In the latest issue of Bike magazine, there's a dyno test of ordinary 95 octane pump fuel versus Shell V-Power and BP Ultimate 102 (just £2.46 per litre!)
They used two modern, high-performance bikes, a Suzuki GSXR1000 and the new BMW S1000RR.
The results? Neither high-octane brew gave any more power or torque than ordinary 95 octane ... not even half a percent more.
They also printed the dyno curves and they are as near identical as makes no difference for each bike ... certainly well within experimental variances.
Especially interesting as the BM has a knock sensor and can adjust its ignition timing on the fly according to fuel quality.
So on these engines (which are mapped for 95 octane fuel at the factory), there's no power gain from premium fuel.
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I could be wrong, but don't these fuels contain additives to clean the engine etc ?
They may not always make an engine produce more power but clean the engine.
Also, wouldn't Japanese cars benefit from higher octane fuel (Japan does not use 95Ron unleaded, it is all super unleaded fuel out there) ?
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I'm surprised it made no difference in the BMW but most (if not all) Jap bikes have fixed ignition maps so high octane fuel will obviously make no difference whatsoever, perhaps BMW have gone the same way as the Japs with their bikes? I'm surprised the magazine even had to test this because anyone with half a brain would have known this fact beforehand. Many cars though do have ignition maps that are advanced or retarded based on the information from knock sensors. BMWs in particular are optimised for high octane fuel, they'll run fine on 95 RON but you will pay a price with poorer mpg and performance.
PSA petrols benefit from high octane too but to a lesser extent.
Most European GM and Ford NA engines are optimized for 95RON.
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It's only >100RON when it's made, it then sits around for months with the VOCs flashing off into the vent pipes while nobody buys it and probably becomes 95RON.
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I've tried to explain it before;EU has unleaded fuel-Japan has lead-free fuel.They are NOT the same.Unleaded fuel has a small amount of naturally occuring lead in it-lead- free fuel has had ALL lead chemically removed.It is a legal requirement that all engines sold in the EU must be able to run on 95 unleaded-OK,some may produce more power on higher octanes but they must be calibrated for 95.
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If the mechanical components/settings of an engine are set to run best on 95RON fuel, simply advancing the timing when a higher RON fuel goes in won't necessarily = more bhp.
Turbo cars can take advantage of higher RON through increasing the boost before knocking can occur. To get an obvious advantage in an N/A car you'd really want to increase compression ratio - such an engine doesn't exist on the roads (I think SAAB were trying to make a variable compression engine, presumably with a turbo, some years ago. I guess it was proving too expensive/tricky/unreliable).
I think the petrol manufacturers suggest some of the additives in their 'advanced' fuels aid combustion and thus act in addition to higher knock resistance... can't say any independent test I've seen has provided irrefutable evidence of increased power in a N/A engine.
Also I think HJ mentioned a comment from Ford (or one of their engineers) that the 2.5 turbo Focus would deliver 20-25hp more at the wheels running on superUL over regularUL. This is almost certainly not true. >10% power increase from 3-4 Octane points is surely not possible - I've seen some tests with Impreza / Golf GTi (turbo) showing 5-7 crank bhp on a dyno - 20+bhp seems a bit exaggerated.
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Also I think HJ mentioned a comment from Ford (or one of their engineers) that the 2.5 turbo Focus would deliver 20-25hp more at the wheels running on superUL over regularUL. This is almost certainly not true. >10% power increase from 3-4 Octane points is surely not possible - I've seen some tests with Impreza / Golf GTi (turbo) showing 5-7 crank bhp on a dyno - 20+bhp seems a bit exaggerated.
I have got one, there is a noticable difference with 99 RON V-Power, less so with 97 Ron Ultimate.
EDIT: I have also heard this from another source, though apparently the claimed 225ps is conservative and is with insurance groups in mind.
Edited by cheddar on 01/02/2010 at 22:55
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It is a legal requirement that all engines sold in the EU must be able to run on 95 unleaded-OK some may produce more power on higher octanes but they must be calibrated for 95.
Why does the manual for my 2005 Smart Roadster say that it requires 98 RON fuel? And why can I only find 97 RON? This seems to be the highest octane fuel available everywhere I look.
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Shell V-Power is 99RON, Tescos sell 99RON too I think.
V-power used to be 98 but I think most of the others make 97 still.
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the magazine laboured this point: they weren't surprised the GSXR power curves were identical but they WERE surprised at the BM's power curves.
Presumably the BM is designed to produce its rated output on 95 octane.
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Neither high-octane brew gave any more power or torque than ordinary 95 octane ... not even half a percent more.
I wouldn't expect it to - in an engine running correctly and not set up to utilise such fuels.
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Anti knock and ECU controlled ignition can advance the ignition to be able to utilise the properties of higher RON in an n/a engine.
I have BIKE though not read it yet, I wonder if the fuel efficiency imprived.
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Without increased compression you'll not get the full potential of the anti-knock though.
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Without increased compression you'll not get the full potential of the anti-knock though.
Look at it another way, with lower compression you could advance the ignition, higher RON enables the ECU to advance the ignition without lower compression.
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My Focus' Owners Guide states that there is nothing to be gained by using a higher octane fuel than the specified 95 RON.
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My Volvo owners handbook says there is, but if it does give any advantage in real terms, it is far too small for my backside-dyno to detect. :-)
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