What ever is at my nearest Morrison's, I do make a trip to Tesco now and then for a full tank of Momentum, but to be honest I have not noticed any difference in MPG or Performance.
What ever is at my nearest Morrison's, I do make a trip to Tesco now and then for a full tank of Momentum, but to be honest I have not noticed any difference in MPG or Performance.
It would pull more timing with momentum 99 as its 99 RON over Shell's 97 or 98 (can't remember)
Octane is an inhibitor which allows the compression to be higher before the fuel detonates (pre ignition / pinking) which is bad for the engine. In order to over come detonation the timing is advanced to send the spark to ignite the fuel before it detonates..
Higher octane means that the compression can get higher and therefore the timing retarded to suit.
Fuel can go off and loose RON over time. If possible always get it from a busy station otherwise you paying for 98 and getting lower.
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Octane is the measure of a fuels knock resistance usually stated as MON or RON or combined ratings. Additives such as lead in the old days, or todays toluene, ethanol etc are added to raise octane rating. Ignition timing is most definitely not advanced to minimise detonation, it is retarded. Detonation occurs when the fuel/air mixture is ignited by the spark, but part of the mixture spontaneously ignites before the flame front reaches it, hence the need to retard ign timing.
This extreme pressure/heat rise is what turns engines into grenades. Compression isn't the only factor in detonation, AFR, boost pressure, ign timing are all factors.
Pre ignition/pinking is a different thing altogether, that is the mixture being ignited by a hot spot such as carbon in the combustion chamber generally at low revs/high load. It can be damaging, but is not as critical as high speed detonation.
Sorry retard, not advance as you said above. I was thinking from memory, what I do on my classic car and which way I turn the Distributor depending on which fuel I put in!
Who are you calling a retard?Sorry retard, not advance as you said above. I was thinking from memory, what I do on my classic car and which way I turn the Distributor depending on which fuel I put in!
The trouble is, what is called retarding ends up advancing, or moving forward when the spark plug is fired, ie it gets fired earlier in the cycle which to some would be classed as "advancing" the spark, while it is being achieved by doing what is traditionally called retarding the ignition.
Not to mention mapping the ignition curve with different advance springs and weights.Sorry retard, not advance as you said above. I was thinking from memory, what I do on my classic car and which way I turn the Distributor depending on which fuel I put in!
if this is the case then V Power is pointless as my guess is that a LOT of people wont pay for itFuel can go off and loose RON over time. If possible always get it from a busy station otherwise you paying for 98 and getting lower.
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Think it only happens after months in the tank for degradation to happen.if this is the case then V Power is pointless as my guess is that a LOT of people wont pay for it
if this is the case then V Power is pointless as my guess is that a LOT of people wont pay for it
Where i am Tesco 99 is £1.28So just went to my local petrol stations for a price check (not had the Leon long).
Shell V Power 99RON £1.39
Tesco Momentum 99RON £1.33
So I'll be used the Tesco then thanks. Didn't think the price would be that much.
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Where i am Tesco 99 is £1.28
Shell V Power is £1.41
no at £1.27 I dont blame you but what do you have to do to get those kinds of discounts?No idea how much Tesco Momentum is as the garage is over 25 miles away so haven’t been near.
V Power near me is £1.35 but with the usually 4-8p off vouchers I’ve been getting using the Shell App, I’ve been partying around £1.27 - £1.31. And compared to BP 95 RON being £1.28, I didn’t think it was that bad a price.
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no at £1.27 I dont blame you but what do you have to do to get those kinds of discounts?