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Honda Jazz Forums => Honda Jazz Mk3 2015 - 2020 => Topic started by: DaveBerks on January 31, 2019, 12:39:11 PM

Title: In a quandary about small cars !
Post by: DaveBerks on January 31, 2019, 12:39:11 PM
I currently driving a Vauxhall Corsa 1.4 automatic while my Jazz EX 1.3 auto is in for repair...for some reason other drivers like to drive into it when it is stationery !  Tailgating seems to be an everyday occurrence in the South East where everyone is in a hurry and safe gaps between cars are a thing of the past.

What I notice is how comfortable the suspension is in the Vauxhall, riding over bumps and seams, and how planted the car feels on the road and how responsive the engine is compared to the Jazz which makes me feel I'm thrashing it to get anywhere over 20 MPH and crashes over bumps and seams on the normally poor road surfaces we now have to pt up with. I suspect the car is very light in order to save fuel.

The Vauxhall feels like cars used to be. The downside ?.....well according to Honest John's Real MPG survey it delivers only 35 MPG ! Dreadful. The Jazz tells me I get 54 MPG which is fabulous economy for a non hybrid petrol car of this size (small family sized hatchback). The Vauxhall is more cramped in the back and the boot is smaller.  It is also noisier notwithstanding the Jazz's CVT acceleration rasp. However it doesn't resist moving at speed like the Jazz engine and drives like a much bigger and more comfortable car.

I wonder how much difference the bigger 1.5 engine in the Jazz makes and whether Honda have done anything at all to improve the poor ride quality of the Jazz, a real disappointment for a modern car. Did they just forget about the need for comfortable suspension on British roads or just run out of development funds after all the tech input and design and space wizardry on the car ?...and they go on and on and on about its practicality ! Yes we get the message.
Title: Re: In a quandary about small cars !
Post by: andruec on January 31, 2019, 01:39:10 PM
Each successive version of the Jazz has seen improvements. The only model I'd ever accuse of being harsh was my first but that was the CVT-7 Sport so was designed with a stiffer suspension. The Mk3 does take bumps a little better than the Mk2 but both seemed fine to me.

As regards performance you might want to consider this: The car you consider to be more performant is the car with the worst fuel consumption. For all the advances in automotive technology over the decades one fact is inescapable: If you want more get up and go you have to burn more fuel.

As regards the Jazz though, so what if you have to press the accelerator pedal further? That's why it's designed with that throw, that's why the engine has that range of RPMs. You as a driver are being given a choice - saving fuel or moving quickly. The engine in your Jazz will take everything you can throw at it (especially since it's a CVT). When you want to move shove the pedal down. You don't have to shove it to the floor but be sure you poke it enough to get the RPMs above 2,500. That'll move the engine out of Atkinson mode and you should get all the power you're likely to need on the public highway - in my experience more than most drivers use.

(*)In case you haven't found it yet there is a 'notch' at the bottom of the accelerator travel in Mk3 Jazz. Push the pedal past that point and you'll get the benefit of 100bhp pretty damn fast in the CVT ;)
Title: Re: In a quandary about small cars !
Post by: Jocko on January 31, 2019, 01:57:41 PM
I think you will find the Corsa is a much newer design than the Mk 3 Jazz. How do the mileages compare between the two vehicles? Both can have an effect on ride comfort.
Title: Re: In a quandary about small cars !
Post by: Downsizer on January 31, 2019, 03:01:42 PM
The ride comfort may be partly related to tyre size.  The Mk 3 EX has 16" wheels, but I think the 15" wheels give a more comfortable ride because of the greater rubber depth.
Title: Re: In a quandary about small cars !
Post by: Jocko on January 31, 2019, 03:09:52 PM
Even similar sized tyres, of different manufacture, can have different comfort levels.
Title: Re: In a quandary about small cars !
Post by: peteo48 on January 31, 2019, 03:31:22 PM
The ride comfort may be partly related to tyre size.  The Mk 3 EX has 16" wheels, but I think the 15" wheels give a more comfortable ride because of the greater rubber depth.

That's a good point. My SE Jazz seems a bit more comfortable than my neighbours EX which has the 16 inch wheels. On the responsiveness issue I do take Dave's point in that it almost goes against the grain these days to push hard on the accelerator. I have found the paddles useful in these circs although I don't use them that often.

The 1.5 does seem more responsive from comments on this forum.
Title: Re: In a quandary about small cars !
Post by: andruec on January 31, 2019, 04:00:35 PM
The ride comfort may be partly related to tyre size.  The Mk 3 EX has 16" wheels, but I think the 15" wheels give a more comfortable ride because of the greater rubber depth.
Good point, I'd forgotten that. I wish Honda didn't bother doing that.
Title: Re: In a quandary about small cars !
Post by: culzean on January 31, 2019, 04:23:55 PM
My wifes MK2 Si had 16" wheels but it now has 15" with slightly narrower and deeper 175/65R15 shoes.  Ride is much nicer and quieter,  and tyres are a lot cheaper and more choice.
Title: Re: In a quandary about small cars !
Post by: richardfrost on January 31, 2019, 04:31:16 PM
Also, your boy racers will target that Corsa whereas they wouldn't want to be seen dead in a Jazz!

When I was insuring my Jazz for my son (it was his 21st birthday present) I paid £3200 for the car and £1100 for the insurance. If I had wanted to get him a Corsa I would have had to spend £3300 on insurance leaving just £1000 to spend on the car. The difference is boy racer appeal.
Title: Re: In a quandary about small cars !
Post by: culzean on January 31, 2019, 05:09:53 PM
Also, your boy racers will target that Corsa whereas they wouldn't want to be seen dead in a Jazz!

When I was insuring my Jazz for my son (it was his 21st birthday present) I paid £3200 for the car and £1100 for the insurance. If I had wanted to get him a Corsa I would have had to spend £3300 on insurance leaving just £1000 to spend on the car. The difference is boy racer appeal.

That may have been true up until the 1.5 engine appeared, now they will be fair game for boy racer scrotes.
Title: Re: In a quandary about small cars !
Post by: DaveBerks on January 31, 2019, 08:21:51 PM
Thanks all for your comments.

It's true that the Corsa has 15 inch wheels whereas Jazz EX has 16 inch, but why are the 16 inch wheels thinner (less  contact with the road surface) than the 15 inch ?...is this to save the manufacturer money ? The 16 inch look better since 15s can look lost in the wheel arch. But this gives manufacturers no excuse for poor ride comfort in my opinion. 

The Corsa design goes back to 2010 (the Jazz is 2015) although the Corsa was heavily revised in 2014.

The Jazz CVT engine clearly has hidden potential but my dealer gave me no information about how to drive it creatively. The downside of driving it faster along twisting poor road surfaces is that one can feel thrown around inside the cabin relentlessly. On longer journeys this can be quite tiring. Motorway driving is fine on good surfaces but is certainly a more 'active' experience that on many similar sized cars as soon as you hit a hill. I hope the new model planned for 2020 pays attention to this aspect but clearly there are few Jazz drivers who complain about it, so who knows. I understand the suspension was improved when the revised model came out in 2017 and Marek Drives' review on YouTube says this has solved his criticism of the car's ride quality. I shall be interested to see how the Jazz feels when I get it back. i certainly prefer its futuristic looks and internal space and flexibility.
Title: Re: In a quandary about small cars !
Post by: culzean on January 31, 2019, 08:44:23 PM
Wider tyres are not so good for MPG as narrower ones, also seems that 15" wheels better for MPG than 16".

Like for like tyres the narrower ones will also be quieter.

Narrower tyres also better in snow than wider ones ( still trying to figure out is this also applies to purpose made winter tyres with special tread pattern and softer compound ).

Part of the ride problem on the Jazz is the torsion beam rear suspension,  but this is the reason the car has so much interior space as the torsion beam setup is so much more low profile and compact than other systems..
Title: Re: In a quandary about small cars !
Post by: Jocko on January 31, 2019, 08:59:58 PM
the Jazz is 2015
The Mk 3 Jazz actually came out in 2014 so there is not a lot to draw between them.
Seating can also make a car feel it handles smoothly. So many things come into the mix.
Title: Re: In a quandary about small cars !
Post by: andruec on January 31, 2019, 09:33:48 PM
Motorway driving is fine on good surfaces but is certainly a more 'active' experience that on many similar sized cars as soon as you hit a hill.
Your EX has Cruise Control and since you own the CVT version there is no need to do anything on a hill other than maintain your grip on the steering wheel ;)

I have driven hundreds of miles at ~60mph in lane one without touching anything other than the steering wheel. If you want to go faster it does require a bit more input but on the odd occasions when I've wanted to get to my destination faster I haven't noticed myself being at a disadvantage to other road users. Yes you have to press the pedal down..but that's what it's for.

Your comments intrigue me because it might explain why I am so often 'at the head of the pack' despite driving a 1.3 litre Jazz. It's because I use more of the accelerator pedal range. I suppose most of the other motorists - like yourself perhaps - only use the top 10% of travel. Other manufacturers might have tweaked things so that the top 10% gets you power - but then you lose finesse and suffer worse fuel consumption. Honda seem to have stuck with the idea that the further you press the accelerator down the more power you get.

Mind you the switch between Atkinson and Otto cycle modes isn't handled all that well in the earlier versions of the Mk3 but I've learnt how to kick past that point.
Title: Re: In a quandary about small cars !
Post by: peteo48 on January 31, 2019, 10:09:58 PM
Interesting post Andruec. I mentioned above about a resistance to opening the throttle and I think I have this to a degree. A few years driving turbo diesels with that effortless low down grunt may have built up that resistance to opening up the throttle a bit more. It may also explain why some motoring journalists compare the Jazz unfavourably to the small turbo boosted petrol engines in many other small cars.

Then there's that Atkinson cycle business which I don't fully understand but is designed to increase fuel economy. Am I right in thinking that a firm press on the accelerator pushes the car through this? Asking for a friend :P
Title: Re: In a quandary about small cars !
Post by: sparky Paul on February 01, 2019, 09:11:16 AM
Yes, you can play about with tyre profile, and it does certainly help, but comparing a Jazz and a Corsa is like comparing chalk and cheese. There's no amount of suspension tweaks can hide the fact that the Jazz is basically a Japanese car designed for Japanese quality roads.

I'll admit, it's is a bit of a generalisation, but they just don't have the suspension travel you get on European car designs, which generally cope with our crappy roads better.
Title: Re: In a quandary about small cars !
Post by: andruec on February 01, 2019, 12:36:31 PM
Then there's that Atkinson cycle business which I don't fully understand but is designed to increase fuel economy. Am I right in thinking that a firm press on the accelerator pushes the car through this? Asking for a friend :P
Hey. The Atkinson cycle uses different valve timings in order to operate more efficiently. Otto cycle is the way most internal combustion engines have always operated. The Jazz isn't a true Atkinson cycle engine but it's a similar principal.

Anyway the Jazz engine seems to operate in Atkinson mode below roughly 2,500 rpm. If you can get the revs above that point you will get better response. In a manual car it's not so noticeable because gear selection and road speed dictate rpm. If you wanted to exit a roundabout quickly in a manual you'd go around it in 3rd or 2nd and then you'll be above 2,500 when you leave. But the CVT breaks that link and - in 'D' mode at least - appears to be engineered to favour low revs.

What I've found is that a quick 'prod' of the accelerator pedal appears to act like a mini-kick down. The ECU will take the hint and bump the revs up. A gradual increase is less effective as it seems that the CVT ignores you at first then suddenly wakes up and takes the hint. It does take a while to get the hang of 'the prod'. It wasn't too hard for me because I've always done it even on older models simply because I don't like to hang about. All the Jazz I've owned have shown a preference for 3,000 rpm when you ask for 'a bit of power' so a quick jab with the Mk3 usually puts you around that mark.

Alternative as some posters here do you can blip the left paddle but then if you're going to use the paddles all the time you might as well not be driving an automatic. Interestingly my last courtesy car was a facelifted Mk3 CVT and it didn't seem to have this problem at all. Possibly Honda tweaked the logic to improve it. I also noticed another change they'd made: If I floor the accelerator my RPMs jump to 4k then gradually rise up to the maximum where they sit for as long as I keep the pedal down. With the face lifted Mk3 they rose to maximum from 4k a lot faster and then started a drop, rise, drop rise sequence like a manual car would. I couldn't feel any gear changes so it must have been clever fakery but it shows that the facelifted Mk3 has had some tweaks to the CVT.
Title: Re: In a quandary about small cars !
Post by: culzean on February 01, 2019, 01:13:02 PM
Interesting post Andruec. I mentioned above about a resistance to opening the throttle and I think I have this to a degree. A few years driving turbo diesels with that effortless low down grunt may have built up that resistance to opening up the throttle a bit more. It may also explain why some motoring journalists compare the Jazz unfavourably to the small turbo boosted petrol engines in many other small cars.

Then there's that Atkinson cycle business which I don't fully understand but is designed to increase fuel economy. Am I right in thinking that a firm press on the accelerator pushes the car through this? Asking for a friend :P

Originally Atkinson cycle engines used funny variable stroke crankshaft and all sorts of unreliable complicated stuff to vary the compression ratio, the idea being that when the power is not required ( slow acceleration and low revs ) you can make engine more efficient by just using enough compression and fuel so that at bottom of power stroke there is 'nothing left' and all power in charge has been used and non goes down the exhaust pipe.  The modern take on Atkinson ( introduced by Honda on the 8th gen Civic 1.8 vtec petrol in 2006 ) is that you leave the inlet valves open longer and allow some of the charge to be pushed back into inlet manifold, this lowers the compression ratio because there is less to compress.  Due to direct injection on mk3 you are only pushing air back into manifold as the fuel is not injected until the air is compressed and ready to fire ( like a diesel) . Because direct injection don't suffer from pre-ignition ( you are only compressing air, not a fuel / air mixture the compression ratio for full power can be high, more than 13:1

I would hope that depending on throttle position ( how far and fast you press pedal ) the Atkinson would be terminated early or never requested, whereas at low throttle openings it can help to improve mpg.   The other thing Atkinson helps with are pumping losses due to pistons sucking against an almost fully closed throttle butterfly at low throttle opening, because power can be controlled by compression ratio and amount of fuel injected and throttle butterfly is servo controlled and not physically connected to the pedal anymore the butterfly can be opened wide and engine will not immediately go to maximum revs, but because power is limited by CR and fuel, the load on the engine will limit revs.
Title: Re: In a quandary about small cars !
Post by: Jocko on February 01, 2019, 01:36:32 PM
Does anyone other than Honda currently use the "Atkinson cycle"?
Title: Re: In a quandary about small cars !
Post by: mikebore on February 01, 2019, 01:57:38 PM

Alternative as some posters here do you can blip the left paddle but then if you're going to use the paddles all the time you might as well not be driving an automatic.

Good post apart from this statement! IMHO there is a massive difference between driving an automatic with an occasion flip on the left paddle, and driving a full manual. The occasional flip might represent 0.1% of driving time but a full manual is 100%.
Title: Re: In a quandary about small cars !
Post by: DaveBerks on February 01, 2019, 02:16:43 PM
Interesting comments all, many thanks from a non-techi person like me :'(

The ingenuity of the engine in the Mk3 (mine is pre-facelift) i.e. Atkinson and Otto (strange bedfellows !) is remarkable but asking the car to move smoothly and intuitively between the two makes me think this is not a marriage yet made in heaven !

Atkinson doesn't want you to leave, you have to 'put your foot down' sharpish and ignore its protesting screams to visit the more exciting Otto and then relent and return to Atkinson who sips petrol like its the most precious nectar there is. The result is something close to a Greek Tragedy for the poor adulterous driver. That little glowing green to blue indicator on the dash remains you of your misdemeanours in drinking too much fuel with Otto (like a normal driver). 'Get back' it flashes or it really is a divorce this time ! "I just wanted some fun" you say "please forgive me. Promise I won't do it again".

I'm joking and exaggerating a little bit but I do think the poor hapless non-technical driver needs better explanations and support from the dealers and Honda on this.  I applaud the engineers' daring and creativity but someone at Honda needs to keep their feet on the ground and their sales people should explain more what Honda are doing and why it is such good idea, as this might avoid some serious misunderstandings later on as well as prevent the start an anti Honda club ! Equally it's clear that motoring journalists can't be relied upon to understand the cars they are reviewing. Most it seems are simply fashion journalists.

I better understand the car now, thanks, I appreciate the perfect quality of Japanese road surfaces, the unbelievable ingenuity of Japanese engineers at Honda and their attempts to design cars which are 'close to the edge' and very clever.....yes...very clever !  ;D.   Just think about the poor customer a bit more please Honda  :-[


Title: Re: In a quandary about small cars !
Post by: andruec on February 01, 2019, 03:26:48 PM
Does anyone other than Honda currently use the "Atkinson cycle"?
Yes, several cars according to Wikipedia (https://en.wikipedia.org/wiki/Atkinson_cycle#Vehicles_using_Atkinson-cycle_engines).

Title: Re: In a quandary about small cars !
Post by: Jocko on February 01, 2019, 04:01:09 PM
Very few non-hybrid models. Obviously the hybrid motor gets round the problems reported here, with the non-hybrid Jazz. Mind you, when I had the 67 plate, manual SE on loan, I wasn't aware it had "Atkinson cycle", and it felt pretty much the same as my own car.
Title: Re: In a quandary about small cars !
Post by: culzean on February 01, 2019, 04:16:17 PM
http://innovatize.blogspot.com/2012/01/interesting-technology-by-honda-i-vtec.html

Here is an interesting article on later direct injection honda engines ( i-VTEC-i ) - it seems that at light loads / low revs the fuel is injected directly into piston bowl during the compression stroke - this enables really lean fuel ' air ratios of 65:1 ( with a corresponding decrease in power)  but during large throttle openings / high revs the fuel is injected during intake stroke where they go back to 14.5:1 ratio.  The engine in the video ( bad quality ) about 3rd one down is a 2 litre fitted to the Honda stream minivan, and article is dated 2012 - don't know if this same system used on newer Jazz engines where they make the air/ fuel extremely lean at low loads and revs and that will explain the lower power rather than the atkinson cycle which is not mentioned on the i-vtec-i DI engine video.  They do mention the 12/16 valve system where one of the intake valves can be left closed at lower revs.

A quick overview of Jazz direct injection engine from New Zealand,  this does mention both direct injection and atkinson cycle in the same engine.

https://www.honda.co.nz/technology/engine/jazzearthdreams/

This is an article on the original atkinson / otto engine in 8th gen Civic 1.8 i-vtec

http://asia.vtec.net/Engines/RiVTEC/

Mazda skyactive engine also worth a look

https://www.popularmechanics.com/cars/car-technology/a20650087/skyactiv-x-engine-mazda/
Title: Re: In a quandary about small cars !
Post by: Downsizer on February 01, 2019, 07:55:58 PM
Thanks all for your comments.

It's true that the Corsa has 15 inch wheels whereas Jazz EX has 16 inch, but why are the 16 inch wheels thinner (less  contact with the road surface) than the 15 inch ?...is this to save the manufacturer money ? The 16 inch look better since 15s can look lost in the wheel arch. But this gives manufacturers no excuse for poor ride comfort in my opinion. 
I don't think the 16" tyres are "thinner" (I.e. narrower tread). They have less depth because there is one inch less rubber diameter to compensate for one inch more metal.  That's why the ride is different.
Title: Re: In a quandary about small cars !
Post by: Downsizer on February 02, 2019, 04:16:27 PM
I currently driving a Vauxhall Corsa 1.4 automatic while my Jazz EX 1.3 auto is in for repair...for some reason other drivers like to drive into it when it is stationery !  Tailgating seems to be an everyday occurrence in the South East where everyone is in a hurry and safe gaps between cars are a thing of the past.

What I notice is how comfortable the suspension is in the Vauxhall, riding over bumps and seams, and how planted the car feels on the road and how responsive the engine is compared to the Jazz which makes me feel I'm thrashing it to get anywhere over 20 MPH and crashes over bumps and seams on the normally poor road surfaces we now have to pt up with. I suspect the car is very light in order to save fuel.
I'm currently driving a hired Corsa in Lanzarote and I notice it is fitted with 195/55 x 15" tyres compared with 185/60 x 15" on my Mk 3 SE Jazz.  I don't know if this is the same in the UK - it may to cope with some of the un-metalled minor roads here.  Personally, I don't much like the car.  It feels heavier and the ride is a bit "wallowy"- does anyone remember the old Zodiacs and  Veloxes?  Also, even with driver's seat fully raised" I feel a bit low, although I am 5' 9". But these are very subjective issues.
Title: Re: In a quandary about small cars !
Post by: sparky Paul on February 02, 2019, 09:37:59 PM
I'm currently driving a hired Corsa in Lanzarote and I notice it is fitted with 195/55 x 15" tyres compared with 185/60 x 15" on my Mk 3 SE Jazz.

The 195/55x15 tyres on the Corsa would theoretically be slightly stiffer, but there's very little in it. I think it was Jocko who mentioned the differences in tyre brand earlier, and in this case, a more pliable tyre could sway it either way.
Title: Re: In a quandary about small cars !
Post by: RichardA on March 12, 2019, 01:56:57 PM
I think you will find the Corsa is a much newer design than the Mk 3 Jazz. How do the mileages compare between the two vehicles? Both can have an effect on ride comfort.
Hard to say, the current Corsa came out in 2016 but is heavily based on the previous gen from 2006.

Japanese cars are normally less good at NVH than European cars.

Sent from my Moto G (5) using Tapatalk

Title: Re: In a quandary about small cars !
Post by: culzean on March 12, 2019, 02:31:19 PM
Japanese cars are normally less good at NVH than European cars.

I think Japanese are always aiming for lowest possible vehicle weight and may skimp on the sound deadening material.  Anyway if it is a choice between slightly higher road noise and much better reliability I guess I will go for reliability every time and buy the quietest tyres I can afford- I think Vauxhall are better now than they used to be, but I had a couple of Vauxhalls years ago and was decidedly not impressed, my first Ford ( Sierra ) and later Japanese cars were many orders of magnitude better.
Title: Re: In a quandary about small cars !
Post by: AlanTR on March 14, 2019, 07:44:11 PM
I recently hired an Opel (Vauxhall) Mokka Turbo (petrol) recently in Fuertaventura. Nice enough car but, in my opinion based on 3 days driving, nowhere near as good as the Jazz.
Title: Re: In a quandary about small cars !
Post by: Paulwhitt20 on March 15, 2019, 08:41:12 AM
"Japanese cars are normally less good at NVH than European cars."

You have not driven a Lexus then.
Title: Re: In a quandary about small cars !
Post by: culzean on March 15, 2019, 10:20:32 AM
"Japanese cars are normally less good at NVH than European cars."

You have not driven a Lexus then.

+1

IMHO Japanese engines and gearboxes better than European and American makes, certainly manual gear changes better as well. Have heard horror stories about VW group gearboxes falling apart inside ( happened on my brother in law Golf a few years ago ).

It was certain Japanese companies ( Honda and Suzuki )
 with their expertise in building lightweight and powerful motorbike engines that revolutionised car engines, reducing the weight, increasing specific power outputs and improving MPG, my brothers 2018 Suzuki Vitara with turbo direct injection petrol engine is one of the  nicest most responsive engines I have driven, with great torque from 1500 revs up and great real world MPG, my brother was a diesel head but I warned him to sell his beloved Ford Kuga before diesel values crashed and he prefers the Suzuki engine.