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This new E10 eco friendly unleaded petrol


Club Member
Nov 24, 2019
I think this has come up in discussions on here in the past, but seems like things have progressed based on this article, stating the change will be happening from Sept 2021.

For those not aware, it says they will be replacing standard unleaded (E5) with the eco E10 and leaving Super Unleaded as the only option for those that need the E5 fuel. It says E10 is fine for all cars post-2011.

The government have an E10 checker tool which states all Ford cars except a 1.8 Mondeo will be fine with E10.


Is there any guidance on whether our cars specifically can run on E10? Just thinking that making a change after 20 years of one fuel may cause some engine related problems? What would the likely damage be if we did?
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Our fuels have had up to 10% ethanol for years in them. I've ran it in all my cars for years and haven't had an issue. Normal cars shouldn't have an issue with it.
I think you'd have more issues with the octane rating of the fuel if anything.

Most cars can handle up to 15% ethanol ratings. Where you run into issues is switching to like e85 where its more ethanol then petrol.


Club Member
Feb 6, 2011
Milton Keynes
I haven't paid too much attention, but I'm pretty sure that all of my local BP garages in MK are E10 for standard fuel and have been for a couple of years. Neither Tiger nor Wildcat have ever been bothered.

Wildcat gets a tank of super-unleaded for every five tanks of normal.

She seems happy enough like that with the usual ignition settings, so...
The air fuel ratio is more the issue then ignition. The ratio for petrol is 14.7 where as with ethanol its 9.8. That's why everything for an E85 car is sized to 30% bigger then petrol. Bigger fuel pump. Bigger injectors. Bigger lines.
The biggest issue I can see happening with E10 over non ethanol fuel is maybe a change in MPG.
I tested it in my 2016 honda a month or so ago and put actual non ethanol petrol meaning 0% ethanol and actually got worse mpg however it is a turbocharged car and 17 years newer. I actually think the octane rating had a higher effect on it.
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Club Member
Jul 11, 2020
There’s a worry that E10 fuel will have a detrimental effect on old fuel lines, diaphragm’s in carbs etc on pre 2001 cars and bikes! There’s a lot of talk on the Honda CBR forum that I’m on about it but like some, I’ve been using Super Unleaded in my 600 for years. It does cost a bit more but apparently (hopefully) it doesn’t go off as quickly as normal unleaded (handy for me because I’m a signed up ‘fair weather’ rider) ☺️
Ethanol's been around for a long time. Im actually really suprised that E10 is even a thought, much less a worry.

My cars a US market car. My steering wheel is on the left, however we have the same fuel tanks, the same fuel filters, the same fuel pumps, the same fuel lines, the same injectors, and the same engine. (Before I changed stuff that is!) It's ran E10 its entire life as well as every other cougar here and they break down because people are dumb. Not because of the fuel.

The only reason Im changing all my fuel system on my build is because I intend on running on E85 in the car. E85 is when you have issues with the fuel breaking things down. And thats because E85 is 85% corn whiskey and 15% petrol.
E10 is barely any corn whiskey and 90% petrol. Not enough to effect anything on a daily driven car.

A vehicle thats parked for extended periods of time there may be issues. Ethanol has a way shorter shelf life then petrol however at 10% ethanol I really don't think you're ever gonna notice without letting something set for many months.
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