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Discussion Starter #1
I went for a drive today (excellent - should be doing it more often) but before I left, I filled up with Shell V-Power Racing premium unleaded.

Now this fuel claims to have a 100 octane rating, but just after I started filling I noticed that it also has a 5% ethanol blend! I have prevoiusly been avoiding ethanol blended fuel just because I don't know enough to trust it but must have had a brain-fart or something when I decided to use it today.

A few things I don't understand -

- If ethanol produces less power per litre than regular petrol, why do Shell blend it in their top fuel? They don't use ethanol in their regular 98 octane V-Power premium unleaded.

- Is 5% ethanol likely to cause any damage to my engine? (Naturally aspirated 1750). Am I just being a nervous nelly?

A few years ago when leaded fuel was on the way out I had a tin particle catalyst fitted - see http://www.fuelstar.com/ This was at the suggestion of my mechanic who had fitted a few and said his customers reported better fuel economy and slightly more torque as well as the lubrication benefit of the tin replacing lead in the petrol. Can't say I've noticed any better economy but it does definitely have more torque. The car is able to pull itself up my driveway on idle which it couldn't do before.

I subsequently started using 98RON premium unlead and never switched back. I tried regular unleaded once of twice but that was a BIG MISTAKE as the engine was pinging like crazy. Now with 100RON premium unleaded I am curious to know if despite having 5% ethanol, this is better than 98RON with no ethanol. Perfomance-wise I can't tell the difference - today's drive was all uphill (well at least the first half) and it was all good.

God I love this car - so I want to be sure I treat it well.
 

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My guess is no it won't hurt anything. Ethanol does have excellent octane boosting abilities however. Infact that might be the only difference between your 98 and 100 octane fuel. I know AVGAS has a fair amount of alcohol in it and if you leave the stuff in your tank and fuel lines for a while it will start attacking the rubber. It burns hotter, cleaner and faster than normal car gas. I run it when I go racing because its way cheaper than race gas ($4.25 per gal vs. $6.75 per gal.) I just make sure I run the tank near empty on the drive home before I refill.

Will
 

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Ethanol is cheaper, helps boost octane, and up to 5% should be fine. In Colorado awhile back they had 10% Ethanol or more and it was pretty crappy compared to the more eastern gas (i.e. Michigan) It does burn a little differently, but so does 100RON :) The main drawback is that you might see a slight drop in gas milage.
 

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Anyone living in what the clean air act designates a "non attainment area", meaning ground ozone levels above a certain level for so may days per year will require use of what is referred to as reformulated gas. The requirement is addition of oxygen to cut down on NOX production. In Denver, Chicago, Metro NY and many other areas you will have ethanol content up to 10% by weight during summer months. California is another story altogether with CARB designating similar requirements year round. Since ADM lobbyists successfully killed the far better MTBE oxygenate in favor of corn derived ethanol, there is a lot of ethanol fuel in US gas pool.
Sorry for my verbose reply, but as blpltGTV points out it has a higher octane number and fuel blenders use it to get their required octane numbers. It will not harm anything. The bigger issue for all of us is probably the lack of valve seat recession additives since elimination of lead in the 1970's.
 

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Discussion Starter #5
Ethanol is cheaper, ...The main drawback is that you might see a slight drop in gas milage.
Hmmm... 100RON 5% Ethanol Premium Unleaded is quite a bit more expensive than 98RON straight premium unleaded...

... so I am effectively paying more for a fuel that will perhaps give me worse mileage and no major performance boost.


I think I'll stick with 98RON for now.
 

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These engines shouldn't need lead or lead substitute. I beleave they were designed to run on unleaded gas in the first place. I wish we got even 93 octane gas here, the best we get is crappy 91.

Will
 

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These engines shouldn't need lead or lead substitute. I beleave they were designed to run on unleaded gas in the first place. I wish we got even 93 octane gas here, the best we get is crappy 91.
Remember - they're talking RON, and you're talking (RON+MON)/2. Octane is reported differently in different parts of the world.
 
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