Because of another forum thread I idly looked up E85 in a Miata, apparently in America there are a number of NA owners who run their cars in stock form (and also modded, but the stock ones were a surprise to me) on E85 without issue and have done for years.
Makes you wonder !
Poor hoses?
I’d expect they would be. 
You’d be surprise (or horrified) to see original top / bottom hoses etc, and radiators “going green” that were fitted at Hiroshima 25 years plus ago. Or are they referring to the inner surfaces as well?
Think they meant the insides, looked like the surface of the moon they said. They also apparently crack on the inside, which isn’t immediately obvious by looking at the outside. But I’ve not seen it with my own eyes, I just know the ones on mine look good and I know it to be a well looked after car, though I’ve no evidence that the hoses were ever replaced.
It’s a total gamble as far as I’m concerned. For all I know, the 99 grade stuff has additives that don’t agree with the compound used in the hoses and it might be doing more damage than the cheap stuff.
It’s also worth considering that there’s probably 5 other things that affect the car’s bits as much or more than how much ethanol you feed it. But I’m uneducated so I think sacrificing a couple extra pounds on the refill will have to compensate for any ignorance. 
As we are being told pre 2002 mazdas are not suitable for e10 can we find out perhaps with the help of Steven Bird & Mazda why not?
Will it just be a case renewing fuel lines with R16 standard fuel hose (E10 compatible) & probably using a fuel stabiliser to combat the hydroscopic properties of E10 or is the issue more complex i.e components
inside fuel pump, injectors ect.which cannot be modified.
Surely the answer should be easily available from Mazda.
As a newly retired mechanic who has customers who are thinking of selling their cars as they want to use them for continental trips where they say E5 is not available it would be good if the answer was just change your fuel lines!
Actually, its not just pre-2002 cars. Its any NA or NB that Mazda are saying are incompatable. Even Mazda UK are making mistakes. Initially they told me any Mazda before 2002 is not compatible, then quickly corrected that to “any new model type” introduced since 2002.
I’ve been exhanging emails with Mazda UK (Emma Seal). Based on the answers received, I think Mazda UK literally has no clue. They have been told by Mazda Corporate in Japan that you can’t use E5 on any NA and NB sold in the EU market. They have no view at all on US specification Mazda Miata and Japan specification Eunos Roadster, merely only giving the trit advice that Euno Roadster owners should consult their Owners Manuals (which are in Japan).
I will try and follow up, to see if they can put me in touch with someone at Mazda corporate. This is a very bad image for Mazda to read of owners selling, or possibly scrapping cars because they think they can’t run them on E10, even occasionally.
As you can see in this thread, I have found evidence that in the US, at the very least, the 1994 Miata (the 1.8 Mk1), 2000 (the NB 1.8), 2001, 2003 (NB-FL 1.8) all contain a section warning owners not to use fuel with more than 10% ethanol as it might invalidate the warranty (ie. 10% ethanol will not).
I can confirm that the Eunos Roadster glovebox book contains no information on fuel grade beyond not using "inferior fuel and not to use leaded fuel (!).
I asked Mazda UK if they could explain what parts, if any, were different on a 1994 Miata that might explain why Mazda would warranty cars running on 10% ethanol. Mazda UK could not explain the differences, merely stating that “vehicles sold in the US markets are subject to very different emissions laws and therefore differ in specification. Unfortunately, we do not have details of these differences as we only have access to the information relating to vehicles produced for sale in Europe”. This is amazing that ~25 years after the first Euno Roadsters hit UK shores, Mazda UK has no information on these cars. Mazda UK I think is managed through Mazda Europe, who are baed in Germany. Maybe they know more. Probably not; Mazda German’s website includes a dire warning that E10 will “permanently” damage these older engines (not just soften a few lines, clog a fuel pump etc). Fears of liability might come into it.
But notably, other Japanese manufacturers are listing much older models as being fine. Honda says any fuel injected Honda is ok. I wouldn’t be surprised if the fuel systems in Japanese cars of the era all came from the same suppliers.
I think Mazda has no interest in the fates of NA and NB cars. They’ve paid lip service in Japan to what were originally EU requirements, to audit materials contained in these cars. The NCs were launched in the period of widespread use of ethanol in fuel. At the time of development, they may well have tested varous materials for compatabiliy. For older cars, no testing might have ever been carried out (which doesn’t mean they are incompatible). Mazda probably did a desktop exercise, and all materials with a unknown go into a pile marked "probably not compatible, but we aren’t boing to spend money finding out).
1994 NA8C Eunos Roadster fuel system part numbers
http://do-da.co.jp/sun-mec/na8s1/
(stick it through a translator)
The fuel pump, BPE8-13-35Z , cross references to Mada fueld pumps listings by UK/ US sellers.
“In tank fuel pump hose”; KL19-13-ZE6
“Fuel hose”; 9935-90-815
US factory microfiche
Fuel pump is the same number as for Japan. “In tank fuel pump hose” is the same part number. Fuel hose" is the same number.
I can’t think of a logical reason why the US market cars would have a different fuel system from Europe and Japan. I supect if I went through all the fuel system part numbers between the US and Japan market cars, they’d be all the same.
If news catches on that owners are abandoning the older models, or even the marque, this cannot be good for the little roadster.
I hope someone at Mazda UK takes a look at this thread. It cannot be right that owners are left like this with no support.
Hi,Thank you for the quick reply to my post.Should we be asking why can I not run my car on E10 as opposed to can I run my car on E10.That question ought to force one of several replies.
In over 50 years in the motor trade I have found that usually any change in a component requires a part number change, so any superceded part number shows that a change from the original has taken place & records of why are usually kept.So if part numbers are the same for E10 vehicles & pre 2002 models that part should be OK?
So if say a fuel pump is not compatible & you purchase a new one should that be OK or is it not fit for purpose?
As to replies from Mazda do they admit to not keeping component & part number records so they cannot answer the question ?
Do they say renew parts that are not E10 compliant with a warning to check for corrosion of metal components due to hydroscopic nature of E10 & advise on adding a fuel stabiliser to protect injectors ect.
Do they say refer to your drivers handbook which was printed before anyone thought of putting any ethanol in fuel ?
After all Mazda does not need to worry of a flood of warranty claims relating to NA or NB models so please just tell us what parts are not compatible with E10 so we can change them & keep a classic car on the road, after all most manufacturers have a heritage division to promote this.
We have been through a similar scenario when fuel lines needed to be renewed & additives or modifications made to vehicles when leaded petrol was phased out.
Playing Devil’s advocate, what’s in it for Mazda for them to help us sort this out and keep the older NA and NB MX5s on the road? I doubt that very many are serviced by the dealer network and the few spares that they sell us probably cause them more problems than they are worth. Their raison d’être is to sell us new cars. Hopefully you were happy with your old MX5 and will buy another, newer, one. If not then it’s no skin off their nose.
Hi hopefully several points will help
Most other manufacturers have a heritage division for their older cars so would it look good for Mazda to show support for their classics.(not just MX5s)
Bad press coming from their failure to support owners & clubs.
Good press from offering a solution to our E10 problems.
Good press by offering a solution before someone else takes the lead & does it first.
Good press by helping us to reduce emissions by the use of E10
Good press by lowering our carbon footprint by not making us having to buy another replacement vehicle
Hopefully creating a increase in parts & work load for Mazda & others by offering a solution.
Also would you buy a vehicle from a manufacturer who turned their back on you ? I most certainly would not & I know a lot of my customers would not either.
Remember I am not asking for a free spares package just tell me what is not compatible so I can change it & if It has to be remade to E10 standards get on with it before someone else shows the initiative & does it & corners the market which again would not be good press for Mazda.
We are talking about the worlds best selling sports car & a global market not a car which only has a small number left.
As a example look at the MG which was fitted with hydragas suspension which is no longer available, that problem has been solved by a independent company who offers a coil spring conversion.
To clarify, while Mazda are saying E10 is ok for post 2002 Mazdas, this is NOT the case fr the MX5, where they are only certifying cars with the MZR engine, ie. the Mk3/NC model.
Yes, Mazda might not be very cooperative because they have no interest in owners of older vehicles, and even less interest in owners of Eunos Roadsters (going back to the days with Mazda UK’s predecessor, MCL< wanted a complete ban on new membershops by grey import owners).
However, Mazda Japan, to much publicity, launched a “TIV approved” NA restoration service, and has remanufactured some deleted MK1 parts. Given the putiful number of cars restored in 2-3 years (a dozen maybe), I suspect they are losing money hand over fist, and its in fact a PR activity.
I asked Mazda UK
I am writing to get some confirmation on the compatibility of some older MX5s with E10 petrol.
According to Mazda UK, and the UK government website, only NC and ND MX5s are “cleared” for use with E10 petrol:
What is E10 petrol? | Mazda UK
GOV.UK E10 EnquiryHowever, according to my research, this contradicts information Mazda has been providing to owners in the United States, since at least 1994.
According to the 1994 Miata Owners Manual, in the section entitled “Protecting your Mazda”:
“Vehicle damage and drivability problems resulting from the following may not be covered by the manufacturer’s warranty:
- Gasohol with more than 10% ethanol
- Gasoline or gasohol with methanol
- Leaded fuel or leaded Gasoline”
The owners manual for the 2000, 2001 and 2002 US market Miatas make similar reference to Gasohol
https://www.mazdausa.com/siteassets/pdf/owners-optimized/2002/mx5-miata/2002-mx-5-miata-owners-manual.pdf
https://www.mazdausa.com/siteassets/pdf/owners-optimized/2001/mx5-miata/2001-mx-5-miata-owners-manual.pdf
https://www.mazdausa.com/siteassets/pdf/owners-optimized/2000/mx5-miata/2000-mx-5-miata-owners-manual.pdfI understand that in 2008, Mazda in Japan made further technical investigations into the compatibility of E10 fuel with older Mazda models.
Could you please furnish me with answers to the following questions:
- Is the information provided in US market Miata Owners Manual accurate with respect to the use of “Gasohol” (fuel with 10% Ethanol)
- Does this information apply to vehicles sold in Europe and Japan during the period 1994 to 2002?
- If this information does not apply to vehicles sold in non-US markets, what are the major differences in the vehicles to cause this?
- Can Mazda UK please provide the results of the technical assessment carried out in 2008 (or thereabouts) to the MX5 enthusiast community?
And in my most recent email (reply awaiting), I literally asked why UK Mk1 MX5s can’t use E10 fuel, but US Mk1 Miatas can.
Franky, I think Mazda UK is little more than a markting outfit (someone from Mazda UK is free to correct this view), and they don’t have a great deal of technical knowledge about legac models.
Mazda UK told me that the entry shown on the DfT’s E10 tracker came from Mazda Japan, verbatum, Even Mazda UK got it mixed up what it meant (by inutially saying 2002+ MX5s were ok, before quickly correcting to NC models).
Ethanol in fuel has been in use in the US since 1978 and at least from 1994, Mazda was including information in Miata handbooks on the use of “gasahol” (10% ethanol fuel).
When Mazda changes a part that is backward compatible, the part number stays the same, but a single letter suffix is added.
At the moment, I am comparing a Japanese parts number source, which is easy to extract into a preadsheet, against a poorly scanned US microfishe.
But I could use this instead:
But if I can do this (draw up a list of part numbers), why can’t Mazda UK (besides nthing in it or them). This smacks of what I heard from a Mazda dealer parts manager, that in the early days of Roadsters coming here, they would fax Mazda UK the question “does this fit”, who would in turn, fax in English the request to Japan, and then, 2 months later, you’ll get an answer.
The UK statement on the MX-5 has always and only said 2005 (NC onwards),
https://www.mazda.co.uk/why-mazda/news-and-events/mazda-news/articles/what-is-e10-petrol/
Mazda need have no obligation on this change to fuel for older cars, they can in good faith help advise older vehicle owners with signposts to find solutions - which is at present keep using E5 fuel that is still readily available.
But it really is for the aftermarket suppliers to spring forth with the solutions to maintain the cars and provide kits and components and I am sure that by the time E5 supply becomes more troublesome there will be ample options to keep older MX-5s on the road.
It’s no good comparing with the use of E10 in other countries. Apparently E10 fuel holds an amount of water vapour which does not condense in the fuel tanks in these other countries because they are warmer places. However the UK has a cooler climate which will effect the E10 fuel causing it to condense into the fuel tank. Over a period of time this condensed water will accumulate to such an extent that it will inevitably be drawn into the combustion chamber of our engines doing irreparable damage.
There are already aftermarket remedies out there to this problem from sellers wanting to make a fortune and most likely they will. However I fear the outcome will be the same except those selling these products will be drinking cocktails on a remote island.
Many parts of the US are much much colder than the UK. Friends in Missouri use E85, and it gets down to -15 in winter (cold enough I know to freeze transmissions). Average winter temps, excluding Hawaii and Alaska, are 0.7 celcius.
The issue not that Mazda supports older cars (but they do), but that the information they provide is accurate. I think inaccurate information has been provided to the DfT. Mazda UK seems utterly dependant on Mazda Japan issuing technical statements (not so in North America and New Zealand, of all places, it seems).
Its ironic that a 1992 Jag, a 1985 Honda, a 1991 Subaru Justy, a 1998 Corolla, and a 1981 Hyundai Steller, will run fine on E10, but apparently a 2004 MX5 won’t.
An initial examination of part numbers, for a 1994 US Miata and 1994 Eunos Roadster, indicates the fuel system parts are identical. A JDM handbook for the year makes no mention of ethanol containing fuel. A USDM handbook for the year indicates that using fuel containing in excess of 10% ethanol may invalidate the warranty. In 1994, ethanol containing petrol was not available in Japan.
In 1994, 87% of MX5s were sold in North America and Japan. It would be curious then that Mazda would substitute fuel system parts in a small market such as Europe for no good reason (fitting ethanol compatible parts would not cause a problem in Europe).
If it is the cae that US market cars might have some parts differences, knowing the part numbers would be useful. I can walk into a Mazda dealer, and order from them any part for a Eunos Roadster from Japan, so the fact the parts would be in the US should not be an impediment.
First of all lets take our hats off to saz9961 for all the research & hard work being carried out.Hopefully we will get a solution to all this & as iainf has stated perhaps it will be a aftermarket company who will provide a solution. Allready one carburettor company is making kits for some of their earlier products to be E10 compatable & the world & its mates will sell you fuel additive/stabiser for E10.
Yes well done for your research. E85 is used but only at high altitudes and pumps suppling this fuel have a recommendation that the vehicle is only used at high altitude or to that effect. Altitude will have an effect on fuel allowing modification of octane levels.
This cannot be the case in the UK as we do not have such mountainous regions.
Just got back from a trip to Madeira where I rented a grotty Fiat Punto: Prior to returning it to its owners I had to fill the tank and visited a BP station. Was perplexed by the labels on the pumps, they offered Regular 95 octane and Ultimate 98 octane. The labels on the pump nozzles stated E5 for the regular and E10 for the ultimate, which is the reverse of what we have here in the UK. Looked like proper official printed labels, unfortunately I didn’t think to grab a picture, had a plane to catch.
Luckily for me, I have an nc but my take on this is that from nc on, nice and simple but pre nc, it’s all a bit complicated and Mazda want to keep things simple for themselves, so will only commit themselves from the nc on.
I doubt rhe American cars were any different with regard to fuel system specs, so going by the American experience would seem the most sensible option.
OOOOOOO stress, fill up with E5, use the roadster with a smile on your face while using the tank of fuel , re fill the tank and do it all over again, your time is always ticking to stress and worry.
M-m
The 2021 November issue of Classic Bike has a well researched article on E10, it is worth a read if you can get hold of a copy.
Dr Paul Ireland is the main source for it, and he has written a very relevant book ‘Classic Engines, Modern Fuels’.
My Daily drive NC (60miles round trip) now does 38 instead of 41 mpg on E10.
It also doesn’t run as sweet.
I occasionally treat the old girl to Super at times and notice a real difference!
I’ve not tried it in my N reg CBR600 yet, but Honda admit it’ll run “Rough when it’s cold, but should be ok”!
Sigh, next they’ll be banning any car/bike modding…
Rick.
