4 speed vs 5 speed

[mbeige]

I support what Niky said, the exact principles (depends on the gearing) came to mind.

Consider that fifth gear as an overdrive to reduce engine RPMs at high speed to minimize fuel consumption. Four speeds also have an overdrive, but comparing the ratios, that fifth gear will almost always yield better fuel economy.

[rion]

self theory: for m/t, the many gears you have, the longer it takes you to reach 100km/h.
kasi nga, a lot of power is lost between shifting those gears... hehe...

[kokey]

Kung AT car mo e mas smooth pag 5 speed sya.





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"It's not fun to own a LEMON"



Think twice before you buy a HYUNDAI.

[niky]

*rion: Not really.

What you're looking at is not the time it takes you to row through the gears, but the amount of power you're using as you accelerate in gear.

The shorter the gear, the easier it is for the engine to accelerate in that gear.

Here's a good example... take your basic mountain bike.

Start off in lowest gear (we'll ignore your front gearset and assume your rear-set is eight cogs)... As you start off, you don't have to pedal very hard... then shift, then shift, then shift... as you go faster, you're still using the same amount of power.

Now, if you have less gears... start off in 2nd... then 4th... then 6th... then 8th... you need to pump harder to get up to speed. So even if you lose less time to shifting, you're using more energy to move yourself.

Most modern 4-speed automatics are geared so that you lack for power on the road, but they have to sacrifice somewhere, and it's often in that first gear, which is much longer than on a 5-speed car. That long first gear makes the engine work harder from a stop... it's like starting your bike in 2nd gear... it takes more muscle to start the bike rolling, which is equivalent to more gas wasted in a car.

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Hell, thought of an even simpler example. Staircases. More stairs, with a shorter step height = easy climb. Less stairs with a taller step height = puff... puff... puff...

[5Speed]

*rion: Not really.

What you're looking at is not the time it takes you to row through the gears, but the amount of power you're using as you accelerate in gear.

The shorter the gear, the easier it is for the engine to accelerate in that gear.

Here's a good example... take your basic mountain bike.

Start off in lowest gear (we'll ignore your front gearset and assume your rear-set is eight cogs)... As you start off, you don't have to pedal very hard... then shift, then shift, then shift... as you go faster, you're still using the same amount of power.

Now, if you have less gears... start off in 2nd... then 4th... then 6th... then 8th... you need to pump harder to get up to speed. So even if you lose less time to shifting, you're using more energy to move yourself.

Most modern 4-speed automatics are geared so that you lack for power on the road, but they have to sacrifice somewhere, and it's often in that first gear, which is much longer than on a 5-speed car. That long first gear makes the engine work harder from a stop... it's like starting your bike in 2nd gear... it takes more muscle to start the bike rolling, which is equivalent to more gas wasted in a car.

-----

Hell, thought of an even simpler example. Staircases. More stairs, with a shorter step height = easy climb. Less stairs with a taller step height = puff... puff... puff...

sang-ayon ako sa mga paliwanag ni kapatid na niky....

[meledson]

*rion: Not really.

What you're looking at is not the time it takes you to row through the gears, but the amount of power you're using as you accelerate in gear.

The shorter the gear, the easier it is for the engine to accelerate in that gear.

Here's a good example... take your basic mountain bike.

Start off in lowest gear (we'll ignore your front gearset and assume your rear-set is eight cogs)... As you start off, you don't have to pedal very hard... then shift, then shift, then shift... as you go faster, you're still using the same amount of power.

Now, if you have less gears... start off in 2nd... then 4th... then 6th... then 8th... you need to pump harder to get up to speed. So even if you lose less time to shifting, you're using more energy to move yourself.

Most modern 4-speed automatics are geared so that you lack for power on the road, but they have to sacrifice somewhere, and it's often in that first gear, which is much longer than on a 5-speed car. That long first gear makes the engine work harder from a stop... it's like starting your bike in 2nd gear... it takes more muscle to start the bike rolling, which is equivalent to more gas wasted in a car.

-----

Hell, thought of an even simpler example. Staircases. More stairs, with a shorter step height = easy climb. Less stairs with a taller step height = puff... puff... puff...

Galing ng explanation!

[rion]

*rion: Not really.

What you're looking at is not the time it takes you to row through the gears, but the amount of power you're using as you accelerate in gear.

The shorter the gear, the easier it is for the engine to accelerate in that gear.

Here's a good example... take your basic mountain bike.

Start off in lowest gear (we'll ignore your front gearset and assume your rear-set is eight cogs)... As you start off, you don't have to pedal very hard... then shift, then shift, then shift... as you go faster, you're still using the same amount of power.

Now, if you have less gears... start off in 2nd... then 4th... then 6th... then 8th... you need to pump harder to get up to speed. So even if you lose less time to shifting, you're using more energy to move yourself.

Most modern 4-speed automatics are geared so that you lack for power on the road, but they have to sacrifice somewhere, and it's often in that first gear, which is much longer than on a 5-speed car. That long first gear makes the engine work harder from a stop... it's like starting your bike in 2nd gear... it takes more muscle to start the bike rolling, which is equivalent to more gas wasted in a car.

-----

Hell, thought of an even simpler example. Staircases. More stairs, with a shorter step height = easy climb. Less stairs with a taller step height = puff... puff... puff...

Oh I see po. but a average driver with a normal car can put atleast a 2 secs delay in a shift diba?

[niky]

Actually, it's probably between 0.5 seconds for your common driver, if they aren't really in a hurry. I've got timing data that show shift times of 0.1 seconds (or possibly better) are possible with a good driver and a good box.

Older ATs take longer than that to shift, and, worse, take some time to "make up their mind" about when to shift. Newfangled DSGs, SMGs, CVTs and the like have shift times that most drivers can't beat, and some economy cars are getting ultra-fast boxes, too.

I'm pretty sure I could shift a five-speed MT Ranger as fast or faster than the five-speed AT box can, but not on every single shift at every single stoplight. And there's no way I can shift as fast as VW's new DSG (8 milliseconds? I can't even blink that fast!)

But the point isn't the time you take to shift, but how much power you use and how long you use it to get to a certain speed. And therein lies the advantage of boxes with more gears, and the advantage of manual boxes over their heavier, inertia-challenged, torque-converter equipped automatic brethren. CVT's another story, though...

[rion]

I see. but how about the delay of the driver in the clutches pedal in a common box ride?