I ended up on SAFED driving exam today (Safe And Fuel Efficent Driving) which is endorsed by the DOT, I was constantly reminded of finding the sweet spot which on the lorry is in the green zone of the rev counter (the rev counter has white, green, white, blue then red). Where is the sweet spot on a 2.0 FSI? just out of curiosity??

Also does anyone do block changing? this was something else that was drummed into me today (none of the above done on the drive home :lol:).

I do block changing when driving hard and approaching a bend. I'm not sure if it's good practice, but when I can see the bend ahead and know roughly what my exit speed is, I would rather go from 4 to 2, than 4,3,2 - less time with a hand off the wheel and no drive to the wheels. Probably totally mis-informed but it suits me.

Sweet spot . . . I have no idea. I know my Octy seems to be most economical at about 50mph (about 1500rpm in 6th), but that speed is generally inconvenient to travel at.

My cars sweet spot is normally in the drivers door pocket:P

Phil:rofl:

I would rather go from 4 to 2, than 4,3,2

Yeah i do that all the time, but this was block changing up e.g. 1,3,5:confused:

I use block changing as I approach a hazard and decide what gear I need to accelerate through it. Don't use it so much going up the box though....

Chris

Also does anyone do block changing? ).

Yup

I use block changing a lot. If I've been a bit silly and revved up 2nd or 3rd, there's little point finding the next gear - you may as well knock it up 2 and cruise on. I'd be interested to hear the principle things in the SAFED course as I always try to drive mine economically when I'm not in any desire to get anywhere fast. Over 35 miles this evening, including my rush hour commute home the car says I got 64mpg. 225 miles done and still indicating 3/4 tank left (I know this is not the reality )

I often go 4-6

I don't often block change up, but have done if for instance I overtake someone so am touching the redline in 3rd, I may go straight to 5th or 6th from there.

In "normal" driving, i.e., gentle acceleration, I cannot see any benefit, at least in a turbo-diesel as I'd be forever dropping off the turbo, even if I held gears to quite high rpm's. I guess the same would apply to petrols too to a certain extent as you'd be dropping off the power band?

Maybe test each theory, SMS, if you have a fairly regular journey to work or something? Try each method for a week and see what difference (if any) there is?

Going up the box, the only time I would block change would be if I could see I would be cruising, eg I've taken 3rd to the red line (about 70mph) and then select 5th. I don't believe cars are well enough geared to make using 1->3 a useful change.

I was lead to believe that the sweet spot on a diesel engine was around the 2k rpm mark (presumably where it develops peak torque) so it is at its most efficient then, and you have power on tap should you need to accelerate. I guess you have to strike a balance though as being in a higher gear cruising will use less fuel than a lower gear at peak torque, but you do lose the flexibility of power and engine braking....

Chris

I'll quite often go 2nd to 4th if I'm accelerating in a 30 zone. Similarly 3rd to 5th in a 50 zone.

Block changing up was covered a while ago in another thread. Personally, I block change 3 - 6 quite a lot, and occasionally have done 1 - 3 - 6, although normally cause I have pulled away quickly and no longer need to accelerate e.g. up to the speed limit.

I always try to drive mine economically

not you Jase, must be your twin

The website (after googling it) is SAFED - Entry

I know i scored "Good" which is good when the four classes are "excellent", "good", "fair", "failed" i was three points out of Excellent at the end of the first run, if i did the test again i would get a "excellent" and have been told if we go for the test again in 6 months that i would breeze it as its based on the advance test.

Maybe test each theory, SMS, if you have a fairly regular journey to work or something? Try each method for a week and see what difference (if any) there is?

Ive tried to measure my mpg going to work, but never get anything consistent, i beleive things like the weather have a say in it, especially when i only have 8 miles to go (each way.)

I was lead to believe that the sweet spot on a diesel engine was around the 2k rpm mark (presumably where it develops peak torque) so it is at its most efficient then, and you have power on tap should you need to accelerate. I guess you have to strike a balance though as being in a higher gear cruising will use less fuel than a lower gear at peak torque, but you do lose the flexibility of power and engine braking....

Chris

The examiner/instructor wanted me to get up to 5th gear asap with as little gear changes as possible and keep it in 5th for as long as possible telling me that you will still speed up at the same speed as being in 3rd at 30mph due to torque, not that i could see this.

I quite often do 1st - 2nd - 4th - 6th. The 2.0 TFSI has more than enough torque to cope so why not use it.

The examiner/instructor wanted me to get up to 5th gear asap with as little gear changes as possible and keep it in 5th for as long as possible telling me that you will still speed up at the same speed as being in 3rd at 30mph due to torque, not that i could see this.

Well he may well know what he's talking about, but in my car that is definitely not the case. I would also question how much fuel would be saved doing that I'd think you'd need more throttle to get going in 5th over 3rd too to get the vehicle into the usable power band....? I'd also be interested to know how much engine braking is available in 5th compared to 3rd?

Interestingly when I first started my RoSPA training, my observer said the biggest fault he saw was people being in too higher gear for their speed. He also said that this is the most likely reason for people having difficulty maintaining 30mph in a 30 zone....

Chris

You've hit the nail there chris, i argued it out that IAM which this guy was also a member of say to stay in 3rd at 30 for all the reasons you mentioned and was also pretty economical as well as keeping the vehicle at 30 etc but he said you could drive just as well in 5th and save fuel (this also included driving up a steep hill at 40 in 5th) when i mentioned that your foot will be clearly glued to the floor he said well it cant use more fuel as its can only burn the fuel its using for that speed.. He couldnt answer where the fuel has gone (paul daniels must have popped along for a magic show).

Post-mapping it was 1st to let clutch come up, hardly if at all touching accelerator. Accelerate in 2nd a bit more, 3rd plant it, then usually 5th until I've merged in nicely and then 6th - that's going up to NSLish

(this also included driving up a steep hill at 40 in 5th) when i mentioned that your foot will be clearly glued to the floor

Not to mention what that can do to the engine - the guy must be a plonka

+ Chris

the biggest fault he saw was people being in too higher gear for their speed. He also said that this is the most likely reason for people having difficulty maintaining 30mph in a 30 zone....

Yup, plus, probably, the gearing is higher these days to give a more even spread of power for these ever faster motors i.e. once upon a time 3rd would probably have got you up to 60mph, now (average, let's say) 80 mph.

Most cars these days don't like 30 in 4th on anything but the slightest whiff of throttle and / or the flat or a slight downgrade.

I will offer a titbit of information here which I discovered in my car, which is going up a long consistant hill (comparative with any load on the engine, e.g, high speed?) the engine was more efficient working hard at low rpm than working less at a higher rpm. By benchmark hill is over a mile at a constant fairly steep gradient, 30mph limit and I can easily maintain that speed the whole way without interruption. I found that in 3rd gear (which gives me about 1800rpm) I was consuming about 20% more fuel than I was in 4th gear (about 1300rpm) even though in 4th the engine was having to work harder (and I was having to depress the throttle more). I don't know if this is a quirk of turbodiesels, but it goes against what I thought . . .

Not to mention what that can do to the engine - the guy must be a plonka#.

But "it will save on vehicle maintance, especially clutches where they will last 50% longer saving us half the £600 it costs for a new clutch" he says.:eek:

But "it will save on vehicle maintance, especially clutches where they will last 50% longer saving us half the £600 it costs for a new clutch" he says.:eek:

Repeat - what a plonka.

Jeepers, I shudder to think what (even a small) lorry engine costs.

OK, they're built for mucho abuse - but what he's recommending IS mucho abuse.

But after saying all that who really cares about economy :revs:

Chris

and to add to my last statement i did agree with "under no circumstances must you pull away in any gear apart from 1st, otherwise you will rip the clutch out over time" :lol:

Arh the good old safed course. Did mine over a year ago, passed with an ecellent pass. tought you todo some things that go against what feels safe. ie going round a bend at 27mph in 6th gear becaused the truck can do it and it safes clutch wear. not convinced myself as it was almost on the antistall 5th gear which i would normally use would make me feel more in control. also useing cruse control in a 30 zone because it improves mpg. would rather have my foot on the gas because as soon as you lift off, the truck begins to slow before you touch the brakes,

After a days training and watch dvd's my mpg on the test was only better than my first normall run by 0.7mpg, i know that some had improvements off upto 4mpg.

still i got my certificate and keyring, and the company are happy because there drivers are all Safed trained.

Not ploughed through the thread, but if you want to drive economically just drive smoothly. You can travel surprisingly quickly without using huge amounts of fuel if you drive smoothly and keep an eye on what's going on around you.