Evo 5 RS
Yawn.
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Shell V-Power Nitro+
- Thread starter Tim.
- Start date
Normal petrol is 95 majority of the tome here. Bp ultimate is 97 and tesco momentum is 99
Where have you got that number from?
Bp is ultimate, which is 97 but vpower is shell which is 99 Ron
Tesco has more ethanol in it, good for RON number but bad for calorific value.
No idea what calorific value is if I'm being honest chip lol.
F31 35d, Berlingo Na
I remember learning about calorific values and octane numbers in A-level chemistry. Can't remember it now though 
Good Ye!
Good Ye!
we used to buy our 102 from the BP in egham which isn't near a race circuit ?
BP102 is not around in the uk any more , but thats because the MSA blue book has everything running on regular pump fuel now so no need to sell it as it was a loophole for pump fuel because x amount of stations sold it .
F1 has run on standard octane fuel and cannot contain additives not in regular pump fuel for some years , not like back in the 80's when fuel burnt your nostrils.
330i. E30 Touring.
Closest track is Longcross. I wouldn't be surprised if it had anything to do with the 2x Ferrari dealers there!
you mean the fact its opposite the countries largest ferrari importer
and longcross does not really get used for motorsport very often does it ?
People often think the RON value is how potent or strong the fuel is, it isnt, and in the case of the tesco stuff its higher RON but actually a weaker fuel.
Or the RON is, is just a measure of det resistance, nothing else at all.
Unless you are high boost or very high comp, a mega high RON fuel is of little or not use, and even if you are then you need a remap to make use of it.
JamesBryan
ClioSport Club Member
Would MON be a more useful number to use as it's a better representation of the performance of the fuel.
With it being tested under more load at a higher rpm and at different ignition timings?
Evo 5 RS
This. I'm guessing the majority don't have the car mapped for higher RON.
Its still only a measure of knock resistance though, rather than of fuel strength, so a higher MON fuel can still need to be run richer than a lower one (E85 for example) so can be bad for economy.
Chip, is it true that some ECU's will adapt for maximum performance up to the point where detonation is a risk? I'm no expert of course, but I understand that some cars will quite cleverly adapt to the fuel being used. And many other factors of course. If this is the case, then surely some cars can take advantage of higher octane fuels even if they're aren't specifically mapped for them?
I ask mainly because mine is mapped for 97+, but I definitely notice an improvement when I've been running 102 for a couple of tanks. Mainly the smoothness at maximum boost at high rpm's in higher gears, which coincidentally is exactly where my car suffers if I use 95.
EDIT: If it matters, my peak boost is somewhere in the region of 21-22 psi, but seems to go higher than that in 5th and 6th gear above 5000rpm.
I ask mainly because mine is mapped for 97+, but I definitely notice an improvement when I've been running 102 for a couple of tanks. Mainly the smoothness at maximum boost at high rpm's in higher gears, which coincidentally is exactly where my car suffers if I use 95.
EDIT: If it matters, my peak boost is somewhere in the region of 21-22 psi, but seems to go higher than that in 5th and 6th gear above 5000rpm.
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Then we get into adding oxygen in race fuels .... again needing to map/jet rich ... gains power to a point then tails off
Again no gain in ron rating
You need a large piece of paper to get anywhere close to describing a fuel (half of which I wouldnt understand with only A level chemistry and a bit of reading since, lol, you need a PHD in fuel chemistry minimum really), but people want it all in one number, lol
Fiesta ST200
F31 35d, Berlingo Na
I want a glass
Trophy #387
I just put £65 of this in the Trophy. I even asked the bloke what the difference was, and he suggested it was a re-branding to spark a few extra sales. It was 144.9p a litre, which isn't even far off I pay for normal unleaded sometimes.
I didn't get a free glass though, da fuq? How did you manage that
I didn't get a free glass though, da fuq? How did you manage that
Them glasses were an old run but were dated for most years of Ferrari's competing in F1 so they have probably added 2012 & 2013 and started punting them again. My dads a taxi so I will have the full set soon most likely.
Chip, some cars definately need higher octane fuel though right? Mine, my dads and mates Honda's never seemed to run right unless it was optimax (other fuels available). I do know there pump fuel is top stuff over there.
Chip, some cars definately need higher octane fuel though right? Mine, my dads and mates Honda's never seemed to run right unless it was optimax (other fuels available). I do know there pump fuel is top stuff over there.
181
The 350z lads are positive your there engines will die if they use standard unleaded.
T
T
The key thing is ignition timing, in the case of a high compression or high boost motor the ignition timing has a much narrower window for peak performance/economy at any given point than on a "normal" engine, and particularly lower down in the rev range where the volumetric efficiency is higher just slightly too much ignition can lead to detonation.
The RON rating of the fuel is its ability to resist detonating from pure heat and cylinder pressure generated from the burn before the flame front actually reaches it and so if you have an engine mapped for 98 RON fuel, and its mapped right on the edge of that detonation, you can end up with some real problems if you run less, to counter this on modern engines there is a knock sensor that detects the problem and pulls a big chunk of ignition timing out to save the engine but that in turn loses you a lot of the performance.
Without the knock sensor though its far worse, the detonation will destroy the pistons and kill the engine.
My turbo would melt if I did a trackday in it on normal unleaded, I could easily remap it to stop that (richen it up a touch more and/or pull a little timing) but I choose to keep it mapped for 98+ only as I get better performance that way and I know im not a wally who is going to put the wrong fuel into it.
When I map cars for people I always explain to them the risks that if they bring it for mapping with 98RON fuel in it that they should never use it on any less, if they want to run it on 95 *EVER* at full throttle, then they need to be bringing it for mapping on that fuel as well, as the only way to guarantee it wont detonate on a given fuel is to map for that fuel.
The downsides to mapping for a 95 fuel if you are going to run 98 is that you will lose performance, but also in extreme cases you can actually end up with others issues, for example if you have a very high comp engine and then boost it as well (ie when people bolt on turbos to a standard comp F4R motor) the fuel needs to have some decent det resistance in order for you to avoid having to run the ignition very retarded, and thats very important because retarded ignition means a less efficient burn and higher EGTs.
The only way I would suggest swapping from one fuel to another on a highly tuned engine is with a switchable map.
Yeah Honda's especially are the cars I have run that you notice a real difference, I guess its because there mapped for the fuel in the JDM.
I just filled up the Clio for the first time with this stuff, £54 went in @ £1.49 and it was pretty empty too, does a trophy have a bigger tank or something?
I just filled up the Clio for the first time with this stuff, £54 went in @ £1.49 and it was pretty empty too, does a trophy have a bigger tank or something?
