I know a couple of threads have been talking about their petrol consumption so thought I'd mention mine
On a run down south at the weekend managed to average 38.74mpg on the 400 mile round trip which I think is pretty good. That is in a '98 1.9 with 165 on the clock. I might not have been the fastest but managed to comfortably sit at 70ish for most of the way there and back.
Running around town I tend to get about 28-32 and I'm happy with that too. Quite a change from the 18 I was used to from the BMW 740!
I got 36mpg today sitting at 80 on the M4 to and from cardiff with a slower diversion around reading in the traffic stop/start - 280 miles total with the roof down all the way
mines a 1.9 with 77k on the clock
think i could have got it to 40 if i'd sat with the roof up at 60 but hey - this car was meant for roof down !
Very nice figures, I got a max of 31.7 on a run to Brooklands the other week in my 2.8 down the A1/M25 on a Sunday doing 70-75 all the way as there was no rush.
And averaged about 23mpg last Sunday on the 18th April Run out Baldock to Northants. Is that good or bad?
Either way, It is a lovely day today so I went topless to work in Milton Keynes, a 60 mile round trip which costs £3.43 more than my usual trip in my Saab 9-3 TiD.
That's value for money fun, it costs 30 quid for one day in an amusement park, that's 10 extra days of running around in my Zed.
groove65 wrote:if our Z3 wasnt a third car, and hence starting no claims bonus from zero, i would have got the 2.8
I was in the same situation with the Z3 but fortunately the other cars were insured on separate policies both in my name with Direct Line. Having done the comparison sites I phoned DL and the nice lady pointed out that my wife was named as the main driver on the Z4 policy. They couldn't officially give her any NCD but they did apply a 60% "bonus". So I insure her Zed and she insures mine and she's building up her own NCD.
Always use 97/98 octane if you can get it - that is what the engine is optimised for. Anything less and you will lose power and fuel efficiency. As an example, BMW's figures for an M3 Evo show a reduction from the fabled 321 bhp (on German 98 octane) to 280 bhp on German 95 octane.
Unfortunately in most of the south of the UK, and particularly the south-west, 98 octane is unobtainable.
Here in France we can buy 98 octane everywhere - for about 2% more than 95, and fuel consumption is certainly better.
On a visit to the UK I did a lot of motorway driving, and 'tested' lots of different fuels, in terms of indicated consumption at steady speeds, and over a tankful. The worst was Tesco (Ashford) 95, which gave about 25 mpg. The best was Esso 97, which gave 37 mpg. BP Ultimate and Shell V-Power were no better than anything else.
High octane fuel is only a necessity in M/// power cars because they have a high compression ratio. They are therefore inclined to pink on lower octane fuels. This leads to the pink sensors backing off the timing from optimum resulting in less power & more heat. In other words less efficiency so lower mpg.
Fuel octane starts to degrade if unused. I get my 97RON from the place right next to a race track, where the trackday cars fill up daily and help keep the tanks stocked with fresh fuel.
Use the Search button before posting newbie questions about hard tops and fitting kits, footwell speaker amps, water in the boot, hood maintainance and those horrific angel eyes. We get like 10 threads a week on the same subject, it's obvious that you haven't searched.
Sorry Robin, but the M Roadster is NOT the only car where high octane fuel provides the optimum performance - the 2.8 has a compression ratio of 10.2, which although not as high as the MR's 11.3, is still sufficiently high for the use of 98 octane fuel to be beneficial.
Like the M engine, the 2.8 will run on anything down to about 91 octane, but only at the price of the ignition timing being retarded to avoid pinking, and so losing both performance and fuel economy.
To quote from the Owner's Handbook:
'Z3 Roadster 1,8/2.8/Z3 Coupe 2.8, M Coupe, M Roadster
This BMW engine is designed to run on:
Super Plus unleaded (octane number 98 RON)
Try to use this fuel whenever possible, so that the car achieves its specified performance and fuel consumption.'
In the case of the 1.9 (Compression ratio 10:1) the minimum fuel rating is also 91 octane, and:
'The rated performance and fuel consumption values are achieved with:
Super Unleaded (95 Octane RON)'
And also:
'For higher performance and lower fuel consumption, it is also possible to use Super Plus unleaded (octane number 98 RON)'
98 octane fuel is therefore no more of a necessity for the M Roadster than it is for the other Z3 models, unless you wish the engine to operate at peak efficiency.
I used BP Ultimate last week which is 97 octane and i've used shell v-power which is 99 octane this week and although i haven't done a full mpg check yet, the v-power seems to be pants, i'm ramping through the fuel and i'm not flooring the Zed all the time either, i'm postive the BP was giving me much better mpg and the car feels ''sluggish'' on the v-power, the power doesn't seem as instant. My car is an 02 2.2 sport.
Here in France at least, I am sure that V-Power contains a lot of enthanol, which is a cheap way of maintaining the octane rating, but like any type of alcohol is a poor fuel.
On an autoroute trip, after using a tank of local supermarket 98 octane at a steady 80 mph/34 mpg level roads, I filled up with V-Power, only to find consumption increased to about 29/30 mpg at the same speed on similarly level roads.
Unfortunately, ethanol-diluted fuels are the future - another reason to buy a larger engined Z3, as it will have more performance left than a smaller one running on the same fuel.
and she's building up her own NCD.
