[Lakes]

Interesting ,thanks xiziz.
You may need to run this test for a year or more.
I remember reading about some guy who did amazing fuel/mileage across the USA. He designed the run, and it was attributed to,  the sub zero temperatures during winter.

interesting claim cold helps economy with diesel , as back in 2008 we had a member named thumper who claimed cold weather was causing his fuel economy to go through the roof said summer helped his economy.
I think in usa just drive on interstates in mid west as I did not see hills at all and no traffic or traffic lights or towns to go through there interstates by pass towns.

[xiziz]

@ChipMIK Yeah, swedish mile/Mil(10km) is a weird convention, useful mostly in rural Sweden where it gets bothersome to say 20 kilometers or 30 kilometers , instead of 2 mil/3 mil. The usual l/mil is weird though with modern cars since they are all just two decimals as opposed to older cars that were between 1 and 2 l/mil. l/100km gives a little more fidelity. km/l is probably a more logical way to calculate, if our fuel sensors were a little more accurate - how much further can I get on the fuel I have.

@Lakes Cold air is denser and less moist gives more power however this is also offset by the fact that lower temperatures make the rubber in the (summer)tires get harder when under 10c(more resistance) and in a diesel it takes a very long time for the engine to reach operating temperature, easily 20km in -20c. Guess the fuel is slightly more dense too, so more fuel per liter.

My winter tires use more fuel than my summer tires, despite being 195/65/15 as opposed to 205/55/16. Winter tires are studded and both have an E marking in fuel economy. I'll see what my new winter tires get this winter, the Kumhos are worn down and I have four (studded) Hankook iPIKE RS 419 in my basement that I'll be mounting in November. And unless wear slows down in the Ventus Prime 2 summer tires they will need replacing next spring, looks like Nokian Green or Conti Eco atm.

[Lakes]

@ChipMIK Yeah, swedish mile/Mil(10km) is a weird convention, useful mostly in rural Sweden where it gets bothersome to say 20 kilometers or 30 kilometers , instead of 2 mil/3 mil. The usual l/mil is weird though with modern cars since they are all just two decimals as opposed to older cars that were between 1 and 2 l/mil. l/100km gives a little more fidelity. km/l is probably a more logical way to calculate, if our fuel sensors were a little more accurate - how much further can I get on the fuel I have.

@Lakes Cold air is denser and less moist gives more power however this is also offset by the fact that lower temperatures make the rubber in the (summer)tires get harder when under 10c(more resistance) and in a diesel it takes a very long time for the engine to reach operating temperature, easily 20km in -20c. Guess the fuel is slightly more dense too, so more fuel per liter.

My winter tires use more fuel than my summer tires, despite being 195/65/15 as opposed to 205/55/16. Winter tires are studded and both have an E marking in fuel economy. I'll see what my new winter tires get this winter, the Kumhos are worn down and I have four (studded) Hankook iPIKE RS 419 in my basement that I'll be mounting in November. And unless wear slows down in the Ventus Prime 2 summer tires they will need replacing next spring, looks like Nokian Green or Conti Eco atm.

xiziz  have to check air quality on the day, just because it is cold does not say it is more dense , can have more water in the air so thats not as dense. I found this out racing we measure air quality on the day for fine tuning.
but thumper claimed the intercooler  was part of cause, but did you know a diesel is not controlled by air? it is a full bore of air and the engine speed controlled by amount of fuel, with a petrol less fuel more air they run lean get hot, with diesel more fuel less air they get hot, so other way around, this is why a diesel has a flat spot off idle but these new ones mask it well.

Why dont you just let a MAF control ECU-MAP instead of seperate measurement or is removed due to restricting flow? (it could just be aspiring sorroung air & not even be mounted on inlet but have a small fan to force air past sensors for live data? couldnt be many grams such a setup would take.

[nzenigma]

temperature, easily 20km in -20c. Guess the fuel is slightly more dense too, so more fuel per liter.

My winter tires use more fuel than my summer tires, despite being 195/65/15 as opposed to 205/55/16. Winter tires are studded and both have an E marking in fuel economy. I'll see what my new winter tires get this winter, the Kumhos are worn down and I have four (studded) Hankook iPIKE RS 419 in my basement that I'll be mounting in November. And unless wear slows down in the Ventus Prime 2 summer tires they will need replacing next spring, looks like Nokian Green or Conti Eco atm.

xiziz  have to check air quality on the day, just because it is cold does not say it is more dense , can have more water in the air so thats not as dense. I found this out racing we measure air quality on the day for fine tuning.
but thumper claimed the intercooler  was part of cause, but did you know a diesel is not controlled by air? it is a full bore of air and the engine speed controlled by amount of fuel, with a petrol less fuel more air they run lean get hot, with diesel more fuel less air they get hot, so other way around, this is why a diesel has a flat spot off idle but these new ones mask it well.
[/quote]

Way back when  we used to experiment with water sprayed into the carby to increase power and reduce fuel consumption.
I still have a Fordson tractor that has two fuel tanks, petrol to start and heat the motor, then switch to Kerosene for normal running. Earlier tractors would switch to Kero and water.

Regarding the winter tyres, the extra energy needed to drive higher traction rubber vs. energy to used for (comparably) dry weather slicks, should noticeably add to fuel consumption.

[xiziz]

I decided to convert this thread into a log thread so I don't clutter this board to much more.

So I finally got around to putting the winter tires on, new for the season Hankook Winter iPIKE RS 419, with 9mm of thread and plenty of studs left. They have done 5000km on my previous car, a volvo S80, but are in good condition, but getting a bit old (2013 manufacture). I'm expecting them to wear out during the winter(20000km).

While I was at it, and against(and with too) a lot of fellow forumites advice, I plugged the EGR, full plate, no holes. Very easy job. I drive 90% in the 1500-2000rpm band, so should be a lot cleaner oil.

Edit: I also got a obd2 reader and torque to get some more instrumentation. /edit


Whats left of my Hankook Ventus Prime 2's. Worst tire is 1mm, best is 2.5mm. Rear passenger seemed to wear worst, both fronts at 2.5mm. I had the car balanced this summer because of the inner thread wear, but it seems to have gotten worse anyway - hope its fine for my new tires.
So I gotta get new summer tires before April, plenty of time to choose - These did just over 50k km. Perfectly okay. They have handled fine until I took them off. Very spongy at pressures under 2.7kg, ~38PSI?
But nice and stable at higher pressures. Only gripe I have with them is that they are very noisy, even with good thread. They are rated E for fuel economy, so could be better there too. Never felt unsafe on water/damp roads etc, but they seem to force themselves into the water instead of dispersing it.


Current fuel log chart for 2017. I think the spike at the end is due to the rear tires wearing down to much, felt more vibrations, car has not rolled as well on fuel cut off so something has happened to the resistance there.

[Dazzler]

Thanks for that xiziz,  all very interesting.   

[xiziz]

Just thought I'd post a table of DPF regens that I have been monitoring. I got torque app and set it to flash an alarm when exhaust temp climbs over 600 - much more reliable than keeping track if the instant consumption gauge shows when coasting.

I've also done two tanks without a single regen and have come to the conclusion that regens hardly affect fuel economy (except when they start 3km from home and you have to take a 20km detour even though its had 72km to start up prior...) in any noticeable way.

Also, driving in -20c seems to make a lot of soot for the filter to burn off, as I get much more frequent regens when its very cold.



Three of the regens are aborted ones, the short ones (ie I aborted the one before and the short one was let go all the way), if they have not been aborted the minimum time between regens seems to be 500km. This is all mostly on the same route, I have not done any longer trips than to work and back home.

Winter tires are averaging 4.67l/100km, but its been a cold and very snowy winter - old ones did 4.57l/100km over their lifetime. Will post a graph on that when I change over to summers.

I can't wait to get summer rubber on again and get a break from the clattering of studs(but we had a lot of snow, and driving on snow is like driving on clouds, soooooo nice and quiet I turn the radio off and enjoy!) 

[Dazzler]

Thanks heaps Xiziz. It is such a different world. DPFs and snow and studded tyres..

[xiziz]

Just a tiny update:


EGR blocked off at mid November 2017. Also winter tires on December first to April first.


(Don't mind the August spike, its only one tank so far where I managed to get 54.5l in after only getting 48l in the previous fill, averages out over time though). Also had the brakes seize over summer.

I can only draw one conclusion, and that is that blocking off the EGR on a modern turbo diesel increases fuel consumption. In my case, its up 8% or ~136l/year...

And then I measured the same five month period 2017 vs 2018 with the only difference that the 2017 was done on OEM Hankooks rated fuel economy F vs 2018 with EGR blocked running Michellin Energy Saver + rated fuel economy B. New rims also saved some 3kg of rotating mass per wheel.
So I believe it might actually be worse, closer to a 10-15% increase when you do the majority of your driving cruising at 70-90 kph.

Is it worth the cleaner oil, presumably longer engine life, higher emissions and less stuttering(more pleasant drive) sub 2000 RPM. I don't know. I gotta think about this one - Its a lot of fuel money, but what is the price of a clogged engine?

I'm gonna have to remove the blocking plate and test a month or two and see the difference on the same tires.

[Dazzler]

Another interesting post xiziz. Like you say, that is quite a marked difference. 

[The Gonz]

Really impressive empirical investigation and a surprising result over the blocking of the EGR valve!

[xiziz]

Yeah, I dont get the maths around how it can be possible. I think the bad brakes that have been deteriorating since about the same time I installed the EGR block plate(thats when I applied the wrong grease to the glide pins). So they probably have contributed some too.

I filled a 4.13l/100km tank today. I will keep the plate in place atleast untill its time for winter tires, then I should be able to deduct the brakes effect.

When I inspected the right rear(that they had off and checked for imbalance at the workshop but said it was fine) I found two new set of weights and the one old set was removed. So there was a balance problem in the tire after all.