Do I need a fuel additive?
 

A question for the diesel forum. Before the industry started offering ULS diesel fuel (low sulfur), I used B20 biodiesel blend in my 2000 NB tdi, and enjoyed the benefits of increased lubricity, and smoother operation over the "dirty fuel" commonly used until 2008/2009 period.
Now I drive a Q5 tdi, using the cleaner ULS fuel, and wonder if I need to use an oil additive to counter the lower sulfur "lack of lubricity" claimed by many. Does anyone have an opinion on this?
I'm not a high mileage driver (8m-10m miles/year), but I do want my tdi to have the best drink that is practical.
Thanks for your learned opinion.
Tenderfoot

I don't know enough about American fuel to help, it seems insane that a new car in this day and age would need some sort of additive, but then again people changing their fuel 10 times more often that required also seems insane but that doesn't stop people doing that either...

Have you asked the Audi dealer you bought the car from?

You could ask the diesel station if the fuel they sell had the lubricants added back in. It appears farmers and others that buy off road in bulk have the choice of them added or not. So somebody should know if the station has them or not.

Or just use B5(the max I think for Audis)if available. B1 might even be enough biodiesel to overcome any lack of lubricants in the diesel.

Good idea troll bait, but typical fuel stations in our part of the woods, don't know additives, cetane, ppm sulfur or anything except "the rest room is around the corner......that'll be $68.59 please".
The folks at Audi forbid the use of any biodiesel at any level, or else risk the warranty. I hate to get back to the blending myself stage as quite frankly the fuel stinks, and the wife doesn't like it in the attached garage. The car runs so smooth and effortllessly, that I think I'll go with it straight from the pump. I would appreciate any user (bioD) comments if any one has tried it with a new tdi.
Comments?
Tenderfoot
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Engines and fuels ate more or less designed for each other. I find it impossible to believe VW (owners of Audi) didn't design their engines and fuel systems to work satisfactorily on the fuel available in the market where they sell the cars. Odds are the owner's manual has some phraseology about additives being unneeded.

The older diesels should use lubricity additives to make up for what has been lost in the newer cleaner fuels. If you diesel was designed for the newer stuff than it should be fine.


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You say above you wonder if you need to use an oil additive in your Q5 to counter the lack of lubricity in ULSD. Did you mean to say fuel additive ?
I do use a fuel additive in my 2011 Golf TDI but more as an insurance policy to increase the fuel lubricity. I use no additive in the oil.

It can happen that engineers don't design for the fuel...a fairly recent example was the Ford Powerstroke 6.0l where Ford's team somehow overlooked the quality of diesel fuel here. I believe that is what caused most of the nightmare scenarios that engine had. I believe Audi engineers are more savvy and you shouldn't need any additives. Having said that, a bottle of Lucas or some Diesel Kleen may not be a bad idea now and then. Won't hurt anything but your pocketbook.

Cogeneration, you are SO right, I meant a fuel additive, not oil as you noted. Guess that one is due to my CRS desease. ULS fuels have nothing to do with synoils for TDi's. Looks like the forum is probably right in that the Audi guys don't think it's needed either. Guess it's the throwback to the early 2000's with our stink fuels. Might try a FUEL additive to see if I see any mpg change. Thanks to all for their comments.
Tenderfoot

Way back when I had my Diesel, I worried about additives for winter use. Normally, stations sold #2 Diesel in summer, and "winterized" #2 in winter. #1, which is actually winter diesel, was harder to find. There were and are additives, usually used at about 1%, said to keep #2 fuel from gelling. As it turned out, the additive cost per gallon was just about the same as the difference in price per gallon between #1 and #2. I used #1 when I could, simply because I didn't have to worry whether the additives worked. If you end up using some sort of additive, keep careful records to see whether it really does result in any improvement in mileage. Then figure whether the improvement in mileage pays for the additive. Remember there is considerable variation tank-to-tank, which might well "swamp" any changes caused by any additive.

I've used a fuel additive in my 2011 Golf TDI for 3 and a half years. I've never seen any mpg increase during that time. Not saying you won't just that I've never seen it.
As for the reduction of sulfur from LSD(<500 ppm)to ULSD (<15 ppm)it is the process needed in the refining to remove sulfur that dried out the fuel.

The fuel additive for older diesels that were not designed to run on ULSD will not increase mileage, but will prevent wear on parts that were designed for the better lubricity of the older diesel fuels. You will not see an mpg gain, but it will prevent an mpg loss from injector/engine deterioration.


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I own a 2014 Audi Q5 TDI and at 13 months of ownership, I average 30mpg (25% city, 75% hwy driving). I have used the fuel additive PS Diesel Kleen since day one. The car runs great! Since fuel pumps with diesels are sensitive, adding Diesel Kleen provides added lubrication and contributes, I believe, to longer life.

Thanks for your reply CHDriver. My dealer thinks fuel ads are not required, and definitely is against use of biofuel even as low as b5! Of course, they also run a repair shop, and issues beyond 50K will be at my expense, so they have a monetary interest in the state of my tdi
Encountering the first spell of cold weather, and the resulting hit in mpg, so I might try an additive to see if it makes a difference. My car is running great, and road mileage is over 32 mpg, so it might be hard to see a measurable mprovement. I seldom shut off the engine until it fully warms up (adding a couple of extra miles to a short trip), so
I might be chasing shadows!


Tenderfoot

Odd about the dealer stance on B5. VW's can use B5, and according to this site, https://www.biodiesel.org/docs/defaul....pdf?sfvrsn=10, so can the Audi's. Because of the lack of straight diesel in Illinois, you use up to B20 there without without voiding the warranty.

Same here even though I am not one to buy into the vast majority of the opinions on the internet which are never based on anything concrete.

I use Stanadyne Performance Formula. My VW dealer sells it under the VW name.

As for needing it to help cold winter starts, considering very few use any additive at all, we would have a ton of cars not starting if it were really needed.

Hello, I have been using a fuel additive called Diesel Mechanic in a bottle. It has lubricity characteristics and it will absorb water in the fuel. I have seen an decrease usage of DEF since I started using on my then new 2013 F350 I would recommend using this additive on any diesel new or old. I have had customers claim an increase of 2-3mpg on older 3/4 ton trucks and all have reported smoother running engines..

Here in Minn we have B5 or 5% biodiesel mandated. It can go as high as 20% although I have never seen it advertised. Bio is the best lubricant you can use in diesel fuel. Just 2% is all it takes to replace all that was removed by ULSD.

Diesel here is winterized down to -30 or more so anti gel is not needed except way north.

Lube is not needed either even in the older diesels. I have a 1999 Dodge Cummins Turbo Diesel. I have 350k showing and have had very little trouble with it. None related to fuel.

If you must use lube Wal Mart 2 stroke TC-3 works pretty well according to the oil tests.

When you travel you just have to be aware of local fuel conditions. I stop at only high traffic stations even if they are a bit higher price.

....additives or top tier D2 from a high turnover station..........
 

.......the information (comparison) is probably out there somewhere (wish I knew where)

ez

The following are the preliminary results of a research study on diesel fuel Lubricity Additives.
There is likely to be further commentary and explanation added at a future time.

PURPOSE:

The purpose of this research was to determine the ability of multiple diesel fuel additives to replace the vital lubricity component in ULSD (Ultra Low Sulphur Diesel) fuel.

HISTORY:

ULSD fuel is the fuel currently mandated for use in all on road diesel engines.
This fuel burns cleaner and is less polluting than it’s predecessor, called Low Sulphur Diesel Fuel.
Low sulphur fuel contained less than 500 ppm of sulphur.
ULSD contains 15 ppm or less.
As diesel fuel is further refined to remove the polluting sulphur, it is inadvertently stripped of its lubricating properties.
This vital lubrication is a necessary component of the diesel fuel as it prevents wear in the fuel delivery system. Specifically, it lubricates pumps, high pressure pumps and injectors.
Traditional Low sulphur diesel fuel typically contained enough lubricating ability to suffice the needs of these vital components. ULSD fuel, on the other hand, is considered to be very “dry” and incapable of lubricating vital fuel delivery components.
As a result, these components are at risk of premature and even catastrophic failure when ULSD fuel is introduced to the system.
As a result, all oil companies producing ULSD fuel must replace the lost lubricity with additives.
All ULSD fuel purchased at retail fuel stations SHOULD be adequately treated with additives to replace this lost lubricity.
The potential result of using inadequately treated fuel, as indicated above, can be catastrophic.
There have been many documented cases of randomly tested samples of diesel fuel.
These tests prove that often times the fuel we purchase is not adequately treated and may therefore contribute to accelerated wear of our fuel delivery systems.
For this reason it may be prudent to use an after market diesel fuel additive to ENSURE adequate lubrication of the fuel delivery system.
Additionally, many additives can offer added benefits such as cetane improver, and water separators or Emulsifiers.


CONTENT:

In this study we will test multiple diesel fuel additives designed to replace lost lubricity.
The primary component of this study is a side-by-side laboratory analysis of each additive’s ability to replace this vital lubricity.
Additionally, claims of improving cetane, water separation or emulsification, bio-diesel compatibility and alcohol content will be noted.
These notes were derived from information that was readily available to consumers (via the label and internet information) and none of this information has been evaluated for validity and/or performance. Cetane information has only been noted if the word “cetane” was used in the advertising information.
The words “improves power” has not been translated to mean “improves cetane” in this evaluation. Information on alcohol content is provided by indicating “contains no alcohol”.
Omission of the words “contains no alcohol” does not imply that it does contain alcohol.
This information was simply missing in the information available to a consumer, however, the possibility of a form of alcohol in these products is possible.
Additionally, information on dosages and cost per tankful are included for comparison purposes.


How diesel fuel is Evaluated For Lubricating Ability:

Diesel fuel and other fluids are tested for lubricating ability using a device called a “High Frequency Reciprocating Rig” or HFRR.
The HFRR is currently the Internationally accepted, standardised method to evaluate fluids for lubricating ability.
It uses a ball bearing that reciprocates or moves back and forth on a metal surface at a very high frequency for a duration of 90 minutes.
The machine does this while the ball bearing and metal surface are immersed in the test fluid (in this case, treated diesel fuel).
At the end of the test the ball bearing is examined under a microscope and the “wear scar” on the ball bearing is measured in microns.
The larger the wear scar, the poorer the lubricating ability of the fluid.
Southwest Research runs every sample twice and averages the size of the wear scar.
The U.S. standard for diesel fuel says a commercially available diesel fuel should produce a wear scar of no greater than 520 microns.
The Engine Manufacturers Association had requested a standard of a wear scar no greater than 460 microns, typical of the pre-ULSD fuels.
Most experts agree that a 520 micron standard is adequate, but also that the lower the wear scar the better.



METHOD:

An independent research firm in Texas was hired to do the laboratory work.
The cost of the research was paid for voluntarily by the participating additive manufacturers.
Declining to participate and pay for the research were the following companies:
Amsoil and Power Service.
Because these are popular products it was determined that they needed to be included in the study.
These products were tested using funds collected by diesel enthusiasts at “dieselplace.com”.
Additionally, unconventional additives such as 2-cycle oil and used engine oil were tested for their abilities to aid in diesel fuel lubricity.
These were also paid for by members of “dieselplace.com”.


The study was conducted in the following manner:

-The Research firm obtained a quantity of “untreated” ULSD fuel from a supplier.
This fuel was basic ULSD fuel intended for use in diesel engines, however, this sample was acquired PRIOR to any attempt to additize the fuel for the purpose of replacing lost lubricity.
In other words, it was a “worst case scenario, very dry diesel fuel” that would likely cause damage to any fuel delivery system.
This fuel was tested using the HFRR at the Southwest Research Laboratory.
This fuel was determined to have a very high HFRR score of 636 microns, typical of an untreated ULSD fuel. It was determined that this batch of fuel would be utilised as the baseline fuel for testing all of the additives. The baseline fuel HFRR score of 636 would be used as the control sample.
All additives tested would be evaluated on their ability to replace lost lubricity to the fuel by comparing their scores to the control sample.
Any score under 636 shows improvement to the fuels ability to lubricate the fuel delivery system of a diesel engine.


BLIND STUDY:

In order to ensure a completely unbiased approach to the study, the following steps were taken:
Each additive tested was obtained independently via internet or over the counter purchases.
The only exceptions were Opti-Lube XPD and the bio-diesel sample.
The reason for this is because Opti-Lube XPD additive was considered “experimental” at the time of test enrolment and was not yet on the market.
It was sent directly from Opti-Lube company.
The bio-diesel sample was sponsored by Renewable Energy Group.
One of their suppliers, E.H. Wolf and Sons in Slinger, Wisconsin supplied us with a sample of 100% soybean based bio-diesel.
This sample was used to blend with the baseline fuel to create a 2% bio-diesel for testing.
Each additive was bottled separately in identical glass containers.
The bottles were labeled only with a number.
This number corresponded to the additive contained in the bottle.
The order of numbering was done randomly by drawing names out of a hat.
Only Spicer Research held the key to the additives in each bottle.
The additive samples were then sent in a box to an independent research firm.
The only information given them was the ratio of fuel to be added to each additive sample.
For example, bottle “A” needs to be mixed at a ratio of “480-1”.
The ratio used for each additive was the “prescribed dosage” found on the bottle label for that product.
Used engine oil, and 2-cycle oil were tested at a rationally chosen ratio of 200:1.
The Research Laboratory mixed the proper ratio of each “bottled fluid” into a separate container containing the baseline fuel.
The data, therefore, is meaningful because every additive is tested in the same way using the same fuel.
A side-by-side comparison of the effectiveness of each additive is now obtainable.



THE RESULTS:

These results are listed in the order of performance in the HFRR test.
The baseline fuel used in every test started at an HFRR score of 636.
The score shown is the tested HFRR score of the baseline fuel/additive blend.
Also included is the wear scar improvement provided by the additive as well as other claimed benefits of the additive.
Each additive is also categorised as a Multi-purpose additive, Multi-purpose + anti-gel, Lubricity only, non-conventional, or as an additive capable of treating both gasoline and diesel fuel.
As a convenience to the reader there is also information on price per treated tank of diesel fuel (using a 26 gallon tank), and dosage per 26 gallon tank provided as “ounces of additive per 26 gallon tank”.


In Order Of Performance:

1) 2% Regular SoyPower biodiesel
HFRR 221, 415 micron improvement.
50:1 ratio of baseline fuel to 100% biodiesel
66.56 oz. of 100% biodiesel per 26 gallons of diesel fuel
Price: market value

2)Opti-Lube XPD
Multi-purpose + anti-gel
cetane improver, demulsifier
HFRR 317, 319 micron improvement.
256:1 ratio
13 oz/tank
$4.35/tank

3)FPPF RV, Bus, SUV Diesel/Gas fuel treatment
Gas and Diesel
cetane improver, emulsifier
HFRR 439, 197 micron improvement
640:1 ratio
5.2 oz/tank
$2.60/tank

4)Opti-Lube Summer Blend
Multi-purpose
demulsifier
HFRR 447, 189 micron improvement
3000:1 ratio
1.11 oz/tank
$0.68/tank

5)Opti-Lube Winter Blend
Muti-purpose + anti-gel
cetane improver
HFRR 461, 175 micron improvement
512:1 ratio
6.5 oz/tank
$3.65/tank

6)Schaeffer Diesel Treat 2000
Multi-purpose + anti-gel
cetane improver, emulsifier, bio-diesel compatible
HFRR 470, 166 micron improvement
1000:1 ratio
3.32 oz/tank
$1.87/tank

7)Super Tech Outboard 2-cycle TC-W3 engine oil
Unconventional (Not ULSD compliant, may damage 2007 or newer systems)
HFRR 474, 162 micron improvement
200:1 ratio
16.64 oz/tank
$1.09/tank

8)Stanadyne Lubricity Formula
Lubricity Only
demulsifier, 5% bio-diesel compatible, alcohol free
HFRR 479, 157 micron improvement
1000:1 ratio
3.32 oz/tank
$1.00/tank

9)Amsoil Diesel Concentrate
Multi-purpose
demulsifier, bio-diesel compatible, alcohol free
HFRR 488, 148 micron improvement
640:1 ratio
5.2 oz/tank
$2.16/tank

10)Power Service Diesel Kleen + Cetane Boost
Multi-purpose
Cetane improver, bio-diesel compatible, alcohol free
HFRR 575, 61 micron improvement
400:1 ratio
8.32 oz/tank
$1.58/tank

11)Howe’s Meaner Power Kleaner
Multi-purpose
Alcohol free
HFRR 586, 50 micron improvement
1000:1 ratio
3.32 oz/tank
$1.36/tank

12)Stanadyne Performance Formula
Multi-purpose + anti-gel
cetane improver, demulsifier, 5% bio-diesel compatible, alcohol free
HFRR 603, 33 micron improvement
480:1 ratio
6.9 oz/tank
$4.35/tank

13)Used used engine oil, Shell Rotella T 15w40, 5,000 miles used.
Unconventional (Not ULSD compliant, may damage systems)
HFRR 634, 2 micron improvement
200:1 ratio
16.64 oz/tank
price: market value

14)Lucas Upper Cylinder Lubricant
Gas or diesel
HFRR 641, 5 microns worse than baseline (statistically insignificant change)
427:1 ratio
7.8 oz/tank
$2.65/tank

15)B1000 Diesel Fuel Conditioner by Milligan Biotech
Multi-purpose, canola oil based additive
HFRR 644, 8 microns worse than baseline (statistically insignificant change)
1000:1 ratio
3.32 oz/tank
$2.67/tank

16)FPPF Lubricity Plus Fuel Power
Multi-purpose + anti-gel
Emulsifier, alcohol free
HFRR 675, 39 microns worse than baseline fuel
1000:1 ratio
3.32 oz/tank
$1.12/tank

17)Marvel Mystery Oil
Gas, oil and Diesel fuel additive (NOT ULSD compliant, may damage 2007 and newer systems)
HFRR 678, 42 microns worse than baseline fuel.
320:1 ratio
10.4 oz/tank
$3.22/tank

18)ValvTect Diesel Guard Heavy Duty/Marine Diesel Fuel Additive
Multi-purpose
Cetane improver, emulsifier, alcohol free
HFRR 696, 60 microns worse than baseline fuel
1000:1 ratio
3.32 oz/tank
$2.38/tank

19)Primrose Power Blend 2003
Multi-purpose
Cetane boost, bio-diesel compatible, emulsifier
HFRR 711, 75 microns worse than baseline
1066:1 ratio
3.12 oz/tank
$1.39/tank

CONCLUSIONS:

Products 1 through 4 were able to improve the unadditized fuel to an HFRR score of 460 or better.
This meets the most strict requirements requested by the Engine Manufacturers Association.
Products 1 through 9 were able to improve the unadditized fuel to an HFRR score of 520 or better, meeting the U.S. diesel fuel requirements for maximum wear scar in a commercially available diesel fuel.
Products 16 through 19 were found to cause the fuel/additive blend to perform worse than the baseline fuel. The cause for this is speculative. This is not unprecedented in HFRR testing and can be caused by alcohol or other components in the additives.
Further investigation into the possibilities behind these poor results will investigated.
Any additive testing within +/- 20 microns of the baseline fuel could be considered to have no significant change.
The repeatability of this test allows for a +/- 20 micron variability to be considered insignificant.

CREDITS:

This study would not have been possible without the participation of all companies involved and dieselplace.com. A special Thank You to all of the dieselplace.com members who generously donated toward this study and waited longer than they should have for the results. You folks are the best.
Arlen Spicer, organizer.

I only had a quick scan through, what's the effect on the oil using Ulsd? I assumed with the low sulphur content, you guys would be able to use similarly long intervals like we do here, 20,000 to 30,000 miles between changes perhaps. But now, if Ulsd removes the lubricants, then perhaps you will still have to change your oil often?

The lubricants in the fuel are needed for the fuel pump and other components of the fuel system; possibly the upper cylinder.

Removing the sulfur from diesel removes these lubricants. The refinery then has to add them back.

The motor oil already has a long change interval for diesels in the US. The oil has a additional additives over the oil for gasoline engines. The oil capacity of diesel engines, at least the V8s in full size trucks that are the common diesel sold here, is also higher. I don't know if or how much the switch to ULSD has allowed the interval to be extended.

I would have thought, with good quality long life oil, and driving mostly on the highway for long periods of time, using Ulsd should give a minimum of 25,000 miles between oil changes, if not more.

Interesting that Audi should forbid the use of Bio in any formulation as here in Canada, B5 is all that's available. Of course they do seem to be in a spot of trouble with fiddling with emissions systems, don't they?

It's because of their emission systems design. If fuel is needed to be injected into the exhaust for regenerating anything, it seems all the German models do so through the engine itself. Biodiesel doesn't vaporize has readily as diesel, so too high a concentration could lead to some getting left behind in the cylinder. Where it can form carbon deposits, or get into the motor oil.

The diesel Cruze, GM trucks, and Ford trucks can handle up to 25% biodiesel. They likely inject fuel for regeneration directly into the exhaust instead of the through the engine.

Another issue the manufacturers have to consider is that it isn't difficult to home brew biodiesel. Which increases the chance of biodiesel not up accepted standards being more likely to end up in the tank. So they have a lower limit to limit warranty payouts in that event.

It appears that other diesel manufacturers may be rooted out, now that VW has been burned down......for NOT burning fuel in emissions tests, as they do on the road. Read one article saying that even gasoline systems have their own problems, if they looked closer at their emissions.
Anyhow, people knew diesels had on-going problems before cheating VW was caught. To all the diesel drivers who got self-righteous about their "clean diesels", vs. "cleaner diesels".....thththththththththt!!!!!

Prof. Mark Jacobson, was blowing the whistle on diesel even before the article below & before present diesel manufacturer cheating was found. Prof. Jacobson was the prime reason I never got a diesel & recent cheatings show diesel pollution is worse than that:
Prius, Part 2: Why hybrids beat diesels | ThinkProgress

Have a look at my post in the "cheating the test" topic. No one is getting self righteous about owning a diesel, most people buy them because they perform better, are more durable, and save a small fortune on fuel costs. I think those still driving petrol cars need to stop convincing themselves gas is green and diesel is dirty, burning fossil fuels is never clean, if you want to dedicate your life to clean living, you'd have to live in a tent and eat grass and ride a bike! ;)

I do read that the European Union members are rethinking their emphasis on diesel. It seems the smog in Paris etc is being noticed with alarm. The question now is, if VW was cheating, is anyone else.


Whatever the case, it should become apparent as it seems actual on-road-testing will become common in addition to the static lab-type testing depended upon in the past which allowed the VW programming scheme. If so, the VW-style cheating won't fool anyone anymore.

Screw emissions, I'd love a diesel car for the fuel economy. The DPF cars would see a huge benefit from the VW cheat, but it seems to me that the impact to anything on an SCR car wouldn't be worth the time to write a cheat code.

Most of the truck diesel I have seen at the pump seems to be B10. It's a spooky greenish-yellow colour. And it foams more than regular diesel, stuffing the tank takes forever. I read that biodiesel technically contains less chemical energy than regular diesel but I haven't seen any measurable impact...not that I can really run a scientific test. I go where they tell me and fuel where they tell me.

We are using 25k or so OCIs on our trucks, both the 12.8l and 14.8l engines. Then again, the oil capacity was some ungodly amount - I forget the number but something like 6 or 8 gallons?

The OCI'S are higher on diesels as the fuel contains more additives and lubricants. The large semi trucks here do 60,000 between changes, a regular large van might do 40,000 and a little car like mine will do 20,000 on each oil change.

I think if the US used similar quality fuels, with less sulphur, some of this diesel emissions bashing wouldn't exist.

I ran a car on biodiesel and got 42-44 mpg (this was the first time I worked out real mpg, as I brim to brim filled it cos there was just this one biodiesel place)- when I switched back to pump diesel, I went up to 52-54 mpg, so yeah I would say biodiesel has less energy! Nice peanut smell from the tailpipe though.

Diesel drivers were self-righteous, when "clean diesels" advertising said they were clean, so they could sell diesels at the beginning of this decade. Diesel drivers still don't care about emissions.... & are still self-righteous.

I disagree entirely, nobody buys a car based on its emissions, most people are only interested in the economy, which does relate to emissions in some respects. The emissions of passenger vehicles are published on the registration documents, but apart from C02, people show little interest in emissions.

Diesels put out less CO2 but more NOX - that's the latest issue.

:eek: Really? How do you account for all the "green" people buying hybrids?

He's got me on self righteous...!

Hybrids have been around for decades, and people buy them because they're after economy, I very much doubt people with hybrids buy them because of low emissions, in fact I think most people would struggle to answer if you asked them how much C02 thier cars emitted!

I have recently had my eyes opened to the mk1 insight, and my reasons for buying it would be:
1 better Mpg than my current car
2 I absolutely love the styling, light green colour, silver wheel trims, groovy interior
3 it will stand out, a head Turner due to rarity
4 free Road tax
5 I d get to feel self righteous - more so even than with my diesel!
6 the eco friendly angle

OK, lets take it one step farther- electric cars. Zero emissions and they are marketed that way by the manufacturers. I can guarantee you that the people who are buying those aren't buying them for the economy. Take a look at Tesla and the people who buy them. I don't think someone dropping $79,000+ for a S model are worried about economy. Have a look at their website: Model S | Tesla Motors What's the first feature that they are selling? Zero emissions.

You and other members from the UK keep going on and on about your emissions road taxes and how it was one of their factors in buying the model of the car they own. Don't give me that BS that people don't buy cars based on emissions.

Let's agree to disagree.

Crossed threads slightly, I was actually talking about the US, where auto emissions are not as openly published and are hard to come by than they are here. As you say, there are very few emission based incentives to buy low emission cars in the US (Road tax, congestion zones etc) so it's more common that car owners chase mpg numbers rather than emission figures.