Unleaded V Super Unleaded

[mark]

so were agreed full fat fuel is good and pinking is bad.

mark

[ghost123uk]

Aside = most (not all, Shell V power is an example) "super" grade petrol does not contain any Ethanol.

The lower grade fuel (and Shell V power) DOES contain Ethanol (usually 10%)

Ethanol is not a good thing for older vehicles.
It can damage the material fuel lines are made of (a very bad thing on a T25 layout)
It can (I have read) damage some of the materials in older design (our) fuel pumps and carbs etc)

It certainly DOES, if left standing for any length of time :-
A) Absorb water (not a good thing)
B) Forms a glue'y mess in the float chamber, fuel pump, injection pump etc (when left in there for months)
C) Slowly dissolves fibreglass (not good for "Café Racer bikes fitted with fibreglass tanks )
D) Goes "off" quite quickly, so if you get your vehicle out after a 6 month lay up (or restoration) it may not start or run correctly.

These issues are well known in the classic car and classic motorbike circles and if (as is often done) they are laid up for the winter, it is important to drain all Ethanol containing fuel out. Or, treat it with stuff you can buy. Or, do as I always do and pay that bit extra for 98ron that does NOT contain any Ethanol.

I recently posted up a technical report elsewhere about the above points, I will try to find it again

E D I T = found it HERE well worth a read ! (esp the last few lines re which fuels DO contain Ethanol - and odd that there are regional variations )

[DevonMark]

I think I am now even more confused!

So, Premium Unleaded may be worse for my van if my timing is set up for standard, and as I don't have the know how to change the timing, I guess I'm best off sticking with standard...

...BUT Premium Unleaded has the advantage of not containing any ethanol, UNLESS its Shell V Power, which does.

I still have no idea which one I should be using :S

[dash]

So, Premium Unleaded may be worse for my van if my timing is set up for standard, and as I don't have the know how to change the timing, I guess I'm best off sticking with standard...

If the van is timed for the lower (95RON) fuel, then running it on higher (98RON) will do absolutely nothing other than empty your wallet quicker.

If it's timed for 98RON and you run it on 95RON it might pink.


As for the ethanol thing, does anyone have any evidence that the seals/hoses/etc in the T25 aren't compatible with E10?

[ghost123uk]

As for the ethanol thing, does anyone have any evidence that the seals/hoses/etc in the T25 aren't compatible with E10?

Probably not, it is more a "vehicles of that era" thing from what I can gather. However suppliers of fuel hose etc nowadays often state "Ethanol fuel safe" in the spec.

The sludgy goo residue thing however is certainly backed up by actual experiences of many folk.

[AdrianC]

I think I am now even more confused!

So, Premium Unleaded may be worse for my van if my timing is set up for standard, and as I don't have the know how to change the timing, I guess I'm best off sticking with standard...

...BUT Premium Unleaded has the advantage of not containing any ethanol, UNLESS its Shell V Power, which does.

I still have no idea which one I should be using :S

"Standard" unleaded = 91RON. Used to be widespread in Germany, now very very rare indeed. Never available in the UK.
Premium Unleaded = 95RON. The common everyday stuff across virtually everywhere. The current standard says maximum 5% Ethanol.
Super Unleaded = ~98RON. Sometimes 99, sometimes 100. More expensive, much less available. Some suppliers use no ethanol, others use 5%.

E10 95RON (10% Ethanol) is widespread in France and Germany, and badged accordingly at the pump. It'll probably spread across the UK soon, but currently doesn't really exist here. I've had a couple of tanks of that through our van, with no problem. Good quality rubber pipe will cope just fine. Poor quality will suffer with the 5% in hours.

[ghost123uk]

As for the ethanol thing, does anyone have any evidence that the seals/hoses/etc in the T25 aren't compatible with E10?

Found this on a technical site HERE that supplies information to the installers of petrol pumps designed to dispense fuel containing Ethanol =



Of course our carbs and injection systems contain aluminium, zinc, brass and solder

Not sure if original fuel pipes ect on T25's are made of anything on the list (Rubber etc ?)


.

[dash]

I know it's an issue with 'old vehicles in general'. The reason I wondered about T25's and VW's specifically is that VW have had a massive presence in South America for a very long time, and South American countries have been using high% ethanol mixes in fuels for a very long time (sugar cane alcohol, etc). May be that they've figured out they need alcohol-resistant rubber compounds a very long time ago, where other manufacturers selling primarily into northern hemisphere markets might have been slower on the uptake.

Just a hypothesis, no idea if it's credible.

[ghost123uk]

You could easily be right there.

[AdrianC]

I know it's an issue with 'old vehicles in general'. The reason I wondered about T25's and VW's specifically is that VW have had a massive presence in South America for a very long time, and South American countries have been using high% ethanol mixes in fuels for a very long time (sugar cane alcohol, etc). May be that they've figured out they need alcohol-resistant rubber compounds a very long time ago, where other manufacturers selling primarily into northern hemisphere markets might have been slower on the uptake.

Just a hypothesis, no idea if it's credible.

The South American vehicles are built locally, though, to local specs - so not sure whether that'd filter back to European production.

Also, I'm not sure that thinking too hard about fuel pipes that are ~25 years old is particularly valuable - no matter whether they're "right" or not, they'll be shagged by now. Better to just replace them and be sure. Over on Samba, there's a constant chorus of "replace the fuel pipes!" whenever anybody new shows up with a new van. OK, they have different and more aggressive fuel chemistry over there, especially with the oxygenated fuels in California, but we're going to have to get used to that this side of the pond too, I think.

They don't seem to have any problems with any components of the fuel system other than the rubber pipes, though. On an injected van, replacing the fuel pipe elbow at the bulkhead is probably a good plan - BW do a stainless replacement for the aging, fragile plastic.

[dash]

I was going to add to my previous post that I'd be less worried about what the last few years worth of fuel have done to the hoses, and more worried about what the last 25 years of UV/Ozone/Heat cycling/Salt/etc have done to them.

[nostalgic]

I try to use 98 octan as the repair books tell you, but all i can find is 97 so have to go by that.
Mind you Ill not be geting it from super market stations any more.