Tesco Super 99 or 97 Octane

[pigapumbu]

Originally Posted by Steve940estate

I have filled the tank on my 940 with Vpower on the odd occasion that I am near a Shell garage and have noticed a difference.

Normally it gets Tesco's or BP but with the Shell it's is a lot smoother and idles slower. I guess the engine runs cleaner with the Shell petrol in it and the management doesn't have to compensate by increasing the revs.

Shame about the price though.

I never believed it myself. Used to put in tesco super. BUt even tesco 99RON to Vpower, I could see the difference. I won't talk about the power difference measured by the arse cause thats not very scientific for us here on the forum but doing fuel consumption runs, then the figure shows a marked improvement. But note, one needs to be careful not to floor the pedal because of the new found 'power' using Shell V-power. No idea why it seems to be better. Maybe what they put in it.

cheers

ps: No need for any arguement but as a forum is, its about exchanging views and sharing info. So if anyone feels whats said or written is all wrong, then it would be nice to know why and whats the facts so we all can make our mind up. There is no need to get personal with the message bearer.

[pigapumbu]

Originally Posted by Viper_7

Yes it's one of the best fuels out there. Sure it costs more but c'mon it's only like a quid or so extra a tank. Drop in the ocean. Compared to the better return and less likely to have problems.


It's all a con though - our cars will run on water really.

Vipes

Yes. And in my V50T5, even though the Shell Vpower is more expensive, with the better fuel economy I get,it breaks even or worse case scenario, I just have to buy one less cheap bottle of wine from LIDL that month. And knowing my car loves the stuff, I intend to use Vpower.

Note, I have no links or work for shell. I just say it as I see it. If Jet comes out with a good fuel and I try it out, if its better I will say so. But for now, Vpower gets my vote. More power, car runs better and fuel consumption improves. what else do I need.

cheers

[st5ve]

I am trying to understand this topic a little better than I already do, so please don't think I am challenging what has been stated or said, I would just like to get to know the subject deeper.

Would I be right in thinking that once you have remapped or chipped the ECU, it no longer has the ability or properties to know what octane of fuel is been used? Therfore the modified ECU always tries to run lean as it is expecting/programed for a higher octane?

Now this is where I probably show total ignorance on the subject, the GDI engine runs lean and has reported problems because of that, re carbon build up. With a ECU that has been chipped/remapped will the engine suffer the same way a GDI engine would?

[pigapumbu]

Originally Posted by bobcat

the ecu wont lean out the fueling thats the point, you get more torque from less air and fuel (thus the same fueling) from greater ignition advance.

for an extreme example of how ignition timing affects torque read up on how antilag works.

higher octance fuel allows higher cyl pressure, thats all!!!!!!!!!!!!!!!!!!!!!

Thanks for the reply. From what I have read I am still not convinced what Georgey Dee wrote is wrong. Perhaps it would have been better to have just put your views out instead of originally saying it was all wrong.

From your explanation or what little of it, I still see it as ECU in our cars are adaptive and able to compensate with what fuel it has. Give it higher octane and for the same drive, it uses less fuel but when needed, it has more torque/power for the same amount of fuel and air (according to your explanation). This its self is better if you ask me.

And if anyone modifies the engine for more power, then it only seems right to say use a higher RON. Whats the point of going down the route of modifying a car for power and then give it lower RON petrol? Doesn't make sense. SO once I modify a car, then every bhp counts and in my view, its best to give it a diet of 99RON so I see all the ponies PLUS it has added benefit with the heat generated in these engines, I don't cause pre-detonation due to hotspots in the engine by using low RON.

Anyway thats how I see it and I can't really see what was so wrong with G.Dee's post. Not like he said, use 99RON so your car will go slower and use more fuel.

cheers

[pyaap]

And now to let the cat among the pigeons.....

http://www.thorneymotorsport.co.uk/t...s_Update.shtml

Hardly a double blinded randomised controller trial for the purists out there, but still slightly more scientific than the hearsay and responding with "more questions than answers" approach which frequently surrounds this issue. And unless someone in Mr. Thorney`s family has married into someone from Mr. Tesco`s family, it should be a considered a fairly unbiased report, again something as rare as hens`s teeth these days.

[davev70]

Originally Posted by pyaap

And now to let the cat out among the pigeons.....

http://www.thorneymotorsport.co.uk/t...s_Update.shtml

Hardly a double blinded randomised controller trial for the purists out there, but still slightly more scientific than the hearsay and responding with "more questions than answers" approach which frequently surrounds this issue. And unless someone in Mr. Thorney`s family has married into someone from Mr. Tesco`s family, it should be a considered a fairly unbiased report, again something as rare as hens`s teeth these days.

thats all fine but it was not tested in a volvo

[pigapumbu]

Originally Posted by davev70

thats all fine but it was not tested in a volvo

So? Sorry don't get your point.

I thought the article was good enough explanation. I read it last year and it made sense then and still carries weight. Anyone wanting to know about using a higher RON on their car best read it an know the facts.

Because its tested on a nonvolvo car means nothing. The facts remain. All modern cars use just about the same technology in their ECU.

Its like when I cook a meal from a recipe, just cause it originates from australia, doesn't mean I need to go and source australian beef, etc. British beef will do just fine (so long not from that surrey farm or shamboo). It makes no difference to the outcome.

cheers

[Georgey dee]

That's the best thing about these Volvos, They'll cut the ignition before any damage is caused. If you're running a MBC and wind it up too much then the detting will be detected. Best not to run it that way though. My 200sx used to just det away and melt spark plugs on 95RON, it was fine on 97RON though. On a cold crisp morning the 97RON wasn't enough and I had to wind the boost off.

If you want the best out put the best in

[bobcat]

Originally Posted by ttacornwall

I am trying to understand this topic a little better than I already do, so please don't think I am challenging what has been stated or said, I would just like to get to know the subject deeper.

Would I be right in thinking that once you have remapped or chipped the ECU, it no longer has the ability or properties to know what octane of fuel is been used? Therfore the modified ECU always tries to run lean as it is expecting/programed for a higher octane?

Now this is where I probably show total ignorance on the subject, the GDI engine runs lean and has reported problems because of that, re carbon build up. With a ECU that has been chipped/remapped will the engine suffer the same way a GDI engine would?

the fundamental issue is the issue dosent run a leaner mixture!!!!!

with higher ron you can run a higher cylinder pressure and thus get more torque.

the reason i gave the example of antilag, is that when in use the engine will still be drawing in a lot of air and fuel, however the engine will be pretty much idling, and still with good afr's. if yo drove it like that you would have s$%t mpg - but that then goes against previous posts in this thread that link mpg solely to the maount of fuel injected.

the reason lower rons fuels make less power is that you can run to much timing advance as the cylinder pressure become so high the fuel\burn becomes unstable. with higher ron you can run more timing and thus higher cyl pressure and thus more torque and therefore more power.

however for those that want to believe its all down from leaning out the mixture - well i hope you never start mapping cars!!!

got to ask, how does the car know what fuel it is running?

[Georgey dee]

So it's the Timing that's altered no the fuel pressure.