Premium fuel.

[midlife]

My Subaru was mapped for the then named "Optimax" from Shell , and then I added some water/methanol injection for more fun.

Drago has it covered in his post above.

Shaun

 

[gavroche]

So , from I gather so far from you lot clever people , it is not worth the extra money.

 

[RichardB]

@Drago has it right. There is a myth that premium fuel is more powerful than regular. It isn't - it just resists engine knock better, and so the engine can run with more advance and higher compression. If the engine isn't designed that way, you will see no benefit in performance, and most aren't. My MX-5 is supposed to be run on premium according to the handbook, but I have used both and have not noticed any difference in power. I took it round France last year and used 98 octane all the way (it was cheaper over there than regular here). The car ran very well indeed and mpg went from 30 to nearly 40, but how much of that was the fuel and how much was driving all day at cruising speeds rather than twatting round the lanes here I can't say.

However, as I understand it, all regular unleaded now contains 5% ethanol (Murco were the last retailer to supply 100% petrol) whereas premium is still unadulterated. If you have a plastic petrol tank, or older rubber pipes in your fuel system, or older seals in your carbs, or you leave the car with fuel in for long periods, you may wish to invest in premium.

 

[vickster]

Yep super unleaded always for me as that's what it says my car should have on the petrol cap (Skoda VRS, so turbo and supercharger on 1.4 engine, 62 reg but only 13k miles done).

I do occasionally put the normal UL in (most recently for the novelty of paying under a quid for a litre) but only ever one tank then back to super, but from supermarket, only a few pennies more, no V Power or the even more expensive BP stuff

 

[T.M.H.N.E.T]

bio-diesel

 

[Fab Foodie]

Does anyone pay the extra few pence for premium fuel and is it worth it? Does the engine run smoother and do you get extra mpg? I have a diesel engine and wonder if I should buy primium diesel?

I run premium fuel about every 4th or 5th tank as opposed to el-cheapo supermarket fuel as it's supposed to help keep the injectors cleaner and in better health (as recommended by Honest John).
In the C8 diesel I found a small MPG improvement and felt it ran a bit smoother. But never felt the cost increase worth the benefit. However fuel being much much cheaper now it might make more sense.
I've just put the first tankful of premium diesel in the Dacia so it's too early to tell.
No harm in trying.

 

[RichardB]

I think it's different with diesel. Premium diesel contains extra detergents and stuff to keep the injectors clean, whereas with premium unleaded it's just a higher octane (and possibly no ethanol). In my Mondeo diesel I occasionally fill with premium diesel before a long motorway run. Four hours at the legal limit leaves the engine noticeably smoother and with a touch more urge.

 

[slowmotion]

I run premium fuel about every 4th or 5th tank as opposed to el-cheapo supermarket fuel as it's supposed to help keep the injectors cleaner and in better health (as recommended by Honest John).
In the C8 diesel I found a small MPG improvement and felt it ran a bit smoother. But never felt the cost increase worth the benefit. However fuel being much much cheaper now it might make more sense.
I've just put the first tankful of premium diesel in the Dacia so it's too early to tell.
No harm in trying.

Yes there is. It costs more!
BTW, I never put in poncy diesel. WVM wouldn't be seen dead with of those pump nozzles in his gnarled hand.

 

[Smurfy]

My mate's Honda CBR 600 wouldn't run properly on anything other than BP. When he bought it the previous owner told him not to chance it with supermarket fuel, and he found out the hard way that this was true when he had to drain the tank and refill with BP. However, very few car engines would be as highly tuned as a Honda CBR 600.

 

[TheDoctor]

So, how do CBR600 owners cope where BP fuel isn't available?
Sounds unlikely, to say the least.

 

[Piemaster]

However, as I understand it, all regular unleaded now contains 5% ethanol (Murco were the last retailer to supply 100% petrol) whereas premium is still unadulterated. If you have a plastic petrol tank, or older rubber pipes in your fuel system, or older seals in your carbs, or you leave the car with fuel in for long periods, you may wish to invest in premium.

Quite handy info that, thanks. I'm taking delivery of an old Alfa Spider in a few weeks ('87). It has twin Webers, yes, actual real carbs and as it won't be doing many miles Premium fuel may well be a better choice.
It may well be the only choice when E10 fuel starts being widely sold, even for newer cars LINK

 

[Smurfy]

So, how do CBR600 owners cope where BP fuel isn't available?
Sounds unlikely, to say the least.

A Honda CBR 600 won't go very far on a tank anyway (well, not compared to a car), so riders will be planning their journey/ride much more than a car driver would.

I think it would still run on poor quality fuel, but not very well. Bear in mind that these are very high performance machines. If I recall correctly, that particular bike red lines at 14000 rpm.

I think @meta lon has had a few bikes, maybe he can comment.

 

[RichardB]

Quite handy info that, thanks. I'm taking delivery of an old Alfa Spider in a few weeks ('87). It has twin Webers, yes, actual real carbs and as it won't be doing many miles Premium fuel may well be a better choice.
It may well be the only choice when E10 fuel starts being widely sold, even for newer cars LINK

I'd take advice from an Alfa specialist on that. It could be fine, but you risk a fair bit of damage if not. It all depends on the materials used. Not just old vehicles, either - Ducati, Triumph and Aprilia in the US (link), boats (link), modern engine parts (link) and so on. It's not as simple as the old leaded/unleaded issue.

My Triumph Sprint had a plastic tank which looked fine, but had spread to about 5mm longer than it was when new, which meant that getting the tank off and on again was a trial of strength, and made routine servicing a Cecil B De Mille number.

 

[Drago]

So, how do CBR600 owners cope where BP fuel isn't available?
Sounds unlikely, to say the least.

the bike retards the ignition to avoid knock, and lose a 3 or 4 brake into the bargain.

 

[tyred]

Is Premium Fuel better for my vehicle and worth the extra expense?

Or

For my Peugeot