Which fuel should it be tuned on?

[colly]

Im getting the car mapped over the next month, over here we have 2 choices of petrol - 95 RON or a 5% bioethanol mix which is 99.2 RON.

I was just wondering what peoples opinion on which one I should map the car on?

I mailed Mazda Australia and they said it\'s not suitabile -

Thank you for your enquiry relating to fuel recommendation and the use
of ethanol blended fuel in a Mazda RX-7.

Many changes have been made to vehicles since the advent of ethanol
blended fuel to prevent the more corrosive nature of this fuel adversely
affecting the vehicles smooth running and life span. Recent Mazda models
have been designed to be able to run on up to 10% ethanol without
concern. In order to achieve this many production changes to the
vehicles have been made, for example to fuel line and fuel tanks.


With regard to your Mazda RX-7, we confirm the use of ethanol blended
fuel in this vehicle is not recommended as this model was not designed
for this purpose.

Please refer to our website where you will find some pertinent
information on the use of ethanol blended fuel.
http://www.mazda.com.au/articleZone1.asp?articleZoneID=2568


Thank you for contacting Mazda Customer Services

Regards
National Customer Service

I don\'t know whether they were just covering their ass or whether it\'s not suitable. I thought a good few of the petrol stations in the UK use a 5% bioethanol mix, is this true and do you think it\'s safe for the 7?

Thanks.

[Timmy]

just have it tuned on what fuel you want to put in the car. for example v-power or bp ultimate or if you don\'t want to worry about getting hold of those just normal 95ron.

[colly]

just have it tuned on what fuel you want to put in the car. for example v-power or bp ultimate or if you don\'t want to worry about getting hold of those just normal 95ron.

There is no V-Power or BP Ultimate over here. I have the option of 95 or a 5% bioethanol mix which is 99.2, I have heard that the 7 is not suitable for a 5% biethanol mix but I thought some on the site may have experience on it and know which of the 2 above is the better option?

[shaunwil]

It may not be the engine that isn\'t compatible. The Fuel Lines may not cope with the increased bioethanol and degrade.

Do a search on //www.rx7club.com for E85. Although I think thats higher % of ethanol.

Shaun

[colly]

It may not be the engine that isn\'t compatible. The Fuel Lines may not cope with the increased bioethanol and degrade.

Do a search on //www.rx7club.com for E85. Although I think thats higher % of ethanol.

Shaun

Yes thats definetly the case for E85, E85 is 85% bioethanol, id only be using E5, do tesco for example not use 5% bioethanol in the UK or is anyone aware of this?

[elford_tim]

Yep, Tescos 99 Octane is supposed to be E5. I vaguely remember (sorry, no sources atm) that something like 5% is still considered safe and that this fuel does conform to the/a British Standard for Super Unleaded. I\'m using it with no negative effects so far, but then again I\'m also using V-Power. Basically depends on where I can fill up.

E85 has a bunch of issues, one of them being the fact that a lot of older fuel lines and gaskets/O-rings degrade when exposed to it; the other one being that you need to inject a lot more of it into the engine (due to the fuel being oxygenated and all that) so running it on a petrol map will cause the engine to run lean.

I\'d still be tempted to experiment with E85 due to its considerably higher octane rating but you\'d have to be able to run the car on an ECU with switchable maps in case you\'re stuck somewhere with no E85 supply.

[colly]

Yep, Tescos 99 Octane is supposed to be E5. I vaguely remember (sorry, no sources atm) that something like 5% is still considered safe and that this fuel does conform to the/a British Standard for Super Unleaded. I\'m using it with no negative effects so far, but then again I\'m also using V-Power. Basically depends on where I can fill up.

They all say it\'s safe alright, Maxol over here claim that it\'s safe for all cars. I had read elsewhere that e5 would not be suitable for the 7, but if people on this site have been using it for a good while with no negitive effects then i\'ll go for it.

[shaunwil]

The only other downside to E85 is that in the UK its just as expensive if not more expensive than petrol and you don\'t get as good mpg.

I\'ve used tesco 99 for a couple of years and been fine.

Shaun