[briers]

Hope to try fuel save soon too. Filled to full with v so its going to take a while to cover 600 miles.

Premium fuel is only worth it from a cost viewpoint if it pays for itself. Got to ask yourself if you care about the additives. On diesel I care.

As for petrol, no. Unless you have a car that won't run on 95ron like an old supercharged motor I had. Or maybe track days on performance motors.

[m@rk]

Since new, my car has only ever had Shell fuel in it.

So I will be using this anyway.

Right now the OBC is showing an average MPG of 36.2 so I will see what it is showing in a couple of weeks time. Should be pretty easy to see if there is any difference or not.

[doughboy]

Not too sure about prem diesel, but its a cert for petrol motors (spesh turbos)

Evolve did back to back standard 335i dyno runs which showed up to +40 BHP extra PEAK power and increase all the way up too between boggo 95 ron and V power 99.

Smoother running, better throttle response and a harder, more urgent, edge to acceleration too,

[kaishang]

Eh? New diesel engines don't have pre-combustion chambers.... pre-combustion chambers are used in old diesel engines where there would be a richer fuel-to-air ratio than the main combustion chamber (ie cylinder) and the initial ignition of the fuel takes place in the pre-combustion chamber to help ignition in the rest of the cylinder/get a flame front propogating out.

Originally Posted by briers

With modern diesel engines that meet Euro reg's, NOX gasses are filtered by recycling exhaust gasses back into the pre-combustion chamber. They can use up to about 40% as a substitute to air in the pre-combustion compression stroke.

[milesr3]

All you need to know about Premium (higher octane) petrol is that all BMW's engine performance and economy figures are measured and quoted on 97RON fuel in the handbooks. 95RON is still the recommended fuel though.

My first tank of FuelSave diesel + Millers gave me 623 miles range on the OBC when I re-filled it last night which is higher than I've ever seen before! It does have the same low rpm hesitation as V-Power though in my car at least, which I've stopped using for this very reason so I've gone back to Sainsbury's City Diesel + Millers.

[briers]

Originally Posted by kaishang

Eh? New diesel engines don't have pre-combustion chambers.... pre-combustion chambers are used in old diesel engines where there would be a richer fuel-to-air ratio than the main combustion chamber (ie cylinder) and the initial ignition of the fuel takes place in the pre-combustion chamber to help ignition in the rest of the cylinder/get a flame front propogating out.

Yes your right, got my words mixed up, it was late.

I was referring to the intake and compression stroke in the cylinder, not chamber.

I still refer to it as pre-combustion as the fuel is only injected at the top of the compression stroke. Just shouldn't of said chamber. Well spotted.

[TMP]

Originally Posted by milesr3

Interesting...For some reason I'd assumed that Ultimate Diesel was GTL too, but having looked at their blurb again you're right - it does just appear to be a regular diesel with increased cetane, detergents and lubricity. I've seen comments on other forums about it smelling a lot like Millers DSP4 as well, so perhaps they use a similar additive.

I think I'll give it another try as I don't recall having the hesitancy problems I get on V-Power with Ultimate...

This new FuelSave diesel is causing my 535d to hesitate like V-Power does now too. I wonder how different FuelSave is to V-Power?

That was one of my thoughts - its kinda the same message as the v-power diesel! Think I am gonna altenrative between Shell FuelSave an BP Ult when I can get it.

[milesr3]

Some updates to my ongoing diesel experiments

I tried a tank of FuelSave diesel when it first came out (actually unwittingly the day before it was launched with all the flags etc) and not knowing it was available I added Millers to it and it gave great MPG but did still have some low rpm hesitancy in my 535d (see post above).

Disappointed that Shell had made another fuel that made my car unpleasant to drive, I went back to Sainsburys City Diesel plus Millers for a couple of tanks and got back the low rpm throttle response with reasonable MPG again.

Then on another forum I saw a mail from Shell saying that FuelSave diesel has a typical cetane rating of 55-58, so there was no point adding a cetane booster and I decided to give it a try 'raw'. I ran my tank right down on Tuesday and refilled with just FuelSave diesel and did my usual 2-way 160 mile drive to where I'm working at the moment.

The car felt pretty good at first, but then about 20 miles into the journey it felt like it mis-fired a couple of times - there was a definite judder and an audible pop in the exhaust and I was getting prepared to pull over, but then it went away and the car started running absolutely fantastic. From this point on the car drove brilliantly, responding really well to light throttle inputs typical of a motorway journey in traffic and the mpg figure started to climb until I'd ended up with an average 40.9 mpg for the journey which is usually 38-39mpg.

I asked Shell about the cetane rating of FuelSave diesel and got the following reply:

Good Morning ,
The Cetane value if Fuel Save diesel is guaranteed 51 typ 55 to 58.

We have had no other feedback regarding the issue you have stated with V power

Best Regards

Sheila De'Ath

Technical Information Services
Shell U.K. Oil Products Limited

So FuelSave diesel has a cetane which is already >= 55 so there is no point in adding a cetane booster to it. From my experience, I've found that my engine is really quiet on FuelSave and the mpg figures I've got show that it is running really efficiently on it. I'm certainly going to stick with FuelSave diesel now as it seems to be just as good as BP ultimate but is much cheaper and more widely available around where I live.

[Walesy]

hmm...I have tried a few tanks of fuel save juice and my car didnt feel right for some reason, back to normal Esso or BP for me these days and it is being a good girl. Dont know if it is something to do with the remap or what but it just didnt feel exactly right or responsive as it is normally.

[carl_d]

Originally Posted by philreid

It seems a lot of you prefer to use the premium fuel over standard Unleaded or Diesel. That's interesting...

So is it worth the extra then?

yes, i get 2-3 mpg more from shell v-power 99 RON

[evil_scooby]

Filled up my 335d with the new fuel save (didnt realise it had changed at first) and got an extra 25 miles out of a tankful without driving any different
Didnt notice any other differences to the car

[pjs]

Managed to fill up today with v power for Sixty Six quid, bargain. 116.9.

[doughboy]

its like a yoyo - up and down by 15quid a tank in a few weeks.

[milesr3]

Just wondering if anyone else is suspicious that the cetane rating of fuelsave diesel has been dropped back to the guaranteed level of 51 rather than the typically 55 - 58 that they claimed when it was launched?

I've been using it exclusively in my 535d since it came out and have noticed an increase in engine noise, decrease in mpg and throttle response in the last few weeks. Could be co-incident with the colder weather, but filling with a tank of Sainsburys City Diesel plus Millers has my engine sounding like it should again on high cetane fuel...

[m@rk]

I have now started to notice a difference.

Used to get between 35.7 and 36.2 on average before and am now getting a constant 37.1 mpg. The only thing that has changed is the fuel so maybe there is something in the claim.

Not a huge different but every little helps these days

[TMP]

Haven't seen any uplift In mpg tbh....