Recommended petrol

[Piet]

Another thing one might try is to have your ECU remapped for the 30% cheaper E85 (Bio ethanol 85% mixture), it will give you slightly less miles a gallon (with a good remapping) and a lot more horsepower (±10%).

One can also instead of remapping of the ECU (which prevents you from getting normal gasoline), build in a black-box that fools your ECU by extending the injector opening time.

These boxes allow you to drive every mixture of E10 till E85. Downside of these boxes are that the fuel-air ratio are not well regulated with high (WOT) throttle situations and will therefore not take advantage of the better cooling properties of the E85 at higher power demands so you will lose the efficiency, which will cause your car to use more gasoline (varying from 20% to 30% more gasoline) So .. black-box = 200€ and more fuel for a price of just 30% less.... will take a lot of time before you earned the 200€ back but... if you drive a lot.. it might be worth it.

With the black-box there is no katsastus problem, just start using normal gasoline before this time and remove (switch off) the box.

Your engine will get much cleaner too as will your exhaust (tail) pipe.

[kimster46]

I have a hatchback mazda 3, 2008 model.I am using shell vpower for more than a year.
In car, it is written like unleaded premium MIN.95RON/ROZ. What does this mean in practice, does E95 go well in this case?

I drive only 550km a month average, so extra cost is not a big concern for me at the moment.

[Piet]

I have a hatchback mazda 3, 2008 model.I am using shell vpower for more than a year.
In car, it is written like unleaded premium MIN.95RON/ROZ. What does this mean in practice, does E95 go well in this case?

In your case the Vpower is a waste of money, your car would do without any problems the E10 (95). If you want (slightly) better milage/performance, you could use the E5 (98) from Teboil (cheapest, they don't sell it at Neste oil Express selfservice without shop) but the even more expensive Vpower is just sponsoring Shell.

However, when you don't mind wasting money, Vpower will keep the Engine cleaner (tested it myself in the past 10 years with the motorbike hence it does not drink that much )

[FinnGuyHelsinki]

Another thing one might try is to have your ECU remapped for the 30% cheaper E85 (Bio ethanol 85% mixture), it will give you slightly less miles a gallon (with a good remapping) and a lot more horsepower (±10%).

One can also instead of remapping of the ECU (which prevents you from getting normal gasoline), build in a black-box that fools your ECU by extending the injector opening time.

These boxes allow you to drive every mixture of E10 till E85. Downside of these boxes are that the fuel-air ratio are not well regulated with high (WOT) throttle situations and will therefore not take advantage of the better cooling properties of the E85 at higher power demands so you will lose the efficiency, which will cause your car to use more gasoline (varying from 20% to 30% more gasoline) So .. black-box = 200€ and more fuel for a price of just 30% less.... will take a lot of time before you earned the 200€ back but... if you drive a lot.. it might be worth it.

With the black-box there is no katsastus problem, just start using normal gasoline before this time and remove (switch off) the box.

Your engine will get much cleaner too as will your exhaust (tail) pipe.

In order to get true flex fuel capability (safely running any mixture of regular gasoline and E85) there has to be a real time ethanol content analyzer, which some of the off-the-shelf "black boxes" do not have. Using regular gasoline with a "dumb" ethanol conversion kit will result in a disaster. It is also possible that some of the original components (fuel pump, fuel lines, injectors, rubber seals,...) of the car are not made for (high content) alcohol fuels, leading to their faster deterioration over time. As the conversion kits can regulate only the fueling, other parameters controlled by the ECU (ignition timing, boost pressure,...) naturally are not affected, resulting in a sub-optimal operation. For reference, with the current prices I'm saving around 15% in my fuel costs (E85 vs. 98E) with a professionally-made, dedicated ECU tune utilizing an ethanol content analyzer, likely I'll never make any actual savings considering the price I paid and how little I drive, but for me that was not the point.

For the OP and kimster46, just get 95E from wherever it is the cheapest/most convenient for you.

[Piet]

In order to get true flex fuel capability (safely running any mixture of regular gasoline and E85) there has to be a real time ethanol content analyzer, which some of the off-the-shelf "black boxes" do not have. Using regular gasoline with a "dumb" ethanol conversion kit will result in a disaster. It is also possible that some of the original components (fuel pump, fuel lines, injectors, rubber seals,...) of the car are not made for (high content) alcohol fuels, leading to their faster deterioration over time. As the conversion kits can regulate only the fueling, other parameters controlled by the ECU (ignition timing, boost pressure,...) naturally are not affected, resulting in a sub-optimal operation. For reference, with the current prices I'm saving around 15% in my fuel costs (E85 vs. 98E) with a professionally-made, dedicated ECU tune utilizing an ethanol content analyzer, likely I'll never make any actual savings considering the price I paid and how little I drive, but for me that was not the point.

For the OP and kimster46, just get 95E from wherever it is the cheapest/most convenient for you.

As said, most cars from after 1992 have no problem what so ever with running E85 on a black-box, the ECU will compensate all that is needed hence knocking sensors and your O2 sensors will tell the ECU how much to compensate the ignition timing and opening time of the injectors. This is the Dumb version as you said. All the seals in the fuel system are already adapted to alcohol containing fuel hence otherwise the cars wouldn't be able to run on E10 either.

But as I said and you experienced, a dedicated ECU tune is far superior in both efficiency and ease of use.. (the Alcohol sensor you only need when you want to be able to use normal gasoline and E85 mixed or want to tune to maximum efficiency to compensate seasonal mixture changes in the E85 which can vary between...well google on that ... )
But....I would like to know where you had your ECU tuned for this and what they charge ..(if it is in Finland), hence I do not have my old dyno place any-more available. ...and a street tune is far from efficient

[FinnGuyHelsinki]

But....I would like to know where you had your ECU tuned for this and what they charge ..(if it is in Finland), hence I do not have my old dyno place any-more available. ...and a street tune is far from efficient

It was done by Artec Power in Kuopio, one of the go-to places for Subarus in Finland, I don't know to what extent they tune other makes (Nissan, Mitsubishi, Mazda that EcuTek they use supports). The price was 1500 euros (EcuTek license, ethanol content analyzer, installation and tune), this was last spring, note that they are usually fully booked for months. I've heard some discussions about open source tuning suites getting flex fuel capability, but I don't know if any commercial tuner in Finland is yet doing those, many are doing straight E85 tunes, though, I just wanted flex fuel "just in case". If there is a make-specific forum for the car you have, I suggest you ask there.

Another issue related to E85 usage is the engine oil, API SN classified are compatible, others may deteriorate with alcohol fuels, making more frequent oil changes a necessity.

[Piet]

But....I would like to know where you had your ECU tuned for this and what they charge ..(if it is in Finland), hence I do not have my old dyno place any-more available. ...and a street tune is far from efficient

It was done by Artec Power in Kuopio, one of the go-to places for Subarus in Finland, I don't know to what extent they tune other makes (Nissan, Mitsubishi, Mazda that EcuTek they use supports). The price was 1500 euros (EcuTek license, ethanol content analyzer, installation and tune), this was last spring, note that they are usually fully booked for months. I've heard some discussions about open source tuning suites getting flex fuel capability, but I don't know if any commercial tuner in Finland is yet doing those, many are doing straight E85 tunes, though, I just wanted flex fuel "just in case". If there is a make-specific forum for the car you have, I suggest you ask there.

Another issue related to E85 usage is the engine oil, API SN classified are compatible, others may deteriorate with alcohol fuels, making more frequent oil changes a necessity.

Thanks for the info but... subaru ... not really my car ... I am old , my car is old and old subarus do not survive Finnish climate

And kuopio... well I could have done a real good street tune before I am there (from south coast area).

[FinnGuyHelsinki]

Thanks for the info but... subaru ... not really my car ... I am old , my car is old and old subarus do not survive Finnish climate

And kuopio... well I could have done a real good street tune before I am there (from south coast area).

If it really is an old car (without an aftermarket ECU), chances are there's no commercial tuner that would make a flex fuel tune for it. Again, a make-specific forum is the best place to ask these kinds of things.

[Piet]

Thanks for the info but... subaru ... not really my car ... I am old , my car is old and old subarus do not survive Finnish climate

And kuopio... well I could have done a real good street tune before I am there (from south coast area).

If it really is an old car (without an aftermarket ECU), chances are there's no commercial tuner that would make a flex fuel tune for it. Again, a make-specific forum is the best place to ask these kinds of things.

Well the ECU is not aftermarket, in my case I actually have to de-solder the original EPROM and either replace it for an EEPROM (Flash) or mount a ZIF socket and swap EPROMs which is really time consuming... I could do with an emulator but...well you know it is good to have a hobby.
The ECU is a Motronic 4.3 (OBD1, so not able to flash it through the OBD diagnostic port).

And I already opened up a topic in a brand specific forum...