406oc.co.uk

I've got a basic model D9, 2.0 Litre hdi, none turbo, putting out 90bhp, unless the police 'breathed on it.
It's got 105,000 ish on the clock.

A couple of weeks ago I took it on its first decent run since I've had it. A 550 mile round trip, from home (near Kirkcaldy) to Congleton and back. According to my trip computer, my average mpg was 50.4.
I was expecting it to be slightly better than this to be honest. 50.4 is what I get on my normal run to work, after a slight adjustment of my driving style.

My route from home to Congleton was,

• a few miles on small local roads, onto the
  A92, a fast dual carriageway,
  M90, fast motorway,
  A720, Edinburgh city bypass,
  A701, fairly fast single carriageway
  M74 / M6, fast motorway,
  several miles on small local roads,
  returning on the reverse route.

On motorway and fast dual I was cruising at 80 roughly, on the single carriageways, usually doing around 60 where that was suitable. My wife has problems with her neck and aggressive cornering or generally rough driving will exacerbate those problems. However I wasn't driving with fuel economy in mind particularly.

With this info' to hand, how does my fuel economy compare to yours ?
Perhaps we can compare against each other, over all of the various engines, what do you think?

That sounds about right for a hdi90. The problem is wind resistance starts to act noticeably against the 406 at 60-70mph (depending on estate/saloon), so backing off that last 10mph might make a big difference to the under-powered hdi90.

You can read up on economical driving techniques all over the place and they do make a substantial difference - I could get 45-50mpg on the motorway in a 2.0 turbo petrol and can do 40-45 in my V6 petrol. "Normal" motorway driving would get me around 28mpg in both cars.

Hi guys

Ive got a 406 2.0 HDi 110 on a 2000. Its done nearly 125k miles now - on my normal run to work which is from bradford to leeds id say am getting around 46mpg - i dont have a computer so ive had to do my own calculation.

My journey is a combination of Motorway (during traffic so ave of 50mph) and local roads.

Am sure i can get better - ive not tried any special driving techniques but think i should give it a go especially were all feeling the pinch......

Anyone have some easy simple tips????

Cheers

harrywy wrote:Anyone have some easy simple tips????

- Accelerate gently, in fact treat all the controls like they're made from eggshells.
- Think about the route and plan ahead.
- Coast up to roundabouts and junctions from a long way back in gear. There's some school of thought now that says you're better off leaving it in high gear rather than changing down, but I'm not convinced by that. Hovewer one thing you should never do is stick it in neutral for the coast (an engine needs a little a little fuel to tick over, but if the motion of the car is keeping it going it'll cut the fuel supply off altogether - free miles ). Further to this, when you're descending a hill take your foot right off the throttle and allow the car to overrun in gear, if you had a computer it'd pretty soon be showing an instant mpg of infinity.
- Carry speed around corners and through roundabouts etc. Braking is wasted energy, accelerating uses fuel
- Stick around 60 if you can stand it, 406s really feel the wind resistance above that.
- Never ever brake!

Oh and MJB's favorite trick is slipstreaming, but I've tried this and I'm just not that comfortable being so close behind another vehicle

DaiRees wrote:Oh and MJB's favorite trick is slipstreaming, but I've tried this and I'm just not that comfortable being so close behind another vehicle

You don't have to get right up someone's backside to do that - cruising a normal distance behind a large truck will make a difference anyhow. A truck's length is sufficient for a noticeable gain in economy and it'll help you engage 'mental cruise control' whereby you'll end up holding a rock steady speed. Drop back a bit when another truck is overtaking to give yourself extra breathing space in case of emergency

mjb wrote:

DaiRees wrote:Oh and MJB's favorite trick is slipstreaming, but I've tried this and I'm just not that comfortable being so close behind another vehicle

A truck's length is sufficient for a noticeable gain in economy and it'll help you engage 'mental cruise control' whereby you'll end up holding a rock steady speed. Drop back a bit when another truck is overtaking to give yourself extra breathing space in case of emergency

There's another slight problem with being "a trucks length" behind a truck, particularly on a two lane dual/motorway, which you probably haven't considered..

Despite what some seem to think, most of us truck drivers do our best to drive with consideration, given the constraints we're working under. We therefore try to minimise the time taken to overtake. I would prefer to overtake you in your car, pull in to allow the queue past, then pass the truck you are slipstreaming. If you're about a trucks length behind when I start the overtake, I would expect to have to pass both of you in one maneouver because one trucks length isn't enough for me to pull in, without cutting you up. Therefore I would be right up your backside, while I wait for an appropriate gap to pull out into. The shorter the distance I have to cover, the less time I'll be blocking a lane and you're already making it over two truck lengths long
Being this close tends to make car drivers nervous. You often seem to assume we're trying to bully you, we aren't, honestly. We are keeping an eye on you in case you decide to do something, in our view, stupid (brake tests anyone?). Mainly though, we're watching for stuff much further in front, that you will see and react to long after we've seen and already reacted to it, and watching our mirrors for the gap we want, to make the overtake. We'd rather not have to pass you in the first place, we'd much prefer you to put your foot down a bit further and travel a bit faster than us, 70 ish for preference. If your happy at 56 ish that's fine by us, you're simply yet another hazard we have to watch out for.

There are truck drivers who will be trying to bully you, but honestly these are a minority. It's the usual story. One idiot spoiling it for everyone else. Consider how many trucks you'll really see in a day. You only really remember the ones which catch your attention. Most of those will be the ones which do something, in your view, stupid.

Hi
All of the aforementioned are valid - also remove any unwanted items, turn off air conditioning and fan,close all windows, check tyre pressures,don't exceed 50mph,park up in a garage over night,avoid night driving, don't use heated rear screen. Remember, any electrical device will be drawing power from your alternator and if you want to witness the effect just turn on your headlights and listen to the engine note change as the load comes on. As others have commented on avoid braking since you are dissipating the energy you have put in to get it going in the first place. Avoid any overtaking since the pressure wave from the other vehicle will hit you and slow you down. 50 mph is well known as the optimum, above this the effect of wind resistance increases at the square of the speed - you can prove this by noting that the accelerator is only pressed about one quarter up to 50mph but you will need to press it two quarters more to go another 20mph approximately. When you have practised all these techniques the thing you will find is you will tire (get sleepy)very quickly and because of the high concentration your ability to drive safely will be impaired i.e. you will start missing vital signs and considering other drivers despite trying to look ahead more. Further you will drive every other motorist mad and increase congestion dramatically I'm afraid.

SimonTNUK wrote:There's another slight problem with being "a trucks length" behind a truck, particularly on a two lane dual/motorway, which you probably haven't considered..

Trust me, after doing it for 18 months I'm very well aware of it

FWIW how I react when about to be overtaken depends on forward visibility, traffic volume and speed differential of the approaching truck. For example if the big scary thing in my mirrors is closing at 10+mph I'll drop back and give myself as much room as possible because I have zero trust for people speeding while driving umpteen gazillion tons around. A 5mph differential in light traffic where I've been able to see the hard shoulder ahead is clear - I'd pull a lot closer to the truck ahead to enable the overtaker to spend less time in lane 2. A truck that's going to take forever, I drop back a bit, match speed with him, and come off the gas as soon as he's in lane 2 enabling a quick overtake

I know how much of a pain the 53mph Micra/Rover/etc in lane 1 is (who always accelerates slightly when a truck moves into lane 2 to overtake the dozy old codger), so try to make my 60-on-the-speedo as trouble-free for other motorists as possible

Although recently I've been having trouble staying in double figures. Damn V6

You wanna watch that!

Especially in Italy!

aren't evos subject to a speed limiter which actually makes them slower than a V6 406, just like the M3 is?

mjb wrote:aren't evos subject to a speed limiter which actually makes them slower than a V6 406, just like the M3 is?

'

Japanese market ones are limited to 180kph...M3's are limited to 250kph!

mjb wrote:

SimonTNUK wrote:There's another slight problem with being "a trucks length" behind a truck, particularly on a two lane dual/motorway, which you probably haven't considered..

Trust me, after doing it for 18 months I'm very well aware of it

I glad to hear it

Another question. Presumably you want to get where you're going reasonably quickly.

Once a faster truck has passed you, would you slipstream the faster truck? Particularly if you could easily and safely pull out behind it.
Would doing so reduce your mpg significantly?

Slipstreaming a truck in my car just wouldn't interest me. I do in the region of 2500 - 3000 km a week in my truck (well my bosses truck), limited to a max powered speed of 90kmh. I enjoy the opportunity to go that bit quicker when I'm in the car or out on my bike.

SimonTNUK wrote:Another question. Presumably you want to get where you're going reasonably quickly.

Once a faster truck has passed you, would you slipstream the faster truck? Particularly if you could easily and safely pull out behind it.
Would doing so reduce your mpg significantly?

Time-wise it really doesn't matter, if you want to get somewhere quickly you drive at illegal speeds - half a mile an hour ain't going to make much difference

Economy-wise, I'm not really sure. In the V6 there's a pronounced difference in economy between 50 and 60 on the speedo, but the turbo just didn't have that so it'd make sense to go for the faster truck, especially given the faster it's going, the bigger and more pronounced the slipstream area, However, if it's fairly busy you may find yourself having to follow it overtaking loads of times, and unless you can time everything perfectly you'll be spending a lot of time driving *against* the high pressure air that enables slipstreaming to happen...

Personally I just prefer to plonk myself behind someone that's doing bang on 60 on the speedo, preferably over that on downhill stretches as a heavy truck ain't going to brake so well

The exception is tanks. Or houses. I didn't care what speed they were doing, we're talking 60+mpg territory behind one of those things - they almost pull you along!

mjb wrote:The exception is tanks. Or houses. I didn't care what speed they were doing, we're talking 60+mpg territory behind one of those things - they almost pull you along!

I can tell you one thing , you would not like a 44 tonners mpg figures .

This week, due to the wind and the weight of my load, I got an average of a little under 36 l/100km, which converts to 7.84 Miles per gallon. This is pulling a 4.0m tall trailer which is only a few inches taller than my tractor unit, which has the full air deflector kit fitted. Mind you, if I get as much as 10 mpg I'm well pleased.
(I think I've mentioned that I cover 2500 - 3000 km a week, I'll leave you to figure out the weekly fuel bill)