Hello folks,

These areas of interest have been covered a number of times, so please forgive this new thread (and the length!).

Fabia 1.4TDI now 96K, owned from new and self serviced since 50K.

I’ve kept a check on fuel consumption since new, so most figures are reliable.

Overall it gives about 73mpg – mixed driving including towing. For the last year I’ve put in Miller’s Sport 4 at recommended dilution. Through last winter the average MPG was 69mpg using supermarket fuel.

And, now to the story!

As the Millers seemed to work well (smoother) I bought a 5 litre bottle. In order to make this useablel, I decanted the correct amount for a 40 litre fill-up into a 330 bottle and topped up with diesel. So, in the garage were a number of ready to use bottles plus a 330 bottle being used to hold the concentrate. Unlabelled!

About 2 months ago I had to travel to a hospital in a hurry. About 80 miles in one and a quarter hours – so flat out when possible. This showed 57 mpg on the computer readout. A real ‘Italian tune-up’.

The following day I filled up the tank and poured in the contents of a 330ml bottle and topped to the brim from the spare can. The car ran beautifully. After about 350 miles, I wondered why the fuel gauge had not moved down: and then it dawned on me – I’d put 330 mls of pure Millers in the tank (which using the nipple technique holds about 56 litres). Arrghhhhhhh,http://www.briskoda.net/forums/images/smilies/eek.gif however, careful refilling gave a consumption of 85mpg. This seemed to make it worth adding lots of Millers; saving about £2-75p per tank. BUT the confounding factors; the weather changed suddenly and the high mpg coincided with hot dry weather. The car’s first summer had also shown occasional 85mpg in hot weather. So was it due to weather change?

Had the ‘Italian tune-up’ cleaned up the engine?

I decided to try again and to an empty tank added 300mls of Millers with the same careful filling. This gave 75 mpg, but again the weather had changed – this time becoming very much colder. A further trial with 50ml gave 73 mpg and with current (11-18 degrees C) temperatures get over 75 mpg using 100ml per normal fill (45 litres ish). This is, I think, double the recommended dilution on the bottle.

This is cost effective with current fuel prices and paying £60 for 5 litres of Millers.

Watching the computer figures (not accurate, but must be comparable) it is clear that this engine takes a long time to warm up (even in summer it takes 8 miles from home) and that the consumption is relatively high until warm. On that basis I’ve bought a Wolverine stick-on sump pad heater (other posters have covered this) from Canada £50. I’ll try and get figures for using it in summer for fair comparison and will let you know how it goes. Sorry, it’s long, but hope someone might find it interesting.

V

Wooow, I got to "Hello folks" then my eyes started hurting. Might want to break that up a bit bud. Pretty unreadable at the mo ...

Millers increases the cetane rating. It wont go past a certain point so it is not going to do much harm however I would check the consumption by brimming (Look at the fuel physically used not the gauge.

Millers increases the cetane rating. It wont go past a certain point so it is not going to do much harm however I would check the consumption by brimming (Look at the fuel physically used not the gauge.

He said he did didn't he?

Italian tune-up is a good one - if you've seen how much gunk accumulates in the EGR/intake manifold it's just not real.

Nipple technique:rolleyes: is so labour-intensive - look at the guides section for how to remove it and have effectively a bigger tank.. It's a POC.

Try the cage mod if you want to maximise (in theory) the MAF sensor's function. You may notice a nice change in mpg as some other members have done. ( slap some silicon dielectric grease in the MAF connector)

Wish I could find Miller's out here....:(

Cheers

Bas

Wish I could find Miller's out here....:(

Cheers

Bas

Was just going to say if you needed someone to post some out to you Id be happy to help.

But Upon thinking more about it, I dont think millers would be something you could post??

Why do people think it's some sort of clever to fill the expansion tank when filling up at the pumps? Ok, not this time of year, but I've filled up, used a litre driving home, and come out the next morning to find the tank's showing about 2l more than it was the previous night.

Was just going to say if you needed someone to post some out to you Id be happy to help.

But Upon thinking more about it, I dont think millers would be something you could post??

There's also the question of whether or not is would be legal to import it.

No way of posting the Miller's matey - thanks for the offer though!

If you do a search on the ventectomy mod - the coefficient of expansion of diesel is so low that it of no consequence.

(I have filled up late at night at 30 deg C and then gotten into the car at midday the next day at 45+ deg C and not a prob....)

No way of posting the Miller's matey - thanks for the offer though!

If you do a search on the ventectomy mod - the coefficient of expansion of diesel is so low that it of no consequence.

(I have filled up late at night at 30 deg C and then gotten into the car at midday the next day at 45+ deg C and not a prob....)

Ah yes, but in your case the tank started out at a similar temperature to the fuel; in mine (and not atypical for the UK in Spring) the fuel was several degrees colder than the tank!

Why do people think it's some sort of clever to fill the expansion tank when filling up at the pumps? Ok, not this time of year, but I've filled up, used a litre driving home, and come out the next morning to find the tank's showing about 2l more than it was the previous night.

Um...your fuel gauge is accurate to the litre?

The expansion tank is overkill on a diesel car, there's little vapour pressure and the liquid changes in density by a tiny amount (compared to say, petrol).

He said he did didn't he?

If he did, I think I missed it :eek:

Thanks for the comments people. Yes, I did top up carefully to the brim using a bottle outside the house. The silicone grease was put in a while ago (I think following your tip Bas) and it certainly made the engine smoother after start-up. Whilst normal filling of the expansion tank may not be needed, I've assumed that it is impossible to be sure the tank is full without using the nipple. Before I remove it; has anyone who has done this had problems with fuel being thrown back during filling?

V

No need to be savage - simply bend the nipple with the nozzle when filling (after the pump has already gone *click* and you'll hear the air escaping as you fill the expansion tank.

whats the italian tune up?

whats the italian tune up?

That's where you have a pizza, some red wine and then drive it like you stole it....

Um...your fuel gauge is accurate to the litre?

The expansion tank is overkill on a diesel car, there's little vapour pressure and the liquid changes in density by a tiny amount (compared to say, petrol).

It doesn't have to be "accurate" in the way that a garage pump does. It just has to be consistent (can you prove otherwise in the general case?) and calibrated consistently every 5l to allow it to be read (when stationary) to an effective accuracy of 1.25l. This is just basic scientific instrument reading!

cheers.

It doesn't have to be "accurate" in the way that a garage pump does. It just has to be consistent (can you prove otherwise in the general case?) and calibrated consistently every 5l to allow it to be read (when stationary) to an effective accuracy of 1.25l. This is just basic scientific instrument reading!

You must have some sort of fancy fuel gauge in your Octy then - the one in my Fabia tells me nothing at all - it just moves from right to left (slowly). The marks mean little more than "Full" "Lots" "About half - but don't bank on getting the same miles you got for the first half a tank" "Enough" "Empty".

Or am I missing something - you said it indicated 2L more in the morning than the previous evening - how could you tell?

You must have some sort of fancy fuel gauge in your Octy then - the one in my Fabia tells me nothing at all - it just moves from right to left (slowly). The marks mean little more than "Full" "Lots" "About half - but don't bank on getting the same miles you got for the first half a tank" "Enough" "Empty".

Or am I missing something - you said it indicated 2L more in the morning than the previous evening - how could you tell?

I stop the car, and look at the position of the needle before switching off. When I get in next morning, I switch on, look at the needle when it's stopped moving, and low and behold, it's quite discernably (about its own thickness) further towards the "full" mark. If you have another expn as to why the fuel has "expanded" or the tank contracted at constant air temperature I'd like to hear it.

Must be a sensor thing mate - I noticed the same thing in my wide's petrol car - I did a google for the coefficient of expansion of derv and it amounts to a few drops difference in 50l volume, no more....

Maybe there's a magic derv fairy?

The thing is, it only does it when the ground is colder than the air, but as I'd typically pump 40ish l of fuel, I'm sure it's nothing to do with the tank expanding or contracting (and that should increase the tank internal volume as the fuel warms up, resulting in a given volume showing a lower reading), and it's consistent in that it's always happened the same way with this car.

Van at work, the fuel needle randomly changes throughout the day. I start off in morning, use some fuel, make first drop, jump back in, and its gone up! Amazing stuff

Anyone know how the fuel tank sender unit works??

Does it have any mechanical parts? Like a float on a hinged lever??

Does it do clever things with capacitence units and very low current electricity??

Or does it use a completely different method??

I ask because temperature can effect things in very different ways with either method of measuring fluid levels inside a vessel.

Aircraft commonly use the capacitence method and it is not unknown for the discrepancy between the delivery gauge and the aircraft gauge to be as much as 10%!!!!!!

Also, taking a gauge reading right after refuelling and another the morning after, they can differ immensely (by the way Jet A1 is basically diesel - I know of people who run their cars on the stuff!!!!!!)

I'm not taking the "night" reading "just aftre refuelling"; it's about 10 or 15 minutes and 7 or 8 miles after, as I park up for the night, so we can eliminate changes in car attitude as a cause.