General engine questions

No-one considered your questions silly. Your questions were answered. Extra help was offered, admittedly some was with a slight sneer about your apparently over-simple approach. You decided not to listen to it and proceeded to shout at us about how you didnt care - WITH CAPITALS - an action guaranteed to piss people off. Think about it this way - if you shouted what you wrote while talking to someones face how long would you expect to last before he smacked you in the face for being ignorant and shouting at him? I'd give you a few seconds.

You can get all the information you like here, just try not to tell people who are answering your questions that you dont want to hear what

He could use a fuel grade sensor, but these are hundreds so i assume he wont. He could use a flick of the switch but if you switch between fuels (tankfulls) with any regularity it is irrelevant as the mixture will be some unknown quantity of each, leaving both settings running like s**te. I would assume he is talking about switching solely to ethanol based, which would be simpler.

Coyoteboy ( snipped-for-privacy@hotmail.com) gurgled happily, sounding much like they were saying :

If somewhat restricting when it comes to foreign travel...

Maybe you people are a bit later than us in Sweden technically... :) E85 has been around for about 5 years, originally it has been used for

powerampfreak ( snipped-for-privacy@hotmail.com) gurgled happily, sounding much like they were saying :

I don't remember seeing it widely available when I was over there a couple of years ago. I'll look out next summer.

The thing to bear in mind is that you're asking questions in a UK group (you'll note the name...) about something which is semi-widely-available in a couple of countries around the world only - excluding here.

If you wanted answers with Ethanol experience, perhaps you'd have done better to ask a Swedish or Brazilian group...

Stuffed ( snipped-for-privacy@rse.non) gurgled happily, sounding much like they were saying :

Exactly.

The first pump in the UK, in March this year, with plans for a whole 9 more.

Brazil originally used 100% ethanol. Brazillian Honda 125 had a very small petrol tank for starting and main tank for ethanol. Engine was started on petrol and switched to ethanol when warm. This prevented carb icing problems on cold engine without having to use a hot air induction system of manifold hot spot.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

The message from Peter Hill contains these words:

I guess that'd be 'cos at best you can get around 95% pure ethanol, the rest being water which won't come out by distillation, needing dessicants to nobble the remainder. I don't suppose it was even that pure at the pump - and all that water would make inlet icing a real menace.

So through the whole discussion about how you need to pump more Ethanol in because of it's lower energy density, you're actually talking about between

I'm confused now...

PC Paul skrev:

Don't be confused. Normally, you fill up either petrol or E85. Some gasstations doesn't have E85 yet. If you have 100% E85 in your tank, you need to add around 33% to the injector-duration. This demand decreases as you mix petrol with E85. If you keep 50/50 you'll need only a 15% additional duration. The finetuning is done by the ecu, so it achieves lambda 1. Actually, some 2.0 GM engines has a very wide lambda area, so extra electronics isn't necessary. It achieves lambda 1 still, with 100% E85.

But... isn't 104 octane *more* energetic than petrol? Or is octane just concerned with ignitability and flame front speed, so ethanol explodes quicker but doesn't have the 'oomph' that petrol would have?

And at a whopping saving of 2p/litre - who would care considering to get the same power you need 30% more?! False economy.

Yes, and no. We only tend to take on the sort of fuels that are worth trying. Morrisons (hardly a large % of the market share lol) plan to have 10 pumps of the stuff and sell it at 2p a litre cheaper than normal. Assuming your modded box uses 30% longer DCs at the same revs thats a significantly more expensive fuel. Pointless. If you were to make it pure ethanol I'd re-map one of my fueling/timing tables and run big boost with it but at that rating and cost its just not worth while.

I think you may be happy to run a daily driving shopping cart on an alternative fuel - im fine with that too. But on my performance engine i'd not bother. I dont think it takes many modifications to the engine, very few in fact, but the tuning of it *properly* in a highly stressed modern engine is critical. If youre putting it in a normal late 90s car then fine, shove an extra 30% through, run your injectors at a DC they arent meant to (which can damage them) and have shorter range on a tankful - be my guest!

Yeah, theres lots of things in brazil that are hacked together and done in a bodge fashion as in 90% of cases it works fine. I know my luck and id be in the 10% that get problems. Hence i wouldnt bother. The thing is youre asking a group in the UK where we have no experience and no interest in using an expensive fuel. Those of us who have the knowledge to tune for the fuel are likely to be running high performance motors and dont want to put an unknown quantity through it.

FPRs at higher pressure put undue stress and wear on injectors. And running lean at 4Krpm and high load is BAD for an engine. It can be very bad.

You dont want to run injectors past 90% if you can help it, they can "float" and deliver unknown quantities and running extended periods at

But in an emergency, when you desperately need to accelerate out of the way of an accident you'll floor it and run lean, the engine will cough and splutter, hesitate and leave you in danger. Just another reason not to bother IMO.

Its very easy to pass emissions tests - in all honesty, they arent that strict.

As ive said from the start, on a normal runabout car you are fine doing this, apart from over-stressing your injectors and causing a possible danger due to not being able to give the full rev range without serious stumbling. However if you consider that unimportant then sure, see how it goes and enjoy the cheap fuel :)

All anyone was trying to point out was that you havent thought of all the problems that are possible, as a vehicle manufacturer would, so you are risking problems. Older engines are far less difficult to break than newer ones so beware if you switch the box to a newer one.=20

It is rare for engines to have more than about 15% trim on a narrowband (1,2,3 or 4 wire oxygen sensor), and generally they have a long and a short term 'trim'. The long term trim is set when the ECU is reset and takes car of big variations, the short term trim is a much smaller % variation and is designed to make smaller modifications so the controller doesnt swing through large variations when correcting creating driveablilty issues. A wideband lambda car (5+ wire) should be able to deal with it but may still need an ECU reset between tanks as they arent generally meant to correct for such massive variations in AFR between tankfuls.

No. The "energetic" value you seek is the lower calorific value LCV. Yes. Ethanol has lower LCV than petrol which is why he needs more to run the same power.

Octane is measure of the anti knock properties, the resistance of the fuel to detonation and pre ignition. Ethanol has higher AKI than petrol. Only way to take advantage of it is to increase compression or boost.

Ethanol is slower burning and needs more ignition advance. An E85/Petrol bi-fuel vehicle will advance the timing and use the knock sensor to detect the best ignition timing for the fuel mix in use.

So the ECU has to both adjust the mixture for Lambda =1 and move the ignition timing.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

Doh. Yes, I remember now. Octane works like viscosity - the opposite to what you'd expect.

Less is more and all that.

Carry on... ;-)