Post by: flashp on March 28, 2017, 07:04:12 pm
I just tried a tank and I'm over halfway through after filling when very low. Now, I'm sure (but can't be certain - placebo) that the car is running better and returning slightly better mpg with it, which the gauge seems to confirm.
It's stage 2 with all the usual parts, 330bhp.
Anyone else had similar experiences?
Of course it could be that V-Power is a slow seller from my local Shell garage and that the Tesco's near me turns their 99 over much more quickly so it's always fresher.
Post by: AJP on March 28, 2017, 07:31:10 pm
Last summer I had a load of misfire issues (there's a big thread on it somewhere) that were finally cured - or so it seemed - with refurbished injectors.
The local Shell I'd always used closed for a few weeks late last year for refurbishment, and when it reopened V Power unleaded was unavailable. A few weeks ago, chatting to the lad serving at the next-closest Shell that do sell V Power, he informed me that the reason my local one stopped selling it was because the tank had become contaminated with water.
It might just be a coincidence, but I couldn't help putting 2 and 2 together. I'm not ruling out the possibility of me filling up with dodgy V Power for god knows how long, causing those misfires. I suppose it's water under the bridge now anyway. And I'd imagine this kind of thing could happen at any garage - Shell, Tesco, whatever.
But back to the fuel itself. I remember reading a big thread on a Skyline forum where this same question was asked. Emails were sent to Shell, and Tesco, and while it sounded like one of the two was a 'proper' 99 ron and therefore 'better', the thread pretty much concluded at V Power being the better of the two.
In my personal experience, I've had half a tank of Tesco 99 a couple of times, and I honestly couldn't tell a difference. Car's also a Stage 2, R-Tech, k03.
I'm inclined to think that if one is indeed marginally better than the other, you'd only feel a massive difference if you were running huge boost and advance.
Back to back testing is the only real way of objectively getting some answers. In fact I do remember a certain Mr Gower doing this very thing on Fifth Gear maybe... a good few years ago!
Post by: Shoduchi on March 28, 2017, 08:12:44 pm
Post by: flashp on March 28, 2017, 08:27:23 pm
Wish I knew about petro-chemistry! :rolleye:
Post by: Shoduchi on March 28, 2017, 08:31:25 pm
I'm inclined to agree, and I think that the Tesco 99 is fresher than the V-Power in this case which is something that crossed my mind initially. Either way, it seems I've located a better quality supply of fuel. :happy2:I wish I knew more too. I have to use a petrol octane booster if I want more power from my engine. Just 98 RON petrol where I live. :wink:
Wish I knew about petro-chemistry! :rolleye:
Post by: flashp on March 28, 2017, 08:32:52 pm
That's a bit off, where are you then?I'm inclined to agree, and I think that the Tesco 99 is fresher than the V-Power in this case which is something that crossed my mind initially. Either way, it seems I've located a better quality supply of fuel. :happy2:I wish I knew more too. I have to use a petrol octane booster if I want more power from my engine. Just 98 RON petrol where I live. :wink:
Wish I knew about petro-chemistry! :rolleye:
Post by: Shoduchi on March 28, 2017, 08:33:56 pm
That's a bit off, where are you then?Lisbon, Portugal.
Post by: flashp on March 28, 2017, 08:41:10 pm
Nice :happy2: I'd trade 1RON point for all your sun, landscape and great roads!That's a bit off, where are you then?Lisbon, Portugal.
Post by: Shoduchi on March 28, 2017, 08:48:11 pm
Nice :happy2: I'd trade 1RON point for all your sun, landscape and great roads!That's a good point. :happy2:
Most of the days I can put my right foot down without much wheelspin since it doesn't rain that often here. On rainy days a powerful FWD loses a lot of its fun.
Post by: AJP on March 28, 2017, 09:11:59 pm
You don't know how envious we are! Still, we can look forward to our annual fortnight of warm weather just the sameNice :happy2: I'd trade 1RON point for all your sun, landscape and great roads!That's a good point. :happy2:
Most of the days I can put my right foot down without much wheelspin since it doesn't rain that often here. On rainy days a powerful FWD loses a lot of its fun.
Then of course it just rains. And rains...
Post by: spesh on March 28, 2017, 09:46:59 pm
Most likely you filled with fresh 99 RON petrol where before the V Power wasn't that fresh. I only recently learned that the higher RON capabilities of a petrol only last about a week in a tank. That's not a great deal of time, unfortunately.
Who on earth told you that because it is utter nonsense. The spec shelf life of super is well above that of standard blendstocks (eurobob being the most commonly known blendstock in the uk for standard unleaded). If you think your super is less than a week old by the time it gets to you car you are mistaken, if you are really really lucky you might get 3-4week old (from refining), in reality your more likely getting a couple of months old and it will be mixed with older again (mostly due to oil terminals running just one super tank so its never run dry before receiving another parcel into it)
Any yes, i work in the industry. The actual differences between tesco, bp and shell super are very very marginal and most perceived differences are down to the petrol station storage rather than the actual fuel (as mentioned by another poster in this thread)
Post by: shoaybmakda on March 28, 2017, 10:05:37 pm
I drive a stock Gti and have no idea if it will make a significant difference but if I'm putting a better grade of fuel in then it's all good.
Dosnt rtech also say when mapping to have a tank full of v power or Tesco 99 in when getting the car mapped? Must be something in it if that's their requirements
Post by: Shoduchi on March 28, 2017, 10:48:22 pm
Most likely you filled with fresh 99 RON petrol where before the V Power wasn't that fresh. I only recently learned that the higher RON capabilities of a petrol only last about a week in a tank. That's not a great deal of time, unfortunately.
Who on earth told you that because it is utter nonsense. The spec shelf life of super is well above that of standard blendstocks (eurobob being the most commonly known blendstock in the uk for standard unleaded). If you think your super is less than a week old by the time it gets to you car you are mistaken, if you are really really lucky you might get 3-4week old (from refining), in reality your more likely getting a couple of months old and it will be mixed with older again (mostly due to oil terminals running just one super tank so its never run dry before receiving another parcel into it)
Any yes, i work in the industry. The actual differences between tesco, bp and shell super are very very marginal and most perceived differences are down to the petrol station storage rather than the actual fuel (as mentioned by another poster in this thread)
I'm glad to know that petrol can withstand longer in tanks before losing its octane level. :smiley:
I already knew about those differences between fuels. It's the additives added to fuels that make the difference between them, the quality of the storage and turnover in petrol stations that matter. I prefer going to busy petrol stations (on low activity hours) because of that.
Post by: rich83 on March 28, 2017, 10:56:59 pm
Post by: PatchySan on March 29, 2017, 01:35:17 am
However my previous MK5 Golf with the 1.6 FSI engine hated it, it knows the difference when I use Tesco 99 fuel as it shakes and vibrates badly on startup in cold days! No idea why but it just seems to happen only on Tesco 99 fuel, didn't have any issues when I refilled it with Shell V-Power after so because of this I tend to use Shell whenever I can as it just seems to be the most consistent for me.
Also Tesco in co-operation with Millbrook Testing had published economy results comparing its Momentum 99 fuel to a "competitors 99 grade premium fuel" which most likely is Shell V-Power as BP, Esso and others only do up to 97 RON here in the UK. Their report showed that on a VW Golf 1.6 FSI and Audi TT 2.0 TFSI (BWA) that the "competitors (V-Power)" 99 fuel to be the most efficient in terms of fuel consumption though the Tesco 99 fuel wasn't that far off to be honest, both were much better than the standard 95 RON fuels on test. Link to the report can be found here (https://d16vpkeamxept2.cloudfront.net/assets/6ca06d648b9541e78fa838fece4a1a23.pdf) if you like these geeky stats.
Post by: Horatio on March 29, 2017, 03:07:21 am
Post by: richtung on March 29, 2017, 07:39:17 am
A quick search indicates the fuel is supplied by Greenergy who also supply Tesco.
I don't have the latest prices to hand but im confident Costco 99 RON will be cheaper than both Shell and Tesco.
A link to the Costco leaflet talking about their fuels https://srv-file1.gofile.io/download/w1ry3d/785ba8c580bf94bda735aa3b2fbcd1e2/Costco-Fuels.pdf (https://srv-file1.gofile.io/download/w1ry3d/785ba8c580bf94bda735aa3b2fbcd1e2/Costco-Fuels.pdf) (originally linked from scoobynet)
Hope this helps!
Rich
Post by: Orc on March 29, 2017, 08:15:15 am
Post by: grey golfster on March 29, 2017, 10:34:39 am
Have to say when I do use Shell I can't tell the difference, either from numbers or seat of pants.
Post by: pudding on March 29, 2017, 10:40:39 am
Any improvement from filling up with a different fuel is because it's cold. Cold fuel has a similar affect/benefit as cold air. It's even more noticeable on a port injected engine which has a return line from the fuel rail. This is why diesels have fuel coolers and MK5s switched to a return-less fuel rail.
An engine that meters fuel via air mass can't suddenly improve it's mpg from octane rating or fuel brand. Mpg is directly proportional to the throttle pedal! If the mpg improves, you are driving the car differently, or there is less wind that day, or the air is a bit denser etc etc.
ECUs do not continuously add ignition advance until it hears pinking, therefore 'tunes itself' to the octane. ECUs are set up with the MBT at the factory, for the fuel specified on the filler flap (98 in our case). The ECU can only retard, it cannot 'add' timing on the fly.
Fuel does not 'go off', certainly not within the time frame of a frequently used car. I've had V power sat in a tank for 11 months whilst working on a project car, and it fired up and ran perfectly on 'stale' fuel.
Any sudden change in behavior from switching fuels is likely down to contamination. The Engine/ECU really doesn't care what's in the tank, so long as it meets the minimum RON. It's all pretty much placebo.
I stopped using Momentum 99 back when I had my R32, because it started misfiring pretty much immediately after filling up with it. Never had that before or since with V power.
What I can tell you about V power is it does seem to contain some nice cleansing additives. I did 60K miles in an old project car. Freshly built engine, V power used exclusively. I stripped it down after 60K at everything in the combustion chambers was spotless :smiley: These additives make NGK Iridium plugs turn orange!
Post by: Dan_FR on March 29, 2017, 11:07:46 am
So many misunderstandings about fuel:
Any improvement from filling up with a different fuel is because it's cold. Cold fuel has a similar affect/benefit as cold air. It's even more noticeable on a port injected engine which has a return line from the fuel rail. This is why diesels have fuel coolers and MK5s switched to a return-less fuel rail.
An engine that meters fuel via air mass can't suddenly improve it's mpg from octane rating or fuel brand. Mpg is directly proportional to the throttle pedal! If the mpg improves, you are driving the car differently, or there is less wind that day, or the air is a bit denser etc etc.
ECUs do not continuously add ignition advance until it hears pinking, therefore 'tunes itself' to the octane. ECUs are set up with the MBT at the factory, for the fuel specified on the filler flap (98 in our case). The ECU can only retard, it cannot 'add' timing on the fly.
Fuel does not 'go off', certainly not within the time frame of a frequently used car. I've had V power sat in a tank for 11 months whilst working on a project car, and it fired up and ran perfectly on 'stale' fuel.
Any sudden change in behavior from switching fuels is likely down to contamination. The Engine/ECU really doesn't care what's in the tank, so long as it meets the minimum RON. It's all pretty much placebo.
I stopped using Momentum 99 back when I had my R32, because it started misfiring pretty much immediately after filling up with it. Never had that before or since with V power.
What I can tell you about V power is it does seem to contain some nice cleansing additives. I did 60K miles in an old project car. Freshly built engine, V power used exclusively. I stripped it down after 60K at everything in the combustion chambers was spotless :smiley: These additives make NGK Iridium plugs turn orange!
Not strictly true. Brand is irrelevant but the calorific value of fuel will vary depending on the brand i.e. the fuel & additives used. The higher calorific fuel will produce more energy per combustion stroke resulting in a lower request (via the right foot) for fuel.
One cause of varying calorific content is the ethanol content. Momentum complies with BS EN 7800 which allows for up to 5% ethanol content. Ethanol has a much lower calorific value than petrol. Tesco admit that the Ethanol content varies between 0 and 4.8% depending on the location and supplier. Just one example.
As for ignition advance - It is surprising when logging a standard car just how much advance there is on a standard map, and just how much correction is going on, especially on 95 RON fuel.
Post by: Paradox1 on March 29, 2017, 11:24:16 am
Test is my main for super unleaded.
Although, if it wasnt so far to drive to, id fill up with sainsbury's . My car performed at its best on that stuff
Post by: flashp on March 29, 2017, 12:38:32 pm
However, the most likely conclusion is that my Shell garages (Rowlands Castle, Hampshire and Farlington) don't have a good quality supply of V-Power.
I think I'll continue with Tesco's and see how it goes longer term.
Post by: reflexsilverfox on March 29, 2017, 01:18:03 pm
Post by: pudding on March 29, 2017, 02:16:11 pm
So many misunderstandings about fuel:
Any improvement from filling up with a different fuel is because it's cold. Cold fuel has a similar affect/benefit as cold air. It's even more noticeable on a port injected engine which has a return line from the fuel rail. This is why diesels have fuel coolers and MK5s switched to a return-less fuel rail.
An engine that meters fuel via air mass can't suddenly improve it's mpg from octane rating or fuel brand. Mpg is directly proportional to the throttle pedal! If the mpg improves, you are driving the car differently, or there is less wind that day, or the air is a bit denser etc etc.
ECUs do not continuously add ignition advance until it hears pinking, therefore 'tunes itself' to the octane. ECUs are set up with the MBT at the factory, for the fuel specified on the filler flap (98 in our case). The ECU can only retard, it cannot 'add' timing on the fly.
Fuel does not 'go off', certainly not within the time frame of a frequently used car. I've had V power sat in a tank for 11 months whilst working on a project car, and it fired up and ran perfectly on 'stale' fuel.
Any sudden change in behavior from switching fuels is likely down to contamination. The Engine/ECU really doesn't care what's in the tank, so long as it meets the minimum RON. It's all pretty much placebo.
I stopped using Momentum 99 back when I had my R32, because it started misfiring pretty much immediately after filling up with it. Never had that before or since with V power.
What I can tell you about V power is it does seem to contain some nice cleansing additives. I did 60K miles in an old project car. Freshly built engine, V power used exclusively. I stripped it down after 60K at everything in the combustion chambers was spotless :smiley: These additives make NGK Iridium plugs turn orange!
Not strictly true. Brand is irrelevant but the calorific value of fuel will vary depending on the brand i.e. the fuel & additives used. The higher calorific fuel will produce more energy per combustion stroke resulting in a lower request (via the right foot) for fuel.
One cause of varying calorific content is the ethanol content. Momentum complies with BS EN 7800 which allows for up to 5% ethanol content. Ethanol has a much lower calorific value than petrol. Tesco admit that the Ethanol content varies between 0 and 4.8% depending on the location and supplier. Just one example.
As for ignition advance - It is surprising when logging a standard car just how much advance there is on a standard map, and just how much correction is going on, especially on 95 RON fuel.
That's a good point and I can see that when comparing diesel to petrol to ethanol, but surely petrol vs petrol is going to have a negligible difference in calorific value? For the ECU to proactively read a difference in calorific value, it would need a fuel content sensor + appropriate compensations.
For one fuel to 'feel' more responsive than another for a given pedal request, and therefore smaller injector duties, it would have to be one hell of a difference in calorific value. I have yet to notice much of a difference between the usual brands, other than WOT conditions where the better fuels don't cause as much timing pull.
Maybe Tesco's ethanol range of zero to 4.8% percentage could explain the inconsistency some people notice?
Yeah, lots of timing at low loads but as soon as it goes anywhere near boost, down it goes, way down.....even to the point of firing AFTER tdc! These engines don't need a lot of timing on load as the combustion chambers are good and direct injection negates the need for a ton of timing to some extent, because higher CRs and homogenized burn the fuel/air mix faster.
Post by: Dan_FR on March 29, 2017, 03:10:50 pm
Quote from: Pudding
That's a good point and I can see that when comparing diesel to petrol to ethanol, but surely petrol vs petrol is going to have a negligible difference in calorific value? For the ECU to proactively read a difference in calorific value, it would need a fuel content sensor + appropriate compensations.
For one fuel to 'feel' more responsive than another for a given pedal request, and therefore smaller injector duties, it would have to be one hell of a difference in calorific value. I have yet to notice much of a difference between the usual brands, other than WOT conditions where the better fuels don't cause as much timing pull.
Maybe Tesco's ethanol range of zero to 4.8% percentage could explain the inconsistency some people notice?
Yeah, lots of timing at low loads but as soon as it goes anywhere near boost, down it goes, way down.....even to the point of firing AFTER tdc! These engines don't need a lot of timing on load as the combustion chambers are good and direct injection negates the need for a ton of timing to some extent, because higher CRs and homogenized burn the fuel/air mix faster.
The point was that our petrol isn't just petrol. It's petrol, mixed with ethanol, benzene and a whole host of other additives and it does vary a lot. The ECU won't see any difference, other than the car will produce more power for the given fuel, meaning less (right foot requesting) is needed. Small changes to mixture need to be compensated for due to the ethanol content affecting lambda reading, but again we're talking a couple of percent which is marginal at best
Going back to the test linked previously as supplied by Momentum, it pretty much sums up that Momentum is better than branded or non branded 95, but that 'other 99' fuels i.e. the unnamed Shell V-Power, is better again
I dunno, I'm far from an expert. I just know that 'fuel' isn't just fuel regardless of brand
Post by: Manny_ED30 on March 29, 2017, 03:57:57 pm
Post by: pudding on March 29, 2017, 05:21:36 pm
Quote from: PuddingThat's a good point and I can see that when comparing diesel to petrol to ethanol, but surely petrol vs petrol is going to have a negligible difference in calorific value? For the ECU to proactively read a difference in calorific value, it would need a fuel content sensor + appropriate compensations.
For one fuel to 'feel' more responsive than another for a given pedal request, and therefore smaller injector duties, it would have to be one hell of a difference in calorific value. I have yet to notice much of a difference between the usual brands, other than WOT conditions where the better fuels don't cause as much timing pull.
Maybe Tesco's ethanol range of zero to 4.8% percentage could explain the inconsistency some people notice?
Yeah, lots of timing at low loads but as soon as it goes anywhere near boost, down it goes, way down.....even to the point of firing AFTER tdc! These engines don't need a lot of timing on load as the combustion chambers are good and direct injection negates the need for a ton of timing to some extent, because higher CRs and homogenized burn the fuel/air mix faster.
The point was that our petrol isn't just petrol. It's petrol, mixed with ethanol, benzene and a whole host of other additives and it does vary a lot. The ECU won't see any difference, other than the car will produce more power for the given fuel, meaning less (right foot requesting) is needed. Small changes to mixture need to be compensated for due to the ethanol content affecting lambda reading, but again we're talking a couple of percent which is marginal at best
Going back to the test linked previously as supplied by Momentum, it pretty much sums up that Momentum is better than branded or non branded 95, but that 'other 99' fuels i.e. the unnamed Shell V-Power, is better again
I dunno, I'm far from an expert. I just know that 'fuel' isn't just fuel regardless of brand
Me neither, I just try to understand things from a tuning / electronics point of view and I struggle to get my head around why one brand of 99 would give better economy than a different brand of 99. Still, it's interesting debate regardless of a factual answer or not! Your theory could be tested by logging pedal requests on a tank of Tesco, and then again with a tank of V power, all in the interests of science.
The only times I've had trouble with fuel was a misfiring R32 on Momentum, and way back in 2004ish when a batch of supermarket fuel was contaminated with silicone, which killed off 1000s of O2 sensors.
Another reason I use V Power is because I always roll up to an empty pump. For Tesco I always have to queue for ages because it's cheaper, especially on Friday lunchtimes. Can't be bothered with that.
Post by: AJP on March 29, 2017, 08:22:16 pm
When I first bought my Gti I didn't know it needed higher Ron fuel until a few weeks of standard unleaded I switched to v power. After finding out Tesco sold 99 Ron for alot cheaper than v power I've always used Tesco 99.Just noticed this. Worth mentioning (if I've interpreted what you're saying correctly) that it's not just for the mapping session you'll need 99 in the tank. It's from then on: If your car is mapped on 99, run it on 99 at all times.
I drive a stock Gti and have no idea if it will make a significant difference but if I'm putting a better grade of fuel in then it's all good.
Dosnt rtech also say when mapping to have a tank full of v power or Tesco 99 in when getting the car mapped? Must be something in it if that's their requirements
It wouldn't do any good at all to stick 95 in a car with an R-Tech map!
Post by: shoaybmakda on March 29, 2017, 09:28:35 pm
But yes your right it would make no sense to go back to 95 Ron. I just went on reading posts that a lot of people said you need 99 in your tank when visiting them.
But even still on my stock car I only use 99 Ron now :smiley:
Post by: AJP on March 29, 2017, 09:32:12 pm
@AJP (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=11926) I have no idea - I haven't visited rtech yet!Good, keep it that way
But yes your right it would make no sense to go back to 95 Ron. I just went on reading posts that a lot of people said you need 99 in your tank when visiting them.
But even still on my stock car I only use 99 Ron now :smiley:
When I bought mine it got noticeably smoother and quicker after a few miles on V Power. I got the feeling it'd been run on the cheap stuff before I got hold of it. No good even for a standard car.
Post by: Kezma on March 30, 2017, 12:21:39 am
Post by: Dan_FR on March 30, 2017, 07:31:02 am
To summarise: Use V-Power if you have one locally and can afford it, otherwise Momentum will do and is better than most other (95/97) fuels
Post by: pudding on March 30, 2017, 09:45:55 am
@AJP (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=11926) I have no idea - I haven't visited rtech yet!
But yes your right it would make no sense to go back to 95 Ron. I just went on reading posts that a lot of people said you need 99 in your tank when visiting them.
But even still on my stock car I only use 99 Ron now :smiley:
I had V Power in mine when it was mapped and I've since used 95 RON without any troubles. Mine's only stage 1 though, so not pushing things too hard.
Polar FIS with the knock regulator channels up is a good way to monitor things.
Post by: grey golfster on March 30, 2017, 02:17:01 pm
I have found this selectability useful when I have not been able to find a supply of higher octane fuel. It does still happen, but less frequently nowadays!
Mrs grey not at all amused by some extended detours that have been needed to buy "special" petrol!
Can't speak for other maps, but guess APR not alone?
Post by: Addymk2 on March 31, 2017, 12:47:20 pm
Sent from my Nexus 5X using Tapatalk
Post by: flashp on April 02, 2017, 09:00:32 am
My APR map has 4 selectable maps, one of which is standard, another modded but low octane. Had this >4 years now. Pleased. The "top map" was done to V Power.I have a SPS switch for my Revo map which covers V-Power/99, 97 and 95 octane fuels. Like you I've not had to use it for this but it's nice to know you could if needed.
I have found this selectability useful when I have not been able to find a supply of higher octane fuel. It does still happen, but less frequently nowadays!
Mrs grey not at all amused by some extended detours that have been needed to buy "special" petrol!
Can't speak for other maps, but guess APR not alone?
Post by: jaylufc17 on April 02, 2017, 11:56:03 am
from memory pretty sure top gear/fifth gear have done a comparison and concluded practically no difference
Post by: richtung on April 03, 2017, 07:22:21 am
Rich