Fuel consumption

Ok, here's a strange one .. strange but good !

Since I've had my new GF I've filled up 3 tank-fulls of petrol, and each time I've worked out the mpg for the previous tank.

First was 27 mpg, then 31mpg, now I've just achieved 32mpg.

This was pretty surprising since between the 31 and 32 fill-ups I changed the jets to 120/135 and expected the mpg figure to decrease.

My only guess is that the PO used regular unleaded and now the Shell Optimax (V-Power as it seems to be called) really is cleaning the engine out. My driving style hasn't changed that dramatically between fill-ups (it was probably worse after I changed the jets !).

Any thoughts, comments or similar experiences ?

Optimax and V-Power are different fuels, Optimax was 97 octane,whereas V-Power is 99...smells nice too!! Check the Shell website,as it explains the differences.Optimax is no longer avaliable. I've had 2 tanks of V-Power and one tank of ordinary unleaded through my car in the past 2 weeks,and am averaging 33mpg.(Which includes the M6 twice at erm...slightly illiegal speeds)Seems better on the Shell stuff,and a bit more perky too!

Should we all be heading for our nearest Shell garage then?

Cheers,

Nige

It was Tom Tom that got us threre.

Tiff - whats this about slightly illegal speeds? I was with you all the home and I would swear that we never got above 70. Or should that be below 70! For the record, I can confirm that Tiff's right foot can be heavy at times (unlike mine). With regards to fuel consumption I have absolutely no idea what my mpg is - although thats a few people I know raving about this V power petrol. Is the extra cost offset by the better consumption? Or is the extra oomph a worthy justification for the extra cost?

Hi Chris
checked petrol consumption for the Wales weekend (filled the tank before we left home, put 29.73 litres in Wales + filled up last saturday 22.70 litres). Total of 423miles (22.70 + 29.73 litres = 52.43 litres divided by 4.546 to convert to gallons = 11.53gallons.) Divide 423 by 11.53 = 36.69 mpg. all fuel was Shell Optimax or V-Power.
Car is an '89 GF carb jetted 115 & 135 with K. & N. filter in the air-box + Luminition + iridium plugs + Janspeed downpipes to freeflow silencer.
All things considered quite happy with this for fuel consumption, will have to learn to drive steadier to improove this I think!!!!! NOT.

Rob.

Unlike yours Dave???? I was trying to keep up with ya!!!!

Last months EVO magazine features a write up on Shell's V Power fuel, which explains loads about its improvements over the optimax which it replaces.
Apart from the benefits of 'cleaning' out your engine, it also boasts to let your engine run cooler and consume less fuel.

The most significant part though was that tests completed on a particular Porsche showed (with its ignition mapping suitably adjusted) over 30 bhp more power (almost 10% more), for that car. Oooooo.!

The main question is though, is the increase in cost per litre (gallon in proper money) outweighed by the increase in perfromance and economy?

Oh, incidently, I manage about 140 miles on 20 quids worth of unleaded at my very best in my GF, but I put that down to using the car to commute in, average speed 20 mph, stop start through town, with the occasional country blast. Anyones's economy worse than that ?

I manage about 140 miles on 20 quids worth of unleaded at my very best

That's still about 28 - 29mpg .. you shouldn't be TOO ashamed, especially if it's stop / start a lot of the time.

Like many, I assumed paying an extra 6p or more per litre for V-Power will only give me a performance boost and never be viable as a fuel economy option. However, I was not aware of the claimed economy benefits of running on V-Power but a higher octane should use less fuel quantity for the same performance so it's not a total surprise (testing on a porsche is not ideal demonstrator for fuel economy).

Therefore, assuming the cost of V-Power is about 6p per litre more than unleaded then you would only need to get 2 miles more per gallon out of your engine to actually make it cheaper to run. Much to my surprise it may actually be more cost effective to stuff V-Power in your tank, and you get 100 Octane as a bonus (don't think even the Turbo boys will squeeze 30bhp extra though!).

I've been running 2 tank fills of regular unleaded then 1 tank fill of high octane (either Tesco 100 Octane or V-Power so far) and have always got more than 35mpg (38mpg+ at the last check with half a tank of V-Power) so I am well happy with the running cost and have not been dissapointed with the performance either (running a standard carb with lumenition ignition and Iridium plugs, both of which improve the mpg as well).

Not tried V power in the X yet, but have tried it in my Integrale and have noticed a bit of extra oooomph!!!

I'll be filling up the bike this week and thought I'd try V-Power in it. Not that it's slow or anything, but you can never have too much power, can you now !!?!

28 - 29 mpg, doesn't sound so bad really. I'm going to give this new fangled V power a go, just for the smell. I think the other reason my economy is lower than others could be down to having K&N's fitted and running a standard ignition system (points / condensor, new but standard plugs etc). Ignition timing is set up properly, runs very well pulling strongly in every gear from low revs without protest and never misses a beat.
The only bit that nags me is the auto choke, the neighbours just love me blatting the throttle on cold mornings to 'kick' it off. I then drive a few miles and when i stop, like at a junction, the revs rise to full choke revs, this is probably where all my fuel is going ! unburnt. Once warmed up its ok and runs at 70 degrees all day then, even in traffic. (kiss of death)

shouldn't grumble, i'd rather be in the exxy doing 25 mpg than in a shoe box with wheels, like everyone else in the Cleethorpes area.

I removed the autochoke earlier this summer and replaced it with a manual system and my mpg has increased from about 26 mpg to about 29-30. I drive 20 miles to work but the autochoke was on for most of that distance on cold mornings.
Changing to manual was definately worth it!
Have tried v power in the Saab but didn't notice any change!

PS I'm a teacher in Porthmadog and 30 exxies driving through the town two weeks ago has been a major talking point since school started! They thought that I had the only one!

Shame they were not a bit older they might of remembered Butlitz when we had nearer 100 X1/9 passing through Porthmadog going to and from
our days out ....again due to the Roberts house hold

Contact then with the Welsh police to let them know we would be in the area was surpise that there were still X1/9s about.