Costco diesel

[Gazwould]

Preeeeeeeeeemium diesel...very successful marketing con .

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[bob6600]

Is Costco premium diesel actually premium, as their premium petrol certainly isn’t premium

It isn't 99 ron if that's what you mean. I was disappointed when they moved from 99 ron to 97 ron just before my local opened! For this reason I use Shell V power instead, although it's very expensive atm.

The premium diesel has more additives, how it compares in the real world, I don't know Ash

 

[DSM10000]

It isn't 99 ron if that's what you mean. I was disappointed when they moved from 99 ron to 97 ron just before my local opened! For this reason I use Shell V power instead, although it's very expensive atm.

The premium diesel has more additives, how it compares in the real world, I don't know Ash

If we are discussing Diesel fuel then the RON number doesn't apply. That is only used to define the ability of a petroleum fuel to avoid pre ignition detonation.

If we want to look at the "quality" of Diesel then we need to know the Cetane rating.

 

[Deleted member 159894]

All fuel comes out the same pipe at the refinery the only marginal change is in some of the additives which are added to the refined fuel before its dispensed and those are very very minor despite all the marketing they spend many thousands on, the main driver for all the so called premium etc adverts is to get you in the shop because thats where they make massive margins.
All the fuel has to be to a minimum standard which is always above the standard set by the car makers, what happens in the tanks at the forecourt however is another matter it has been known for a few hundred litres of the wrong fuel to get into the wrong tank!

How does that work then?

I don't understand why premium fuel drives more people into the shop over ordinary fuel.

 

[Rory]

I seem to recall that Costco add the additives at the forecourt - if that's correct, maybe they forgot to put them in.

I know my car is some way off the tech that is used now, but I tried all different fuels and additives, inlcuding Costco diesel, and could never feel or hear any difference (and I think I have a reasonably good mechanical sympathy).

The one fuel that seemed to repeatably make a difference to MPG was Sainsbury's City Diesel - on a run the car would show over 50MPG using that, where I couldn't get it past high 40's with other fuels. This would be long steady motorway trips down South.

 

[bob6600]

If we are discussing Diesel fuel then the RON number doesn't apply. That is only used to define the ability of a petroleum fuel to avoid pre ignition detonation.

If we want to look at the "quality" of Diesel then we need to know the Cetane rating.

It was in response to Ash's comment about their premium petrol not being premium

 

[Erfan]

If we are discussing Diesel fuel then the RON number doesn't apply. That is only used to define the ability of a petroleum fuel to avoid pre ignition detonation.

If we want to look at the "quality" of Diesel then we need to know the Cetane rating.

This is from a 4 year old post on Costco UKs Facebook page. At that time it said it's premium diesel has a minimum 51 cetane rating.

https://m.facebook.com/CostcoUK/photos/a.681661168580753/1836931416387050/?type=3&comment_id=1837630809650444

You will see at that time they state they offer 95 and 99 Ron petrol...but users mention only 97 Ron is available now. I don't know if they have subsequently changed the diesel cetane rating.

 

[Erfan]

Post in thread 'Costco Premium Diesel vs Shell V Power Diesel Octane' Costco Premium Diesel vs Shell V Power Diesel Octane | General Discussion


Shows other suppliers cetane rating

 

[Dryce]

I seem to recall that Costco add the additives at the forecourt - if that's correct, maybe they forgot to put them in.

Story doing the rounds for years used to be that the only difference between branded and supermarket fuel was that the delivery driver mixed in different additives.

I suspect that won't work with RON99 vs RON95 fuel - but then I also suspect that if you stick RON95 fuel into the RON99 pumps the majority of purchasers wouldn't notice as their car engine management systems don't make any special adaptation to RON99 fuel. And as for those who do have engines that benefit from RON99 fuel I would suspect that that they don't drive the engine hard enough often enough to get the benefit that often (But arguably there will be those who would notice the benefit on those occasions when they actively exploit it).

 

[gadgetgricey1971]

Filled up with Costco fuel a few times. (Not local, so just when popping over to get stuff
Never had any issues

 

[HB]

Story doing the rounds for years used to be that the only difference between branded and supermarket fuel was that the delivery driver mixed in different additives.

I suspect that won't work with RON99 vs RON95 fuel - but then I also suspect that if you stick RON95 fuel into the RON99 pumps the majority of purchasers wouldn't notice as their car engine management systems don't make any special adaptation to RON99 fuel. And as for those who do have engines that benefit from RON99 fuel I would suspect that that they don't drive the engine hard enough often enough to get the benefit that often (But arguably there will be those who would notice the benefit on those occasions when they actively exploit it).

Back in 2002 when I had an E46 M3 (sensational car) super unleaded wasn’t as easily available as it is these days. On the odd occasion I put normal 95 into it and the engine would pink on light throttle applications. Stick Shell Optimax back in 98 Ron I believe and it was back on song. Today, the new M5 parked in the driveway says 95 Ron is fine to use in the fuel cap - strange.

 

[Erfan]

I got a call from Costco who said:
- No other adverse reports from drivers
- No water detected in fuel and it's checked daily
- Their fuel is the same base fuel as Shells' best diesel. It comes from the same refinery, but Shell has its additives included at the refinery whereas Costco do it onsite. Both use the same additives from the same supplier but in different volumes. I asked what cetane rating their fuel is and he said he didn't know what a cetane rating was.

I will see if there is a return to "normal" when I fill up with Shell next time. As others posted, maybe it's unrelated to fuel, but I need a mix of Columbo and Arthur C Clarke to figure it out

Although the above has been discussed many times before, I wanted to update for thread completeness.

PS. He said Leeds will be next to get a fuel station this year, and then next year Reading will be the next one.

 

[Gazwould]

What's Cetane

 

[bob6600]

What's Cetane

From Wiki

Cetane number (cetane rating) is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It plays a similar role for diesel as octane rating does for gasoline. The CN is an important factor in determining the quality of diesel fuel, but not the only one; other measurements of diesel fuel's quality include (but are not limited to) energy content, density, lubricity, cold-flow properties and sulphur content

Cetane number - Wikipedia

en.wikipedia.org

Costco's Cetane (from another site)

in accordance with BS EN 590, our Premium Diesel has a minimum cetane number of 51. All of our fuels are additised on site using bespoke additive packages. Whilst we are unable to comment on any specific competitor we believe our fuels offer the benefits you would associate with a premium branded fuel.

 

[Gazwould]

You fell...