[geordie]

So despite multiple software flashes at BMW service (Including the 'lurching update') I still had brutal lurching on my '11 X3 35i.

I was about to drive it into the river. Then my wife decided to try putting in 93 octane Chevron gas instead of just 91. Wouldn't you know it, the lurching is 100% GONE.

So, as usual the answer is just fixed by spending more money

Thought this might be helpful if some of you were still experiencing lurching after the software updates.

Power is also WAY higher.

[Mingstar88]

which 91? we are using 91 vpower shell, am tempting to try 94 petro for winter

[nyalpine90]

doesnt it say premium gas unleaded on gas door?

[lbjgh]

nop, it says MINIMUM 89 octane.

Originally Posted by nyalpine90

doesnt it say premium gas unleaded on gas door?

[Mingstar88]

Originally Posted by lbjgh

nop, it says MINIMUM 89 octane.

on my 35i it says 91
on 28i loaner i drove it was 89

[geordie]

In Canada, the 35i says use 91 octane (which is considered "premium" gas here). 87 is considered "regular".

So 93 octane that I'm saying helps with the lurching would be above the spec of 91 BMW says the turbo needs.

[lbjgh]

Maybe my Canadian car is unique.

[somf]

My Canadian MY2013 35i M-Sport delivered in Sept 2012 also says 89 octane just like lbjgh

[E92LNGCGY]

I tried Husky 94 octane and didn't do a thing. What other gas stations offer 94?

[epiphone3]

Originally Posted by E92LNGCGY

I tried Husky 94 octane and didn't do a thing. What other gas stations offer 94?

PetroCanada now sell 94 octane in Calgary at several locations. However, any PetroCanada that carries the 94 octane now has up-to 10% ethanol in all grades (like Husky). Higher Octane number but the fuel has lower energy content due to the ethanol.

[E92LNGCGY]

Originally Posted by epiphone3

PetroCanada now sell 94 octane in Calgary at several locations. However, any PetroCanada that carries the 94 octane now has up-to 10% ethanol in all grades (like Husky). Higher Octane number but the fuel has lower energy content due to the ethanol.

No wonder when I tried Husky 94 it didn't have the kick at higher RPM. I used to put 94 in the 325 and I can feel a difference.

[lbjgh]

Higher octane just means the fuel is less susceptible to predetonation.

Just like epiphone3 said some of the highest octane fuels contain ethanol to prevent predetonation.

I use the lowest grade fuel on my motorcycle. and aim for 91 octane for the car.

[Radioactive]

Octane Booster Additive anyone?

[twistediron]

ridiculously expensive and barely effective. dyno tab is cheap, but they claim a 2 tab setup gives you 17 points (4 bucks) so 4 bucks a tank gives you 92.7 octane instead of 91. long way to go to match race gas

Originally Posted by Radioactive

Octane Booster Additive anyone?

[vanheiser]

Originally Posted by somf

My Canadian MY2013 35i M-Sport delivered in Sept 2012 also says 89 octane just like lbjgh

Mine also show what lbjgh picture shows on my 2013 35i M-Sport. I kept filling in 91 from Esso Canada. But starting to wander if its possible to just use 89. Not really keen on trying though.

[epiphone3]

Originally Posted by vanheiser

Mine also show what lbjgh picture shows on my 2013 35i M-Sport. I kept filling in 91 from Esso Canada. But starting to wander if its possible to just use 89. Not really keen on trying though.

If you read the manual, BMW states in it that 89 AKI is the minimum that you can use and that you may here knocking from the engine (especially in high temperatures). They claim the knocking won't damage the engine but my perspective is that you probably didn't buy a premium vehicle with a highly tuned power plant to run it with a knocking engine.

My 2 cents is as follows: for the miniscule differnce in cost per tank of fuel between 89 and 91, why take on all the risk that comes with running the lower grade fuel. Fuel's cheap, pistons are expensive.

[nyalpine90]

i always put premium gas BP or Sunoco 91 or 93

i think sunoco offers 93 bp offers 91 not sure though

[gareth12468]

Originally Posted by Mingstar88

which 91? we are using 91 vpower shell, am tempting to try 94 petro for winter

I've tried PetroCan 94 and all I can say it's not worth the money.....

[lbjgh]

Probably because you are pumping ethanol into your car which has less energy.

This is a good read: http://www.thestar.com/wheels/articl...rmance-engines

Originally Posted by gareth12468

I've tried PetroCan 94 and all I can say it's not worth the money.....

[geordie]

My 35i 2011 Canadian version says 91 minimum:

[lbjgh]

I wonder if vehicles on the left coast are labelled differently due to the possibly that the car will be operated at higher altitudes??

Anyway, below is the info from the manual.

Originally Posted by geordie

My 35i 2011 Canadian version says 91 minimum:

[paul386]

Originally Posted by geordie

So despite multiple software flashes at BMW service (Including the 'lurching update') I still had brutal lurching on my '11 X3 35i.

I was about to drive it into the river. Then my wife decided to try putting in 93 octane Chevron gas instead of just 91. Wouldn't you know it, the lurching is 100% GONE.

So, as usual the answer is just fixed by spending more money

Thought this might be helpful if some of you were still experiencing lurching after the software updates.

Power is also WAY higher.

Increased power is just a figment of your imagination.

So is the lurching for that matter. If the lurching stopped its because you are driving more aggressively.