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Old 25 August 2005, 14:08   #1
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Unleaded or super unleaded?

Here's something to ponder.

If I use unleaded I can pull 34Kn @ 5000 RPM and get 1.2 MPL. If I used super unleaded any idea how much extra vroom could I get and would the extra cost of SU payback with a better MPL.

Has anyone tried SU?

Tim'mers.
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Old 25 August 2005, 14:18   #2
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No, but I'd have my money on "no difference at all"
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Old 25 August 2005, 14:27   #3
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I thought that the super unleaded was just a 'marketing ploy' till I put some by mistake in my bike.
I noticed the increase in power within 1 mile of leaving the station. It wasn't just noticable, it was very noticable.

Try some, what have you got to lose (a few quid maybe) and report back to the forum with your findings.

I for one would be interested.
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Old 25 August 2005, 14:32   #4
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Never done any mathematical calculations on this, but I switched to Super unleaded a while back...and I'm sure I get a bit more vroom now
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Old 25 August 2005, 14:51   #5
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Be careful guys!

I know a bit about this as I sometimes work for a company that prepares fuel stations for switching to Super Unleaded and then goes back to the stations about six months later and starts to sort out the problems with the tanks!

Firstly yep you will get more woomph cos it is a different blend of fuel
Thats the good bit,

The blend contains a lot more Ethanol than normal petrol and whilst this is good for whoomph it is also much more hydroscopic and causes clotting , to a degree, of the fuel which can have an adverse effect on your injectors.

So if youare gonna run it then ensure you take the normal condensation prevention steps and you should be fine. better still run it from daytanks!

If memory serves me right Esso, Total, Jet, Texaco amd all the supermarkets all use fuel from Vopak terminals. So its all the same stuff so you can shop on price without worry about the quality.

of all the fuel companies Tesco by far has the best tank maintenance policy so their fuel is usually pretty good.

BP and Shell use propritry fuel
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Old 25 August 2005, 14:52   #6
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never tried it in a boat but i tried a tank full of shell optimax in my hyundai v6 coupe once. very noticable on acceleration not sure of effect on fuel consumption or top end.

does any one know of the boat engine manufacturers stance on these "high performance fuels". what do the engine handbooks say...
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Old 25 August 2005, 14:57   #7
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Quote:
Originally Posted by Rogue Wave

Firstly yep you will get more woomph cos it is a different blend of fuel
Thats the good bit,

The blend contains a lot more Ethanol than normal petrol and whilst this is good for whoomph it is also much more hydroscopic and causes clotting , to a degree, of the fuel which can have an adverse effect on your injectors.
That's interesting Rogue "Rock n Roll" Wave,

I stick it my old Aston with which has Weber carbs...any deteremental effects there do you think?
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Old 25 August 2005, 15:35   #8
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Rogue, it is going in an oldish Mercury 3 carb unit which would probably run on camels p*** if it had too. I was interested by the fact that I heard you get about 10% increase in power but it is only 5% more expensive than ordinary unleaded.

I have worries that my unit may not take to higher octane fuel. The book says "Regular leaded, Premium, Low lead and lead free auto gas with a min octane of of 86" but they dont give a max...

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Old 25 August 2005, 15:50   #9
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Quote:
Originally Posted by Swifty
Rogue, it is going in an oldish Mercury 3 carb unit which would probably run on camels p*** if it had too. I was interested by the fact that I heard you get about 10% increase in power but it is only 5% more expensive than ordinary unleaded.

I have worries that my unit may not take to higher octane fuel. The book says "Regular leaded, Premium, Low lead and lead free auto gas with a min octane of of 86" but they dont give a max...

Tim - wouldn't worry mate, with your current costs can you honestly afford to be adding extra cost to your fuel bill

PS made to Allington and back inside the island on 35 litres at 17 nautical miles, running at 25-30 knots all the way there and back

PPS see you mid channel ish
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Old 25 August 2005, 15:51   #10
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I never heard of a higher octane fuel causing any problems. I used to run race cars on AVGAS and occasionally bunged it in my road ride with no side effects. Mind you, they were different motors then for sure. High octane fuel probably a waste of money in many motors not tuned to take advantage of it. In any event, you could hardly call todays "high performance fuels" such with a straight face. Compared with what we had 20 years ago, it's like weak antelope tinkle.
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