Today I.....

gills said:
Today I......discovered we're back on summer diesel! I filled up this morning (after forgetting my card PIN at the pump and having to go in to pay contactless on my phone!) 20 miles later and the DIS is showing mpg in the high 70s, rather than the mid to high 60s that I've been used to for the last 6 months. Should mean I'm back to low 70s for a tank full - fingers crossed....
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Is there really that much difference between summer and winter fuels? Do you know what they're adding / subtracting to reach the different seasonal specs?

I'm been meaning to catch up on your thread and see how all the tweaks and winter-easing accessories worked out :cool:
 
Rusty911 said:
Is there really that much difference between summer and winter fuels? Do you know what they're adding / subtracting to reach the different seasonal specs?

I'm been meaning to catch up on your thread and see how all the tweaks and winter-easing accessories worked out :cool:
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It shouldn't be quite as much as I got today! It's something around a 10% difference in calorific value between summer and winter diesel in the UK. They leave out some of the heavier hydrocarbons and add waxing inhibitors to keep the diesel liquid at sub-zero temperatures.

I've not updated my project thread in a while, but my fuel economy has held up over the winter to around my long term average, rather than dropping below it. If the summer figures pick up as I'm hoping, then the block heater and aero tweaks should have given me a 10% improvement in economy over the winter months. Things should become clearer over the next few weeks.... ..
 
I thought the 10% increase in my Crystal one's MPG in this tankful was mainly to do with not having the Webasto come on so much/so often with the warmer days, even if the mornings are still a little nippy. Do we get winter diesel in the South?
 
Any info (fact) to support winter diesel having a calorific value 10 % below summer diesel?
I find this hard to accept. Willing to learn though.
Mac.
 
I’ve noticed my fuel consumption improving slightly with the temps now being 7-11 degrees round here, but nowhere near 10%
 
dj_efk said:
I’ve noticed my fuel consumption improving slightly with the temps now being 7-11 degrees round here, but nowhere near 10%
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You don't have a Webasto on an ATL :) When it was 1-2 degrees at both ends of the day and having to clear frost in the mornings, I was only getting 52-53mpg because it was on the whole time. More recently it's been jump in and go, and the external temperature has been over the 7°C cutoff by the end of the morning run and higher still in the evening, and I'm showing 57-58mpg on the DIS for this tankful.
 
C0D5123B-28EF-4456-B9BB-CD6E0E415637.jpeg

Made some A2 wall art for the garage from an A2 brochure. The brochure never saw the light of day in the cupboard but will now be on full view in the garage.
 
Rusty911 said:
Is there really that much difference between summer and winter fuels? Do you know what they're adding / subtracting to reach the different seasonal specs?

I'm been meaning to catch up on your thread and see how all the tweaks and winter-easing accessories worked out :cool:
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Strangely and back to front from what's been said is fuel contracts when cold and therefore you can squeeze more fuel in the tank and colder air should increase efficiency, warm fuel expands and the warmer less dense air reduces economy so the temperature does affect fuel efficiency but not in the way being stated, I could be wrong and please correct me if so but I'm pretty sure that's a ruff explanation.
 
Mka306 said:
Strangely and back to front from what's been said is fuel contracts when cold and therefore you can squeeze more fuel in the tank and colder air should increase efficiency, warm fuel expands and the warmer less dense air reduces economy so the temperature does affect fuel efficiency but not in the way being stated, I could be wrong and please correct me if so but I'm pretty sure that's a ruff explanation.
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You are correct, but other factors are in play
The engine is far less efficient at cold temperatures so on short runs there is a lot of energy taken to bring the engine upto operating temperature
Once at operating temp then the colder air being more dense = more oxygen and the colder fuel will equal more power per gram of fuel
However in the winter on shortish runs this is killed by the heating up of the engine
Plus the energy sapped by the cabin heater etc
Also there are additives added to winter diesel to prevent waxing which have a detrimental affect on fuel economy

paul
 
Also, like us, our cars are pushing through an ocean of air. You wouldn't need much of a change in density before effort required for speedy movement changed.

Therefore in cold weather, engine output in BHP terms may increase once temperature finally reached, but you'll then consume more energy pushing through that gloopy cold thick air :)
 
Rusty911 said:
Also, like us, our cars are pushing through an ocean of air. You wouldn't need much of a change in density before effort required for speedy movement changed.

Therefore in cold weather, engine output in BHP terms may increase once temperature finally reached, but you'll then consume more energy pushing through that gloopy cold thick air :)
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Your technically correct but the difference in air density will have little to no effect under 56 mph after that it starts to play a part

Have you ever noticed how much more power the car seems to have on a cold slightly damp winters morning (once the engine is fully up to temp). This is due to the cold dense (more oxygen in the air charge) and the slight dampness as the effect of prolonging the burn in the cylinders. All this equally more power per gram of fuel. This effect is more prevalent in none turbo engines but it’s still there with the turbo just a little harder to detect

Paul


Sent from my iPhone using Tapatalk
 
Just to round out the initial batch of work on the project-that-didn't-get-a-project-thread-car (or Ptdgaptc as it might catchily be called):

1) Shifter mech removed, stripped, cleaned and greased up with silicon grease. This led to:
2) Seats out wet valet as the above nearly got me to this stage anyway.
3) Found the recent gearshift cables had been put in wrong which explained why one cable was resting hard on the other near the g/box. Fitted them correctly. Suspect person that had fitted them had failed to notice (as I did initially) the 90 degree turn-collar that retracts the locating pins that either hold the cables in place or allow them to be released. Suspect they simply tried to push them into place, failed and just left them floating. Was just relying on the clips at the shifter end. Shift is definitely better than it was but has more than an element of classic car about it (and not in a good way). The gearbox does have some noise at rest when the clutch comes up. As the engine sounds quite happy and car in general isn't a bad old Hector, if it stays I'll wait for a budget six speed to crop up and add that.
4) Test drive revealed near instant heat from vents and after four miles hoses still cold. By time I was back home gauge bang on 90dC, hoses just getting warm so I'm calling the whole thermostat thing case-closed.


a) Still to go at some point: 2x door check-strap refurbs, wiper arm refurb plus wiper goes 'over centre' so to speak at bottom of travel before parking so need to look at that.
b) Hub cap refurbs all round.
c) Poss swap bonnet and front bumper for better ones.

Possible additions:

i) Heated seats (have kit here).
ii) Parrot (have kit here not currently used).
iii) Improve soft-touch in places.
iv) New shocks all round but they need to be a bit budget'y on what is a leggy cheap old thing with zero history.

Anyway, I'm going to say it's avoided the scrapman / breakers and will do me as a daily very nicely for now. It came to me through nice circumstances and the PO is delighted to see it back on the road for a few more years. I also must say, I just love these in the silver, which really shows off the contrasting black trim.

Result to date:

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P1030496sm.jpg
 
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