Theory behind better FC for Manual trasmission.

[Chalk]

Guy, understand MT generally have better FC than AT.

But AT oso have the traditional 4 gear and the new CVT.

So in those 3 types of transmission which have the BEST FC and which one LOUSIEST.

 

And wats the science behind MT having better FC.

[Eyke]

read:

 

Manual - http://auto.howstuffworks.com/transmission.htm

 

Auto - http://auto.howstuffworks.com/automatic-transmission.htm

 

CVT - http://auto.howstuffworks.com/cvt.htm

[Siyexcalibur]

AT uses hydraulic coupling, hence more transmssion losses

 

Best to worst

MT, CVT, AT

[Mustank]

i think MT is metal gear push metal gear so mim enengy loss

 

i think AT is liquid gear push liquid gear so more energy loss

[Jeff89]

i think its becoz for MT transmission, you can get to the higher gears without harsh accleration. MT transmission also allow u to shift gears at lower RPM. which make it more fuel efficient. you don need to rev that high to change gear, unlike in auto trans. With MT trans you will also get more power.

 

FC is also dependent on the driver most of the time. And your right foot. Haha.

 

Thats my thinking la if i am wrong please correct me. i still newbie.

[Octopus]

Also MT allows you to cruise down slope in neutral gear.

[Friendstar]

ok this is layman's term

 

 

how u change gear using MT? using ur arm power

 

How u change gear using AT? using torque convertor. Where the energy comes from? petrol combustion.

[Chalk]

i know how they work ... tks

[Xefera]

don't think transmission loss = bad FC

 

IMHO, its down to how the torque converter works in an automatic transmission. perhaps it requires more energy, therefore power => burn more fuel to drive the transmission train.

Whereas in a MT, the transmission drivetrain is less complicated, basically just the clutch assembly and driveshaft.

[Chalk]

and wat do u guys think is the most efficient speed to save petrol at highway ... 80??

 

and will u whack to 80 then cruise or slowly go to 80 then cruise ... assuming open road... no downslope....

 

i think i will whack to 8o then cruise ... hee hee ... maybe we need some scientist on this ...

[Mustank]

i think most AT has onli 4 gear while MT has 5 gears

 

so MT more efficent

[Dcat]

Be it AT, CVT or MT, it all depends on your right foot

[Watwheels]

To put it simple, it's the transmission medium that makes the difference.

 

MT: clutch plate.

AT: hydraulic action(oil)

CVT: rubber band....I mean steel belt.

 

Now DSG(dual clutch transmission) is most ideal since it has the direct transmission like the MT and it shifts like an AT without the bad FC.

[Xefera]

remember sometime back there was this guy from the states that held the records for travelling the longest distance or something like that, as part of Shell promotion. He did mention that smooth acceleration and cruise at between 60-70kmh is the best way to stretch the petrol. Think he did the Singapre-Genting round trip (600+km) on a single tank of petrol in a Subaru Imprezza, somemore with petrol to spare

[Chalk]

yah i remember .... impreza some more leh ...

thot fc lousy .... if he use fit or vios can go penang maybe ...

[Chrispie]

  Quote

and wat do u guys think is the most efficient speed to save petrol at highway ... 80??

 

and will u whack to 80 then cruise or slowly go to 80 then cruise ... assuming open road... no downslope....

 

i think i will whack to 8o then cruise ... hee hee ... maybe we need some scientist on this ...

 

Read somewhere that car is most efficient at 90km/h. Any more than that, the car will be spending more power overcoming drag per unit km moved than the actual traveling itself. Depends on car to car, but i guess cruising at 85-100km/h most of the time will give you best FC.

 

I once did Sg-KL 2 way on a single tank.. avg abt 100km/h. So could be quite true..

Edited April 16, 2008 by Chrispie

[Nolicense]

from fluid mechanics, in air, 70-80kmh is the limit of linear drag. above that is square of drag coefficient and cube of drag coefficient.. forgot all that formula stuff liao..

Edited April 16, 2008 by Nolicense

[Xefera]

penang? that one stretch a bit too much lah, round trip 1500km leh

 

unless he driving a car with 99L fuel tank then maybe. bugatti veyron?