Shell Optimax Test Results...

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Thu 8 Nov 2001 18:54
Shell Optimax Test Results... - Steve Shepherd
Hi,

Been suggested I post the following here after posting it on [www.clubgti.com/forum]

Deatails as follows:

Well I said a few weeks ago that I would give you the long term test results for using Shell Optimax in my car. The results are detailed below as follows:

[b]Vehicle: Mercedes E280T 204bhp V6 Advantgarde
[b]Registered: 01/12/00
[b]Starting Mileage: 34916
[b]Closing Mileage: 39414

[b]Total Mileage covered in Test: 4498
[b]Date test run: 01/10/01 - 31/10/01
[b]Fuel used: Shell Optimax 98 Ron
[b]Time engine running in test: 95 Hours 39 Minutes!

[b]Amount of petrol used during test: 739.39 Litres
[b]Cost of petrol used during test: £582.01
[b]Average cost per litre: 78.7 pence
[b]Average speed during test: 47 MPH
[b]Average MPG during test: 26.9 MPG
[b]Pence per mile cost: 12.94 pence

[b]Average MPG prior to test: 24.1 MPG
[b]Mileage above MPG based on: 12176
[b]Cost of petrol for above mileage: £2009.12
[b]Average cost per litre: 78.5 pence
[b]Pence per mile cost: 16.50 pence

The results are obviously conclusive, an increase in the MPG over 4500 miles of 2.8 MPG is obviously excellent, I can not compare the running costs because in the last few weeks petrol prices have dropped considerably, giving an unfair comparison. However, I think the pence per mile figure tells a very interesting story....

Since 1st November I have put in standard Tesco unleaded (69.9p per litre) and have not noticed a great drop in performance, probably because the Optimax has done it's job and lined the relevant bits etc, however I am now only averaging 25 MPG having covered just over 1000 miles!

I will leave everyone to make up there minds on this, but I for one will be using Optimax wherever possible. I did find it hard at times doing the mileage I cover finding a Shell station at the right time in my journey....

I hope that this information proves useful... I know that the vehicle it was tested on was not a VW, but I think it gives a fair result.

Thanks



Steve

[img]www.theentertainer.com/sshepherd/black/gti.jpg[/img]
Club GTi Member No: 12973
'02 Mk4 GTi 20v T (Not till March as been let down by importer) [:(]
(www.abcsom.co.uk]
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Thu 8 Nov 2001 19:16
Re: Shell Optimax Test Results... - Bob H
Steve,
An interesting and comprehensive set of results; any saving in the region of 10% in mpg is remarkable.

I note that you include your average speed during the test(47mph) but not in the statistics before and after the test. Could it be that you were driving in 'economy mode' during the test or were the speed & driving conditions comparable?

Bob H
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Thu 8 Nov 2001 21:33
Re: Shell Optimax Test Results... - Honest John
Many thanks to Steve. Please, lets have more like this. Not merely economy improvements, but also improvements in performance and tractability. Is Optimax worth the extra cost because it gives you more bhp and torque? Or is it giving you better economy? Or it is giving you both?

HJ
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Thu 8 Nov 2001 23:09
Re: Shell Optimax Test Results... - ladas are cool
could i use this stuff in my lada riva 1.3, or my citroen bx 16trs.
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Fri 9 Nov 2001 07:30
Re: Shell Optimax Test Results... - Andy P
I seem to remember that more power and better economy were mutually exclusive. More power requires more fuel..economy drops.


Andy
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Sun 11 Nov 2001 16:27
Re: Shell Optimax Test Results... - Ben Chapman
Considering the relatively small gains in performance that may be achieved using Optimax in place of 95RON fuel, the only real way to measure the difference would be to run a car filled with 95RON fuel on a chassis dyno (rolling road), and then run the same car at a later date on the Optimax fuel. I think the results would be quite interesting. I can see one problem, does anyone have a rolling road we could use!?

Ben
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Fri 9 Nov 2001 09:16
Re: Shell Optimax Test Results... - Cliff Pope
Not necessarily mutually exclusive. Improved efficiency could show itself in both more power AND better economy, surely?
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Fri 9 Nov 2001 09:20
Re: Shell Optimax Test Results... - John Slaughter
Cliff

It'll be a balance, surely?

Regards

JS
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Fri 9 Nov 2001 11:27
Re: Shell Optimax Test Results... - Andy P
Unless you significantly increase the energy stored in the fuel, there is no way you can get more power AND better economy. More power requires more energy. More energy means more fuel.


Andy
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Fri 9 Nov 2001 12:24
Re: Shell Optimax Test Results... - John Slaughter
Andy

You are right that the calorific value of petrol is identical for all octane ratings, so each gallon contains the same amount of energy. Octane rating is only a measure of the tendency of the fuel to preignite.

However, the higher octane rating theoretically allows the engine to run more efficiently, and provided there is the correct 'map' in the ECU and a knock sensor system to take advantage of the higher octane rating, it is feasible that more useable energy can be extracted from the same gallon, because the ECU operates the engine differently. The result will be more power, better economy or a combination of the two.

As has been said, if the car has a relatively simple ECU, optimised for 95 octane, then it cannot, I believe, take advantage of the higher octane fuel, and there is no benefit to be gained.

I've checked my BMW hanbook and it says 'rated performance and fuel economy' are achied with 95 octane, and ' for higher performance and lower fuel consumption' it is possible to use 98 octane. This indicates a different set of operating parameters for the higher octane fuel.

I really must try it sometime, but there are few Shell garages near me.

Regards

John
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Fri 9 Nov 2001 13:06
Re: Shell Optimax Test Results... - Andy P
Big question is, can you drive in exactly the same way when using this new Shell petrol as you did before? During the school holidays, my fuel consumption improved by 3mpg simply because there were less hold-ups.

Only when I see figures taken under reproducible conditions by a respected independant testing laboratort will I believe any claims that Shell make for this fuel.


Andy
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Fri 9 Nov 2001 13:35
Re: Shell Optimax Test Results... - John Slaughter
Andy

Yes, getting comparable test results is not easy except in a laboratory, but I believe that given the appropriate engine which can take advantage of this higher octane fuel, efficiency can be improved. What use the driver makes of that improvement is a completely different question, but doesn't affect the science.

Regards

JS
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Fri 9 Nov 2001 09:29
Re: Shell Optimax Test Results... - Dan J
Hmm - I am still quite sceptical of this Optimax fuel. My car's ignition system is switchable between 91(?!)RON and 95RON and obviously left on 95. Virtually all modern day UK cars are tuned to run on your common or garden 95RON unleaded (we got conned there didn't we? Lose 4 star to gain 3 star without the lead...).

My point is, if you have a car tuned or capable of utilising higher octane petrol (Morris Marina!!! but am sure there are plenty of other cars capable, Volvo 850R etc) then you will see the benefit of the extra "power" in the petrol. Ie driving the car as usual will result in marginally better economy and slightly higher engine output will be available if the car is driven hard. A car simply tuned for 95RON petrol, whether it has a knock detector or not, only has the ignition mapped for burning the watered down stuff (ie 95RON) and so how can Optimax possibly have any effect?

Example from experience: Volvo 240 with 2.1 'economy' engine desgined for 2 star petrol. Would run of virtually anything as it happens but it did not matter whether the car was given 2,3 4 star or unleaded, performance would be the same. Volvo 240 GLT 2.3 engine tuned for 97RON/4 star - very fast car with sweet engine which ran like a dream from 4 star or later LRP/Super Unlead but the car would run extremely roughly on 95RON Unlead and would pink etc.

Maybe I am missing the point here, but on your average run of the mill 95RON car, how can higher octane fuel possibly make any difference?

I look forward to being proved wrong...
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Fri 9 Nov 2001 19:01
Re: Shell Optimax Test Results... - Steve Shepherd
Thanks for all your comments,

The only thing I can really say is from the results above, it was an average month for me, several long dealys on our countries motorways, 3 weeks of normal school term one with half term (The preivious miles of 12k+ would have included the 6 weeks summer holidays).

The increase in performance was noticable, mainly in the increased power under kickdown, but also just the the way the engine pulled in general, just a nicer drive....

Since switching back to normal 95RON I have noticed the loss of this additional smoothness and power, plus the mpg has now dropped to 25.4 on the last 1600 miles.....

I will leave you to decide....
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