CVT vs 4AT/5AT

[Iziz]

Sorry but beg to differ... whether cvt or not is not the catch on being a more premium package. Perhaps its just the way nissan package their varieties thats all. in fact cvt is not really as expensive as a conventional AT per se but just the maintenance being a little out of the norm thats all. hence, maintaining cvt may cost much more than maintaining a normal AT or MT. we know that a cvt basically works like a pully and belt, so, if ur car is heavy, u'd need a tougher pulling mechanism here. if this is not well designed or a compromise in the quality, it will give u nightmare. a more hardy gear train is the audi chain type cvt that offers a tough and accurate pull than a conventional one that has a risk of being torn or worn easily. consider an audi if u like cvt. so far, the japs have been trying hard.

 

Nissan has packaged it this way, hence I am just explaining how the products r structured. As to how good/bad the CVT is, I leave it up to the consumer to experience for themselves as I am in no position to tell them wad they should/should not like.

 

I also beg to differ on your last statement, "consider an audi if u like CVT", sometimes its a matter of being pragmatic, aka value for money. Does tat also mean tat consider a Merc 7-gtronic if u like autos? As much as I am not trying to defend Nissan, but ur statement is a little too belittling to Jap cars.

Wad Japs have/have tried to do is make cars affordable to the masses and they have quite successfully done tat IMHO. They did it once with auto gearboxes and now Nissan is doing/attempting to do it with CVTs and I am of coz hoping it is successful

 

In an utopian view, it would be nice to go to the top-of-the-line for everything since it would be a quality product but in reality we do have a budget/a targetted financial plan to adhere to hence splurging on cars might not be a top priority for most of us, hence a Jap CVT (using as an example only, not trying to push my product) might be a more viable option to experience CVT rather den buying an Audi.

 

Yups, I agree, the Japs r trying hard

[Iziz]

Eh, for CVTs, use the "over-drive/sport" button, it beats flooring the pedal

[Vicz]

Yes, it is true. I do agree that bigger vehicles too would not have any problem if the manufacturer choose an appropriate gearbox, be it cvt or not. it is possible to do it, just how well they design it thats all.

[Vicz]

Well, don't worry, i m not trying to pose a negative impression on nissan's products. in fact i was just comparing between cvt and cvt, m not trying to belittle the japs, hav not utter a word that nissan's cvt is not good, did i? we have to agree that audi's cvt is one of the best, yes? likewise, if u compare auto to auto, yes, merc's 7-gtronic is one of the good one, yes? if u ask me which clutchless mt is good, then, i'd have to say vw's dsg, yes? cost has not been factored into my remarks. honestly, i find that nissan's approach is towards a more fuel efficient line, in order to have better fc, a fuel efficient engine alone is not good enuff, i believe perhaps that's one reason why nissan is trying to put cvt in many range of their product, it is a very good thing bcos cvt works best with fuel effiecient engines. to me, the japs too have their fuel efficiency up in their sleeves, yes? they are good at this....

i m not a "believer" of a certain brand or country of make, my take is that the ang mos & the japs just have their respective focus thats all...they focus on different needs and markets and they have their own beliefs.

[Vicz]

cvts usually do not act upon like a conv AT by kicking it a gear down to save the rev so that u could get abundant amount of torque to kick up while u overtake. the feeling u get also won't give u alot of confident to do the it, but in actual fact, it is doing the job (that is to say: a matter of feeling). do bear in mind that a gear down for conv AT means a big ratio change but this change will not be felt in a variable change.... anyway, i reckon that since the focus of a cvt gearbox is more or less for the purpose of better fc & smoother rides, therefore, it may not address the overtaking as too much a priority.

well, may be i should say that some of us couldn't adapt to cvt bcos different drivers have different needs and habit... there will never be a one size fit all formula in this world.

[Droll]

2 other things about CVT

1. some do not have auto-crawl option. meaning if you leave it in gear and let go of brake from stop position, the car does not crawl forward. this can be a problem esp when you are on a hill.

 

2. some people not used to hearing the engine revving at a fixed RPM while the speed is still increasing. i wasn't used to it when i first drove my CVT. felt kinda weird... but after a while you will get used to it.

[Flameblade]

care to share which car are u refering to ? cause by right all CVT/ auto cars will start to move forwared if u put it in P and let go of the hand brake and foot brake (on a flat road).

 

On a slope (underground carpark kinda of slope etc), ur car by right will either move forward abit (if the slope is not too steep) or it will hold ur car in its position and not let it roll back. Well unless u have some weight in ur car whereby it will start to roll back. Think something on the line of halfcluth.

 

My 2 cents.

[Droll]

the car was a CVT MINI One. i had it remapped to maintain the idle RPM > 1000 then it was fine. the autocrawl only engages when it is > 1000 rpm.

[Ff2004]

Interesting replies.

 

I have learnt a lot from you guys indeed.

 

Thanks

[Ff2004]

That is to say that CVT is there to smoothen the gear changes so that we do not have the jerky feel that is all.

 

If one does not mind the jerky feel he/she can opt for a 4AT loh since there is no difference only the gear change is smooth without jerky feel during change of gears?

 

I heard CVT provide good FC as it is more efficient than 4AT but some drivers with 4AT have also achieved a fanastic FC which is very much close to a CVT drivers.

 

I have never try CVT before so I do not know how bad it is when doing overtaking. Is it that bad till we do not have the confident to overtake or when full load going up the slope?

[Flee]

go and test drive latio, both CVT and 4AT. I did, and i preferred the 4AT. CVT is jerk free, but lacks the oomph. Also, the latio's 4AT does not really have gear shifting jerks. Very smooth. Didnt feel any jerk at all, magbe slightly only when gear shifting. But i hardly feel it. FC-wise, not much diff between the 2. Prob 1 to 2km/l saving for the CVT?

[Dipstick]

overtaking is a chore with cvt. so no cvt for me.

 

That's exactly what puts me off CVT....... I just can't stand the CVT slack of my previous ride, a 2001 Lancer. No more CVT for me until I am sure the "slack" problem has been taken care of.

[Ff2004]

 

Thanks a lot!

[Droll]

general rule of thumb for power loss from engine to wheels

1. manual - 15%

2. torque converter auto - 25%

3. cvt auto - 10%

 

yes, cvt is ultimate more efficient. however, cvt has something called the rubber-band effect and i absolutely hated it. i had to change my driving habits for overtaking. you have to really anticipate when you are ready to overtake at least a few seconds before actually stepping down on the pedal. because it takes a few seconds for the RPMs to spool up to the optimal power band before your car begins to accelerate.

 

what i ended up doing last time was to put it into steptronic mode and downshift gears to get high rpm then wait until the coast is clear and i can initiate my overtaking. quite a strain on the engine.

[Knighthunter]

Do you have support regarding to your figures mentioned above? As far I know the one which create power loss is mechanical linkage. In the manual car the power is transeferred by means of friction plate to the gearbox. This is ZERO power loss from engine to gearbox, except the friction plate is worn out that's another story. Manual gearbox is only type of transmission with almost no slipage loss, therefore most performance car is using electric manual gear (ex. selespeed in alfa romeo)

The loss on CVT and AT gearbox are similar, since these gearboxes need torque converter to transmit engine output to gearbox input shaft.

Without torque converter it's not possible to stop the car with idle engine in AT or CVT equipped car.

 

If CVT generate less loss than manual transmission, that is doubtful.

[Totalkaputt]

for my latio cvt,there is a clutch that engages at around 20 km/h so as to reduce the transmission loss from the torque converter. therefore the torque converter is only used to launch and prevent stalling when car is stationary. however i do believe that the cvt has a higher transmission loss than manual.

[Droll]

knighthunter:

 

i have seen dynocharts of a few friend's manual cars. all are around 15% power loss for manual vs what manufacturer claims as engine bhp.

 

you can check for dyno charts of other regular torque converter auto boxes and see it varies around 20-25% i believe.

 

CVT is the hardest one to dyno since it is heavily computer controlled. the 10% i quoted was from an article i read some time ago.

 

i think the manual gearbox you are referring to with virtually no power loss are those specially engineered for high performance cars like ferrari, formula 1 cars, etc. it's quite different from the regular street-going 5 or 6 speed manual boxes. you are right that if you can reduce slippage to a minimum then power loss will be minimal.

 

btw, there are CVT gearboxes that don't come with torque converter.

you can read this article: http://www.vtec.net/articles/view-article?article_id=12111 and see there they use 30% power loss for auto and 15% power loss for manual.

 

so i'm no expert just speaking from various sources of info i gathered. don't flame me. :) i'm still learning.

[Clarence07]

I am no car expert. So here is one layman experience.

 

Been driving a auto Lancer GLX 1.6 (CVT) for about 4 years. I feel that the pickup for the lancer is not as good as other brands of Jap car which I had test drive (like Honda or Toyota) *not advertising for any car distributor* But when the CVT lancer picks up to about 50km/hr, you can feel the power kicks in and it can hold its own to other Jap car.

I am a 'leisure' driver who seldoms exceed 2,200 rpm when I pickup or in expressway (usually between 80 km/hr to 100km/hr). So for FC wise, I am hitting about 11.5km to 12km per litre which I think is quite average for a CVT car.

A Honda salesman told me previously why Honda changed from CVT to normal 4AT was because Honda received many complains about the CVT belt which does not last long. However, *touch wood* after 4 years, I am still happily driving my CVT lancer without any major repair work done for my CVT.

 

cheers