Down to chemistry why there is less power. Affects all engines in the same way.
Another daft question from a newbie…
2005 1.8vvt, what fuel? E10 or E5 super? Worried about the ethanol content of the E10, despite the label saying 95 Ron on the fuel cap.
A fair few people on FB stating E5 only, but that seems to be based only on performance issues.
Just checking with as many forums/people as possible.
There’s a government checking tool you can use, but post-2002 Mazdas can officially use E10. I wouldn’t, because the car will run worse.
In this thread, we had the reply from Mazda UK. They were going with whatever Mazda Japan told them. The wording from Japan was ambiguous. The exact wording sent from Mazda is used on the government website. The 2002 date referred to models introduced after that date. I don’t think Mazda UK actually validated what Japan told them. So no, officially, a 2002-2005 NB-FL is not E10 friendly according to Mazda.
The is despite Mazda USA saying its ok since 1994 (as per owner handbooks). Mazda UK or Mazda Japan can’t be bothered to actually check if there are any parts differences in the fuel system between US and EU. Mazda UK’s line is they are guessing there are differences due to emissions requirements. I’m not sure how emissions standards lead to fitment of down=specced fuel lines and seals for Europe, They have also said they are not responsible for any Non-EU cars.
So attitudes have not changed since when MCL tried to take over the club, and they were very anti-grey import.
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I suspect that asking or tasking an engineering department to go back to the specification parameters and possible variants of supply to test if a 5% increase in Ethanol content over the 5% that is already present is not considered the best use of the companies resource for cars that are at least 20 years old and well beyond what they would consider their normal life cycle. Why stick your neck out and have potential problems by saying it is OK, and then have potential brown sticky stuff fall on you because someone decided to change a part with a Euro Parts one and now wants to set the internet alight with how bad Mazda is for not designing a better 30 year old car.
If you live in New Zeeland, they would say that the 5% stuff is bad, but obviously it works. Latest BWM’s list that 25% is OK, you have to make the decision as to if the 10% in new fuel is catastrophically worse than the 5% in the golden wonder fuel at present.
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Because back in 1994, Mazda put in the US owners handbooks as long as you didn’t use more than 10% ethanol (gasahol), your engine warranty would not be voided. In the litiguous US, that had meaning.
Back in 1993, or perhaps earlier, Mazda had already done the tests. No need to repeat them. They must surely know what is the difference, if any, between the various markets. In fact, back in 1996, if you needed a part for a Eunos Roadster from Mazda, the approach was to go to the dealer. The Dealer sends a fax request to Mazda Cars Limited, who’d shrug their shoulders, and forward a fax to Hiroshima. Someone who understood English would translate it, and then, someone would cross reference the part number.
Notably, Honda say E10 is fine with any Honda with fuel injection. Toyota; mid-90s i believe. These companies haven’t done new testing to satisfy a market of 450 million souls. But dug out the same lab results they performed decades ago. Gasohol was introduced in 1979…
As it is, Mazda Japan issued wording, copied verbatum by the UK government, that implies any Mazda made since 2002 is ok with E10. Mazda UK tell me that’s not the case. So much for issuing litigiously conservative (play it safe) statements.
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There you go then.
Hello all.
I’m new to the world of MX-5s, though it has been my dream car for many years.
I currently have mine running on E5 99, primarily Shell V-Power or Esso Supreme. Although that changes depending on which E5 I can find when I need it if driving, my local is Tesco Momentum.
But it got me thinking, whenever E5 is NOT available, for example in the continent where it has been missing for a while now, additives would need to be used (my family also have MX-5s and they use them).
Now I know that my car will run on E10 without issue but it’s always good to run it on the fuel it was intended for. So with that in mind, which additives would you recommend for those instances I can’t get hold of E5 petrol?
And how the bloody hell do I use them? 
Nice to meet you all on this, my first ever forum post since joining club… Please be kind.
~ Mike
G866 CLC “Elsie”
1990 1.6 NA
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I may get shot down, but…
Some say it’s fine to run on E10, others say never as the fuel pipes on old(er) cars will disintegrate as they react with the higher ethanol percentage in E10.
You can get the flexible pipes changed to E10 friendly type and the engine will happily run on E10 but not as well as running on E5.
I add a bottle of Redex to my Eunos E5 fill up if it’s a full fill, or half a bottle if a half fill. 2 for £5 at Aldi or over £6 a bottle at my local BP!!! Guess where he buys them from 
Personally, I only run my 1993 Eunos on E5 and I run my 2018 ND on E10 with every third fill up on E5 but no additives.
I try to never fill up with supermarket brands unless in real need.
I say don’t write off supermarket fuel… check this guy out. I use Momentum exclusively now. 0% ethanol and higher RON than claimed.
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Not 0% in this test
You are correct, I was quoting the most recent test info.
It was by a different youtuber, albeit not as new.
I think things like this depend on where one is the country and their distribution sites.
I’d guess, and it is only a guess, that the ethanol content varies depending on location, and maybe even time of year, and maybe even fill to fill.
Personally I only ever use RON99 (Esso/Momentum/V Power), usually ESSO’s brew.
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I’m a bit of a philistine. I use supermarket (Sainsbury’s) E10 with the ArchOil AR6900-P MAX, at the recommended dilution rate of 1:1000 in my 1999 1.8 NB. It’s been running as sweetly as ever, and whilst it continues to do so, I’ll be using this combination.
Putting it in is easy-peasy - just squirt into the top chamber of the bottle the amount required and then pour it into the fuel filler.
Thanks for all the replies.
I’m based in Chesterfield half a mile from J29A, so Tesco (albeit 10 miles round trip) is my closest E5 station.
There IS a Shell services at J29A so I CAN put V-Power in, and have done before.
However.
As it’s a service station, it cost me 188.9p/L…
Weirdly, when I took a trip up to York to visit friends the other week, I found an Esso services on the A64 that sold Supreme 99+ for 165.9p/L. So obviously location is a pain.
My local Tesco for Momentum I think is like 154.9p/L.
My dad uses that for his TT. Completely different car I know but that’s where the recommendation comes from.
I have read up on E10 conversion kits and the rubber fuel lines etc. but I think I do agree with the Jeff and will put E5 in wherever I can. I haven’t actually put a full tank in yet. I think I’ve filled just below 3/4, and never let it drop below 1/4 (assuming those VERY out of proportion marks on the gauge are the quarter marks ). I’m assuming the ratios will be listed on the back of each bottle?
I’ll give Redux and ArchOil a try, see which I prefer. Just for the eventuality that I will need E10 at some point (I am hoping to go to the continent in it in the summer for example). If they really are that easy to use them it puts my mind at ease. I still have “buyers paranoia” since this is a dream car of mine.
I appreciate everybody’s input and will have a look at the links posted too.
Cheers
~ Mike
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If your Hoses are new and your car is standard then E10 will be fine. If your car is modified ie turboed then you can get into issues.
We were trying to tune my turbo on E10 and it was just knocking too badly, put Shell E5 in (higher octane) and we were able to get rid of knocking and the increase in tunable power was eye opening.
If your car is tuned for E5, then only but E10 in for an emergency and dont drive it hard.
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My car is unmodified. Any aftermarket bits have been things like anti-fire/theft additions or style choices.
From what I’m aware it’s been well looked after, rebuilt in the 2010s. It’s most recent change was a new clutch and shocks in 2019.
It’s still the original NA engine, gearbox etc. and I have no intention of turbo-ing it. I might put a cobalt exhaust on later down the line, but I’m focused on getting her in 100% working order first 
~ Mike
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Which parts of Europe would that be, I had heard E5 Ron 95 is being phased out but not Ron 98 or Ron 102 ?
If you go back through this thread, there is evidence that 10% ethanol was fine in the litiguous US, on NAs and NBs, not even impacting the warranty. But Mazda Europe are fairly gormless in this respect, and lazy. It didn’t take me that long, using public sources, to identify that all the critical part of the NA fuel system, whether US, Europe or Japan have identical part numbers, Mazda UK tried feeble excuses aong the lines of “different emissions requirements” (no), before finally admitting, they just went with whatever the factory said, which was, “we are not interested in the old models”, and also that they, Mazda UK, have no interest in the grey imports…
Mazda Germany were telling owners that 10% ethanol would literally destroy their engines…
Meanwhile Honda; if its a fuel injected car (made since about 1982), its fine.
I suspect, for Japanese cars of the last 40 years, all their seals and lines come from the same manufacturers and use the same materials. Japanese industry is basically run by cartels; massive companies that control everything.
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I have been told by a few people that E5 completely has been phased out.
I certainly didn’t find any when I drove through France last year to get to Le Mans?
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