I can't notice the difference between 'v-power' and '99 tesco' yet. I usually use 'tesco 99' but yesterday I had to go to shell, filled up and got my self a Ferrari Enzo.

 

Quite! You can get bad batches of ANY fuel.

The most prominent mappers that I've spoken to have all said Vpower would be there first choice by far for a Scooby, with BP ultimate being down on the list somewhere below coal! Tescos is, by all accounts, pretty well liked by scoobies too.

Ns04

 

thats another new keyboard with coffee on it, thanks

 

not your pc so doesnt matter

 

good point

 

Opps sorry!

Nevermind, mop it up and save it in case you run out of fuel and the only nearby station sells BP ultimate!

Scoobies don't like Decaffinated though!

 

You saying that V Power is cr@p is a bit like saying Goodyear F1s are cr@p cos the handling of the car was a bit unpredictable after a blow out.

I'm not disputing you may have had a problem with it, but just because you had a problem, doesn't mean its the fuels fault. I cover 32000-35000 miles a year in an 06 STi and almost exclusively run on V Power, never had any problems - and that goes for the Optimax I used before V Power in the other 4 Scoobs I've owned.

Gareth

 

has this car been remapped ever considering you mods?

 

Tesco 99



Shell V-Power



While the figures are identical within tolerances that matter - I think the curves should speak for themselves.

So that should end that little argument

 

But unless this was done on the same day with the exact conditions you can't compare.

 

Both days were cold, both were overcast, and both days were fairly wet. The Tesco 99 day, from memory, actually being slightly colder - and therefore, the advantage, if any, should have been Tescos. One of them was not done in the heat of summer and the other in the depths of winter.

My personal opinion is that anyone who believes that a difference of a few millibars of pressure, a degree or two of temperature, or a couple of % of humidity is going to make a noticeable difference on a normal road car on your average rolling road is being a bit optimistic about the sensitivity of the ECU. The conditions were, in my mind - and that of the rolling road operators, close enough to have not made any difference to the result.

 

there does seem to be a lot of variance on Vpower lately: I started getting a lot of knock recently (over a few tank fulls) which I started to dial out (Apexi) but then after filling up and driving 6 miles, leaving the car overnight the knock has dropped right down to manageable levels!
just when I was getting worried!

filled up twice since and all still seems good (gonna add some advance now to get back to the old settings again)

cant find a Tesco garage near me 8(

 

As Prasius has said there are so many variations that can affect results. How long was the fuel sitting in your cars tank, how long was the fuel been at the pumps. Temperature, Humidity, Atmospheric Pressure etc etc etc.

Tesco 99 might well be on par with V-Power from a bhp point of view but Shell spend millions a year on fuel development, so I know where I'll be putting my money.

There is more to fuel than peak bhp figures.

 

Quite possible that the extra ignition advance has highlighted a looming problem..?
Or the bugeye's notoriety for random cels..?

What gets me with these threads where people say, "I put 95 in and it's fine...! "
well I'm sure my scoob would run OK too, but would it be giving it's best possible performance..?

Simple answer, NO..!

Why run a car like an scoob on something that's not going to allow your car to perform at it's best..? And please don't say I didn't buy an Impreza for the performance..!

PS Esso SUL is up there with the best of the rest and would be my choice if V-power/T99 were not available..

 

AGREED!!!

v power is 1 off the best performance fuels you get!!!

 

Because you live in England where you cannot use the cars performance anyway so why quibble about which petrol to use.

Your car was made to use the cheapest, crapiest petrol England has to offer ie 95 RON

Your car will run happily all its life on 95 RON petrol unless you change the manufacturers programming of it.

Yes you may get better performance out of 97, 98, or 99 RON petrol, then again you may not.

When I started running my standard MY00 on 100 RON V-Power it hated it and did not run properly at all, I had to get it remapped to use the extra RONs that Subaru had not envisaged my car running on.

Also the V-Power we get here is much better than the crap they sell you in England and it is also 100 RON not 98/99. But then again the BP Ultimate we get here is also 100 RON and not the 97 you get in England.

 

^When you're referring to the UK in future, please remember it's the UK, not England!

 

I didn't refer to the UK I refered to England where the OP comes from, but I suspect it is the same in the other countries of the UK aswell.

Plus if all you could find to complain about in my post was UK/England then I can't have been far wrong with what I wrote

 

 

not if he has a jap import, they were built to run on a higher grade of go go juice

 

I would also like to add that my MY03 Blobeye WRX (UK) has a sticker on the inside of the fuel flap saying "98 RON Minimum" - so please be aware that whilst UK classics are fine with std 95 RON, Newages (or at least Blob's) are not reccomended by the manufacturer to use 95 RON standard unleaded.

 

You replied as I was about to as my 05 WRX (EU) also has the same sticker "98 ron minimum", so I think you may need to rethink that one Wurzel..!

 

I like to agree with jasonius here.

My UK STi is designed to run on 98ron fuel and from what I'm lead to believe after the first mapping session is the car had been run on 95ron for some time. What this had done is reduce the ignition multiplier from x16 to x8, permanantly pulling timing out because of this. So the cars a designed to run on 98ron, the denso ECU's will tollerate 95ron but at a cost.

I also agree with, why spend your money on a performance car like the Impreza and twine about how much it costs to run. You could buy a Citreon AX GT for £500 and have as much fun in it on B roads. You dont need to be doing 100mph to get a grin, you just choose twistier roads.

V-Power (98ron in the UK despite the new name) is the one of the best fuels available in the UK in my opinion, Tesco 99ron is principally a great fuel.

I use V-Power.

I've never had a problem with it, always had good results, only problem is finding a Shell garage.

I have never used Tesco 99ron. ESSO Super I have used but never booted the with it in as I had no Knock detection then.

There were some tests done that showed ESSO Super being the second best after V-Power (Tesco 99ron wasn't tested though).

Ask a good mapper which is the best fuel for an Impreza, they will have a good idea due to how the engine reacts to each fuel. Its a question they've always asked me before the mapping session starts, "What fuel have you got in?".

 

Maybe the octane rating of vpower is encouraging the ecu to run a touch more advance? Just a thought... especially when combined with cold damp weather?

 

Ive ran V power for over a year now and since my remap with Bob Rawle on 02/02/08. My car is mapped for v power and its awesome, Bob said only use V power or tesco 99 RON

Simple as ...end of!!!! lol

 

I'd take the word of the masses here. V-power is the best pump fuel there is. Admittedly followed closely by Tesco 99.

But the OP's ignorance over people way more knowledgable than he or I is a tad misplaced.

I run V-power in a 500bhp UK classic and get det on anything other than V-power or Tesco. I can however feel a slight dip in performance when using Tesco. But this is only after a good few miles of a refil from near empty after using V-power.

To say its crap is quite frankly talking bollix

 

i read about a month ago that if you run your car for 12000 miles on v power instead of normal unleaded it only costs you £85 extra
a bit off topic just food for thought

 

Code 21 is "Water Temperature Sensor" apparently, Subarus are a bit odd in that they use their own two-digit trouble codes as well as the 5-digit standard ODBII ones.

Not sure how changing your fuel would affect the functioning of that sensor, most likely the ECU just cleared the fault itself. If the sensor is reading incorrectly, but not actually dead, then there will be times when it is giving a valid (but incorrect) value and other times when it is giving a value that is completely out of range triggering the CEL. Once the CEL is triggered the ECU may switch to a more cautious setting, in this case probably whatever settings it uses if it needs to reduce engine temperatures.

You should probably get that looked at (as well as any other sensors that may be on their way out) before you try to do a comparison of various fuels.

 

I think a lot of it is to do with how much fuel the garage sells. If they do not have high turnover, the fuel degrades by a few RON whilst in the storage tank. With fresh fuel, 99 RON is usually 101/102, but old fuel could easily be 97/98.

I used to use the Esso filling station on the perimter road by Heathrow Airpot. Their fuel turnover was humungous and the car went noticeably well on it. Buying Esso from a local filling station in deepest Oxofrdshire, and the car felt "flat" within a few miles.

 

Your bang on with that one mate