in a warm place and a poor seal will go off very quickly. The Toluene and the Benzine will be the first to go. That's why super unleaded goes off faster.

petrol stations in Oz were doctoring fuel with up to 50% toluene with no probs so 15% should be quite safe. Super unleaded contains 16% anyway.

So go on then try it !!

[codprawn]

Originally Posted by Chris

So go on then try it !!

Oh I will be!!!

My main worry is that I have fibreglass tanks. I should be ok if I only add enough to boost the octane up to super unleaded standard.

All i need now is to decide which mega outboard to get. Just seen some rumours that yam will be launching a 400hp version of their silly 350 - would make a bit more sense then!!!

I just wish suzuki would bring out a 350 or 400!!!

[ALANT]

Having worked somewhere that had a plentiful supply of tolulene and the health and safety precautions I would not bother not worth the effort.

Look forward to Codders getting a new engine he should be at about 15000 postings by the time!!!!!! so the end of the season?

[Lugnut]

If anybody is worried about toluene, give Xylene a try .Not much difference, but I have extensive personal experience with the latter.

I've personally used it (Xylene, that is) in half a dozen performance vehicles with both standard fuel tanks and plastic NHRA approved fuel cells. No soot, no fuel system problems, and one hell of a lot of fun once I got the tuning for my engine sorted out.

The majority of the time I ran 25% Xylene, 75% 92 octane unleaded gasoline. But on occasion would run up to 33% xylene, never more because it was no longer cost effective when compared to race gas available at the drag strip.

I know gents who have used toluene, but it isn't readily available near me.

FYI, one of the fist things I did when I bought my new-to-me RIB was throw 4 gallons of xylene in the 20 gallon tank. I've found over the years that Xylene cleans out fuel systems WITHOUT braking up varnish/deposits into particles that clog carburator jets and fuel injector spray patterns. They simply dissolve.

In case it's not apparent by now, I'm a believer. lol!

Chuck