Gear Change & Overrun Questions
Discussion
Hi guys. Bit new round here, but I drive a 1998 Hyundai Accent MVi & am 19. Been driving (on road) almost two years.
I take a lot of pride in my driving (unfortunately unlike many young drivers, who just want to show off!)
I have two main things that bug me when driving, and just looking for some suggestions / tips on them.
The first issue is changing gear. I have driven a wide range of vehicles since passing my test (2 astras, omega mv6, omega 3.2, vectra 2.0 sri, corsa 1.2, agila 1.2, laguna 1.6, laguna 2.2 dci, peugot 307 d and my current hyundai) and have had this issue with all the cars I have driven. I like my gear changes to be smooth, refined and quick. I kinda got used to "dipping" the clutch when I was learning to drive, rather than fully depressing the pedal, much to my driving instructor's annoyance! The main reason I got used to doing this was I could get a really smooth and quick gear change, matching the revs nicely when picking up the power again. This is all very well when it works (90% of the time) but there's always those gear changes I manage to crunch
- mostly when under pressure / faced with a tricky situation ahead. Are there any better tactics for tackling gear changes?
Secondly, the other thing that bugs me is when you're driving down a hill and take your foot off the accelerator. The car goes into overrun, and usually this is accompanied by a slight jerkiness (sometimes even getting a touch of the kangaroo petrol), and then a slight jerk when you take the power up again - this really annoys me. Is there any way round it, or is it down to how the vehicle's ECU cuts off the fuel etc...?
Any info would be great.
Cheers
I take a lot of pride in my driving (unfortunately unlike many young drivers, who just want to show off!)
I have two main things that bug me when driving, and just looking for some suggestions / tips on them.
The first issue is changing gear. I have driven a wide range of vehicles since passing my test (2 astras, omega mv6, omega 3.2, vectra 2.0 sri, corsa 1.2, agila 1.2, laguna 1.6, laguna 2.2 dci, peugot 307 d and my current hyundai) and have had this issue with all the cars I have driven. I like my gear changes to be smooth, refined and quick. I kinda got used to "dipping" the clutch when I was learning to drive, rather than fully depressing the pedal, much to my driving instructor's annoyance! The main reason I got used to doing this was I could get a really smooth and quick gear change, matching the revs nicely when picking up the power again. This is all very well when it works (90% of the time) but there's always those gear changes I manage to crunch
- mostly when under pressure / faced with a tricky situation ahead. Are there any better tactics for tackling gear changes?Secondly, the other thing that bugs me is when you're driving down a hill and take your foot off the accelerator. The car goes into overrun, and usually this is accompanied by a slight jerkiness (sometimes even getting a touch of the kangaroo petrol), and then a slight jerk when you take the power up again - this really annoys me. Is there any way round it, or is it down to how the vehicle's ECU cuts off the fuel etc...?
Any info would be great.
Cheers
hougtimo said:
Secondly, the other thing that bugs me is when you're driving down a hill and take your foot off the accelerator. The car goes into overrun, and usually this is accompanied by a slight jerkiness (sometimes even getting a touch of the kangaroo petrol), and then a slight jerk when you take the power up again - this really annoys me. Is there any way round it, or is it down to how the vehicle's ECU cuts off the fuel etc...?
This happens in my car, I think it's called driveline shunt.On the "a picture paints a thousand words" basis:-
(turn your speakers on)
http://uk.youtube.com/watch?v=fTScu7jOJd0&feat...
(thanks Reg)
You may guess the gentleman's training by his steering technique -
(you know - the technique that lots of drivers who do NOT use it say they
"hate" or "can't do")
;)
As to second point - my car MAY produce that effect,
if I used overrun down hill.
My "normal" is to, say, on approach to steep downhill in 30 limit,
take SECOND gear.
(turn your speakers on)
http://uk.youtube.com/watch?v=fTScu7jOJd0&feat...
(thanks Reg)
You may guess the gentleman's training by his steering technique -
(you know - the technique that lots of drivers who do NOT use it say they
"hate" or "can't do")
;)
As to second point - my car MAY produce that effect,
if I used overrun down hill.
My "normal" is to, say, on approach to steep downhill in 30 limit,
take SECOND gear.
Edited by 1950trevorP on Sunday 3rd August 09:22
Changing gear quickly can hide a multitude of sins. If you want to improve your technique, make a point of changing gear reeaaallly slowly. Take a good ten seconds over it, ensure that you are at constant speed (not accelerating or decelerating) beforehand and have the clutch fully engaged before you roll the throttle open and start accelerating afterwards. If you get it right there will be no perceptible jolt at all during the change, just the acceleration easing and then resuming. Doing this will force you to control the engine speed accurately. If you don't do this you are relying on timing to match revs, which is fine on the occasions you get it right ...
Once you can do it you don't need to take ten seconds over it of course, doing it this slowly at first is just a way to train yourself to use the correct technique.
If you suffer from drive line shunt on torque reversals, you may be able to drive round it by making the throttle change very slowly so that the shunt occurs with *almost* no torque. One of my cars has very stiff transmission with quite a lot of backlash and this can easily be provoked into violent shunting. For this I often feather the clutch during torque reversals or when going through a load/rev range where shunting is likely to occur.
Once you can do it you don't need to take ten seconds over it of course, doing it this slowly at first is just a way to train yourself to use the correct technique.
If you suffer from drive line shunt on torque reversals, you may be able to drive round it by making the throttle change very slowly so that the shunt occurs with *almost* no torque. One of my cars has very stiff transmission with quite a lot of backlash and this can easily be provoked into violent shunting. For this I often feather the clutch during torque reversals or when going through a load/rev range where shunting is likely to occur.
Edited by GreenV8S on Sunday 3rd August 11:10
hougtimo said:
This is all very well when it works (90% of the time) but there's always those gear changes I manage to crunch - mostly when under pressure / faced with a tricky situation ahead. Are there any better tactics for tackling gear changes?
This is where forward planning will help, because you don't have to think on-the-spot what you're going to do - you've made up your mind. It's not easy at first, but it's doable. - mostly when under pressure / faced with a tricky situation ahead. Are there any better tactics for tackling gear changes?Also, practice separating gear changes from braking. This forces you to do forward planning, and is a lot harder (at first) than it sounds...
Do recognise that you carn't avoid a change in fore & aft pitch on a gear change. By breaking the drive the car pitches forward, then re-engaging the drive throws it back again.
Instead manage the pitch change to your advantage by first leveling off the acceleration to a constant speed & then shift up, picking the the drive gently and progressively accelerating once the clutch is fully engaged.
You carn't rush a change and be smooth (unless you own one of thoes twin clutch DSG jobs). Going down in gear, try to keep a little gas on to "match up the revs." or at least be gentle on the clutch release. Doing the latter under braking means the car is already pitched forwards and so the shift is disciused. TreverP suggest's this is unnaceptable but I would ask what he does down hill or where overlap is otherwise required.
Instead manage the pitch change to your advantage by first leveling off the acceleration to a constant speed & then shift up, picking the the drive gently and progressively accelerating once the clutch is fully engaged.
You carn't rush a change and be smooth (unless you own one of thoes twin clutch DSG jobs). Going down in gear, try to keep a little gas on to "match up the revs." or at least be gentle on the clutch release. Doing the latter under braking means the car is already pitched forwards and so the shift is disciused. TreverP suggest's this is unnaceptable but I would ask what he does down hill or where overlap is otherwise required.
Edited by MDO on Tuesday 5th August 11:24
Edited by MDO on Tuesday 5th August 11:25
MDO said:
Do recognise that you carn't avoid a change in fore & aft pitch on a gear change.
. . . . . . . . . . .
TreverP suggest's this is unnaceptable but I would ask what he does down hill or where overlap is otherwise required.
a) that is exactly what you can achieve.. . . . . . . . . . .
TreverP suggest's this is unnaceptable but I would ask what he does down hill or where overlap is otherwise required.
b) I would do as all who have been trained (brainwashed?) as per myself would do.
CALL a BGOL beforehand.
BUT that would be at such a speed (some would call "clutch-in zone") that
rev-matching and balancing momentum are not the most important factors.
Example:- Chummy following closely as I prepare to turn into a residential road.
I would modify my "norm" of just backing off, then trying for as smooth a rev-match gearchange into second,
TO:- BRAKING up to the sharp turn and changing WITHOUT having gone onto gas first.
That being what chummy does - and what he expects you do.
I like my gear changes to be smooth, refined and quick. I kinda got used to "dipping" the clutch when I was learning to drive, rather than fully depressing the pedal, much to my driving instructor's annoyance! The main reason I got used to doing this was I could get a really smooth and quick gear change, matching the revs nicely when picking up the power again. This is all very well when it works (90% of the time) but there's always those gear changes I manage to crunch
Ouch - dipping rather than properly disengaging the clutch is worrying. Yes the change may be smooth but you are taxing the sychromesh hubs unnecessarily with even the merest mismatch let alone getting it wrong. (All adds up to premature wear to the gearbox) No wonder the instructor was not too happy !
Ouch - dipping rather than properly disengaging the clutch is worrying. Yes the change may be smooth but you are taxing the sychromesh hubs unnecessarily with even the merest mismatch let alone getting it wrong. (All adds up to premature wear to the gearbox) No wonder the instructor was not too happy !
Jules2477 said:
I like my gear changes to be smooth, refined and quick. I kinda got used to "dipping" the clutch when I was learning to drive, rather than fully depressing the pedal, much to my driving instructor's annoyance! The main reason I got used to doing this was I could get a really smooth and quick gear change, matching the revs nicely when picking up the power again. This is all very well when it works (90% of the time) but there's always those gear changes I manage to crunch
Ouch - dipping rather than properly disengaging the clutch is worrying. Yes the change may be smooth but you are taxing the sychromesh hubs unnecessarily with even the merest mismatch let alone getting it wrong. (All adds up to premature wear to the gearbox) No wonder the instructor was not too happy !
9 out of 10 isn't particularly good consistency for something as fundamental as gear changing either.Ouch - dipping rather than properly disengaging the clutch is worrying. Yes the change may be smooth but you are taxing the sychromesh hubs unnecessarily with even the merest mismatch let alone getting it wrong. (All adds up to premature wear to the gearbox) No wonder the instructor was not too happy !
Further to the gear changing bit I would actually like to pose a question(s) which hopefully someone in the know with the latest teachings will pick up. Are double de-clutch sustained or boost changes still taught at any stage of advance driving these days ? If so, this might benefit the author of this thread to practice with slower, more refined, and mechanically sympathetic gear changing ?
Although not necessary with modern gearboxes, the view was that this method was the considered the ultimate in mechanically sympathy even though boxes are extremely resilient to alsorts of abuse these days.
When I moved onto the higher advanced levels (which wasn't all that long ago) The technique was taught for ultra smooth downward gear changes. Double de clutch a brief explaination if not familiar - declutch, move lever into neutral position -- engage clutch, rev match and sustain -- declutch, gear -- engage clutch. Sounds a bit fragmented but in reality, practice makes this is a highly polished, smooth and fluid action. Not a racing change but certainly quick enough for normal and most high speed police driving situations. Although I haven't driven a police car in anger since the late 90s, it was still in play for class one but not required for basic driving.
The real test of course would be get onto a vintage crash box, that really sorts the men from the boys !
Although not necessary with modern gearboxes, the view was that this method was the considered the ultimate in mechanically sympathy even though boxes are extremely resilient to alsorts of abuse these days.
When I moved onto the higher advanced levels (which wasn't all that long ago) The technique was taught for ultra smooth downward gear changes. Double de clutch a brief explaination if not familiar - declutch, move lever into neutral position -- engage clutch, rev match and sustain -- declutch, gear -- engage clutch. Sounds a bit fragmented but in reality, practice makes this is a highly polished, smooth and fluid action. Not a racing change but certainly quick enough for normal and most high speed police driving situations. Although I haven't driven a police car in anger since the late 90s, it was still in play for class one but not required for basic driving.
The real test of course would be get onto a vintage crash box, that really sorts the men from the boys !
Edited by Jules2477 on Thursday 7th August 06:27
Jules2477 said:
Further to the gear changing bit I would actually like to pose a question(s) which hopefully someone in the know with the latest teachings will pick up. Are double de-clutch sustained or boost changes still taught at any stage of advance driving these days ? If so, this might benefit the author of this thread to practice with slower, more refined, and mechanically sympathetic gear changing ?
Although not necessary with modern gearboxes, the view was that this method was the considered the ultimate in mechanically sympathy even though boxes are extremely resilient to alsorts of abuse these days.
When I moved onto the higher advanced levels (which wasn't all that long ago) The technique was taught for ultra smooth downward gear changes. Double de clutch a brief explaination if not familiar - declutch, move lever into neutral position -- engage clutch, rev match and sustain -- declutch, gear -- engage clutch. Sounds a bit fragmented but in reality, practice makes this is a highly polished, smooth and fluid action. Not a racing change but certainly quick enough for normal and most high speed police driving situations. Although I haven't driven a police car in anger since the late 90s, it was still in play for class one but not required for basic driving.
The real test of course would be get onto a vintage crash box, that really sorts the men from the boys !
No double de-clutch isn't taught as a matter of course (within Police schools), it is not a competency within the syllabus they are required to be proficient in.Although not necessary with modern gearboxes, the view was that this method was the considered the ultimate in mechanically sympathy even though boxes are extremely resilient to alsorts of abuse these days.
When I moved onto the higher advanced levels (which wasn't all that long ago) The technique was taught for ultra smooth downward gear changes. Double de clutch a brief explaination if not familiar - declutch, move lever into neutral position -- engage clutch, rev match and sustain -- declutch, gear -- engage clutch. Sounds a bit fragmented but in reality, practice makes this is a highly polished, smooth and fluid action. Not a racing change but certainly quick enough for normal and most high speed police driving situations. Although I haven't driven a police car in anger since the late 90s, it was still in play for class one but not required for basic driving.
The real test of course would be get onto a vintage crash box, that really sorts the men from the boys !
That doesn't mean they can't double de-clutch should they wish, or that it won't/can't be introduced on an individual's need basis should it provide greater accuracy & consistency for them.
Edited by vonhosen on Thursday 7th August 06:56
vonhosen said:
Jules2477 said:
Further to the gear changing bit I would actually like to pose a question(s) which hopefully someone in the know with the latest teachings will pick up. Are double de-clutch sustained or boost changes still taught at any stage of advance driving these days ? If so, this might benefit the author of this thread to practice with slower, more refined, and mechanically sympathetic gear changing ?
Although not necessary with modern gearboxes, the view was that this method was the considered the ultimate in mechanically sympathy even though boxes are extremely resilient to alsorts of abuse these days.
When I moved onto the higher advanced levels (which wasn't all that long ago) The technique was taught for ultra smooth downward gear changes. Double de clutch a brief explaination if not familiar - declutch, move lever into neutral position -- engage clutch, rev match and sustain -- declutch, gear -- engage clutch. Sounds a bit fragmented but in reality, practice makes this is a highly polished, smooth and fluid action. Not a racing change but certainly quick enough for normal and most high speed police driving situations. Although I haven't driven a police car in anger since the late 90s, it was still in play for class one but not required for basic driving.
The real test of course would be get onto a vintage crash box, that really sorts the men from the boys !
No double de-clutch isn't taught as a matter of course (within Police schools), it is not a competency within the syllabus they are required to be proficient in.Although not necessary with modern gearboxes, the view was that this method was the considered the ultimate in mechanically sympathy even though boxes are extremely resilient to alsorts of abuse these days.
When I moved onto the higher advanced levels (which wasn't all that long ago) The technique was taught for ultra smooth downward gear changes. Double de clutch a brief explaination if not familiar - declutch, move lever into neutral position -- engage clutch, rev match and sustain -- declutch, gear -- engage clutch. Sounds a bit fragmented but in reality, practice makes this is a highly polished, smooth and fluid action. Not a racing change but certainly quick enough for normal and most high speed police driving situations. Although I haven't driven a police car in anger since the late 90s, it was still in play for class one but not required for basic driving.
The real test of course would be get onto a vintage crash box, that really sorts the men from the boys !
That doesn't mean they can't double de-clutch should they wish, or that it won't/can't be introduced on an individual's need basis should it provide greater accuracy & consistency for them.
Thank you, I thought this was probably the case, I knew that it had been dropped from all basic advanced courses years ago. But It had been retained as desirable to demonstrate the extra finesse expected from class one drivers - I see there is another thread on DDC now and it is something I still use in normal driving.
[
Edited by Jules2477 on Friday 8th August 02:04
Right, just want to clear things up a bit here as we seem to have a degree of snobbery going on (no offense, guys).
1. When "Dipping the clutch" I must stress that the clutch is fully disengaged before I make the gearchange...
2. my 90% statistic is probably wrong. Don't read too much into that. In reality, I probably crunch 1-2 gear changes every month (I'm driving 2k-2.5k per month).
Whats more, I attended my first session with an IAM observer, who couldn't see anything wrong at all with my gearchanges / rev matching.
1. When "Dipping the clutch" I must stress that the clutch is fully disengaged before I make the gearchange...
2. my 90% statistic is probably wrong. Don't read too much into that. In reality, I probably crunch 1-2 gear changes every month (I'm driving 2k-2.5k per month).
Whats more, I attended my first session with an IAM observer, who couldn't see anything wrong at all with my gearchanges / rev matching.
Edited by hougtimo on Saturday 9th August 08:12
Gassing Station | Advanced Driving | Top of Page | What's New | My Stuff