Biofuel is an RS2/S2?

[Golfboy666GTI]

I had to put 10 litres of 98 octane biofuel (10 per cent bioethanol) in my RS2 today, mixed with about 10 litres of standard 98.

Is it OK to run biolfuel in these cars?

Is anyone doing it?

Pros and Cons?

This is what I put in my RS2:
http://www.gullpetroleum.com.au/publ...Cat=6&SubCat=9

Religiously I run BP Ultimate 98, it was just today I got caught out

[S2central.net]

Dunno if this is same stuff as 'E85' that can had in parts of Europe. I *think* you are OK with a small amount, but I am pretty sure that people who is it 100% (EspenW is the main man I can think of) run with higher fuel pressures so their existing ECU s/w can cater for it properly. By all accounts it is great stuff when setup properly as the euro version has very high knock resilience. Again - dunno if this is same juice you are talking about so don't just take my word for it, but 'E85' is a good term to start your research with.

[S2central.net]

Just read that back... I was working stupid late last night... seems I have lost the ability to type

[fish]

I wpould think you are ok with that, over here i have heard that there is approx ´5-10% ethanol in all the regular 95 octane fuel...

[EspenW]

Yup, biofuels work rather well, especially in a turbo car. Most petrol is 5% ethanol, and 10% is on the way. Even at such small percentages, the ethanol will have a positive effect, but you really need to step up to the good stuff, E85, which is in another solar system vs petrol when it comes to performance (and engine safety).
I gained more than 20% peak torque on E85. 4th gear pulls as many G's (approx 0.48 as 3rd gear did on 99 octane)
60-90mph in 3rd gear on Ethanol is 2.69s vs. 3.06s on 99 octane.

Attached is the G-Force curve showing E75 (winter mixture) vs 99 octane v-power.

[driftin jo]

What you are talking about would be E10 , 10% ethanol .
E5 has been accepted by all manufactures as OK and as such can now be sold as normal petrol without the E5 label .

E5 is supposed to have an octane rating of 99 RON and some people have said that this is what tesco 99 RON actually is.

Just recently I have been mixing my own juice (petrol) I have been buying a few large Gerry cans of E85 and mixing it in with normal 95 RON rather than paying the premium for V-power or other 99 RON .

I have tried mixing up 2% , 3% , 4% and 5 % and tried to see if I could make an acceptable mix so as to achieve an octane rating that I don't loose the edge over the high priced 99 Ron stuff.
I have found that it only takes about 3 % E85 to make a good mix but this will probably increase when the weather gets warmer .
The only thing Is I cant quantify is just how much ethanol I have in my mix as the “normal” petrol I am mixing the E85 with may or may not contain up to 5% ethanol already !

This is a concern and I am keeping the mix down for now until I get a wideband as the only problem would be going lean as a result of too much ethanol in the petrol .

The other thing to note is that going over board with the ethanol without adding more fuel is not going to gain anything beyond the octane rating you need as the ethanol has less calorific value thus makes less power per litre .

For ref.

One litre of Unleaded has a calorific value of 31 MJ.

One litre of Bioethanol has a calorific value of 21.2 MJ.

One litre of E5 has a calorific value of 30.51 MJ.

So you can see that E5 has 1.645 % less calorific value normal unleaded , as the gain in octane far out weighs the loss in calorific value in our cars ~E5 is going to be a good fuel , beyond this you really should measure AFR with a wideband just to be safe and then compensate with an adjustable fuel pressure regulator if necessary , this is what EspenW does with his mixes from E85 to 99 Ron.

Espenw , if you are reading this can you tell us at what concentration of ethanol do you need to increase fuel pressure to avoid the car running lean ?

This would be very helpful as I don't have a wideband yet .

[EspenW]

Totally depends on setup (turbo, injectors, software, etc), so there is no rule.
You'll have to fine tune the pressure when you get the wideband

[vertigone]

Hi Guys,

Here with my 3B I can drive 50/50 Sp95/E85, no pbs at all car runs great, spark plugs are good color
I ve tried to put 100% e85, car runs good as a daily driver but when you're on WOT, it's another story ... you feel like something brakes the car in I revs = no good !

My other car (polo g40) runs 100% E85, 3.5 FPR and 240cc injectors (stock are 194cc) : no pbs at all after many years of race tracks

hope this help

Cheers !

[driftin jo]

Hi Guys,

Here with my 3B I can drive 50/50 Sp95/E85, no pbs at all car runs great, spark plugs are good color
I ve tried to put 100% e85, car runs good as a daily driver but when you're on WOT, it's another story ... you feel like something brakes the car in I revs = no good !

My other car (polo g40) runs 100% E85, 3.5 FPR and 240cc injectors (stock are 194cc) : no pbs at all after many years of race tracks

hope this help

Cheers !

Given that the stoichiometric ratio for petrol is 14.7 and for E85 it is 9 a 50/50 mix would require about an 11.85 AFR .
Now I know that our cars are set up to run rich on boost and the outcome of 50/50 would probably not be too lean but you would have no rich safeguard on boost and I would think that if everyone tried this a few people would end up with melted pistons !

I would be adding more juice at 50/50 mix for sure
.
Anyway when the weather gets warmer and I finally fit my wideband I will be having a good play with E85/ 95RON mixes so that I can quantify what you can get away with on a homefried ABY set up.

[robins]

Biofuel story - Pistonheads

Just read

http://www.pistonheads.com/news/defa...?storyId=24900

The report suggests that the UK could soon be using 15% biofuel and the higher ethanol content can damage seals and some alloy materials found in older engines.

Does anyone know how to find out if the S2 fuel system is ethanol friendly?

or is this story just scaremongering?

[EspenW]

Just read

http://www.pistonheads.com/news/defa...?storyId=24900

The report suggests that the UK could soon be using 15% biofuel and the higher ethanol content can damage seals and some alloy materials found in older engines.

Does anyone know how to find out if the S2 fuel system is ethanol friendly?

or is this story just scaremongering?

Most cars since at least around 1985 should have no problems. My Golf (1986) has been running on up to 90% alcohol since 2006 and the RS2 since 2008. No ill effects, just massive performance gains as it is a completely superior fuel.

[Golfboy666GTI]

Most cars since at least around 1985 should have no problems. My Golf (1986) has been running on up to 90% alcohol since 2006 and the RS2 since 2008. No ill effects, just massive performance gains as it is a completely superior fuel.

Thats good to hear.
So you havent changed any hose fittings, joints, valve guides etc?

[HuwSy]

Will we need to consider any engine remapping to take better advantage in this fuel change when it comes in?

[A80Avant]

yes, definitely!

[EspenW]

Thats good to hear.
So you havent changed any hose fittings, joints, valve guides etc?

No, none of those.
The changes that I did was to allow for increased flow of fuel (mainly pump and injectors)