Low emission E10 fuel

[Delanor]

Is this for real E10 possibly freezing fuel lines.

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Del.

[Ainmhidh]

Whether or not there are actually going to be issues with water/ethanol mixes settling in your fuel tank (why would it be more of a problem than just water condensation, without the ethanol? The ethanol would make the freezing point much lower anyway) - that does read as a barely disguised advertorial for a fuel additive.

[Neilparry]

Surely If a problem like this were to occur in the first year of E10 fuel being used, the fuel manufacturers would be forced into adding an additive into the production process rather than costing the consumer an extortionate amount on top of the ever rising costs of fuel


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[Dr. FrankenRex]

That certainly sounds like an advert in wolf's clothing tbf

Also this additive 'reduces emissions and increases mpg to save consumers money' - by spending money...

EDIT: The fuel conditioner is for Diesel according to their website! Talk about a clickbait article

https://sulnoxgroup.com/products/

[Delanor]

I agree it does look like an additive push but there are issues with E10 being hygroscopic hence why non compliant cars may/will suffer problems also for any compliant cars: "It is a hygroscopic, which means it absorbs water from the atmosphere, leading to condensation in fuel tanks if the car remains unused for long periods of time." which like others my RX-8 does especially in winter.

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Del.

[ChrisHolmes]

The opening paragraph cripples the integrity of the article with the quote the condensation occurs when water vapour comes into contact with a warm surface when the world knows condensation occurs on cold surfaces! They may own Luxurious Magazine but come on “my wife and me”

[warpc0il]

Condensation in fuel tanks is an issue if...
- the tank has a breather to atmosphere.
- there is a significant airspace above the fuel level.
- the atmosphere is damp.
- there are significant changes in ambient temperature.
- there are significant changes in ambient air pressure.

Get enough of these and it doesn't matter if the vehicle is being used or not; actually using a vehicle is often the greatest cause of temperature changes around the tank.

However, as with most modern cars, our tanks can breathe in but not breathe out, and the EVAP system maintains a positive air pressure above the fuel.


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[RenesisRaceBuggy]

Is this for real E10 possibly freezing fuel lines.

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Del.

Fun fact, we used to *add* ethanol to old SPi and carb systems on race cars to stop it freezing in the lines in the carb body, or even freezing the throttle body shut in the winter when idling or driving between stages.
Strange that their sh*t fuel additive advert claims the other way...

[warpc0il]

...and then you have the ill-informed home modifies that remove the TB connection to the cooling system, whose sole purpose to prevent icing in the intake, and somehow think they're "adding powar"

https://en.wikipedia.org/wiki/Carburetor_icing

[Delanor]

Is everyone using just E10 fuel in their RX8 without problem although the RX-8 is deemed OK by Mazda to use it I wonder if that is still applicable on cars that are getting on 20 years old now.

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Del.

[PaulAV]

I only use E10 car runs fine on it

[New Duke]

I've stuck to E5 unleaded for 'reasons'. But I wouldn't have any concerns about putting E10 in.

[Neilparry]

I’m running E5 normally Tesco momentum in my Daily Mx5 because it’s not compatible with E10. And not getting any difference in performance or mpg. So costing me 6-8p a litre more for the privilege.


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[350matt]

You should get a small improvement in mpg with E5 over E10, purely on the difference in fuel density as the E10 will flow more fuel for a given injector opening time
in my expierence its about 5% for a NA car , so tricky to spot on a 30mpg car as you should increase to 31.5mpg


basically if the fuel cost for E5 is more than 5% greater its not worth it ( from that point of view)

[Milos_Balunovic]

Its not because it has lower viscosity. It's because of "energy" density, ie to be more accurate more fuel is needed to meet the target lambda and the ECU will build fuel trims. You can see it on the OBD.

Premix at 1% changes the viscosity much much more (actually changes the viscosity significantly) yet its barely noticeable on construction since energy doesn't change.

[Neilparry]

Driving the 5 is pretty much like driving the 8
Instead of waiting for the beep I’m looking at the red line which makes it difficult to get any economy out of her. 30 mpg I wish


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[warpc0il]

You should get a small improvement in mpg with E5 over E10, purely on the difference in fuel density as the E10 will flow more fuel for a given injector opening time
in my expierence its about 5% for a NA car , so tricky to spot on a 30mpg car as you should increase to 31.5mpg

basically if the fuel cost for E5 is more than 5% greater its not worth it ( from that point of view)

Your conclusion is correct but your reason is wrong - close but still wrong.

It isn't the mass density (weight/volume) or viscosity (resistance to flow) that's different, because they're (almost) exactly the same.

It's the energy density (energy/volume) that's poorer, which means it takes more fuel to create the same power.

Basically you get less of a bang for your buck.

In practice the PCM can't do much about that by changes in mapping, so the car is just that little down on power, as if the brakes were dragging slightly. Therefore, if your driving style and road conditions are the same, the fuel consumption suffers by about 5% - see I told you that you were right

Edit: I'd written this before Milo's answer was posted, and then it sat waiting for me to hit the [Submit] button
Still posting anyway, as it agrees with Milo's main point, just with different words.

[Milos_Balunovic]

Warp oil. The EVU/PCM can compensate for the lack of fuel.
The ecu maps target lambda.
Lambda will read leaner than target, ecu will adjust in closed loop and build LTF. Ltf is active even in open loop.

Lambda will read 1 at stoichiometry for what ever fuel is in it. Ie for petrol 14.7:1 for diesel 14.6:1 (or something like that) for ethanol 9.7:1...

The difference i. E10 E5 E0 , 100octane stoich is so little that ecu compensates for it without any problems.

[Dr. FrankenRex]

The RX8 ECU runs a set fuel trim in low rpm operations and idle. It doesn't flick over to AFR and lambda until up in the rev range and under high throttle applications IIRC.

As such if you want it to 'learn' how to run properly on E10 or E5 you need to do the fuel trim reset procedure by disconnecting the battery and having it re-learn the ST and LT fuel trims.

This'll cost way more in letting the 8 sit idling than you'd save by switching from one to the other, so may as well just have at it either way.

[New Duke]

Sometimes the forum just needs the clarity that I can bring to certain issues. This is one of those times!

The science talk is fine but really what counts is:

E10 - contains more animal feed and food waste
E5 - contains more dinosaurs for a pitiful 5p more a litre (that's less than 5% of the pump price for anyone watching the pennies)

Dinosaurs are cooler than corn and rotten banana skins, therefore E5 wins.

[warpc0il]

and there's me thinking that E10 is basically giving your engine tequila shots

[PaulAV]

and there's me thinking that E10 is basically giving your engine tequila shots

We all know no one likes tequila, just like ethanol in petrol, it'll get you there but no one likes it having it

[Milos_Balunovic]

The RX8 ECU runs a set fuel trim in low rpm operations and idle. It doesn't flick over to AFR and lambda until up in the rev range and under high throttle applications IIRC.

As such if you want it to 'learn' how to run properly on E10 or E5 you need to do the fuel trim reset procedure by disconnecting the battery and having it re-learn the ST and LT fuel trims.

This'll cost way more in letting the 8 sit idling than you'd save by switching from one to the other, so may as well just have at it either way.

The rx8 is in closed loop up to medium load and quite high rpm. While in closed loop the ecu is constantly chasing target lambda. (Why lambda and not afr is becouse the exhaust sensor feeds back lambda not afr, which is only used for aprox conversion of maf to required fuel, in mazda this is 13.7-13.8 something like that).
The closed loop will change the fuel trims constantly to adjust for any changes to the fuel, air filter etc. You dont need to do any resetting of the car.

As long as the ecu is running closed loop fuel trims are changing.

EDIT: the long idle is the adjustment only for the IDLE controls, ie choke, throttle opening and advance etc to maintain smooth idle. nothing more.
LTF learned here is only appplicable to this rpm/load and will be further adjusted by the "running" LTF's as well. and the idle LTF dont ever apply to high load and or high rpm areas.

[Steve.82]

Would avoid chopping and changing between ethanol levels for this reason. LTFT is slooooow to change. Not a problem in closed loop as the STFT is fast to adapt, but did seem to effect open loop before I spent some time making mine entirely open loop. At least the stock map is so rich this will not leave it too lean flat out.

[350matt]

are there any dyno runs chaps to show the delta between E5 and E10 on a rexi chaps ?
I mean we all know its fine on 95 octane and there's not benefit much to be had on 98

however the difference in ethanol content is quite recent ?
plus the Shell Vpower flavours of fuel contain more lubricant than the lower grades so potentially better for tip seal life