Fuel

[matthewe30]

What is the best fuel in uk?
I looking for e85 or high octane petrol(100)

[craigieeb]

Cant go wrong with Shell V power Nitro plus

[Brianmoooore]

Best fuel by far is propane. It has an inherently high 'octane', mixes readily with air to form a combustible mix, doesn't wash oil off of the bore walls, doesn't contaminate your oil with all sorts of corrosive nasties, and doesn't need an extra 50% of fuel while the engine warms up.
Petrol, on the other hand, has to have its octane rating artificially boosted, only mixes with air as a mist and will drop out and return to being a liquid if given half a chance, the liquid readily washes the oil of your cylinder bores, causing ring and bore wear, and the acids it puts into your oil attack all your bearings.
Nasty stuff, that would have never caught on in the first place, if there had been an effective method of transferring liquid propane from bulk storage into a vehicle's tank.

[aimlessrock]

assume your taking about LPG Brian?”¦if so are the benefits of such a conversion really that good?

[ross_jsy]

Not really. Think how many millions of cars world wide run just fine on petrol and you realise it's just sensationalistic bollocks.

It's a better fuel yes, but so what? Petrol is easy to fill up with as it's available in literally every petrol station, and you don't have to have a large ugly tank taking up space. And you hardly see cars stranded at the side of the road daily from bore wash do you?...

And yes it's cheaper, but your MPG goes down when compared to petrol so the savings aren't as large as you originally think. Unless you are doing some decent mileage don't get led down the it will save you money route as a decent LPG install isn't cheap.

[Brianmoooore]

Liquid propane = LPG, in the UK. (Rest of the world tends to have a mixture of propane and butane).
Those are the facts, and I could add a safety advantage as well. Bomb proof steel tank with automatic shut off valves, containing a liquid that would blow away as a gas in the breeze in the very unlikely case of a tank leak, versus a plastic container filled with highly flammable liquid that would likely pool all around you if ruptured.
The disadvantages are that you have to use 20% more of the stuff to make up for its lesser density than petrol, and that it has no upper cylinder lubricating properties at all - even less than unleaded petrol.

[Brianmoooore]

Not really. Think how many millions of cars world wide run just fine on petrol and you realise it's just sensationalistic bollocks.

It's a better fuel yes, but so what? Petrol is easy to fill up with as it's available in literally every petrol station, and you don't have to have a large ugly tank taking up space. And you hardly see cars stranded at the side of the road daily from bore wash do you?...

And yes it's cheaper, but your MPG goes down when compared to petrol so the savings aren't as large as you originally think. Unless you are doing some decent mileage don't get led down the it will save you money route as a decent LPG install isn't cheap.

I never mentioned running costs!
The only reason "Petrol is easy to fill up with as it's available in literally every petrol station" is because it got a head start, for the reasons I gave in my OP.
"You don't have to have a large ugly tank taking up space." So what do you carry your petrol in then? Your petrol tank takes up plenty of space, but it was designed into the car from the start, just as a LPG tank could be if starting from scratch.
No, you don't "see cars stranded at the side of the road daily from bore wash ", but you do often see the results at MOT test time.

[ross_jsy]

Yes, if cars were originally designed to run on LPG with tanks in place of the regular petrol tanks and if LPG had the infrastructure that petrol has, however we live in the real word, not hypothetical land.

I only mentioned running costs as that tends to be the main reason for going LPG so I assume it would help aimless a bit with his question.

Not knocking LPG, but I just feel it's a lot of compromise unless you are doing large mileage

[Brianmoooore]

Original question was "What is the best fuel in uk?", and that's the question I answered in my first post.
When I posted that, I hadn't even noticed what forum I was in (arrived from the home page "latest posts" list), and originally assumed it was a typical E30 chat question. With its enhanced RON, LPG is even more suitable for this forum, although in the UK only, there is no exact formulation for Autogas, and the RON of every tankfull can't be guaranteed.

[ross_jsy]

Interesting, what is the RON rating of LPG on average?

[Brianmoooore]

Around 110 or so seems to be the accepted figure, but I've no evidence to support it.

[Mikey_Boy]

All valid points above and Brian is right to promote LPG as it's very good on some levels.

However, Octane is only part of the story in making up a good fuel. Heating value plays a big part as do other things like being able to store the fuel easily (liquids are pretty easy, gas is more challenging and costly), the mix of molecules to promote combustion (fast or slow burn).

The safest fuel to store is DIESEL as it's not flammable, but classified as combustible. Kerosene used in planes is a pig to store as it's flash point is very low along with gasoline - the light molecules in gasoline (butane and propane) boil off at very low temperatures making its fire hazard a real problem - amazing it's the fuel of choice really.

For a turbo engine, octane and more octane is best alongside a high heating value. Octane provides the resistance to knock which allows more boost, more spark advance or both (remember that boost kills engines less than spark so better to have more boost and less spark advance - there is a nice compromise to be had) and the heating value that provides the energy.

So, in this instance, I would suggest that DIESEL is the best fuel for a turbo engine, and given how successful diesel turbos have been in the last 15 years as they provide all of the above - knock resistance (not because of octane, but because you have to squezze it so hard to make it go bang), high heating value and safe to store...

But of course the question is for E30s - I would suggest any major branded high octane fuel will do you proud (Shell, BP, Total) - I would avoid supermarket fuels as they tend to have less additives than other fuels (how they can charge a lower price).

I would avoid Ethanol where you can - whilst it's high octane (around 130), its heating value is very low and in high concentrations you need a lot of stainless steel and special seals to ensure it doesn't eat its way out the of the car....

[scallyally]

Seem to remember some time ago a news item re increased use of Methanol in petrol as a cheap substitute and problems arising in older cars.

Perhaps Mikey_Boy can enlighten us?

[Morat]

Both vehicles in my household run on LPG. I'm not going back to (pure) Petrol running. There are plenty of people who knock LPG but they are, without exception, sitting somewhere on the spectrum running from "ill informed" to "too stupid to understand the science". You can make a case for LPG on pretty much any petrol powered car. BMWs are especially well suited since they have high quality cylinder heads which cope easily with the slightly higher cylinder temperatures that LPG produces.

Diesel is an interesting choice of fuel. It's ideally suited to high torque, low revving, reliable, simple engines that will chug along all day every day with the minimum of maintenance. They run relatively cool, they don't need complex electronics, they don't need particularly high quality fuel.
The downside is that they're smokey, noisy and have a very narrow power band. But that doesn't matter when you're running an industrial engine. The further you push the design parameters away from tractors, trucks, generators and the like towards high performance cars with very taxing emissions targets, the more complicated and therefore more costly and less reliable diesel engines become. They need turbos, exhaust recirculation, ECUs, fancy crankshafts that can manage high revs at 14.1 compression etc etc.

The simplest way to get a powerful, clean car engine is to take a petrol engine and run it on LPG. LPG produces the same power as petrol, for lower fuel cost and lower emissions. The conversion cost is typically less than the premium you would pay for a diesel engine on the second hand market.

Would you rather drive THIS

or This

I'm sure there are deals to be had, but who wouldn't take the 545?

[Mikey_Boy]

It's a really interesting debate. I have questioned many engine designers and engineers about what is the best fuel for an internal combustion engine. Universally they say that engines are designed around what's available - therefore diesel and gasoline and they try to minimise the compromises of both fuels within the design and cost parameters they have.

If pressed however and with a blank sheet of paper, most engineers would like either propane or hydrogen as an ideal fuel - hydrogen because it doesn't have any carbon in it. Remember the 7 series cars modified to run on hydrogen??

Bottom line is all fuels are a compromise - early cars were all designed to run on bio fuels (yes really) like ethanol from corn and diesel from rape seed - fossil fuels came about as a cheaper non food based alternative and the rest is history.

Both methanol and ethanol have their issues in gasoline but both have been blended into fuels for decades. Ethanol up to 5% has been around in UK fuels for ages and 3% methanol can be used as an alternative - methanol is a bit cheaper than ethanol but it causes problems as it attracts water so most fuel blenders avoid it. Indycar use it in the US and having worked with it during my Cosworth days I am not a fan - it burns with a colourless flame so it's tricky to see when you have a fire until it's far too late!!