I have just recently purchased a new Kia Rio Diesel (1.5l) and am very impressed with it.
Since this is my first diesel engined car I would imagine that I am driving the car wrong (I.E driving it like a petrol car).
My first tank full worked out at 46mpg and I expect this to increase as I get more used to the turbo (I am a bit heavy footed) and the car racks the miles up.
1st gear is very short but 2nd and 3rd gears are very nice and long.
Would I get better economy if I used 1st gear to just start moving then change almost straight away into 2nd gear ?
30mph is a bit of a pain as in 3rd gear the engine is 2,000 rpm but in 4th its 1,250 rpm, so its sounds like I am labouring the engine in 4th. What gear is best ?
So my question is, what is the best way to drive a diesel engined car ?
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If you want to minimise wear on the clutch, get into 2nd as early as the car can take it.
1st gear is low so that the car will pull away while 'off-turbo', eg. under 1500rpm but then will feel very under-geared.
Aim to drive around 1800-2500rpm (cf. 2000-3000rpm for gentle petrol engine driving) for most of your driving, but don't forget to use the full rev-range every so often to keep the pipes clean!
If you enjoy a more spirited drive, you'll probably find revving the nuts off disappointing - just enjoy the fat wave of torque from 2-3.5k rpm pushing you along.
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Yes, revving diesels is fairly unrewarding in every way.
I wouldn't worry about your driving technique though. If you have any mechanical sympathy you will soon find yourself changing up at just the right moment for smoothness and economy, making due allowance for gradient, load and so on. You have already noted that an early change into second seems a good idea...
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Diddy,
30mph/3rd, 40mph/4th, 50mph/5th works for most diesels of the size you have.
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Driving a Yaris diesel (2003)..
Change from 1 to 2 c 15mph
2 to 2 around 25 mph.
3 to 4 - 27-30 (depending on style, where I am -- willl go to 50 easily.
Will travel in 4 from 24mph (1250rpm) , happily at 30mph(1550rpm) and 70 (c3500rpm)
5th 35 upwards.. (2800rpm at 70).
Occasionally drive it hard to clear out the soot..- 70mph+ for 20 miles..or lower in 4th..
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Hello,
Here are few tips that one should always keep in mind while driving either you drive petrol car or diesel it is for your safety as well as for fuel effeminacy.
Adjust your rear view mirror in right angle, vehicle body should occupy 1.3 rd of the mirror and the rest is rear traffic for side mirrors.
Make sure that gear is in neutral before starting the car if engine dies not respond to the first try wait for 10 second then try again
Be careful while driving on wet roads don?t drive too fast on slippery roads
Always wear seat belts.
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Avoid low gears.
For short trips (1 to 8 Km) use public transport, using car for short trips affect fuel efficiency of the car.
Avoid AC while driving in cities, use of AC reduces fuel economy of the car by 9%
Drive at safe speed.
Avoid sudden stopping
Don?t use clutches unnecessary
Keep an eye on break oil, coolant and engine oil level.
Regards,
sarah_9
Edited by rtj70 on 12/09/2009 at 11:37
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The diesel drivers must be up earlier than the petrolheads, good advice from the regulars!
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I generally change up earlier in my petrol Charade. I tend to go 1st-2nd either at 10 mph or if the road is flat or downhill, I start in 2nd ( not be riding the clutch I might add ). 2nd-3rd at 20 mph and into 4th at 30mph. 5th depends on the road but on the flat 35 mph, hilly areas 45ish.
Unless your Rio has particularily long gearing, I cant see the sense in revving it over 2500 rpm at any time other than overtaking. 25 mph in 2nd in the diesels I have owned would have made a right racket!
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Different engine I know, but this applies to other diesels I've driven. In Mrs. DP's mkIV Golf PD 130 you don't need to go outside the 1500-2750 RPM range in daily driving. You might extend it to 3500 RPM, perhaps 3750 if you want to make extra progress, but really it's unnecessary. It takes some adjustment if you're used to petrol engines.
The only exception I've found to this is the 1.9 dCi Renault unit fitted to our old 54 plate Grand Scenic, which apart from the very bottom where it dropped of boost, was happy at any point in its entire rev range. A beautifully linear power delivery with the usual midrange turbodiesel shove, but equally happy to be extended to its redline like a petrol engine with no tailing off of the grunt until it hit the governor. Was also uncannily smooth however hard it was working. One of the best four pot diesels around and cruelly overlooked because of its early reliability problems!
Anyway, I digress, sorry.
Cheers
DP
Edited by DP on 12/09/2009 at 10:36
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Fourth sounds too high for a 30. Very easy in a high gear to wander up over 35 and into flash, bang points territory. Third will probably be right most of the time, still relaxed but the engine pitch change with speed will be pronounced enough to alert yuo to excursions over the limit.
If you need to keep even lower, urban multihazards, schoolkids etc then second may not be too low.
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Some tips:
* Don't park the car directly under your neighbour's window. The diesel startup noise will not strengthen your friendship
* Do get some sort of gadget to prevent misfuelling it with petrol. You can buy a simple gadget for £30, which will give you peace of mind and possibly save you a huge bill.
* Don't assume that you will always be sufficiently alert and focused at the pumps to never make a mistake.
* Don't run out of fuel. When you get that emergency supply, your engines may need to have its pump reprimed before it'll run again.
* Don't pick your nose for at least 24 hours after refuelling. Remember that little bit of diesel you spilt on your finger at the pumps? The diesel smell will linger much longer on your finger than the petrol smell.
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For pootling along in 30 / 40 limits I use 5th in the Passat TDI. 60-odd MPG, 1000RPM, very quiet, and still just enough oomph to accelerate gently if needed.
What I want to know is whether it's better to accelerate briskly to, say 60mph and go into 5th, or gently through the gears until I get there a bit later.
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For pootling along in 30 / 40 limits I use 5th in the Passat TDI. 60-odd MPG 1000RPM very quiet and still just enough oomph to accelerate gently if needed.
The Golf doesn't like that. The engine vibrates noticeably if asked to pull from under about 1300 RPM, and there's very little there at 1000 RPM, particularly in the higher gears. My personal experience with the PD engine is aiming for 2000 RPM as an average gives superb wallop when you want to accelerate, but still returns mpg figures well up into the 50's.
With regard to the best approach to acceleration, I don't find much in it as long as you don't boot it through the gears which obviously reduces MPG significantly. Keeping up with traffic flow and being sensible seems to be just as good as deliberately accelerating slowly. One of the features of this engine I really like is its ability to return excellent economy "without trying". Just drive it remotely sensibly out of town and it does 55-57 mpg with no conscious effort at all. The Renault engine needed conscious effort to see 50 mpg.
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I don't know if this could damage the clutch but Once the engine is warmed up I have not been using 1st gear at all to pull away from stand still.
Also I tend to keep in 3rd at 30mph (as 4th is too high geared and the engine sounds like its on the edge of labouring).
On the Rio diesel the gearing is as follows :-
1st - very short (sounds like i am revving too high at 20mph) but great in traffic jams crawling.
2nd - is like a normal cars second (nothing special)
3rd - great gear for accelerating on motorway slip roads (changing out of 3rd at 60mph at 3,000rpm)
4th - feels like 5th gear in my previous petrol car (great up till 80mph at 3,000rpm)
5th - feels like 6th gear (change into at 60mph 2,000rpm and great all the way up the rev range)
Incidentally 5th gear has gearing of 30mph per 1,000 rpm (same as most 6th gear cars)
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* Don't pick your nose for at least 24 hours after refuelling. Remember that little bit of diesel you spilt on your finger at the pumps? The diesel smell will linger much longer on your finger than the petrol smell.
Now, now, NW, the advice should be "wear gloves" when refueling a diesel or a gas mask if its petrol!!
Hard to improve on the advice given - I've driven a number of different diesels, and the best advice (as someone has said) is get to know your engine and that will tell you the best gear for driving in a 30 zone - for my 1.9TDi its 4th, but I can get away with 5th... but the old 1.4 it was 4th, never 5th! All engines are different, take the time to get to know its "feel"!
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"Here are few tips that one should always keep in mind while driving either you drive petrol car or diesel it is for your safety as well as for fuel effeminacy."
'Fuel effeminacy' conjures up a wonderful picture in my mind, which is probably best left to everyone's imagination.....
Seriously, I'd always start in 1st, even if you change up very soon - and also 3rd at 30 mph is recommended by most professional drivers as it (a) is less likely to cause the engine to labour, and (b) makes it easier for you to keep to the speed limit. (I'm sure you have no problem with that!)
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Some good advice so far,
Forget about MPG, that will settle when you find your driving style. Personally i get 42-44mpg out my 180bhp diesel. If i try REALLY REALLY hard i'll get an extra 2mpg and it is COMPLETELY unnecessary and incredibly boring trying to eeek 2mpg more. I'll only get high 48's on flat A-roads or m-ways. So its all relative to where you drive.
It takes time to adjust from petrol but do the following:
- Ensure all engine checks have passed before driving off
- Don't go over about 2.2k until warm
- If you need to go uphills when cold keep the revs more towards 2.2k
- Change gear at mean piston stoke
- This is roughly your max torque range which for most diesels is circa 1.9k - 2.6k
- Never EVER labour the engine
- Most diesels need at least 1.2k MIN on a flat road - absolute MIN!
- Never go uphill at 1.2k ever
- Ensure you are at least at the start of max torque band for going uphills
- This not only helps prevent labouring, it also prevents over fuelling and reduces excess smoke / soot build up
- When accelerating do it as smoothly as possible which really helps MPG
- Dont stab the throttle and dont baby feather it
- Get up to speed fairly quickly but smoothly gradually pushing the throttle further
- I dont know what the car is like but normally you should only need 50% throttle, 70% max
- When accelerating between mean piston stoke (roughly max torque) the car is producing power for the least amount of fuel so most efficient for acceleration or going uphills. So you normally change gear at the top of the band max.
- A basic rule of thumb is 10mph per gear roughly. 3/30mph ... 4/40mph.
- Sitting just below the start of max torque is a decent RPM to maintain a steady speed. As i said, on a flat road 1.2k min for lower speeds. 1.5k is a nice point to sit at. But as i said, its all dependant on your engines torque band.
- Make sure, if you have been at 50mph +, idle the engine for at least 30seconds before turning off. This helps dissapate the heat away from the turbo as the oil circulates and cools.
- Before you reach your destination try to keep the RPM at about 1.5k to help cool the oil before switching off.
- I tend to get all my stuff together as i sit on my drive before turning off, the last thing i do before leaving the car.
- Giving it roughly 15 seconds, just to help cooling
Now for the health. The better the fuel, generally the less smoke. I personally use v-power diesel but shell diesel extra is a very good fuel, just as cheap as supermarket in most places. Always use good fuel. Never labour the engine as the turbo doesnt kick in so to produce the power over fuelling occurs and that leaves a lot more unburn't fuel creating thick carbon deposits in the EGR / DPF / fuel pump / oil / engine. Most soot build up happens at low engine speed, labouring, in traffic or by keeping the revs too low. By following the advice above, i.e. accelerating between max torque will ensure you hit max cylinder pressure which, providing the journey is longer the 15 miles and you are using good fuel will create enough heat to burn off or reduce the amount of carbon build up.
But occasionally you should smoothly take it up to max power several times. Take it on the m-way which creates an abundance of heat or driving at or just below max power for 5 or 10mins (normally roughly 3.5k) will also create a lot of heat to help burn off soot. Then give it some fairly hard acceleration blasts, don't over cook it though as sharp throttle dumps a lot of fuel and can actually be counter productive if you plant the throttle.
All in all, this should help ensure the healthy running of a diesel engine. Never ever lug a diesel around on ultra low revs like people used to. Aim for max torque on the move and just under to maintain your speed.
Edited by OldSkoOL on 12/09/2009 at 21:32
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I'm very wary about quoting any rpm/torque figures when I've not driven that make and model of car - diesels vary so widely that such "general" advice can be very misleading. Some can be extremely flexible and pull from as little as 1k, but some, like a Corsa 1.5TD I had had nothing until nearly 2k and the turbo didn't cut in until 2200!!
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I'm sure he can take my theory and apply his own torque figures.
Really he should work out his mean piston stroke which is when his engine is running at low frictional horsepower loses and high volumetric efficiency. The formula i use is RPM*engine stroke length(inches)/6
However i do know his engine is a common rail unit and common rail engines by design use a couple of variants of fuel pump and injector designs. Most CR diesels do produce max torque by 2k RPM. His engine mapping / turbo boost pressure is very similar to the toyota variants and that is 1.95k RPM to 2.5k RPM.
Diesels of the past do vary as you say but newer common rail engines do normally reach max cynlinder pressure between 1.8k say in the fords to 2k in BMW/Toyota/Honda.
Edited by OldSkoOL on 13/09/2009 at 14:07
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I forgot to say mean piston speed for best volumetric efficiency and loss frictional horsepower loss should be between 1,200 and 1,500.
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What I was saying (and I stand by it) is ignore the rev counter initially and drive the car to get the "feel" of the engine and what its most comfortable with gear-wise for any given speed... I think people can rely too much on the rev counter these days and what the engine is "suposed" to do according to all the published figures... before rev counters were a standard fit we had to rely on our own feel for the car and engine and I still feel its a far better way of learning the best way to drive a particular car than relying on the rev counter or the manufacturers engine output figures..,.
Edited by b308 on 13/09/2009 at 14:21
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Please be careful when refuelling not to spill any diesel, so that those of us who don't use the filthy, smelly stuff don't have to get it all over our shoes and car carpets. Thanks in hope. ;-)
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just drive it like you stole it
it should still return 40mpg and keep quick fit happy in the tyres dept
toodles pip.....
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