Going on from a thread that's doing the rounds on Visordown at the moment, just wondered what folks' views on Optimax/BP Ultimate were. Do they make much difference to the bike? Is it psychological? Or is there a definite improvement in the bike's feel and performance ie something you could feel in a 'blind' comparison??
I have to admit that I've done back 2 back tanks of fuel using 'normal' u/l then Optimax and tbh I can't really tell. I remember on my older BM's it would sometimes work the other way to expected, ie the 'super' fuel would make the bike vibrate like hell, then filling up with 95RON would smooth it out.
The only bike which I've found really does benefit is the MZ - it runs a very high (for a 2T motor) 10:1 compression so seems to like the higher octane (doesn't go any quicker though!). It's noticably smoother and fouls the plug a lot less in traffic (it runs an NGK Iridium anyway - very highly recommended if you've a stroker).
I can only give a definitive answer to this, with regards to C*rs.
Subaru tuned my car earlier this year and the fuel makes a subsatntial difference.
The quoted output with 95 ron fuel compared to 98 is over 8 bhp different. This is official quoted figures as per Subaru UK.
Optimax is 98 i believe.. and Bp Ultimate 97 or 98?
There a definite difference in the car...and I have convinced myself there's a difference on the boxer too.
cheers pb
I know Lloyd has said his bike feels the same,but mine's like chalk and cheese,with standard unleaded in it's bloody awfull with an increase in vibes through the bars and the motor is a lot flatter,i can't tell the difference between the various super unleaded, anyone will do!!!.
Strangely haven't tried Optimate in the Junes Stilo Abarth but at the rate that sups fuel it's a exspense i can well do with out!!!
PB - virtually all modern cars run knock sensors which means some (if they're set up for it) can make, especially so in the case of yours, full use of higher octane fuels. The loss in power whilst using the weaker brew is due to the sensor retarding the ignition to stop detonation.
Looks like BM are using a knock sensor on the new K12 as it needs 97/98RON to give max welly. I've heard as much as 10% is lost if 95's used.
Interestingly, our car (a Citroen 2.2HDi) likes BP Ultimate diesel very much - it's demonstrably quieter and smoother. No quicker but certainly more free-revving (if a Diesel could ever be described as such!).
BP Ultimate definitely makes a difference in the car... the computer that shows mpg indicated an improvement of about 3 mpg for the same motorway cruising speed and I could definitely feel that less throttle was required. Not sure I can justify the extra cost though
After this I tried it in the bike for a trip out into grey Norfolk to meet Mike (boxertools) and it felt a tad smoother and revved a little quicker at the top end, nothing dramatic, but noticeable nonetheless. Since this one tank I've returned to Tesco's 95 bog standard stuff and it does seem to be running pretty rough... I blamed it on the caning I gave it with the BP in there but reading the above posts I might try another tank of Ultimate... if it smooths out again I could be destined to run on expensive fuel
Have to say I never noticed the difference with Optimax though so maybe it's all psychological?
Adam
Forgive me father for I have sinned... ex S owner moved onto pastures new with four cylinders and a chain... and back to a twin, albeit in a V.
Whether it makes any difference with a standard Boxer engine is debatable. Certainly, the octane rating would make no difference to an engine that doesn't have knock sensors unless you manually advanced the ignition. It's possible that Optimax could create a more consistant burn and hence make the engine feel smoother, but it won't create any more power.
Shell rely on the fact that most modern cars (and some bikes) are fitted with knock sensors and so will feel more lively if you fill them with a higher octane fuel, as the ecu will automatically advance the ignition to match. All Mr Average knows is his car goes better with Optimax/Ultimate and puts it down to this wonder fuel rather than the engines ability to take advantage of the higher octane.
stempy wrote:
Shell rely on the fact that most modern cars (and some bikes) are fitted with knock sensors and so will feel more lively if you fill them with a higher octane fuel, as the ecu will automatically advance the ignition to match. All Mr Average knows is his car goes better with Optimax/Ultimate and puts it down to this wonder fuel rather than the engines ability to take advantage of the higher octane.
Hi gromit ,
Unfortunately my car keeps it bloody retarded once it retards it!
Each time it recognises bad fuel it retards by 4 degrees...twice as a max, then it has to be taken to the dealer to be reset. Nice eh
I noticed, when I moved house, that now I fill up with Shell I get 48-50 MPG on my trip to/from work. If I fill up at a BP station I only get about 40MPG. I have deliberately tried to get better at BP (I have some issues with Shell, a long story going back 20 years) but have had to concede to the fact that Shell gets me a significant saving, and 30 more miles to reserve!
Both these are for "ordinary" unleaded 95RON. Ive notice no significant difference with higher octane stuff.
