RE: The best (and worst) gearbox in the world

RE: The best (and worst) gearbox in the world

Author
Discussion

AmitG

3,300 posts

161 months

Friday 17th November 2017
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fido said:
If you could combine a DCT with a small CVT, to bridge the ratio between each gear, then you could keep an engine at peak rpm. Though not sure how you could jump quickly from the higher end to the lower end of the CVT. Maybe a DCT with dual CVTs?
People have WTF'd this comment, but Toyota/Lexus are thinking along these lines with their new "multi stage hybrid" transmission.

https://youtu.be/orJh-lk-gz0

As far as I can tell, it couples the standard hybrid power split device (e-CVT) with a 4-speed auto transmission. 3 of the 4 speeds in the auto transmission are normally used, and within these, the e-CVT can either be continuously variable or can have up to 3 simulated ratios - giving up to 3x3 = 9 forward speeds. The 4th ratio in the auto transmission is used for final drive. So a total of 10 forward speeds, and loads of flexibility around shift points. Gear ratios can be skipped easily. And unlike previous Toyota hybrids, you can shift manually.

It's fitted as standard in the hybrid versions of the LC and new LS - so it's real, not a concept. I really want to try one out, but the new LS starts at £75k, and I can't afford it frown


CABC

5,589 posts

102 months

Friday 17th November 2017
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JMF894 said:
Reminds of my Saab 900T Sensonic back in the day........................
quite liked mine.....when it worked!
it depreciated like a stone though. a lesson learnt.

buggalugs

9,243 posts

238 months

Saturday 18th November 2017
quotequote all
AmitG said:
fido said:
If you could combine a DCT with a small CVT, to bridge the ratio between each gear, then you could keep an engine at peak rpm. Though not sure how you could jump quickly from the higher end to the lower end of the CVT. Maybe a DCT with dual CVTs?
People have WTF'd this comment, but Toyota/Lexus are thinking along these lines with their new "multi stage hybrid" transmission.

https://youtu.be/orJh-lk-gz0

As far as I can tell, it couples the standard hybrid power split device (e-CVT) with a 4-speed auto transmission. 3 of the 4 speeds in the auto transmission are normally used, and within these, the e-CVT can either be continuously variable or can have up to 3 simulated ratios - giving up to 3x3 = 9 forward speeds. The 4th ratio in the auto transmission is used for final drive. So a total of 10 forward speeds, and loads of flexibility around shift points. Gear ratios can be skipped easily. And unlike previous Toyota hybrids, you can shift manually.

It's fitted as standard in the hybrid versions of the LC and new LS - so it's real, not a concept. I really want to try one out, but the new LS starts at £75k, and I can't afford it frown
That’s interesting so there’s the normal Toyota hybrid sun and planet gears with the motor generators attached with another few sets behind them like in a conventional auto. Presumably no torque converter. I wonder what the advantage of doing 3x3+1 is though vs just simulating 10 speeds with the cvt.

Car Fan

162 posts

117 months

Sunday 19th November 2017
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Loyly said:
BuzzBravado said:
The CVT in the Jazz universally panned as well. I have a friend at Honda who admitted it was a terrible move, they just couldn't sell them at all. My only personal experience of CVT was the Prius and i hated every second.
I have the Honda CVT in my Jazz Hybrid and I love it. It has a few quirks that could be better though.

My biggest irritation is the throttle opening from standstill. A CVT doesn't 'creep' by impulse like a torque converter, they open the throttle slightly and drive themselves at low speeds. However, the ECU seeks to minimise and slow throttle opening at low speeds for emissions purposes. It can be a bit jerky pulling away sometimes if you're not smooth and consistent with the throttle. You can usually predict the situations in which this will occur and it's like there is a fight between your input and what the car wants to do. As mentioned earlier, reversing up a steep hill requires a steady foot as the ECU struggles to meter out drive at a low throttle opening.

On the plus side, it works brilliantly for day to day use. It seemlessly integrates drive from the electric motor when it's needed and phasing from purely electric drive to petrol power is very smooth. It certainly works to get the most from the wheezing little 1.3 engine, and performance is quite spritely up to 60mph because it never pauses to change gear. It's never revving towards that sweet spot of peak power, it just dials up an RPM and sits there until you lighten the throttle pressure to settle into a cruise.

At 70mph, load depending, it'll settle down to 2000rpm or less, which is an impressively low and refined number for a small petrol. However, the economy drops off over 70mph in line with the performance (a cruise at 90mph returns only 40mpg on average). It does have seven 'gears' accessible by shifter paddles on the steering wheel, although it'll revert back to CVT quickly unless you keep tapping up and down the ratios using the paddles. I never use them, even when driving on B roads. They don't really serve a purpose other than give the car a familiar mode to those who find the CVT alien.

For a small car like mine where economy is the goal, then a CVT really trumps a torque converter. In bigger cars, I'd prefer a torque converter or DCT, unless we're talking about the superb CVT that the top end Lexus models use.
I have a CVT Jazz as well (albeit a conventional petrol model rather than a hybrid), and really like it. I tested cars such as the Fiesta Powershift (which has a dual-clutch transmission) and found the Jazz CVT to be superior in terms of smoothness and fuel economy. I think that comments about sluggishness come from users who are afraid to use the full rev range - if I put my foot down in mine, the revs will jump to around 4500 rpm and hold there as the car's speed steadily increases, which can seem alien at first but I got used to it quickly. Honda VTEC engines thrive on being revved, after all. Of course you wouldn't make a habit of routinely flooring a Jazz, though, and it does respond best to smooth and steady inputs.

I hope that the CVT will prove to be reliable as I want to keep this car long-term. I have noticed that it appears to be quite maintenance-intensive, requiring a fluid change every 2 years/25k miles, and it is very important to use genuine Honda fluid as apparently problems can arise if a substitute is used. I have a service plan to cover this for the next few years, but may look into purchasing the fluid and learning to change it myself once the car is out of warranty.

I'm very surprised by the initial comment about the Jazz CVT being "universally panned" and difficult to sell, actually. As far as I am aware, the CVT Jazz has always been in strong demand amongst the typical buying demographic (i.e. the elderly). I suspect BuzzBravado's friend might actually be referring to the i-Shift automated manual transmission (which I am told was terrible) that was dropped after Honda reverted to the CVT as a result of customer feedback.

anonymous-user

55 months

Sunday 19th November 2017
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I’m going to say the autobox on my daughters first car. Suzuki swift 1.2 sz3. The thing was missing a gear and the over drive function was pants. Around town it was fine but getting it up to speed for even a short motorway stretch felt dangerous. 4 speed auto. Major let down.

bimbeano

97 posts

163 months

Sunday 3rd December 2017
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CDP said:
I wonder what the probability of trouble on the Audi CVT is? I've heard horror stories but don't know if it's common or just very loud complaints.
I have had an A4 Multitronic for 10 years now .. 105,000 miles and it still works perfectly (touching wood). Actually i've never had any problem with this car.
I think that is mainly because of the way i treat it (like with all of my cars), cold engine (or car for that matter) i ALWAYS go very soft and slow on the 'throttle' and rpm the first few miles. As for the A4 , i have never really mistreated it even though i've done a few 'high' speed runs from Brussels to Paris from time to time.

andy118run

880 posts

207 months

Thursday 20th May 2021
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Hmmm.
3.5 years on, a little bit of a thread resurrection.
Currently looking for a replacement auto transmission car for the wife.
She very much likes the Juke. These have a CVT transmission and I'm reading of a few transmission failures in the Juke.
Not sure if internet scare stories or a real issue.
Probably looking at a N/A 1.6 petrol - though noted that someone in this thread says they are pretty grim to drive.
Not too worried as I won't drive it much. Surely a Nissan Approved car with a warranty for £7 or 8 k would be ok?
Wouldn't it??

RoverP6B

4,338 posts

129 months

Monday 24th May 2021
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Good God, I'd rather just admit I've given up on life and spend the rest of my days in bed.

Can I suggest that either she needs a better, more interesting car, or you need a better, more interesting wife?

PH User

22,154 posts

109 months

Monday 24th May 2021
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RoverP6B said:
Good God, I'd rather just admit I've given up on life and spend the rest of my days in bed.

Can I suggest that either she needs a better, more interesting car, or you need a better, more interesting wife?
Cars for most normal people are just transport, so she probably doesn't need a better or more interesting car.


RoverP6B

4,338 posts

129 months

Tuesday 25th May 2021
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PH User said:
Cars for most normal people are just transport, so she probably doesn't need a better or more interesting car.
Even so, there are far better white goods cars than a CVT Juke. If the lady in question wants a small crossover, can I suggest a Skoda Yeti?

Cold

15,252 posts

91 months

Tuesday 25th May 2021
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RoverP6B said:
PH User said:
Cars for most normal people are just transport, so she probably doesn't need a better or more interesting car.
Even so, there are far better white goods cars than a CVT Juke. If the lady in question wants a small crossover, can I suggest a Skoda Yeti?
But that's a terrible suggestion if she wants a CVT Juke.

RoverP6B

4,338 posts

129 months

Tuesday 25th May 2021
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Cold said:
But that's a terrible suggestion if she wants a CVT Juke.
If she wants a CVT Juke, she needs to try some better cars. The Juke does precisely nothing well. The boot is tiny, with a high loading lip. Leg and head room are both lacking. Never mind the wretched engine and transmission. A 2-litre DSG Yeti would be so much better in every way.

Cold

15,252 posts

91 months

Tuesday 25th May 2021
quotequote all
RoverP6B said:
Cold said:
But that's a terrible suggestion if she wants a CVT Juke.
If she wants a CVT Juke, she needs to try some better cars. The Juke does precisely nothing well. The boot is tiny, with a high loading lip. Leg and head room are both lacking. Never mind the wretched engine and transmission. A 2-litre DSG Yeti would be so much better in every way.
Her parameters of what is a desirable car are most likely entirely different to yours.
If she wants a Juke then surely the best course of action would be for her to have a Juke, because anything else isn't a Juke and therefore is inferior to her. Little else matters.

RoverP6B

4,338 posts

129 months

Tuesday 25th May 2021
quotequote all
Cold said:
Her parameters of what is a desirable car are most likely entirely different to yours.
If she wants a Juke then surely the best course of action would be for her to have a Juke, because anything else isn't a Juke and therefore is inferior to her. Little else matters.
More to the point, why does she want a Juke? It's a tool for a job, like any car. By any objective, rational, practical measure, it is a poor tool for the job. Aesthetic taste is, of course, wholly subjective, but I've never heard anyone say the Juke is stylish or good-looking.

Limpet

6,322 posts

162 months

Tuesday 25th May 2021
quotequote all
Cold said:
RoverP6B said:
Cold said:
But that's a terrible suggestion if she wants a CVT Juke.
If she wants a CVT Juke, she needs to try some better cars. The Juke does precisely nothing well. The boot is tiny, with a high loading lip. Leg and head room are both lacking. Never mind the wretched engine and transmission. A 2-litre DSG Yeti would be so much better in every way.
Her parameters of what is a desirable car are most likely entirely different to yours.
If she wants a Juke then surely the best course of action would be for her to have a Juke, because anything else isn't a Juke and therefore is inferior to her. Little else matters.
Precisely.

My dad has a CVT Juke. I can't see the appeal at all, but he loves it. As the only one who drives it, he's the only one who has to love it.

PH User

22,154 posts

109 months

Tuesday 25th May 2021
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Limpet said:
Cold said:
RoverP6B said:
Cold said:
But that's a terrible suggestion if she wants a CVT Juke.
If she wants a CVT Juke, she needs to try some better cars. The Juke does precisely nothing well. The boot is tiny, with a high loading lip. Leg and head room are both lacking. Never mind the wretched engine and transmission. A 2-litre DSG Yeti would be so much better in every way.
Her parameters of what is a desirable car are most likely entirely different to yours.
If she wants a Juke then surely the best course of action would be for her to have a Juke, because anything else isn't a Juke and therefore is inferior to her. Little else matters.
Precisely.

My dad has a CVT Juke. I can't see the appeal at all, but he loves it. As the only one who drives it, he's the only one who has to love it.
Different people like and want different things. If she likes a juke then that's what she should get. Other cars might do some/most things better, but they aren't better at being a juke.

anonymous-user

55 months

Wednesday 26th May 2021
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Speed addicted said:
I've driven a few cars with CVT gearboxes, most recently a Mitsubishi outlander hybrid (was looking at company car options) and I just can't get on with them at all.
It might be my driving style, or too many old crap cars in my history but to me they just sound like a slipping clutch.

Can't get on with them at all, and I certainly wouldn't buy one. My left knee has pretty much given up so I'm limited to automatics, while car shopping I read reviews to make sure that whatever I'm looking at isn't CVT so I don't waste time test driving any more of them.

I don't care if they're faster/more economical/better, I like to hear the engine climb through the rev range. Even in an auto.
The Outlander PHEV is particularly horrible.