[magic77]

Being a recovering diesel user as well, all this petrol is new too me after 10 year absence.

Having filled up with Shell Vpower the other week as was doing the RR I get lot more petrol smell from the exhaust when iddling.

Never noticed it before running 95ron just wondering if anyone else from the few have spotted this

[rocketretro]

I can certainly detect a stronger smell at the pump when filling, so no surprise it if it comes out of the exhaust that way.

[magic77]

ok , have to say never felt the smell was stronger at the pump but never paid attention.

Out of interest do you find any difference between 97 and 95 on the car, its says its designed for 95 ron but the old age 95 vs 97 does intrigue. I tend to run 95 and every few full tanks drop in 97 to help clear the engine especially when going for a long or hard drive.

[HighlandPete]

Originally Posted by magic77

Out of interest do you find any difference between 97 and 95 on the car, its says its designed for 95 ron but the old age 95 vs 97 does intrigue. I tend to run 95 and every few full tanks drop in 97 to help clear the engine especially when going for a long or hard drive.

This where BMW seem to give mixed messages. Both 3 & 5-series data states the N55 engines are designed around RON 98 fuel. BMW clearly state "output and fuel consumption figures apply to RON 98 fuel". Then state "BMW recommends RON 95".

Part of this may be the comment that we can run on RON 91 and higher. Filler covers typically state RON 95 (91 - 98).

My N55 is a sweeter running engine on RON 97/98, idles smoother, not convinced mpg is much different in local use. Not seriously 'tested' for long repeatable trips, where different fuels often show the mpg variations. Using RON 98 (Shell Optimax) when I had the M62 V8 engine was definitely noticeable, both for power output and consumption.

HighlandPete

[magic77]

Might run it for a while on vpower and see , off in a month to the ring so will be filling up with vpower all the way there and back

Have done similar when I run a D and it proved. Most of my driving is pottering around town however might dig a bit more as I recall reading vpower was better for the HPFP so might be a better bet to pay extra when I can

[Lorcan]

The different smell doesn't mean the car is running richer necessarily, it's more likely due to the use of different "aromatics" in the fuel blending process. Higher octane fuels often have a lower specific density and less heat energy than lower octanes, their advantage comes from their ability to run more boost/compression/advance without knocking (detonation).

[magic77]

Valid point, it does have certain aromatic flavour to it. Smells damm better than my diesel use to. U:

Just glad I have the black tips on my exhaust as the chrome just get so dirty quickly

[Lorcan]

The amount of soot generated can also vary independent of mixture. Toluene and other Benzine derivatives are very sooty.

[rocketretro]

Different smell, yes the aroma of 'performance' I suppose and an extra two quid a tank.

[magic77]

I'm curious about the HPFP is it a better for it and I suppose if it also recuded carbon build up in the manifold bring it on