GolfGTIforum.co.uk
Model specific boards => Golf mk7 => Topic started by: benmartingolf on 20 May 2015, 20:51
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Hi all,
I hopefully pick up the new motor next week and I know the GTI can run on just unleaded but are there any disadvantages to using it or advantages to using super unleaded?
Some people say you can get better fuel economy with the super unleaded but does anyone see any major differences either way?
Thanks, Ben
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if I was buying a new gti it would get the super unleaded as extra cost per tank is minimal :smiley:
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I think il try to use super unleaded as i think even though you can use unleaded super unleaded is recommended. But I just didn't know if anyone saw any differences.
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if I was buying a new gti it would get the super unleaded as extra cost per tank is minimal :smiley:
But it is set up for RON95. It won't be able to benefit from RON98 fuel like the R can. Extra cost per tank minimal? 9% more, for perhaps a slightly better set of detergents and no mpg gains - throwing money away. If the GTI could run appreciably better on RON98 then VW would be recommending it.
Running an R on RON95 will be a false economy though - it will be running more efficiently on RON98, your 10p/L savings buying RON95 will be negated with lower mpg as the car ends up igniting it earlier than it would like to avoid pinking.
Contrary to popular belief, RON98 isn't any more calorific than RON95, it is less volatile so it can be squeezed further (greater compression ratio, or same compression ratio at a higher operating temp) without pinking before it is intentionally ignited by the spark plug. Running a RON95 optimised car on RON98 fuel just means that the fuel isn't being compressed to its full potential before ignition and at best will ignite in the same way as RON95, at worst you could get an incomplete burn (unlikely, as petrol of both types have a low flash point). The only obvious advantage then is running a tank through for any detergent cleaning benefits.
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Most modern cars have adaptive ECU's (learning) which monitors the quality of fuel in the tank, after 2 - 3 tank fulls of Super Unleaded you'll notice the difference, it also keeps the engine clean.
I have been using Shell Optimax, V-Power and Nitro since 2000 in various cars and its worth paying the extra few £££'s per tank full in my opinion. :cool:
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Save the cash. This is from my GTI manual:
(https://dl.dropboxusercontent.com/u/23724295/Golf%20Forum/MK7%20Golf%20GTI/Fuel.jpg)
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Il be taking the manual to bed when I get it. A little bedtime reading. From what I remember its always been an interesting debate.
The difference at the pumps is around 5p per litre i think.
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Il be taking the manual to bed when I get it. A little bedtime reading. From what I remember its always been an interesting debate.
The difference at the pumps is around 5p per litre i think.
Around 10p a litre like for like around me. Shell RON95 = around 114p/L, shell 99 = 124p/L. I can get Esso/Tesco 99 for around 120p/L if I shop around, so that 5 or 6p difference is comparing Esso Supreme 97 to Shell Vpower 99.
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Most modern cars have adaptive ECU's (learning) which monitors the quality of fuel in the tank, after 2 - 3 tank fulls of Super Unleaded you'll notice the difference, it also keeps the engine clean.
I have been using Shell Optimax, V-Power and Nitro since 2000 in various cars and its worth paying the extra few £££'s per tank full in my opinion. :cool:
Cleaner car, for 10p/L? Possibly/likely. Placebo effect? Very likely. A RON 95 optimised car won't advance the timing to take advantage of RON98/99, but a RON98 optimised car will retard the timing to run RON95 without pinking. Smart timing alteration is designed to adapt to the use of lower quality fuel than is desired, due to lack of availability, not to make the car overperform when given a diet of higher RON fuel. In previous years between 2000 and now, VW were optimising certain cars (including the GTI) that sat below the R32 and were optimised for RON98.
At the end of the day it's your money. :whistle:
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Matt your wasting your time explaining it. Placebo effect will always win over scientific knowledge :wink:
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Matt your wasting your time explaining it. Placebo effect will always win over scientific knowledge :wink:
Or VW engineering development and set-up. :whistle:
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https://youtu.be/WTaBngvsPrc
I'll just leave this here, and help fuel the fire a little more.
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https://youtu.be/WTaBngvsPrc
I'll just leave this here, and help fuel the fire a little more.
So the "best" premium fuel gave 2.1% more hp than the worst, but will on average cost 9% more right now than standard RON95, one of the 3 premium fuels gave no discernible gains over the 2 standard fuels and no mpg data was available.
Is the MK6 GTI in ED35 tune officially recommended to use RON95 or RON98? How quickly will the cars ECU adapt properly to change in fuel to be using it optimally? Not the complete story from that flawed experiment.
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https://youtu.be/WTaBngvsPrc
I'll just leave this here, and help fuel the fire a little more.
So the "best" premium fuel gave 2.1% more hp than the worst, but will on average cost 9% more right now than standard RON95, one of the 3 premium fuels gave no discernible gains over the 2 standard fuels and no mpg data was available.
Is the MK6 GTI in ED35 tune officially recommended to use RON95 or RON98? How quickly will the cars ECU adapt properly to change in fuel to be using it optimally? Not the complete story from that flawed experiment.
MK6 GTI setup for 95 RON,the older EA113 based engines in the 6R/ED35 retained the existing 98 RON recommendation.
If you run a modified ECU or a tuning box, super unleaded will give more scope for gains.
The Dyno runs in that video were filmed at RTECH.
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I do love the 95vs98/99 octane debate. I used premium in mine to keep the engine clean. I wasn't expecting it to start spitting fire. Obviously when it was mapped it's a totally different story.
With the R only V power goes near it.
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The choice is easy here in Ireland. You use regular unleaded or you walk :laugh:
Super unleaded hasn't been available here for as long as I can remember. That tells you all you need to know. VW / Audi / BMW retail the exact same GTI's, R's, RS4's, M3's as they sell to you guys. We "make do" with ordinary unleaded and it works just fine.
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The R will pull back on power though as its specifically tuned to use 98minimum.
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:grin: "Dyno Runs"
We all know how accurate they are !
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:grin: "Dyno Runs"
We all know how accurate they are !
True, some are better at operating them than others...
The video itself doesn't show any 'surprise' results but you'll often read 'yeh yeh the published figures must be under quoted' :grin:.
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In fairness I have tried both and mpg/performance wise I haven't noticed any difference. The only difference that I could notice between Shell regular(95RON) and V Power Nitro (99RON) is the sooty exhaust pipes with 95RON. The soot builds up slower on them with 99RON. Thank God for Cif Lemon that keeps them as new after each wash.
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I'm sure I feel a difference :rolleyes: seems to run slightly smoother/quieter.
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There has never been a consensus on this, and the differing opinions on here show that.
I've always seen more mpg from super unleaded. Over 10k miles (all recorded in a fuel app), I've consistently gotten 30+ miles more per tank on Tesco99 over standard fuel. That's around 10% more and the fuel is 5p more expensive which is less than 5%, so it's worthwhile for me. As for responsiveness that is more subjective and can't really prove unless dyno'd.
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I tried 99 in my GTI and didn't notice any real difference in power nor consumption. However, when I've been forced to use 95 in my R I notice its worse on both counts. Therefore I only use 99 now :smiley:
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:grin: "Dyno Runs"
We all know how accurate they are !
True, some are better at operating them than others...
The video itself doesn't show any 'surprise' results but you'll often read 'yeh yeh the published figures must be under quoted' :grin:.
Any potential differences in results due to changing the fuel are negated by the lack of accuracy of the results from the dyno.
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I've run my last 2 gti's on predominantly on Super (usually Shell V Power Nitro+) and will be running the R on it (which it is optimised to). No real discernable difference in power or improved mpg, but always been as smooth as you like.
The debate will go on...
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Save the cash. This is from my GTI manual:
(https://dl.dropboxusercontent.com/u/23724295/Golf%20Forum/MK7%20Golf%20GTI/Fuel.jpg)
This reads very generic to me and not specific to the GTI unless Iv'e missed something. It fails to mention WHAT the GTI needs! It just says if you run extra RON you will have no benefit dependant on the engine . i.e. this could be in a 1.4 golf (no benefit) or a GTI manual possible benefit
Under my fuel cap it says 95 minimum, as someone has mentioned the ECU knows what's running through thus put 99 in and the ECU adjusts giving a little more performance but it will run on whatever.
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To me it reads as if to say "fill with whatever it says on your fuel cap", but don't fill with less than that (in some countries, petrol with a RON as low as 87 can be found at the pumps).
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This reads very generic to me and not specific to the GTI unless Iv'e missed something. It fails to mention WHAT the GTI needs! It just says if you run extra RON you will have no benefit dependant on the engine . i.e. this could be in a 1.4 golf (no benefit) or a GTI manual possible benefit
It read generic because all Golfs with exception of the R are tuned to run on 95 RON. The R handbook will be different. You are literally burning money putting higher grade in.
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I've posted this before but it seems appropriate to do so again.
All about Octane and how some cars will never take advantage of higher RON fuels.
https://www.youtube.com/watch?v=D9nhXNarFdg
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I've posted this before but it seems appropriate to do so again.
All about Octane and how some cars will never take advantage of higher RON fuels.
https://www.youtube.com/watch?v=D9nhXNarFdg
Very interesting, not seen it before. I have not been using super unleaded and now I know I am throwing money away if I do. Thanks for posting.
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I've posted this before but it seems appropriate to do so again.
All about Octane and how some cars will never take advantage of higher RON fuels.
https://www.youtube.com/watch?v=D9nhXNarFdg
Some people will still disbelieve it though, unfortunately.
Putting RON 98 fuel into a RON 95 optimised car just makes the cylinder ignite it earlier and at a lower compression ratio than the fuel was designed for. RON98 fuel isn't more calorific, it just resists a higher compression ratio without pinking. The timing on a RON 95 car may well be able to advance, but it can't alter the car's compression ratio to make it compress the RON 98 fuel more.
Definitely more opportunity to cause damage to a RON 98 optimised car running on 95 than a 95 optimised car running RON 98, having to ignite the RON95 fuel prematurely to avoid pinking.
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This thread is right up there in my top 5 of most mundane topics yet.
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Is that mundane or pointless Craig :grin: :grin:
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Both sum it up nicely Chris :grin:
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Contrary to popular belief, RON98 isn't any more calorific than RON95, it is less volatile so it can be squeezed further (greater compression ratio, or same compression ratio at a higher operating temp) without pinking before it is intentionally ignited by the spark plug. Running a RON95 optimised car on RON98 fuel just means that the fuel isn't being compressed to its full potential before ignition and at best will ignite in the same way as RON95, at worst you could get an incomplete burn (unlikely, as petrol of both types have a low flash point). The only obvious advantage then is running a tank through for any detergent cleaning benefits.
MH,
The compression ratio does not change. In order to avoid pinking with lower grade fuel the car retards the ignition timing to avoid pre-ignition (pinking/knocking) using (in most cases) knock sensors. When the ECU detects pre-ignition it retards the ignition until none is detected then progressively in small increments increases it until it reaches a pre-programmed limit or pre-ignition is detected again. However, in a car optimised for 95 RON fuel it will never advance the timing to a point where it can take advantage of the more expensive fuel. Pre-ignition is bad and can cause serious damage to an engine - holed pistons etc.
You are correct to say that the calorific value of the 98 RON petrol is little more than 95 RON; however, you will generate more power if the car is optimised for 98 because you can run more advanced timing...
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Contrary to popular belief, RON98 isn't any more calorific than RON95, it is less volatile so it can be squeezed further (greater compression ratio, or same compression ratio at a higher operating temp) without pinking before it is intentionally ignited by the spark plug. Running a RON95 optimised car on RON98 fuel just means that the fuel isn't being compressed to its full potential before ignition and at best will ignite in the same way as RON95, at worst you could get an incomplete burn (unlikely, as petrol of both types have a low flash point). The only obvious advantage then is running a tank through for any detergent cleaning benefits.
MH,
The compression ratio does not change. In order to avoid pinking with lower grade fuel the car retards the ignition timing to avoid pre-ignition (pinking/knocking) using (in most cases) knock sensors. When the ECU detects pre-ignition it retards the ignition until none is detected then progressively in small increments increases it until it reaches a pre-programmed limit or pre-ignition is detected again. However, in a car optimised for 95 RON fuel it will never advance the timing to a point where it can take advantage of the more expensive fuel. Pre-ignition is bad and can cause serious damage to an engine - holed pistons etc.
You are correct to say that the calorific value of the 98 RON petrol is little more than 95 RON; however, you will generate more power if the car is optimised for 98 because you can run more advanced timing...
I think you misread my post. I know the compression ratio on an engine does not change (the fundamental reason why a RON95 optimised car cannot noticeably take advantage of RON98 fuel even if ignition timing is advanced), I was stating that RON98 fuel can be compressed further without pre-ignition than RON95 i.e. in an engine with a higher compression ratio that is optimised for RON98 fuel.
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I dont care what you all say, I get double shell points with V-Power and I have a fuel card, so god bless pointlessly expensive fuel :wink:
On a serious note tho, I have to admit I am in 'notice a difference' camp when it comes to V-Power, even when I tried it in my old megane as a young idiot once, and I swear it was a nicer car to drive on that tank.
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I dont care what you all say, I get double shell points with V-Power and I have a fuel card, so god bless pointlessly expensive fuel :wink:
Best part is when you come home from work, open the door and find the fuel vouchers on the doormat :evil:
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This thread is right up there in my top 5 of most mundane topics yet.
I agree
Fuel tanks empties. Fuel goes in.......And repeat !!
......Next :whistle: :whistle:
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I think shell are s4ite. I give them my card and they never swipe it properly and then my account balance is always wrong. Pi44 poor :angry: