Been told not to use BP Ultimate?
22 December 2014, 03:41 PM
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Been told not to use BP Ultimate?
Guys Ive been told not to use BP Ultimate from a member on here but he couldn't give me an answer as to why?
I've just had a forged engine rebuild on my 2005 STI, I'm still in the running in process and have been using Taxaco Premium, but was going to start using BP as it's closer to me.
Can anyone tell me why I should use it?
I've just had a forged engine rebuild on my 2005 STI, I'm still in the running in process and have been using Taxaco Premium, but was going to start using BP as it's closer to me.
Can anyone tell me why I should use it?
Last edited by Fletch84; 22 December 2014 at 03:42 PM.
22 December 2014, 03:46 PM
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22 December 2014, 03:52 PM
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22 December 2014, 03:54 PM
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Good stuff
22 December 2014, 04:46 PM
#13
it also depends on what fuel was in the car when it was mapped , if it was mapped using 97ron fuel then bp would be fine, thats what i've been told before i think from andy forrest .
from the internet
Unfortunately, this is where the myth of what gasoline’s octane rating really means creeps into the picture. Time and again, people will be told that high octane fuel burns cleaner or more completely, and that it will give them extra power and better fuel mileage than Regular octane gasoline because it contains more ‘energy.’ These blanket statements are simply not true. In fact, the octane rating for gasoline has nothing to do with the amount of power locked inside of it – it actually relates to just how much a fuel can be compressed before igniting. The higher the number, the less likely it is to ignite under pressure.
Why would anyone want to produce a fuel that was actually harder to ignite once inside an engine? To understand the role that octane ratings and ignition pressures play in a motor, it helps to be familiar with the term ‘knock.’ Essentially, when gasoline is sprayed into a cylinder by a fuel injector and mixed with oxygen, engine designers expect it to remain there in vapor form until it is time for the sparkplug to light it up, causing the explosion that drives the piston down to generate horsepower. The timing of this explosion is critical, as gasoline that ignites too early causes ‘knock,’ which reduces engine output and efficiency and which, in worst-case scenarios, can actually physically damage an engine.
In most engines, knock is rarely an issue because the compression ratio – that is, the pressure that the air/fuel mixture is put under in the cylinder – is low enough that Regular gasoline’s octane rating is sufficient. There is absolutely no benefit to running Premium fuel in a standard motor, since it will never be able to take advantage of that gasoline’s higher knock resistance. However, more aggressive engine management schemes, especially those found in turbocharged or supercharged vehicles, can turn up the compression to a high level, requiring much higher octane gasoline to avoid knock.
How can you know whether your car actually requires Super gasoline or whether it can get by on Regular? Almost every vehicle will list the octane rating necessary to run it safely inside the owner’s manual. Some luxury or sportscars might even place a small reminder on the gas gauge itself stating ‘Premium Unleaded fuel only’ to make sure you don’t forget.
To wrap things up: no, you won’t see a power or fuel efficiency increase by running high octane fuel in an engine that has been tuned and designed for Regular gas, nor will doing so perform any extra ‘cleaning’ inside the motor. On the flip side, running low octane fuel in an engine built for Premium can increase the risk of engine damage and will certainly impact that unit’s overall performance. The next time someone tries to pass these myths off on you, you can try explaining to them how octane ratings really work
from the internet
Unfortunately, this is where the myth of what gasoline’s octane rating really means creeps into the picture. Time and again, people will be told that high octane fuel burns cleaner or more completely, and that it will give them extra power and better fuel mileage than Regular octane gasoline because it contains more ‘energy.’ These blanket statements are simply not true. In fact, the octane rating for gasoline has nothing to do with the amount of power locked inside of it – it actually relates to just how much a fuel can be compressed before igniting. The higher the number, the less likely it is to ignite under pressure.
Why would anyone want to produce a fuel that was actually harder to ignite once inside an engine? To understand the role that octane ratings and ignition pressures play in a motor, it helps to be familiar with the term ‘knock.’ Essentially, when gasoline is sprayed into a cylinder by a fuel injector and mixed with oxygen, engine designers expect it to remain there in vapor form until it is time for the sparkplug to light it up, causing the explosion that drives the piston down to generate horsepower. The timing of this explosion is critical, as gasoline that ignites too early causes ‘knock,’ which reduces engine output and efficiency and which, in worst-case scenarios, can actually physically damage an engine.
In most engines, knock is rarely an issue because the compression ratio – that is, the pressure that the air/fuel mixture is put under in the cylinder – is low enough that Regular gasoline’s octane rating is sufficient. There is absolutely no benefit to running Premium fuel in a standard motor, since it will never be able to take advantage of that gasoline’s higher knock resistance. However, more aggressive engine management schemes, especially those found in turbocharged or supercharged vehicles, can turn up the compression to a high level, requiring much higher octane gasoline to avoid knock.
How can you know whether your car actually requires Super gasoline or whether it can get by on Regular? Almost every vehicle will list the octane rating necessary to run it safely inside the owner’s manual. Some luxury or sportscars might even place a small reminder on the gas gauge itself stating ‘Premium Unleaded fuel only’ to make sure you don’t forget.
To wrap things up: no, you won’t see a power or fuel efficiency increase by running high octane fuel in an engine that has been tuned and designed for Regular gas, nor will doing so perform any extra ‘cleaning’ inside the motor. On the flip side, running low octane fuel in an engine built for Premium can increase the risk of engine damage and will certainly impact that unit’s overall performance. The next time someone tries to pass these myths off on you, you can try explaining to them how octane ratings really work
Last edited by gary77; 22 December 2014 at 05:05 PM.
22 December 2014, 09:14 PM
#24
22 December 2014, 09:16 PM
#25
Octane booster (toluene) is a product of refining oil just like petrol, so however the high octane fuels are made it's all the same at the end of the day.
22 December 2014, 09:18 PM
#26
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BP Ultimate is actually little better than 95 ron in real terms and under some circumstances worse, its the worst possible fuel you could use ... and two ron makes a huge difference you must use the fuel grade the car has been mapped for, Gary77 has summarised things pretty well, I would add that Subaru turbo engines are very finicky, air/fuel ratio and ignition timing have a far greater impact than on an Evo, say, a failing fuel pump will cause lean running and an engine to detonate itself to death very quickly, also, a Subaru flat 4 is designed from the outset to use Japanese quality fuel, which we simply do not have in the UK. If I map a car for Shell V Power then using the Tesco Momentum is never an issue ... it is marginally "worse" in terms of det resistance but its never worth running a car that close to the edge.
22 December 2014, 09:25 PM
#27
BP Ultimate is actually little better than 95 ron in real terms and under some circumstances worse, its the worst possible fuel you could use ... and two ron makes a huge difference you must use the fuel grade the car has been mapped for, Gary77 has summarised things pretty well, I would add that Subaru turbo engines are very finicky, air/fuel ratio and ignition timing have a far greater impact than on an Evo, say, a failing fuel pump will cause lean running and an engine to detonate itself to death very quickly, also, a Subaru flat 4 is designed from the outset to use Japanese quality fuel, which we simply do not have in the UK. If I map a car for Shell V Power then using the Tesco Momentum is never an issue ... it is marginally "worse" in terms of det resistance but its never worth running a car that close to the edge.
Surely the knocking sensing works?
What's your view on toluene as octane booster?
Thanks boosted
23 December 2014, 04:13 PM
#28
i would guess it would have been mapped for shell vpower . but whatever it was mapped with thats what he should use
23 December 2014, 10:16 PM
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Bob will be better on the specifics for certain Subaru engines, but for each RON lost on many turbo engines running 8 - 9 CR, a bar of boost and a four valve pent roof combustion chamber with port injection and a correctly sized turbo, you might say you would retard by a degree, richen by say 0.01 lambda and drop the boost by a PSI as a guess of a starting point.
I just pulled these out my *** as a rough guess of what I would try and test.
I just pulled these out my *** as a rough guess of what I would try and test.