Mpg how do you rate yours.

[dickt]

Golf 2.0TDI GT with DSG.
There have been a number of threads about mpg, here and on other sites. My old 170 tdi GT with DSG easily gave me 45 mpg. My Mk 7 2.0 tdi GT with dsg struggles to reach 45 mpg, even though I have it in eco most of the time.. I have checked the computer generated numbers, with top to top checks, and the computer numbers are OK.

[maisbitt]

I’m averaging 45mpg (indicated) on my GTD since new. 1600 miles in and I have seen absolutely no improvement in my mpg. This car has DPF regens a-plenty compared to my previous car, a 170TDI Scirocco and has less pull in 5^th/6^th gear above 60mph as well, despite supposedly being 14PS more. 33% below published combined figures on my commute, my Scirocco was 6% below published combined figures and 10% above on a long motorway run. I doubt I will ever get within 20% of the combined figure on my commute – it would have to rise to 54mpg!

One thing’s for sure – V-power Diesel is ***** for MK7 TDIs – my mpg dropped right off to 42mpg using 2 tanks of that stuff and power/response was noticeably off too. Unlike V-power petrol, the only gain for the Diesel is it’s cleaning power. It is less dense (and therefore holds less chemical energy to combust) than regular diesel, although it does burn cleanly – I never had a single active regen with the stuff.

Currently using Esso (its is 3p per litre than regular Shell and 11p less than V-power in my locality) and I have bought a big can of millers a week ago. Starting to get up to 48mpg on the ½ tank with millers additive if I can do a commute without a regen, despite the colder weather kicking in. At an additional fuelling cost of 1.2p per litre it could well be worth it.

[rapport25]

Millers hey!!! The old jungle juice :-) I have tried that before and I dont really think it works in improving MPG.

I think it makes the car smoother and the engine quiter but mpg has to many factors to consider. If it works for you great. But I think its very subjective. I would suggest a clean car with tyre pressures slightly higher and the obvious brake early and change gear early all the usual stuff.


Also, nitrogen filled tyres. Thats what mine will be getting. Longer tyre life less heat and improved mpg. And not forgetting no supermarket fuel. I always use standard shell diesel because of its cleaning power.

[jk88]

Also, nitrogen filled tyres. Thats what mine will be getting. Longer tyre life less heat and improved mpg.

I filled my tyres with 78% nitrogen, works a treat

[Norbreck21a]

OK , 3 questions,

1. Is this Nitrogen stuff urban myth or is there any tangible evidence that it actually does have an effect on mpg / tyre life ?

2. What do you need when you need to top your tyres up ?

3. Whereabouts and how much can you get this done for ?

I'm not saying it doesn't work, just would like to hear a little more about it ?

[maisbitt]

I gave a bit of thought to the Millers before I bought it, as it is the only additive that is recommended by plenty of people and isn't regarded as snake oil - even "honest John" car website endorses it.

My car is quieter and smoother (especially at idle) with it and it is supposed to raise the Cetane rating of your fuel by between 3 and 4 points, which helps the diesel start to combust a little earlier - that gives the fuel a better chance at fuller combustion and hopefully less soot for the DPF to process. My mpg was picking up a bit on its own anyway since I ditched Shell V-power, but for the last 200 miles I have averaged 47mpg instead of 44 (indicated). At an additional cost of 1.2p per litre of fuel (I got a 5 litre can delivered for £62 and you use 50mL in a full tank of fuel), I'm not going to sweat it.

Once up to speed I do all the economical stuff to preserve my momentum like seeing a situation in the distance that is going to make the cars in front brake, so I come off the throttle early, don’t accelerate to a situation that requires braking, like a roundabout or junction etc. I am probably onm the brakes only about 60% of the time that some of my mates are. Unless I'm accelerating moderately hard, I change up/down pretty much when the computer prompts me too. What I would do normally is in tune with what the MFD would like me to do when driving economically.

Nitrogen filled tyres - now I do believe that is a bit of Snake oil. Costco bang on about their nitrogen filled tyres. As soon as you put the tyre on the rim you have normal air in it at atmospheric pressure. The tyre only gets to around 2.4 bar when inflated. Unless they were inflating and purging back to atmospheric pressure 3 times with nitrogen before topping up, I would say that a "nitrogen filled" tyre still has a good 8% oxygen in it. Both Oxygen and Nitrogen act pretty much as ideal gases (Boyles law) at the operating temperature range of a road going tyre. Both have a very low boiling point (-196C for Nitrogen and -183C for Oxygen). I can see the benefit for F1 drivers when even the tiniest incremental advantage could be the difference between 1st and 2nd place, but on a road going car it is a bit of a gimmick.
As long as the air going into the tyres is dry, there's no issue (water properties do change a lot over the operational temperature range of a tyre). Most garages have a dried air supply, and now the cooler weather is upon us, just topping up with a compressor, the air will be pretty dry as at cooler temps atmospheric air can hold far less water at it's saturation point. Ever been to somewhere like Prague in the winter months, where despite it being -10C there isn't a spot of ice around anywhere? That's because the air is so cold that it's bone dry, so there's no dew to drop anywhere.

[rapport25]

1. Is this Nitrogen stuff urban myth or is there any tangible evidence that it actually does have an effect on mpg / tyre life ?

Nitrogen tyres runs lot cooler which means less wear. They are said to improve MPG if only by a small amount. For me its a no brainer tyres last longer & mpg is improved

2. What do you need when you need to top your tyres up ?

Go back to the garage that filled them for you. I have only had to top mine up twice in a year.

3. Whereabouts and how much can you get this done for ?

Alot of places now offer this service.

I'm not saying it doesn't work, just would like to hear a little more about it ?

[rapport25]

I gave a bit of thought to the Millers before I bought it, as it is the only additive that is recommended by plenty of people and isn't regarded as snake oil - even "honest John" car website endorses it.

My car is quieter and smoother (especially at idle) with it and it is supposed to raise the Cetane rating of your fuel by between 3 and 4 points, which helps the diesel start to combust a little earlier - that gives the fuel a better chance at fuller combustion and hopefully less soot for the DPF to process. My mpg was picking up a bit on its own anyway since I ditched Shell V-power, but for the last 200 miles I have averaged 47mpg instead of 44 (indicated). At an additional cost of 1.2p per litre of fuel (I got a 5 litre can delivered for £62 and you use 50mL in a full tank of fuel), I'm not going to sweat it.

Once up to speed I do all the economical stuff to preserve my momentum like seeing a situation in the distance that is going to make the cars in front brake, so I come off the throttle early, don’t accelerate to a situation that requires braking, like a roundabout or junction etc. I am probably onm the brakes only about 60% of the time that some of my mates are. Unless I'm accelerating moderately hard, I change up/down pretty much when the computer prompts me too. What I would do normally is in tune with what the MFD would like me to do when driving economically.

Nitrogen filled tyres - now I do believe that is a bit of Snake oil. Costco bang on about their nitrogen filled tyres. As soon as you put the tyre on the rim you have normal air in it at atmospheric pressure. The tyre only gets to around 2.4 bar when inflated. Unless they were inflating and purging back to atmospheric pressure 3 times with nitrogen before topping up, I would say that a "nitrogen filled" tyre still has a good 8% oxygen in it. Both Oxygen and Nitrogen act pretty much as ideal gases (Boyles law) at the operating temperature range of a road going tyre. Both have a very low boiling point (-196C for Nitrogen and -183C for Oxygen). I can see the benefit for F1 drivers when even the tiniest incremental advantage could be the difference between 1st and 2nd place, but on a road going car it is a bit of a gimmick.
As long as the air going into the tyres is dry, there's no issue (water properties do change a lot over the operational temperature range of a tyre). Most garages have a dried air supply, and now the cooler weather is upon us, just topping up with a compressor, the air will be pretty dry as at cooler temps atmospheric air can hold far less water at it's saturation point. Ever been to somewhere like Prague in the winter months, where despite it being -10C there isn't a spot of ice around anywhere? That's because the air is so cold that it's bone dry, so there's no dew to drop anywhere.

Thanks for such a detailed reply.

I used Millers for nearly 2 yrs. And I think its a complete waste of money on a new car. Decent quality fuels and that it. As for the nitrogen you made some valid points. BUT!! I think we will agree to disagree.

[maisbitt]

Thanks for such a detailed reply.

I used Millers for nearly 2 yrs. And I think its a complete waste of money on a new car. Decent quality fuels and that it. As for the nitrogen you made some valid points. BUT!! I think we will agree to disagree.

There is a very good argument for air and not nitrogen in your tyres. Nitrogen filled tyres would have been the death of James Bond and Jason Bourne. When you are forced off the road and into a lake by a villain, they will be waiting for you to surface to finish you off. This is where the air filled tyre really pays dividends, they will wait a few mins and then assume you drowned and leave. Maybe I will mention this to Costco next time I get tyres there - they're very big on safety when the insist new tyres go on the front, despite there being a good reason for not wanting the OEM rears put on the front because the OEM front set wore unevenly.

Should You Fill Your Car's Tires With Nitrogen?

[rapport25]

There is a very good argument for air and not nitrogen in your tyres. Nitrogen filled tyres would have been the death of James Bond and Jason Bourne. When you are forced off the road and into a lake by a villain, they will be waiting for you to surface to finish you off. This is where the air filled tyre really pays dividends, they will wait a few mins and then assume you drowned and leave. Maybe I will mention this to Costco next time I get tyres there - they're very big on safety when the insist new tyres go on the front, despite there being a good reason for not wanting the OEM rears put on the front because the OEM front set wore unevenly.

Should You Fill Your Car's Tires With Nitrogen?

at your comments above.

As for the link, shocked!!!!!. Sounds like a waste of time & money.

Reaches for a thread about the snake oil TBC.......