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P4N Lotus

Fuel Choice For Evora, Elise, Exiges?

19 posts in this topic

What fuel is recommended or are people using in their cars ? I was told this week the shell super unleaded delivers 25% more mpg than supermarket fuel for 5% more cost ? Any thoughts and what are people using?

 

fuel / car / typical mpg / any comments on better or worse performance ?

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No way you get 25 % more mpg. The various independent tests that have been done, show that cars with knock sensors etc that can automatically take advantage of higher octane fuel get single digit % improvement in power and similar or less improvement in mpg.

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A couple more mpg maybe but no way 25%. This question was bought up at donington last Friday and I just use supermarket standard fuel in my 111S as its only a k series engine.

This got some negative reactions so I plan to try some super and will see if it runs any better.

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I believe the K series will only benefit if the car has been tuned for higher octane (e.g. Vhpd), standard cars are setup for standard fuel and don't have a knock sensor so doesn't adjust automatically for different octane levels.

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Tests few years ago showed o benefit in performance on a k series , small benefit from added cleaning agents.

Yota moat ran best and for longest on tesco super for some reason , although new fuels might now be better.

For me it's a bit like oil, tyres and brakes-why wouldn't you put the best available in your car, although mine only does 4/5 k per year, might not if it was 15k daily driver . I reckon from my occasional study of cost mileage is they pan out almost the same, the extra miles cost the extra money

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I've tried all the higher grades in my Evora and haven't noticed any difference in performance or economy! I usually get between 22 and 24 mpg (old school) so I just use the  Tesco's, Morrisson's ordinary stuff etc. Thrashing around the roads in north Wales has never been good for fuel economy but the roads are great so I don't bother. cool.png
 

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Only shells finest or Tescos 99 for everyday.

 

As someone said to me, you wouldn't feed your racehorse McDonald's....

 

I know it improves performance on a rice rocket as that's what it's been mapped on. But I still can't understand why you would put a lower grade of petrol in your pride and joy... I've probably been brainwashed by the masses though.... :-)

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Have only pot best she'll now with addednitro whatever that really means in Elise and now in Evora, dose that mean I am wasting money oh well can live with that ,daily commute 6 miles and it is my race horse . Predictive text not coping with the beer ,I fear. 

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On the k I sometimes use vpower for the cleaning benefits and cleaner burn.

 

On the st I use vpower as it is mapped for it (but always did before that map)

 

I use vpower diesel on the Volvo, again for the better burn these low emissions systems on oil burners seem quite fragile so think prevention is better than cure

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My own experience of running the higher octane fuels has been a "measurable" degradation in fuel economy when running LOWER grade (i.e., UL95). When factoring the diffence in cost vs routinely acheivable fuel economy, the higher grade fuels work out positively over time. That said, any improvement in economy doesn't run to 25%! At worst, overall cost of running higher octane fuels has been cost neutral; at the other end of the scale, I have seen measurable benefit in running costs.

 

Despite popular and incorrect urban myth, octane values have no DIRECT effect on performance. Octane values are a measurement of a fuels resistance to detonation - a higher octane will slow the propagation of the flame-front. In reality, these properties combined allow you to "tune" to engines timing and compression such that the engine better optimises the fuel-burn in order to extract more energy from the burning fuel-air mixture (more performance).

 

Modern ECUs where so designed can adjust to higher octane fuel. These benefits are of great importance when the engine is heavily loaded. Pre-ignition (i.e., detonation a.k.a "knock") can be reduced or eliminated by altering fuelling ratio's and timing - or through using higher octane fuels. However, there are limits imposed by both the engine design and ECU control parameters.

 

Fuel additives (such as detergents) also have an important contribution to the performance of an engine. Keeping combustion chambers clean will improve burn - and importantly help to prevent hot spots that can also lead to pre-ignition issues - and in extreme cases lead to engine failure.

 

In summary, within reason, and if your car is able to utilise higher octane fuel, it shoul cost you no more to run than cheaper lower octane. There are obvious extremes, such as race fuel that costs an arm and a leg (low volume production, higher cost, limited shelf life). As for this OP's question, the best advice is to follow the manufacturers recommendation...

 

For the Evora and Exige V6 engines, this is Super Unleaded (minimum 97RON) - although Regular Unleaded (min 95RON) is acceptable for short periods when avoiding high engine loads.

 

If you are likely to drive your can enthusiastically, higher octane fuel is an investment in longevity and reliability.

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Have only pot best she'll now with addednitro whatever that really means in Elise and now in Evora, dose that mean I am wasting money oh well can live with that ,daily commute 6 miles and it is my race horse . Predictive text not coping with the beer ,I fear.

 

Now here's a fella who'd fit right in at a Sutton Chapter meet :-)

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I had to put a tank of the cheap stuff in the VHPD in France once. It ran like a bag of spanners ( even more than normal ) Never again.


Have only pot best she'll now with addednitro whatever that really means in Elise and now in Evora, dose that mean I am wasting money oh well can live with that ,daily commute 6 miles and it is my race horse . Predictive text not coping with the beer ,I fear. 

 

Sign him up Jon     :)

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My own experience of running the higher octane fuels has been a "measurable" degradation in fuel economy when running LOWER grade (i.e., UL95). When factoring the diffence in cost vs routinely acheivable fuel economy, the higher grade fuels work out positively over time. That said, any improvement in economy doesn't run to 25%! At worst, overall cost of running higher octane fuels has been cost neutral; at the other end of the scale, I have seen measurable benefit in running costs.

 

Despite popular and incorrect urban myth, octane values have no DIRECT effect on performance. Octane values are a measurement of a fuels resistance to detonation - a higher octane will slow the propagation of the flame-front. In reality, these properties combined allow you to "tune" to engines timing and compression such that the engine better optimises the fuel-burn in order to extract more energy from the burning fuel-air mixture (more performance).

 

Modern ECUs where so designed can adjust to higher octane fuel. These benefits are of great importance when the engine is heavily loaded. Pre-ignition (i.e., detonation a.k.a "knock") can be reduced or eliminated by altering fuelling ratio's and timing - or through using higher octane fuels. However, there are limits imposed by both the engine design and ECU control parameters.

 

Fuel additives (such as detergents) also have an important contribution to the performance of an engine. Keeping combustion chambers clean will improve burn - and importantly help to prevent hot spots that can also lead to pre-ignition issues - and in extreme cases lead to engine failure.

 

In summary, within reason, and if your car is able to utilise higher octane fuel, it shoul cost you no more to run than cheaper lower octane. There are obvious extremes, such as race fuel that costs an arm and a leg (low volume production, higher cost, limited shelf life). As for this OP's question, the best advice is to follow the manufacturers recommendation...

 

For the Evora and Exige V6 engines, this is Super Unleaded (minimum 97RON) - although Regular Unleaded (min 95RON) is acceptable for short periods when avoiding high engine loads.

 

If you are likely to drive your can enthusiastically, higher octane fuel is an investment in longevity and reliability.

 

The owners handbook that came with our V6 Exige (page 66) states UNLEADED fuel with a minimum octane rating 95 RON, which I checked with our Elise (2011) SC handbook (page 90) this also states minimum grade of UNLEADED fuel 95 RON; your comment regarding min 95 RON I think the Lotus handbook is referring to min 91 RON

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The owners handbook that came with our V6 Exige (page 66) states UNLEADED fuel with a minimum octane rating 95 RON, which I checked with our Elise (2011) SC handbook (page 90) this also states minimum grade of UNLEADED fuel 95 RON; your comment regarding min 95 RON I think the Lotus handbook is referring to min 91 RON

I believe you'll find that European legislation requires that all new cars be "capable" of running on UL95. Whether it is "recommended" or "advisable" to run low (or lower) octane fuel is another matter entirely. You'll note that your manual does caution against running lower octane fuels at high engine loads.

 

In general, subject to avoidance of specific blends or additives that can chemically attack elements of the fuel system, running higher octane is benign - or beneficial where the ECU mapping accommodates. Running lower octane, such as UL91, risks severe engine damage.

 

As an observation, the Evora placarding states UL97 Super as minimum fuel requirement.

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