|
Product specs, over and above the BS, have a real benefit, I believe. See www.chemecol.com/publications/automotive.html Also have to consider how the retailer is managed, and if fuel is sold on price, the standards of the fuel, additives like detergents, water content, even the octane or cetane may be "overlooked". However, if you think its all the same, carry on! Its your engine.
|
All the additives on the site that you link to are requirements of the British Standard,
"These and other diesels are also treated with various additive packages to help meet legislative and functional standards. "
The stating of, and certification of, the Octane level are also legal requirements as is water content.
Seriously you are just fooling yourself. The fuel comes from EXACTLY the same place. One of the products my company trades is crude oil and its derivatives, honestly it is the same stuff there is no magic ingredient.
|
This discussion could drag on without definitive answers, and the link shows the issue has been delved into in the past: www.honestjohn.co.uk/forum/post/?f=2&t=6701, where it is clear that additive packages are applied to the tanker load on a bespoke basis.
Without access (it costs £35 to buy) BS EN 228 re 95 octane petrol, my guess is that additives such as detergents are not required by the BS. Therefore, fuel meeting BS requirements can be sold, but the fuel may not contain detergents etc etc if Mr Cheapo Supermarket doesn't see the need:)
Shell and Texaco would waste their time and be liable for fraudulent trading if their products did not have the claimed benefits.
Enough already.
|
Shell and Texaco would waste their time and be liable for fraudulent trading if their products did not have the claimed benefits.
It's always puzzled me, that if Shell Optimax had quantifiable benefits, Shell would advertise those benefits. Or are the selling snake oil ?
I have to grow old - but I don't have to grow up
|
Foolproof snake oil test.
Try a couple of tankfuls, measure your mpg and observe the running and performance of your car.
You notice no difference - snake oil.
You notice improvements - you decide whether they are worth the extra.
Either way Mr Petrol Station & Mr Oil Company both very happy!
On a more serious note I should have thought that performance cars, particularly with turbos are more likely to benefit from higher octane fuel. I base this on SWMBO's old Saab 900turbo, where the recommended super unleaded reduced an otherwise substantial turbo lag.
|
|
|
Shell are advertising the benefits! It has a higher RON rating thus is more combustable and thus, if your car can deal with it, will provide more power and improved mpg and acceleration.
RON has nothing to do with additives, its like alcoholic content of beer!
|
Its a long time since I did chemistry but I thought that higher Octanes where to do with preventing pre-ignition? - the original reason for adding lead to petrol was to increase the octane and prevent "pinking".
I would presume that higher performance cars require higher octane because they are set up to get the maximum from the petrol at the right time and the higher octane makes sure it doesn't combust until the optimum time.
|
Modern car _with knock sensor_ can use the higher octane fuels:
they _more or less_ self adjust to get the best out of the fuel:
better fuel, better performance and/or economy.
As per previous posts - try it!
|
I always fill up with Sainsburys CityDiesel in my Xantia. I note with interest the claim of roughly 10mpg improvement from using Shell's diesel.
Is it worth me switching from Sainsburys? They are usually the cheapest and also right at the bottom of the road. I've no idea where my nearest Shell garage is, but if I can increase economy by that much it may be worth finding out!
|
Four star used to be 98RON. Then came along "unleaded" fuel, there was "premium" 95RON (like three star), and super 98RON (well it used to be at shell). Leaded petrol gradually deteriorated untill they sold 97RON leaded. When LRP came out many companies decided it was not worth putting a 98RON and a 97ROn fuel on the forecourt. So they sold 97RON lrp for one price, and 97RON super without the expensive additive for more money. How nice of them.
With LRp disapearing shell decided to sell the fuel they have been selling in germany here. They claim it is 98.6RON. these figures are relative octane numbers and are a scale which illustrates how much iso-octane is present in the fuel. It is not easy to understand, eg 98ron is far purer than 95ron.
Whether it is worth running your car on 98RON fuel will depend on the compression ratio, and whether the car has been mapped to take advantage of 98RON fuel. My mum 850 T5 is mapped for 98, so it makes quite a difference. In my old Jetta 16v it could make 10% difference to fuel economy. But in the mondeo i dont htink it makes much differnce at all. Horse for courses. A friend had a carlton 24v and that was only mapped for 95RON.
Ben
|
Sorry for this...
But I can help but wonder which veg oil give the best MPG in a diesel?
Steve.
|
I have had good results with Asda Samrt Price veg oil, but the performance is nothing compared to Marks and spencer's organic variety.
HTH
|
I have to use a octane booster for my P6 V8 as it was designed to run on 100 Octane 5 Star. I used to be able to get my hands on Bayford Thrust 4 star which was expensive but the garage has stopped doing it now.
I was thinking about having the value seats done and going unleaded but I only do 2500 miles a year in it if that; it's not worth it.
I've found that 97 unleaded with the obligatory Millers (you get funny looks dosing the tank sometimes) leaves a nasty flat spot at 2,000rpm and 2,500rpm. When that's near the peak torque output band of the V8; you feel it.
So I use Shell Optimax with a dose of Millers and its very sweet, no flat spot but nowhere near as good old fashioned 4 star.
|
3500S, I was under the impression that the RV8 already had hardened seats due to the all Ally construction of the engine. I run my SD on 95 RON inleaded with no problem - just knocked back the timing a couple of degrees to stop knock. What CR does the P6 run? The SD runs 9.35:1 so it doesn't tend to knock anyway. The old P5 ran higher compression than the SD and P6 as it made more power (as I guess you know) so I would imagine they want 100 RON too.
Back to fuel - Its a bit cheeky how Super UL is quite a bit more expensive than LRP when its much the same stuff but without the Lead Replacement additive!
|
|
All Rover V8's have soft value seats prior to the SD1 EFi V8's. My V8 is a 1972 with the power increase that came with the 'S' of that year. I think the compression ratio a large 10.5:1. It will knock without an octane booster.
|
|
I always used to fill up with sainsburys diesel on the way to work,however since switching to shell i,ve found or imagined the car running smoother and easier to start. Now i may be imagining it, but am managing 45mpg over a mix of motorway 85+ fast dual carrageways 60+ and a lot of stop/start urban driving all done with 10 bags of cement in the back, don,t ask.
|
I think it varies according to what car you drive. Shell Optimax used to make my H reg Merc 190E (1.8) run really well - improving both the MPG and acceleration. The handbook did in all fairness recommend 98 RON fuel however.
In my 01 Mondeo it doesn't make any difference at all so I don't bother with it now.
As a point of reference, in the "old days" my dad used to reckon that Jet petrol was cheap and made the engine "pink" in his various 1.6 and 2.0 Ford Capris
|
I\'ve been reading this thread with much interest and, indeed have commented above that there must surely be no difference between supermarket and \'branded\' fuel. However, I must know eat my words.
Normally, I use the Tesco at the end of the road, but I was passing a Shell garage and noticing that I was low on fuel, I decided to give Optimax a go. I have to say it\'s made my Granada much smoother and more eager, and the worrying loud metallic chattering noise (never heard pinking as bad as that before) under heavy acceleration has vanished. I am now a complete convert. Trouble is, it\'s 5p a litre dearer than Tesco. Worth, it though.
Watch out for squirrels\' tails. Far too bushy for my liking.
|
|
The real cost might be less than 5p per litre if you experience an improvement in economy. If it has stopped the pinking and the timing is set right you certainly should do.
|
Well, more good news. As I'd misjudged my fuel gauge, I had to fill up at Tesco again. But this time I used LRP. And the pinking has now vanished entirely. Pity LRP's on the way out...
I think the guy I bought the car off may have been telling porkies when he told me I could use unleaded. So, while I can still get it I think I'll stick with LRP. And Optimax, of course, whenever I'm near a Shell station.
|
Pity LRP's on the way out...
I agree Rob. I have a motorbike that doesn't get used very often (<200 miles a year), and although it's supposed to run on unleaded, it seems far happier on LRP, and before that I ran it on 4 star when they phased out 2 star. The last time I did fill it with unleaded, it melted one of the plugs. Not only that, but the unleaded petrol seemed to "go off" as well. I never had any problems until unleaded came along. I took the bike out for a spin at the weekend and had no choice but to refil with unleaded as I couldn't find any LRP on the 3 previous forecourts I stopped at. Only time will tell if the old spark plug and petrol "going off" problems re-occur again.
|
I suppose I could use super unleaded and an additive but asides from being dearer than LRP, don't you have to add the additive (!) to a full tank? I can very rarely afford a full tank of petrol.
There is a garage only a ten minute drive from me selling good, proper old-fashioned full fat petrol, but I have no idea how much it would cost. Any ideas? If it's not too bad then I might treat the Granny to a little sip of champagne!
|
As I have related before on this subject my son in law was a tanker driver for Texaco. All the vehicles are in fact owned by Woncanton but in texaco livery.
They deliver to both supermarket sites and to their own Texaco garages but the additives are different.
These are added when the tanker is filled by a dispensing unit which the driver has to use with a card given to him by the offfice, which automatically adds the additives to be used dependant on the customer.
So certainly there is a difference where you fill up from in relation to which additives are used.
|
|
|
|
