RON95 vs RON99

[markjay]

Thats true optimax was a disaster on launch the GTL process and additives package was hopeless to begin with. I live by the motto never buy version 1 of anything let the early adopters make all the mistakes and learn from them, its a lot cheaper learning from other peoples mistakes.

Yep - this why Microsoft had Windows NT started from version 3...

 

[markjay]

Having trawled through this thread I am interested to see people claiming that they get more mileage out of "a tank of fuel" when they buy 98 or 99 instead of 95. Whilst it undoubtedly will have some effect, the sheer number of variables affecting MPG means that it is very difficult to decide whether it is the fuel itself that is making the difference. I used to monitor fuel consumption by brimming the tank on my C230k and over the years have had the opportunity to monitor its appetite over long 6,000 mile jaunts across Europe and Western Russia.
Let us look at just some of the factors which I believe influence your MPG.

1 Driving Style acceleration (how far into the carpet does your foot go? Kickdown?)
2 Top speeds, gears, rpm (the more it spins the more fuel it uses)
3 What direction is the wind blowing in (following or against you).
4 Lights, stereo, air conditioner, heater, fan (they all use power)
5 Are your tires pumped up properly (this makes a big difference)
6 Do you travel with the windows open (increase wind resistance)
7 How much crap do you carry around in the boot (increased weight)
8 How many passengers do you carry around (more dead weight)
9 Routes which you take (flat or loads of hills)
10 Route which you take (in town - loads of start stop lights - or not)
11 The amount of traffic on the road (less traffic, less changing speed)

My experience on long trips on my own is that fuel consumption can vary by as much as +/- 10% for no apparent reason. However, the single most influential factor on THESE trips was my top speed. In Germany, I tended to use alot more fuel than in Lithuania and Latvia where the limits are very low.

So unless, you want to give up part of your life and keep a mileage log in the car I suggest that we all quite worrying about it. I did.

Les

PS the best thing I did with my 11 year old car was to chuck 2 bottles of injector cleaner into the fuel tank. The engine feels much smoother on acceleration now but maybe just me trying to justify improving things. A mechanic once recommended it to me. One thing that the more expensive fuel does prevent is causing the fuel senders in the tank to play up and tell you that your tank is empty when you know its full.

Not sure about the immediate mpg saving from using high-octane fuel, but I am convinced that the additives in these super-fuels (rather than the high-octane itself) keep your fuel system clean which in turn leads to long-term saving on fuel as mpg will not deteriorates over time as it does on other cars due to dirty injectors etc.

I have been using Redex for years (before switching over to super-fuels), and when taking the injector rail off cars with 40 or 50k miles the thing was squeaky clean, shiny and no deposits.

 

[DITTRICH]

Well a bottle of redex fuel system cleaner is around £3.60 and assume a 62 litre c class tank. £3.60/£1.13=3.2 litres. MPG would need to increase by 65.2/63.0= around +3.5% to justify the purchase. I don't think this is detectable under normal circumstances. Mind you your point about dirty injectors is well taken (I thought it was how clean the nozzle bit is which affects the uniformity of the "spray") but since we can't say how much the economy deterioriates with no cleaning we can't say if it is worth it. But I just count beans for a living rather than maintain cars.

 

[markjay]

Well a bottle of redex fuel system cleaner is around £3.60 and assume a 62 litre c class tank. £3.60/£1.13=3.2 litres. MPG would need to increase by 65.2/63.0= around +3.5% to justify the purchase. I don't think this is detectable under normal circumstances. Mind you your point about dirty injectors is well taken (I thought it was how clean the nozzle bit is which affects the uniformity of the "spray") but since we can't say how much the economy deterioriates with no cleaning we can't say if it is worth it. But I just count beans for a living rather than maintain cars.

Dear Beancounter

You are quite right that we can't work-out if the long-term saving by keeping the injectors clean is worth the extra cost of super-fuels or Redex. And we will also have to throw into the equation the cost of having the injectors cleaned every now and then..

But regardless of the cost, in my book clean injectors are better than dirty ones....

 

[BTB 500]

Just to remind everyone that when Shell Optimax was first introduced.... they had the same fiasco. iirc the initial deliveries of the new super-fuel had too much additives, and this damaged some engines (which Shell paid for).

That was called "Formula Shell" ... about 25 years ago. IIRC it was normal octane, but with efficiency and cleaning additives. The former caused pinking in some engines.

 

[Shamaz Majid]

UPDATE TO THIS THREAD.

Now used 2 tankfuls each of Tesco Momentum 99 and Shell V-Power in my 300ZX, and I can definitely say that with the Momentum, the car definitely feels better. Obviously both perform better than 95 RON!

Not saying this will be true for everyone, but for me the Tesco product is definitely better.

 

[markjay]

UPDATE TO THIS THREAD.

Now used 2 tankfuls each of Tesco Momentum 99 and Shell V-Power in my 300ZX, and I can definitely say that with the Momentum, the car definitely feels better. Obviously both perform better than 95 RON!

Not saying this will be true for everyone, but for me the Tesco product is definitely better.

Nice try, Jack Cohen!