Adventures in Hypermiling - Increasing MPGs
Recently I've been doing a lot more miles in my VW Polo 1.4TDI (75ps, 2004), about an average of 1500 miles in a 12 day period. So I've been trying to get as many MPGs as possible. Here's what I've found out:
Doing the same routes (generally the same route between Sheffield and Liverpool) but varying depending on weather/traffic etc (picking the quickest with least traffic, and a mix of motorways and B roads).
I was getting an average of 49-54mpg when I wasn't really thinking about MPG and when I wasn't doing so many miles. I checked tyre pressure, removed unnecessary items from the car, (I already have AC off). There is no trip computer, so I'm getting these figures after the fuel warning light comes on, and then I'm refilling the tank to full.
However, I made the following changes to the speed I drove:
Stick to max 70mph: 51-54mpg
Stick to max 65mph: 57-59.72mpg
Stick to max 60mph: 63.91mpg (I also switch off the engine at long stops at red lights)
Stick to max 57.5mph: 64.05mpg (expected a bigger improvement)
Back to 60-65mph: 59.72mpg
Next I'm trying some Redex to see if it makes an improvement, and am sticking to a max speed of 60mph.
What have you done that has made a noticeable difference?
Thanks
Josh
Re: Adventures in Hypermiling - Increasing MPGs
Changed cars :p
Going from a 140ps 2.0TDI A3 to a 150ps 1.4TFSI A3 dropped my mpg from 55-60 to 50-55 - and it's become a lot more wind-dependant :p
I already knew the same thing about speed that you discovered - though the new car is slightly more speed dependant than the old one was. Tyres have made up to 2mpg difference at most so I pick based on grip primarily.
Re: Adventures in Hypermiling - Increasing MPGs
I used to try this on my old 206 diesel but I didn't have the patience. In most cars you'e going to struggle to get 10Mpg+ etc verses must get there quick driving (60Mph vs a figure I won't admit to in public). It really requires dedication to the cause. Do be aware that having the AC off long term will cause it to degas and need more maintenance as using it lubricates the system stopping seals drying out or so I've heard - I just leave it on as the cost of fixing is greater than the fuel saving at a guess.
Re: Adventures in Hypermiling - Increasing MPGs
I use cruise control whenever possible and safe. Reduces minor variations in speed and the small bits of unnecessary acceleration which drinks fuel. 50mph average speed limit zones are really good for fuel consumption figures!
Re: Adventures in Hypermiling - Increasing MPGs
I have been doing the same recently between Plymouth and Newquay, although in a 272ps car which doesn't really lend itself to economy!
I have found the biggest differences are had from how fast I accelerate. Getting up to speed slower seems to get me a much better mileage, although the roads are quite winding with lots of reasons to change speed. I am guessing on a drive with a lot of motorway, your not going to see the same.
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
peterb
I use cruise control whenever possible and safe. Reduces minor variations in speed and the small bits of unnecessary acceleration which drinks fuel. 50mph average speed limit zones are really good for fuel consumption figures!
I use the adaptive cruise control in my car as often as I possibly can to try and increase mileage, but I find that most of my speed variations are caused by other road users, either hogging the middle and outer lanes, forcing me to slow down from 70, or just people overtaking me at 71 or 72mph and taking three weeks to do so, causing me to get hemmed in behind a truck while they overtake.
I honestly believe, as a country, our driving standard is appalling and when I come to power, I'm sending every single person in the country on a state-funded theory class to try and drum home some basic facts about driving to help save some fuel and some lives.
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
Hoonigan
I use the adaptive cruise control in my car as often as I possibly can to try and increase mileage, but I find that most of my speed variations are caused by other road users, either hogging the middle and outer lanes, forcing me to slow down from 70, or just people overtaking me at 71 or 72mph and taking three weeks to do so, causing me to get hemmed in behind a truck while they overtake.
If you're worried about mileage just sit a safe distance behind said truck at 56mph, stick some calming music on and arrive refreshed and having used a minimum of fuel and polluted a minimal amount.
Re: Adventures in Hypermiling - Increasing MPGs
good experiments :)
The place to most save with most cars, is to learn the torque curve and use it.
example - Skoda (VW) 1.9 TDI 130 that I drive.
1500 revs... way off boost... crap mpg
1900 revs.. spot on... gentle whiff of throttle to maintain speed on hills etc.
2200 revs... not quite as good.
So... forget your road speeds for a while (up to motorway) and focus on your peak torque. If you're off it... you need more fuel injeted to maintain oomph
Re: Adventures in Hypermiling - Increasing MPGs
This may be obvious to most people (but not to me at the time)
But
0-10mph 1st gear
11-20mph 2nd gear
21-30mph 3rd gear
31-40mph 4th gear
41-onwards 5th gear
This plus anticipating the areas where its going to slow down and speed up and adjusting your speed gradually saves a bit of fuel.
I mean i get an extra 40 miles before i have to fill up, also only fill up to half a tank because of the extra weight and also take anything out of the car that is not needed and is weighing it down.
making sure your tyres have enough tread and at the correct tyre pressure too helps.
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
Ravens Nest
0-10mph 1st gear
11-20mph 2nd gear
21-30mph 3rd gear
31-40mph 4th gear
41-onwards 5th gear
My Golf is telling me to change up way before your table there.
I'm usually
0 - 8mph 1st gear
9 - 15mph 2nd gear
16 - 22mph 3rd gear
23 - 31mph 4th gear
32 - 40mph - 5th gear
41+mph 6th gear
That's in a 2.0 turbo diesel.
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
Hoonigan
My Golf is telling me to change up way before your table there.
I'm usually
0 - 8mph 1st gear
9 - 15mph 2nd gear
16 - 22mph 3rd gear
23 - 31mph 4th gear
32 - 40mph - 5th gear
41+mph 6th gear
That's in a 2.0 turbo diesel.
Maybe its the engine size, mine is a 1.4 Honda jazz.
I used to go straight to 4th - 5th gear at 30mph so i was putting a lot of pressure on the engine and gears.
Maybe your gear shifts are correct for a 2.0 i guess.
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
Ravens Nest
Maybe its the engine size, mine is a 1.4 Honda jazz.
I used to go straight to 4th - 5th gear at 30mph so i was putting a lot of pressure on the engine and gears.
Maybe your gear shifts are correct for a 2.0 i guess.
Also 6 gears so probably closer together in the mid-range.
It also depends what sort of gearbox you have, my 57 focus has quite a close-ratio box and will take 5th at 35, but be sitting at 4000 revs at 80, whereas the CX-5 with an auto sits at about 2500 revs at the same speed (off the road network of course, I would never condone speeding)...
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
Ravens Nest
This may be obvious to most people (but not to me at the time)
But
0-10mph 1st gear
11-20mph 2nd gear
21-30mph 3rd gear
31-40mph 4th gear
41-onwards 5th gear
It you're going to fuss like that, get an automatic. They have more gears, they should select them at the optimum time.
That compares to the old Alfa 166 I used to have with a 2.5l V6 with an awesome red line up around 7.5K. Pull away in second, when you get to 70mph you might want to change to 6th and who needs the gears in between. Damn I still miss that car :D
Still, back to the topic. The dirty secret of modern turbo engines is that they are only economical when you *don't* use the turbo. My current petrol car has a dashboard switch which on long boring journeys I switch to the supposedly "Natural" setting and there are two changes it makes for economy:
1/ The throttle response is changed so you have to really mash the pedal into the carpet to get the car to go.
2/ The turbo starts kicking in at 2100 rpm.
Stick it in the Dynamic (sport) mode and the turbo spins up at 1900 rpm instead, so you are pretty much always on boost. That 200rpm makes quite a difference, specially in roadworks on the motorway where a steady 50mph in 6th doesn't need the turbo and gets awesome mpg but flick the sporty mode on and see the mpg drop. At 70mph it is always above 2100 so always on a bit of boost.
The car is capable of about 40mpg, but I get bored and distracted which is dangerous so I actually get about 33mpg. I only get 40mpg on motorways.
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
DanceswithUnix
It you're going to fuss like that, get an automatic. They have more gears, they should select them at the optimum time.
But then you have to drive an automatic and they're not as engaging or fun. We test drove the Golf GTD with the DSG gearbox and yeah, the shifts were quick and make the car feel like one long gear, but it wasn't anywhere near as fun as slotting the gears in and rowing back down into a roundabout or whatever. VW's claimed MPG is also a fraction lower on the DSG model than the manual.
I also don't know if I agree with your point on a car losing efficiency if you use the turbo. While turbos are largely used to increase power, they're also wicked at recovering lost energy through the exhaust and transforming it back into energy within the engine in the shape of additional air for a bigger bang with leaner fuel mixtures. Someone may tell me my thinking is wrong there.
Based on the above, if I stick the boost/power/temperature screen on the centre console, at 70mph my turbo is producing around 19PSI of boost on the flat, moving up to around 21-22PSI on an incline.
Re: Adventures in Hypermiling - Increasing MPGs
Quote:
Originally Posted by
Hoonigan
Someone may tell me my thinking is wrong there.
Your thinking is wrong there ;)
The basic problem is that any air you put in the engine needs to have the correct ratio of fuel added to it.
An NA petrol engine is actually very efficient at wide open throttle, hence the "how far you can go on a pint of petrol around and around a track" competitions don't have a throttle, they just turn the engine on for a bit and then coast. The problem is at part load petrol engines are rubbish. To get around that, you use a small petrol engine so it is closer to running flat out, but when you actually want to go flat out you spin up a turbo to make the effective capacity of the engine bigger. The turbo isn't free though, you have to burn more petrol to push the turbine blades around but the idea is if you are pushing that hard you already gave up on economy :D
Surprised at the DSG box being worse economy, on my car the equivalent "TCT" robot twin clutch gearbox auto option is one tax band lower than my 6 speed manual. I have other cars for fun driving, I do wonder if I should have got the auto for this one as it is the car we always use for dull motorway trips.
Re: Adventures in Hypermiling - Increasing MPGs
So, based on all of that information, are you telling me that if I removed the turbo from my car somehow, I would return better MPG figures for the same speed of travel? That doesn't make sense to me at all.