In the latest Jan. 2006 Evo magazine, there is an article on comparison tests on 8 different brands of petrol, including supermarket fuels. They used a Golf GTI and a BMW M5 and did rolling road tests to get power/torque figures, and on-road "driving feel" tests.
Makes quite interesting reading. I know they did a similar thing on Fifth Gear recently, but I missed it.
Has anyone seen a similar tests to these conducted on diesel fuels, I would like to see if they get similar findings?
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Makes quite interesting reading. I know they did a similar thing on Fifth Gear recently, but I missed it. Has anyone seen a similar tests to these conducted on diesel fuels, I would like to see if they get similar findings?
The fifth gear tests were probably the best I've seen yet, as they were very scientifically done, the write-up is on their web-site, but in summary over the several different vehicles they used it went as follows :-
Shell petrol - significant improvement
BP petrol - tiny improvement
Supermarket petrol - worst
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Further to my last post, its a pity they cant do something like this for diesel fuel, as I think this varys even more than petrol.
I recently filled up with Shell diesel after having run very low after a tankfull of Sainsburies diesel.
The difference was remarkable in terms of smoothness, quiet idle and noticeable lower consumption.
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To be fair Roly that's not strictly true. The one of the cars used (a subaru impreza) was designed to run on 97 octane fuel, so when the shell optimax (97RON) and the BP ultimate(97RON) showed better performance than the (95RON) supermarket fuel it was hardly surprising.
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To be fair Roly that's not strictly true. The one of the cars used (a subaru impreza) was designed to run on 97 octane fuel, so when the shell optimax (97RON) and the BP ultimate(97RON) showed better performance than the (95RON) supermarket fuel it was hardly surprising.
Agreed, I must have missed that bit ! I thought they were testing like with like, ie 95 RON so you are perfectly correct.
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Correct me if i'm worng, but isnt' optimax 98Ron and BP ultimate only 97?!
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I previously used City Diesel from Sainsburys (as Roly93), now use Shell Diesel Extra which is a vast improvement. The great thing is that it costs the same as normal diesel from other outlets and I don't have to pay the premium as with BP Ultimate.
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Evo (Edition 44 in June 2002) tested fuels a while ago, using a device to inspect the combustion chamber and valves. Seemed to be clear that using ordinary unleaded caused deposits to build up. They ran each engine (of 3 makes) on unleaded for 1500 miles, then inspected and photographed. Then on a diet of Optimax for 1500 miles, followed by inspection etc. Valves were cleaned up. BTW, the accompanying tests on performance showed most gain in the mid-range, over the 95 octane fuel.
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I've tried to find the Fifth Gear info. on the website but couldnt find it.
In the Evo article, their main recommendation above all others is to use a busy filling station, as they say petrol can go off if left sitting in the tanks for weeks. Even when filling up with the higher octane fuels they got a few bad batches.
The findings of the rolling road company were that different cars run better on some fuels than others, so stick to the one that your car feels better on.
On supermarket fuel, they found some were very good, others not so, as it could be very variable (eg. Asda get fuel from 7 different fuel companies), but at least they're busy so fuel should be fresh.
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I've tried to find the Fifth Gear info. on the website but couldnt find it.
Type in 'BP' into their search facility, and its the article called 'Fuel for thought'
The findings of the rolling road company were that different cars run better on some fuels than others, so stick to the one that your car feels better on.
Mine runs 'better' on Jet fuel (generally more smother idling etc) but economy wise, runs 'miles' (:-p) better on Shell with up to 3 or so MPG difference.
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Shame they didn't try petrol + acetone. That would have stirred it up! :-)
www.honestjohn.co.uk/forum/post/index.htm?t=33064
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