difference ng 4 speed automatic against 5 speed manual transmission

[xenix]

Out of curiosity lang, parehas ba ang gearing ng automatic and manual transmissions considering na 4 speed ang automatic at 5 speed ang manual? bakit hindi na lang silang parehong 5 speed?

[alwayz_yummy]

nope hindi, maaring iba ang ratio ng matic sa manual. pero di naman nagkakalayo...

mas maraming gears ang matic than manual in reality, masyadong packed,e...

or just a marketing hype na din..

[OTEP]

The ratios are different. Iba ang spread ng ratios ng 4A/T sa 5M/T to account for the lesser available gear selections. The axle ratio can be different also.

There was a time when 4 speed a/t's were considered the 'norm' in the industry just like the olden times when a 3 speed manual came standard with cars.

Nowadays, production costs and packaging constraints dictate the number of speeds in a transmission.

[orly_andico]

a conventional manual transmission uses a sliding gearbox. an automatic uses a double planetary gearset. more expensive.

that's why automatics used to have 4-speeds and most still do; only the newest and higher-end cars have 5-speed automatics.

the automatic also doesn't need a short first gear because it has a torque converter, which increases the torque. so the 1st gear on an automatic is kind of equivalent to 2nd gear on a 5MT.

the 4th gear on a 5MT is the 1:1 ratio gear. the 3rd gear on a 4AT has the same function.

although i must admit, the viscous coupling torque converter and the longer gearing of the AT means driving it is a bore. unless it's a Ford SUV or Merc AMG with gobs of torque.... never driven one of those.

[OTEP]

Newer Lexus sedans already claim to have 8 speeds. I just don't know if this is via conventional gears or via CVT (which is cheating because CVT technically have an infinite number of gears between low and high ).

[rion]

automatic being slow because it only has 4 speed is not true. many people thinks like this...

however, automatic is slower and feels soft because it runs on pressure hydraulics...

though I encountered some few a/t that feels fast and you feel a strong drag. but the actual acceleration is still in question...

with continuously variable transmission (CVT), no idea why they have 7 speeds. Honda hatch ek9 and City.
probably 7 speed doesn't mean 7 gears?

and why this old technology was never succesful over hydraulics.

[alwayz_yummy]

cvt ata is stil in the development stage... di nga dumating dito yung mga HRV na CVT, mga hyper-cvt ng nissan for the low-displacement engines

[orly_andico]

automatic being slow because it only has 4 speed is not true. many people thinks like this...

however, automatic is slower and feels soft because it runs on pressure hydraulics....

No, no.. automatics are generally slower than manuals with the same car and engine because...

1) the automatic usually has 4 speeds, so the gears are taller, meaning the engine has to produce torque lower in the RPM powerband
2) the torque converter is a viscous coupling, unlike the clutch
3) there is more loss in an automatic than in a manual

[Camgen6]

Newer Lexus sedans already claim to have 8 speeds. I just don't know if this is via conventional gears or via CVT (which is cheating because CVT technically have an infinite number of gears between low and high ).

Sir Otep, conventional 8 speed auto tranny yata at di CVT. Ang alam ko kasi Toyota/Lexus ay gumagamit ng CVT sa mga Hybrid nila di ko lang alam sa bagong LS600H na ilalabas nila.

[rion]

No, no.. automatics are generally slower than manuals with the same car and engine because...

1) the automatic usually has 4 speeds, so the gears are taller, meaning the engine has to produce torque lower in the RPM powerband
2) the torque converter is a viscous coupling, unlike the clutch
3) there is more loss in an automatic than in a manual

my point over most people thinks automatic being slow because it only has 4 speed is not true. because most people think it has the same gear size and works same like a m/t but only powered by computer.

heck most old conventional a/t don't require a computer to shift, but the tranny itself sensing the pressure load. (works like a mechanical clock where the big hand and the date moves on a certain point of the seconds and the minute hand)

the viscous coupling is also present in m/t differentials.

the difference is that viscous coupling in the a/t tranny is powered by hydraulic pressure.

it's not the clutch that make a m/t faster but the engine and tranny itself having physical contact. unlike a/t where the engine pushes it's tranny by pressure and hydraulic pressure has more power loss...

cvt ata is stil in the development stage... di nga dumating dito yung mga HRV na CVT, mga hyper-cvt ng nissan for the low-displacement engines

ngek, how come it is still in development stage where the history of cvt is already old. they probably doubt the success of cvt and considered the cost.

[SIZE=1]No More Gears: A Timeline of CVT Innovation[/SIZE]
[SIZE=1]1490 - da Vinci sketches a stepless continuously variable transmission [/SIZE]
[SIZE=1]1886 - first toroidal CVT patent filed [/SIZE]
[SIZE=1]1935 - Adiel Dodge receives U.S. patent for toroidal CVT [/SIZE]
[SIZE=1]1939 - fully automatic transmission based on planetary gear system introduced [/SIZE]
[SIZE=1]1958 - Daf (of The Netherlands) produces a CVT in a car [/SIZE]
[SIZE=1]1989 - Subaru Justy GL is the first U.S.-sold production automobile to offer a CVT [/SIZE]
[SIZE=1]2002 - Saturn Vue with a CVT debuts; first Saturn to offer CVT technology [/SIZE]
[SIZE=1]2004 - Ford begins offering a CVT[/SIZE]

looks like same on hydro and hybrid cars. ang tagal.....

[yebo]

and why this old technology was never succesful over hydraulics.

a cvt a/t still has the hydraulic torque converter in a conventional a/t. the cvt only replaced the planetary gear system of the conventional a/t. in other words...

conventional a/t = hyd torque converter + planetary gear system
cvt a/t = hyd torque converter + cvt

[rion]

a cvt a/t still has the hydraulic torque converter in a conventional a/t. the cvt only replaced the planetary gear system of the conventional a/t. in other words...

conventional a/t = hyd torque converter + planetary gear system
cvt a/t = hyd torque converter + cvt

ah ok, kaya pala my atf yung mga cvt. looks like hydraulic technology will stay for good.

so it looks like it's still not as efficient as m/t in straight run. but only more efficient in gear shifting because power and momentum is not lost there, unlike m/t and conventional a/t.

kaya pala cvt is not applied to racing. like Subaru Prodrive using the hydraulic only for moving the automatic stick. but the tranny itself still works like a manual.

conventional a/t is also less efficient because it is lot heavier than m/t.

[orly_andico]

Maybe the future is not CVT.

Audi's double-clutch Direct Sequence Gearbox is moving downscale from the Audi's to the Volkswagens. You can now buy a Golf with a DSG.

[alwayz_yummy]

mahal ang DSG gearbox, pero ok siya...

cvt talaga, mas efficent siya over sa conventional manual kasi nga infinite number of ratios between uppen and lower...kaya for me yung local nating jazz/city na may cvt(w/ 7-speed mode) ay parang 5-in-1 siya:

1. conventional CVT
2. sport-mode CVT
3. 7-speed mode-auto
4. sport mode 7-speed mode-auto
5. 7-speed manual mode...

[pup2]

I guess the hydraulic is the reason why there is often 'hesitation' between stepping on the gas and actually moving pag AT?

True, bilib na bilib ako sa CVT -- parang the best compromise sa ayaw o hindi kaya mag-manual. Subaru's prodrive thing is the most responsive A/T I've ever driven (without the SS). Paano kaya nila ginawa yun?

[alwayz_yummy]

ferraris ata are running na on specialized automatic transmission, optional nalang ata ang manual...

tsaka most top-end model na bnebenta dito puros matic talaga...best compromise talaga cvt lalo na yung sa local nating city/jazz.. kung CVT mode mo siya, di ka makakaramdam ng shift-shock talaga, linear ang takbo at power transfer! kung di ka aware or sanay ka sa rinig lang ng makina, di mo mamamalayang 80kph ka na...

[rion]

I guess the hydraulic is the reason why there is often 'hesitation' between stepping on the gas and actually moving pag AT?

if your a/t is having a very strong hesitation feeling when you quickly step on the gas... you can eliminate it a bit by loosening the kickdown cable a bit. it is a hydraulic fluid control attached to your gas pedal cable (usually wrapped in orange colored rubber). however, don't rely on the feeling. too loosen might feel smooth, but in reality you did not notice that you are steping the gas deeper.

Subaru's prodrive thing is the most responsive A/T I've ever driven (without the SS). Paano kaya nila ginawa yun?

stock Subaru a/t is cvt right? the Subaru a/t i mentioned earlier was for world rally. (only 6 millisecs power and momentum lost) I'm not sure if they also use it for stock subaru's.

how about those paddle shifters? what's the difference? how many speed do they have?

[alwayz_yummy]

hehehe..feeling ko na-OOT na tayo.. 4speed matic at 5-speed m/t lang e...napunta tayo sa cvts at kung saan saan :D