Clubjazz - Honda Jazz & HR-V Forums
Honda Jazz Forums => Honda Jazz Mk3 2015 - 2020 => Topic started by: edam on May 01, 2018, 11:47:50 PM
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I have started to notice that when my car changes gear it is not that smooth
Yes mine does change gear but only in "S" and only between 1st and 2nd if they exist.
It does "clonk" for want of a better word.
I know the CVT,s dont have gears ,I have driven enough of them, but this one does.
Anybody else notice this??
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I am new to CVTs, I know how they work and mine has seven virtual computer generated gears. I can select them in "D" or "S" mode using the steering wheel gear selectors, providing that the computer is happy about appropriate speed etc. On my car the CVT will do a virtual downshift if you accelerate even slightly hard, the CVT instantly drops to an appropriate ratio. This may be the " jolt" you are feeling in "D" or "S" auto mode. I find for normal driving the CVT is best left to sort the ratio it requires, it is better than me at doing it and I have driven cars, HGVs, and Fire Engines for more years than I want to remember so I have a rough idea about gear selection. Has your car had the 25,000 mile CVT fluid change?
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The CVT has a starting clutch. Could that, disengaging, possibly be what is being felt? As a non CVT driver I may be pi**ing in the wind.
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The CVT has a starting clutch. Could that, disengaging, possibly be what is being felt? As a non CVT driver I may be pi**ing in the wind.
The MK3 CVT does not have a starting clutch, it has a torque converter.
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The torque converter does have a lockup clutch which should not be felt operating. It will lock or release the torque converter as the car passes through a set (low) speed, lock for increasing, unlock for decreasing speed. The pump and turbine will have matched speed when it locks. This is not a Honda torque converter but it is a good example.
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The MK3 CVT does not have a starting clutch, it has a torque converter.
That's a much better arrangement. I'll have to give a Mk 3 CVT a try. I'd like am automatic Jazz, if I could live with the CVT.
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In my view the MK 3 CVT is the best thing since sliced bread. There is no 'clonking' of any sort, either up or down the box.
When you change down using the paddles, all you hear is the engine speed change to match the road speed.
As has been said, the change to a torque converter, has made the whole experience very smoooth!
In normal motoring the engine speed never gets much above 3000rpm which is only half of it's available range and if you do want to make good progress, when your in a hurry, then there is the 'S' mode, which can certainly wake the car up!
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+1 for S mode. Don't use it often but there are certain situations where you want a more rapid response and it delivers that very well.
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If there's anything clunky with the CVT box then it needs looking at. I've always found it to be very smooth. Did the service people forget to change the CVT fluid at the last service (every 2 years / 25k miles)?
As for S mode, I recently untentionally did a journey in S mode and was wondering why the fuel consumption was about 15% higher than usual (then I noticed the gear stick position). Apart from more responsive behavour, the engine revs always stayed higher than when in D.
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I had a couple of Vauxhall automatics with "Sports" mode buttons. I loved that mode, you just couldn't afford the fuel!
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There shouldn't be any kind of clonk. For the most part the CVT should feel smooth and seamless. However there are a few things that mar this:
* Kick-down. Like all automatics if you push the accelerator to the floor the transmission will assume you mean business and will select a significantly lower ratio and the car will surge forward.
* ?!? I've noticed that sometimes if you manage to activate kick-down by mistake then lift off the car can be quite violent. I think it's probably the equivalent of a manual driver selecting 3rd at 50mph then lifting off. This seems to be more common if you depress the accelerator past the gentle click at the bottom of its travel. It's not clear if that click has any particular meaning although it's been suggested that it's the speed limiter override switch.
* Engine mode switch over. Around 2,000 rpm the engine switches to/from Atkinson cycle (efficient but can't pull the skin off a rice pudding) and Otto cycle ('traditional' mode - full power available). Unfortunately early Mk3s don't handle this well:
* When accelerating at low speed (away from roundabouts being a common issue) you can suffer something akin to 'turbo lag' unless you first move the accelerator pedal aggressively. I think of it like a 'half kick-down' and if you get it wrong the engine will be sluggish until it finally gets the message at which point it will surge a bit as it changes mode. I believe that the recent face-lift has significantly addressed this issue.
* When ascending a moderate incline the car can start to lose speed and if you only gradually depress the accelerator there will again come a point when it suddenly wakes up and the car will surge forward a bit.
* On the face-lift version during kick-down the engine will sound more like a manual (RPM rising and falling) but it should still feel smooth. It also seems to give more engine braking in this mode than the original version.
After a couple of months all of these became rare events. The half-kick down in particular I've got to a fine art. Just aim to get the car up to 3,000 when you want to pull away. A quick jab on the accelerator gives it the message without initiating a full on kick-down.
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The roundabouts thing is interesting. Some roundabouts are not for the faint hearted especially some motorway type roundabouts which intersect 2 motorways and other A Roads. The M60/M67 roundabout at Denton in Greater Manchester is such an example. In drive you can be picking up speed a bit too slowly and can almost get bullied. That's when I drop into S mode and the car is transformed then and accelerates briskly when you open the throttle.
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I have started to notice that when my car changes gear it is not that smooth
Yes mine does change gear but only in "S" and only between 1st and 2nd if they exist.
It does "clonk" for want of a better word.
I know the CVT,s dont have gears ,I have driven enough of them, but this one does.
Anybody else notice this??
This might be a red herring, but have a look at this thread:
https://clubjazz.org/forum/index.php?topic=9214.msg49004#msg49004
That’s all about a strange clanking/groaning/clicking noise when taking up drive from rest, apparently caused by a faulty engine or transmission mount. It’s not clear whether that fault only occurs with manual boxes or whether it might happen with CVTs as well.
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I have started to notice that when my car changes gear it is not that smooth
Yes mine does change gear but only in "S" and only between 1st and 2nd if they exist.
It does "clonk" for want of a better word.
I know the CVT,s dont have gears ,I have driven enough of them, but this one does.
Anybody else notice this??
This press release about the Mk3 (https://hondanews.eu/eu/en/cars/media/pressreleases/58052/2015-honda-jazz2?utm_campaign=Syndicated_58052&utm_medium=RSS_All%20Press%20Releases&utm_source=hondanews.eu) includes the following:
"For the 2015 Jazz, Honda’s popular, optional CVT is a newly-developed unit delivering better fuel economy and significant improvements to driveability. An all-new CVT control logic was developed specifically for European markets to deliver the direct and linear feeling expected of a manual transmission. This results in vehicle speed matching accelerator pedal position more closely for a more direct feel, while engine speed increases proportionately to accelerator pedal position for a more linear feel.
The CVT’s driveability is given a more natural ‘multi-gear’ feel through the use of new control software exclusive to Europe which simulates seven speeds and provides optimised gear change mapping. Two new additional programmes provide situation-specific enhancements."
The emphasis is mine.
Are you maybe noticing this?
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The MK3 CVT does not have a starting clutch, it has a torque converter.
That's a much better arrangement. I'll have to give a Mk 3 CVT a try. I'd like am automatic Jazz, if I could live with the CVT.
The clutch mechanism in CVT Jazz's was changed to a torque converter for the early 2011 facelift when the i-shift was dropped.
Vic.
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The MK3 CVT does not have a starting clutch, it has a torque converter.
That's a much better arrangement. I'll have to give a Mk 3 CVT a try. I'd like am automatic Jazz, if I could live with the CVT.
The clutch mechanism in CVT Jazz's was changed to a torque converter for the early 2011 facelift when the i-shift was dropped.
Vic.
Yeah. To be fair I preferred the clutch idea as I've always been a bit sceptical of torque converters. I never had any problems with my Jazz Sport clutch.
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To be fair I preferred the clutch idea as I've always been a bit sceptical of torque converters. I never had any problems with my Jazz Sport clutch.
Torque converters have been used since the 30's, on everything from railway locomotives, buses, trucks, industrial plant, cars, and even in marine applications. They virtually run for ever, and do their job brilliantly. They use a little energy but they don't wear out and leave you stuck at the side of the road. The life of a bus is about as hard on a transmission as you can get, and they will run for 1,000,000 miles.
I am a great fan of the torque converter.
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To be fair I preferred the clutch idea as I've always been a bit sceptical of torque converters. I never had any problems with my Jazz Sport clutch.
Torque converters have been used since the 30's, on everything from railway locomotives, buses, trucks, industrial plant, cars, and even in marine applications. They virtually run for ever, and do their job brilliantly. They use a little energy but they don't wear out and leave you stuck at the side of the road. The life of a bus is about as hard on a transmission as you can get, and they will run for 1,000,000 miles.
I am a great fan of the torque converter.
+1
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I'm a lot less bothered now that we have locking TCs.
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Torque converter explained - and a locking torque converter still needs a clutch (for those that like clutches).
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Thanks Culzean for the torque converter video.
In the early 80's I had a Honda Accord with an automatic gearbox. It only had two speeds, Lo and Hi but it had a very efficient wide ranging torque converter (TC).
You would start off in Lo and the TC would do its thing and then you would select Hi and the TC would react again.
I doubt there was a lock-up mechanism but the system worked very well and in those days fuel consumption wasn't an important topic.
Vic.
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In the early 80's I had a Honda Accord with an automatic gearbox. It only had two speeds, Lo and Hi but it had a very efficient wide ranging torque converter (TC).
You would start off in Lo and the TC would do its thing and then you would select Hi and the TC would react again.
I doubt there was a lock-up mechanism but the system worked very well and in those days fuel consumption wasn't an important topic.
That seems a rather primitive system. Just like my 1978 Honda Melody. My 1985 Vauxhall Carlton had a three speed transmission with a TC that locked up once you were up to a reasonable road speed. You only needed to select Drive.
My 2001 Volvo S40 had a five speed transmission. When you put it in Winter setting, for snow and ice, it started off in 5th and the TC did all the work.
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I'd have thought that if you don't need/want the torque multiplication that most of the work of the TC can be done by the CVT. You still need to decouple the shafts when the output is stationary but as soon as the shaft ratios enter the working range of the CVT it could do the job of the TC.
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I'd have thought that if you don't need/want the torque multiplication that most of the work of the TC can be done by the CVT. You still need to decouple the shafts when the output is stationary but as soon as the shaft ratios enter the working range of the CVT it could do the job of the TC.
The torque multiplication is only for the first few seconds of movement from a standstill. Once moving the CVT takes over. It gives torque power for a brisk step off from a standstill. It is noticeable in the 1.5 even at gentle running in takeoffs. Using running in power (up to 3,000 revs) in a 1.5 is a bit like driving a 1.3 with some gusto. I am looking forward to using the vtec when the running in is complete!
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The clonk I get when it seems to be changing gear is unlike that you get from kickdown or using the paddles.
It could be occurring when the engine is changing "mode" so will look out for that . If you keep the revs up it does not occur.
Lastly I like to use the " S" on roundabouts and on slip roads to a motorway