Swift Cee

Hi chaps , just wondering (as u do!) Ive gone over to V-fuel and my performance has dropped ( quite a bit) anyone else had this problem.

Im not sure what the Ron is with the new stuff but the fella in he shell garage told me it was the dogs nuts.

I dunno? maybe ive got another problem!!!

import turbo 93.

cheers

swift

WRX_monkey

I filled up with this stuff the other day, not all shell garages have it yet and was a bit surprised when found v-power, according to the leaflet its 99ron. I'm still running in my newly built engine in so taking it easy, but didn't notice any difference. Optimax was 98ron, but I'm sure I read somewhere its closer to 98.6ron, can't quite remember.

BigChris84

the best way to look at it is that its new fuel, so i doubt very much that shell would have downgraded it in anyway...

and for your car to have "dropped performance" so drastically simply by changing to v power would suggest something more than the fuel you are using.

myblackwrx

iTrader: (1)

How's the performance dropped (not boosting properly etc)

silent running

Put in a trial tank the other day on my Power FC mapped WRX. No difference to Tesco 99 that I can tell so far. Apart from the V-Power is loads more expensive. I'll stick with it for a few tankfuls and see if anything changes though.

FISHBOY

Ive been told V power is 99.6 ron compared to 98.4 Optimax

My car loves drinking the stuff!

rob4620

where do you find tesco 99 it's not at any of the tesco's near me?

what would adding octane booster to 99 ron fuel do to the fuel/map/ engine, any ideas?

Scott.T

iTrader: (2)

If your not changing the map on an apexi-PFC to suite the V-Power you probably won't notice any difference anyway, as the PFC won't advance on it's own.

Standard or mapped stock ECU's that are mapped correctley, may well be running the full advance available anyway. These also won't notice much difference.

If you car has detted and pulled timing, then you fill with V-power it may advance for a while, until it dets and pulls timing again.

Just becuase you didn't have a Knocklink flash doesn't mean the ECU hasn't seen minor det and pulled timing.

silent running

I'm used to a certain low level of detonation which varies with other factors that I'm also used to monitoring. Seeing as octane by definition is a fuel's knock resistance, watching for differences in the pattern of detonation seen on the FC Commander would seem to be a logical way to compare the two fuels. The 'bum dyno' reveals no difference. The Commander readouts and numbers so far reveal no difference in underlying detonation. My point being that if the V-Power had any slight octane advantage, I shouldn't need to remap it to see a reduced underlying detonation level assuming the same ignition and fuelling. The fact that so far things look the same leads me to believe that remapping would not find any extra power on 'V-Power' rather than Tesco's 99.

Rob - I've been using Tesco 99 for quite a while now - it's available all around East Anglia which doesn't help you much if you live far in the north! But even getting it in Norfolk and Suffolk was quite an occasion. In recent months the price has varied between 95.9 and 100.9 at the very most. It's always either 3p or 4p more than standard Tesco unleaded.

Scott.T

iTrader: (2)

Marginal differences in low level Knock count on the FC commnader doesn't mean there are different levels of detonation.
The noise level generated by the burn can vary the knock count. Different fuels can burn in a different manner due to their different content.

Tesco 99RON burns different, I believe due to it's methanol content.

I've not used Tesco 99RON enough to be sure, but when I first used it the background noise seemed slightly higher then Esso SUL. Neither of these gave high Knock Counts. The highest being about 14.

silent running

I have to disagree here. I'd say that 'marginal' differences in low level knock count - if repeatable - DO mean that you have different levels of detonation, even if only to a small extent. 'Noise level generated by the burn' is what the knock sensor is listening for. If it's burning properly it won't hear it, if it burns in some other way to cause detonation it will hear it, simple as that.

As I said, I am happy to give V-Power a go over a few tankfuls, but I approach everything from a sceptical point of view and at present do not believe that 99 octane V-Power will give me any performance advantage or additional safety margin over 99 octane Tesco's fuel. I know what Tesco 99's knock readings look like on the Commander and what it feels like to drive. After a few tanks of V-Power I'll be able to compare the two fuels and decide which makes more sense to buy.

rob4620

reading evo magazine this month and they have a reveiw on fuels, when the put the new bp 102 in a porsche 996 carrera gt it instantly gave it 25bhp over bp 97 super, when they re-mapped it to the 102 it made an extra 48bhp over the 97 ron that 12.5% extra power than standard, so there is something in all this fuel malarkey.

andythejock01wrx

5th gear got 5bhp difference for a new Golf GTi and 14 bhp for a Newage Sti between 95Ron and 98.6Ron (Optimax).

I asked Andy F about this and he said it depends on the state of tune of the vehicle.

Having said that, VPower is 99Ron so you wouldn't expect to be able to feel the difference (as the Actress said to the Bishop !) between it and Optimax.

silent running

Yes I read that Evo report as well. Since super unleaded started being available at the pumps mags have tested performance cars with different fuels and surprise surprise the ones with more sophisticated ECUs managed to produce more power on higher octane fuel. I don't think Evo and other mags do enough 'like for like' testing. You could come away from that article thinking that it's BP's special magic fuel that made the Porsche so powerful, and not just that you could put ANY 102 octane fuel in and get very similar results. Just as if you put 95 octane normal unleaded in your unmapped WRX import, you will wreck your engine with too much hard driving - regardless of whether you use fuel from Tesco's, Asda's, Shell, BP, Texaco, Esso or get it direct from the Sultan of Brunei.

To my mind, and I may be in a minority here, high octane and low price is what my Scoob needs, not a brand name. It's bad enough that I struggle to get mid 20's mpg, without having to spend over a pound a litre on the stuff!

Jolly Green Monster

iTrader: (4)

I think you are mistaking engine noise for detonation.

Simon

silent running

Maybe. As I say, I will watch the traces for a few weeks and see what happens. I occasionally have a big spike on the overrun or on light throttle cruise, which can't seem to be got rid of with mapping, so if V-Power doesn't give me these spikes then I'll go back to Tesco 99 and see if the occasional spikes pop up again, just to be sure.