what octane for ,67 4.2 high comp. no.7e525141_9

[warren]

we have a choice here in Aussie of 91, 95 or 98 octane at the pump so, what is the best for the high comp eng. WAZZA

[abowie]

1E34749 uses BP 98 exclusively.

[Heuer]

Jaguar recommended 101 octane, known as 5* in period. Closest we can get to that in the UK is Shell V-Power at 99 RON and Tesco Momentum 99 RON. BP Ultimate is 97 RON. Australia has a similar choice of fuel although Germany has Shell V-Power at 100 octane for some reason. If you are going to use anything less expect a drop in power and efficiency together with the possibility of damaging pinking. If you want to run on lower octane fuel you should retard the ignition, something which modern vehicles do automatically via their knock sensor. High ambient temperatures and load will exacerbate the tendency for the engine to knock.

For the number of miles you do in your E-Type it makes no sense at all to use anything less than 99 octane except in circumstances where you can't find it. Half fill the tank with 95 octane, drive with a light throttle and fill up with the proper stuff as soon as you find any.

[Peter Harrison]

Hi All, I am definitely a fan of the V-Power product. However, if one is "caught short", are any of the octane booster products recommended? Peter H

[Heuer]

Hugely expensive if you want additives that will actually work. I occasionally have to put 95 in the tank but I generally only put in a few gallons to get me to me to somewhere that has the high octane stuff. It is then a case of not using too much throttle and don't let the engine bog down. If you have a 8:1 compression engine then it is not a problem. More of a worry is the amount of ethanol they are putting in 95 octane fuel which I believe can be up to 10%. That stuff can make a real mess of the E-Type's fuel system.

[Alty Ian]

Dave

FYI from a reliable source (not the suppliers who will tell you nowt) Esso premium 99 octane fuel which eminates from Ellesmere Port fuel depot and serves the north/midlands does NOT have 5% ethanol in it at present, whereas Shell V power does, indeed all shell fuels do.

For those who wish to avoid ethanol (E5) which is in ALL makes of 95 RON unleaded fuel and most premium fuels as well. (but not esso at the moment).

Not sure whether other depots add E5 into the tankers before it leaves (it isnt stored as it rots their systems and absorbs moisture so fast !

[SEJohnson95]

91 RON? Blimey, I wouldn't put that in my car! You're talking to the chemistry undergraduate here : P hehe

[Heuer]

Ian

The pump should have both the RON and E numbers on it by law. e.g 95 RON E10 which is now the mandatory grade across the EU. In France they warn you at the pump not to use 95RON E10 in pre 2000 cars. Shell Nitro+ is 99RON 5% Ethanol but it seems they are not required to put this on the pump.

[Alty Ian]

Yes I know they are supposed to but few if any do, even the garages cant tell you what's in their fuel and if you ask the oil companies they trot out the same line about what legislation states. Because Ethanol is so bad for their systems they have left it to each depot to dispense it. Total chose not to put it in as they were about to be bought out by Esso, which is why most if not all Total stations have disappeared now and the lack of E5 in esso premium is related to this. Eventually E5 will go in and EU legislation will soon make it all e10 in the UK as I'm sure you know. I know someone in the trade

[steve3.8]

In this months Octane suppliment magazine there is news that BMH are to sell VP Racing ethanol free fuels in 19 litre drums with pouring spouts , 100 octane leaded and unleaded . It can be delivered to your door or collected from St Helens , Merseyside . Santa Pod are customers 8) . Seems they are looking for agents , which is the key as it will be down to cost and availability for it to be worth it for us .

[david muir]

Have been in touch with BMH...the leaded petrol will be ~?3.80 per litre plus ?25 delivery for 19 litres!!..............doubt I'll be buying any!