Why Manual cars are more fuel efficient than automatic?

[margallar]

you guys are trying to compensate for fuel by driving like a "dadi amma" - every engine has a specific usable powerband. Some engines dont even have the torque of a 2 yr olds arm muscle at low rpm.

...

back to the question, the reason manuals get more economy is mostly due to the reason of lack of losses in the torque converter and also due to more gearing control with manual - the automatic transmission cannot "see" what the human can.

can we get that powerband in the lower rpm range by changing the camshaft

[ZainMahdi]

^^thats what vtec/vvti is for. Or rather, they change the timing. A 3 stage Vtec Civic has surprisingly good torque around 2k rpm. Won't stay below 85 kph on a highway in good weather (H)

[Umairlal]

Define early shifting? I shift gears at 2000 rpm in my Cultus VXR with no problem. It can cruise at as low as 1300 rpm without lugging or knocking. As for engine damage, it can still go above 130 kph at 310000 km.

Pressure / load on engine.. I heard some where.. seniors can guide u better

[humair_sultan]

بھائی سب آپ کو ُاپر اُپر کی کہانی سنائیں گے دراصل مینول گئیر میں 5 گئیر ہوتے ہیں مگر آٹو گئیر میں صرف 4گئیر ہوتے ہیں جس وجہ سے آٹو گئیر زیادہ فئیول خرچ کرتی ہے

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[Xulfiqar]

بھائی سب آپ کو ُاپر اُپر کی کہانی سنائیں گے دراصل مینول گئیر میں 5 گئیر ہوتے ہیں مگر آٹو گئیر میں صرف 4گئیر ہوتے ہیں جس وجہ سے آٹو گئیر زیادہ فئیول خرچ کرتی ہے

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aap ko shayad ilm nahin hai - aam toar pe japani automatic jiss me O/D aata hai - woh 0.8:1 ke ratio pe chalta hai - jo ke aam japani manual gaari ke paanchwa gear (5th gear) ya double taap kehtay hain - uss ke barabar hai.

aam japani aatometick ka teesra (3rd) gear 1:1 chalta hai - jo ke aap ke manual gear ke 4th gear ya taap gear ke barabar chalta hai

[capsat]

xulfiqar saheb yead double taap keya hota hai ? konsay ghyr ko double taap boltay hain

[tanveer780]

xulfiqar saheb yead double taap keya hota hai ? konsay ghyr ko double taap boltay hain

5th gear ko

[ZainMahdi]

xulfiqar saheb yead double taap keya hota hai ? konsay ghyr ko double taap boltay hain

In most cars, both 4th and 5th gears are overdrive gears. Maybe that's why 5th is called "double taap"

[imrananr]

In most cars, both 4th and 5th gears are overdrive gears. Maybe that's why 5th is called "double taap"

I think with manual gear box 4th has a gear ratio of 1:1, hence it's not an overdrive.
The 5th gear is an over drive, I mean a bigger gear is the driver and the smaller is driven, hence less torque but more speed.

[ZainMahdi]

I think with manual gear box 4th has a gear ratio of 1:1, hence it's not an overdrive.
The 5th gear is an over drive, I mean a bigger gear is the driver and the smaller is driven, hence less torque but more speed.

Very few 5 spd manuals have 4th as a direct ratio. Check out the following 4th gears of common cars:

Khyber/Cultus: 0.914
FX (and maybe Mehran?) : 0.900 (almost the same as Khyber and Cultus)
Margalla: 0.969
7th gen Civic : 0.970
8th gen and 9th gen Civic: 0.948
City ivtec MT: 0.923
Santro: 0.920

In fact, I don't think you can find any economy FWD MT car with an exact 1:1 gear. They will be slightly overdrive ratios.

[imrananr]

Very few 5 spd manuals have 4th as a direct ratio. Check out the following 4th gears of common cars:

Khyber/Cultus: 0.914
FX (and maybe Mehran?) : 0.900 (almost the same as Khyber and Cultus)
Margalla: 0.969
7th gen Civic : 0.970
8th gen and 9th gen Civic: 0.948
City ivtec MT: 0.923
Santro: 0.920

In fact, I don't think you can find any economy FWD MT car with an exact 1:1 gear. They will be slightly overdrive ratios.

You are right, but it's a very little difference and taken as 1:1

[Xulfiqar]

the dubbal taap gheyr is a word coined by old truck drivers of Pakistan, I wonder what they will call the 18 speed transmissions used in trucks nowadays.

anyway - I wrote the general reduction ratio of small eco japanese car gearboxes. The reason I said japanese was that MB made 4 spd automatic transmissions for decades where the 4th spd was also called "direct drive" - aka 1:1

[faiz.aslam.121]

the dubbal taap gheyr is a word coined by old truck drivers of Pakistan, I wonder what they will call the 18 speed transmissions used in trucks nowadays.

anyway - I wrote the general reduction ratio of small eco japanese car gearboxes. The reason I said japanese was that MB made 4 spd automatic transmissions for decades where the 4th spd was also called "direct drive" - aka 1:1

I've driven that kind of truck before, Bedford
The clutch was solid and the steering.... Meh.

Sat inside a FAW truck- much better lol.
It had synchronizers- so no double clutching, cannot remember how many gears, but it had a little shift button behind gear level for hi/low gears.
A bonus was that it had cruise control- which the wapda driver didn't know about

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[Xulfiqar]

I've driven that kind of truck before, Bedford
The clutch was solid and the steering.... Meh.

Sat inside a FAW truck- much better lol.
It had synchronizers- so no double clutching, cannot remember how many gears, but it had a little shift button behind gear level for hi/low gears.
A bonus was that it had cruise control- which the wapda driver didn't know about

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that button is the gear split - it forces the transmission to go into double reduction. did the truck have a shift plate riveted to the dashboard too?

[Xulfiqar]

can we get that powerband in the lower rpm range by changing the camshaft

sorry missed this post.

you cannot apply this "fix" if your engine design is not torquey e.g. oversquare engine.

[saboor73]

CRZ manual is very less fuel efficient than automatic Prius.

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bcoz crz is tunned for power not for economy

[saboor73]

drive an manual car at speed of 50km/h on bright in decline position with out pressing clutch and pressing accelerator you will get your ans

[faiz.aslam.121]

that button is the gear split - it forces the transmission to go into double reduction. did the truck have a shift plate riveted to the dashboard too?

I honestly cannot remember, lemme find a picture

[sami_voodoo]

sorry missed this post.

you cannot apply this "fix" if your engine design is not torquey e.g. oversquare engine.

Why would an oversquare engine not produce the same torque as an undersquare engine (for the same displacement)? As for low RPM torque, as far as I know, it's more a dependent on cam timing and lift and intake runner length than the engine bore/stroke ratio.

[ahmed.xohaib]

in automatic car automatic gears run due to hydraulic pump that hydraulic pump needs some power that power comes from crankshaft so due to which another load is applied on engine as there is no other source for providing power except engine...... thats why auto cars have less milage than manual....................