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Engine addicted to SVO??


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Is my 200tdi addicted to SVO? It runs better, more power, more poke across the range on SVO or SVO mixes than it does on 100% diesel. I had to fill up at Sainsburies (with diesel) the other day and wondered where all the grunt had gone. The pump and injectors have all been overhauled and its spoilt with how often its serviced and maintained!

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I did wonder if it could be the diesel - every time I float that thought though, folks tell me it cant be!

I might try a tank from somewhere else next time and see. It was just weird though - I was ticking along on a high % SVO mix, quite easily able to go from 70-80 to overtake on the motorway, pulled off, filled up so was close to 100% diesel and it was an effort to get to 70 after that. 100 miles later I finished that bit of the journey, put 30 litres of veg in and back to being fine again.

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There are lots of conspiracy theories on this and I've seen many people talk about cheap / carp Supermarket fuels..

All fuel in the UK needs to meet a minimum specification and the Supermarkets typically buy their fuel from the bigger refiners / brands. The only differences are likely to be any additives, which are typically cleaning agents (i.e. they do not aid combustion) so long term use of a high end brand fuel "may" result in a cleaner engine internally.

 

That all said, I always use Supermarket fuel (Having bought fuel for a major supermarket in the UK in the past as one of my roles) and never had any issues.. When I use other brands while away from UK, or supermarkets I don't notice any perceptible difference in performance.

A few years ago when I changed the head on my TD5 @150k ish miles the internals were in fine fettle, looking no worse than any other Diesels I've seen.

I'm just wondering if your pump / setup is somehow optimised for Veg oil Rich, without you knowing how or why!! :)

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It may be Neil. DieselBob did say he had adjusted it for slightly better performance. He knew I run on veg but didnt say it would affect running on diesel.

This occasion wasnt the first time i have noticed this. I guess any seller of fuel could have a bad batch??

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A plausible explanation I've heard regarding supermarket fuel is that they buy up whatever they can cheap. This probably means it's fuel getting near the end of its "shelf life". We all know what stale fuel in an old mower is like... Having done some tests myself, I don't buy supermarket fuel. My 1.8t Audi does around 25 miles per tank less on supermarket stuff than Esso, BP or Shell. Given the meagre difference in price, I'll go branded every time. 

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This wasn't the exact thread I was trying to remember, but Simon does mention his findings: 

 

SimonR:

Quote

I kept accurate fuel & mileage records for over 10 years.

What I observed.....

Supermarket fuel is typically 4 to 5% cheaper than most of the others but achieves 4-5% lower MPG - so costs the same. However, if there is a forecort fuel station near a supermarket, they are generally no more than 1% more expensive but achieve 4-5% more mpg - saving 3 to 4%

Premium Diesel is about 8% more expensive than regular - but gives about 11% more MPG (or acceleration if that's what you are after).

Best result is to buy Premium from the fuel station near the Supermarket to get an overall 7% saving.

As did I:

Quote

My experience of going from Tesco normal petrol in the pug to the Esso super unleaded was that I got a noticeable increase in MPG. I went from getting 30-35 normally (38-40 on a run) to getting 38-40 no matter how I drive.... and I don't hang about much!

I should add the MPG is calculated brim-to-brim with a fuel app on my phone.

 

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So I wonder how it would seem if I filled up with esso or bp? Might give it a go. Theres a relativley cheap texaco on the a303 I might try as I pass it twice a week if I am not using the M4

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I guess you could argue this is all subjective without any figures as a comparison.

There is more energy in a litre of diesel than a litre of svo so the opposite should be true in theory. There are a lot of scientific papers onnthe subject which can be googled that deacribe the difference in viscosity which could be affecting how the different fuels are being injected into the cylinders by your engine. They also talk a lot about deposits formed from svo. 

 I know you say your pump and injectors are well maintained; have you tried running a few tank fulls of straight diesel with an injector cleaning additive to see what happens? Also, is the fuel filter clean and water free?

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18 minutes ago, reb78 said:

So I wonder how it would seem if I filled up with esso or bp? Might give it a go. Theres a relativley cheap texaco on the a303 I might try as I pass it twice a week if I am not using the M4

Which one? There is a shell garage near to me on the west bound A303 just after Podimore which is now a Texaco.

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45 minutes ago, monkie said:

Which one? There is a shell garage near to me on the west bound A303 just after Podimore which is now a Texaco.

Thats the one Phil. By the American diner. A lot of the time its as cheap as the supermarkets at each end of my journey. Its always a lot cheaper than the nearby Esso. 

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55 minutes ago, monkie said:

I guess you could argue this is all subjective without any figures as a comparison.

There is more energy in a litre of diesel than a litre of svo so the opposite should be true in theory. There are a lot of scientific papers onnthe subject which can be googled that deacribe the difference in viscosity which could be affecting how the different fuels are being injected into the cylinders by your engine. They also talk a lot about deposits formed from svo. 

 I know you say your pump and injectors are well maintained; have you tried running a few tank fulls of straight diesel with an injector cleaning additive to see what happens? Also, is the fuel filter clean and water free?

It was just a feel. In the time taken to fill up the 110 lost its ‘spriteliness’! I was on the M5, pulled off at the A358 at Taunton because tge sainsbury there is often 7-10p cheaper per litre than a lot of other supermarkets. Filled up, back on the motorway and it was just a bit more hard work with nowhere near the ease of speed than ten mins before. 

Filters are all good (nearly new aroubd fhis fill up). No water (I can see this as I have a facet duralift as a lift pump and water would gather in the clear bowl on that if present). 

ETA - this is more about performance than economy. I have given up worrying about the latter!

Edited by reb78
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2 hours ago, reb78 said:

It may be Neil. DieselBob did say he had adjusted it for slightly better performance. He knew I run on veg but didnt say it would affect running on diesel.

This occasion wasnt the first time i have noticed this. I guess any seller of fuel could have a bad batch??

He set mine up to.  The timing is a little advanced.

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For what its worth my TDCI Transit connect does not like supermarket diesel but runs better on the shell /esso premium diesels , or like others have said is it in the mind , I have found that a good blat to get it properly hot now and again helps in my case as I do doodle around quite a bit locally .

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I'm not sure about Diesel, as I've just changed engine and I'm still testing my average full tank MPG, but in my 2010 Astra 1.8 SRi, I used to get 28mpg on Supermarket 95 fuel (the 1.8vvt engine is thirsty), 30mpg on Supermarket 97, but 32 on Shell Vpower. There was also an obvious eagerness on Vpower. 

Currently I'm running my Disco 200tdi on Morrisons Standard. I'm currently doing 26mpg or 320 miles to a tank. I've got two more tanks to do to get my 5 tanks, then I'm going to switch to BP standard and see what I get with that. Afterwards I'll try Morrisons Premium and then BP premium. Finally I'll try Shell premium, as from experience, shell is usually the best. 

I've always found Shell to be the best.

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6 minutes ago, Pappa Smurf said:

I'm not sure about Diesel, as I've just changed engine and I'm still testing my average full tank MPG, but in my 2010 Astra 1.8 SRi, I used to get 28mpg on Supermarket 95 fuel (the 1.8vvt engine is thirsty), 30mpg on Supermarket 97, but 32 on Shell Vpower. There was also an obvious eagerness on Vpower. 

Currently I'm running my Disco 200tdi on Morrisons Standard. I'm currently doing 26mpg or 320 miles to a tank. I've got two more tanks to do to get my 5 tanks, then I'm going to switch to BP standard and see what I get with that. Afterwards I'll try Morrisons Premium and then BP premium. Finally I'll try Shell premium, as from experience, shell is usually the best. 

I've always found Shell to be the best.

What about power and performance though?? This seemed like night and day for me veg vs diesel with enough time to fill up in between. 

Edited by reb78
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I didn’t see much difference in mpg or performance on the Tdis, but the TDCI did far, far better for both on BP ultimate than BP regular, and was a world apart from supermarket stuff.  The big difference I found on the Tdis was Texaco an Q8 regular - both had a very big drop in performance and economy, and the Texaco made the engine a good deal rougher, so I never used them again.  It could have been a contaminated station that I got the fuel from, so I couldn’t fairly claim it’s typical of those brands.  But I know for certain that the BP Ultimate made the TDCI perkier, smoother, cleaner and gave about 4mpg better returns over months of trials on the same route.

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I'd be tempted to run a tankfull of premium (BP Ultimate, Esso Super, etc.) through it and then give it a go on non-supermarket stuff - possibly invest a couple of quid in a new fuel filter.

Certainly a couple of friends who are or have been involved with the oil industry reckon Esso/Exxon are about the most exacting (or picky) when it comes to quality standards.

Anecdotally, friends of my folks had a car from brand new that they filled up almost exclusively at their local supermarket (and kept every receipt, as some do) and the car conked out due to blocked fuel filter, to the point where the main dealer volunteered to write a supporting letter for them to claim against the supermarket for the work as apparently they were not the first case the dealer/techs had seen. I believe modern stuff has finer filtration due to the common-rail high-pressure pumps etc. and it sounded like the dealers were familiar with the issue with supermarkets perhaps being less thorough than they might.

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