Why Manual cars are more fuel efficient than automatic?

[autotranny]

what is the ideal RPM for an automatic car at idle ? 800, 1000 or less and if one tunes the engine so that it runs on low RPM's while in idle (say 300) does that effect the fuel economy i.e. does that make the car more fuel efficient ?

[Xulfiqar]

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.

torque is what moves you, a longer stroke also creates a longer "TDC" time which translates as more punch aka more pedalling power to the crank. under square engines have longer con rods too and wider crank throws all the merrier for the moment arm. The downside is that such engines are quite fat and do not want to rev easily.

shorter stroke also equates to less duration from tdc to bdc which leads to low vacuum signal activity in the intake - thats why all manufacturers tune the cams of such engines for high rpm breathing. The whole result is that the shine at high rpm

[Xulfiqar]

what is the ideal RPM for an automatic car at idle ? 800, 1000 or less and if one tunes the engine so that it runs on low RPM's while in idle (say 300) does that effect the fuel economy i.e. does that make the car more fuel efficient ?

this is highly dependant on the engine and the stall speed of the torque converter.

[capsat]

what is OVER SQUARE aur UNDER SQUARE engine educate me in desi zaban please @xufliqar :D

[imrananr]

what is OVER SQUARE aur UNDER SQUARE engine educate me in desi zaban please @xufliqar :D

Engine cylinder bore to stroke ratio.
In sports cars we have greater bore size than the stroke.
Normally, the piston stroke length is greater than the bore size. The greater the length of stroke the lesser the engine rpm and vice versa.

[capsat]

Engine cylinder bore to stroke ratio.
In sports cars we have greater bore size than the stroke.
Normally, the piston stroke length is greater than the bore size. The greater the length of stroke the lesser the engine rpm and vice versa.

this is already in #42 , explain it in URDU please

[Xulfiqar]

pistun ke umoodi harkat ka kul fasla agar uss ke qatr se kam ho tau aisay engine ko "oversquare" kehtay hain - iss ke barr akss agar umoodi harkat ka fasla piston ke kull qatr se zyada ho tau aisay engine ko undersquare ke ism se pehchana jaata hai.

oversquare engine mein taaqat zyada paida nahin hotee kum chakar pe kyunke piston apni umoodi hudd pe zyada der therta nahin hai ke uss waqt uss ko poori dehen ki taaqat ka saamna ho - iss ke ilawa aisay engine ki piston ko crank se munsalik karne ki dandee bhi kum qadd ki hotee hain - yeh kum qadd ki dandee ki waja se crank pahiya pe chota ya kum moment arm ka asr hot hai jiss se kam natieejatun taaqat miltee hai.

aisay engine ka faida ye hota hai ke iss ki zindagi khaasi lambee hoti hai kyunke piston ki kull bahisaab raftaar kum rehtee hai banisbat crank ke pahiye se jiss ka nateeja kum vibration (please help me here with correct word) aur piston ki golaee barqrar rehna kyunke iss ko eik tarfa dhakka nahin lagta.

I had a meetha paan and thought this up - kaisa?

[abc01]

Thurthale for vibration in urdu

[capsat]

pistun ke umoodi harkat ka kul fasla agar uss ke qatr se kam ho tau aisay engine ko "oversquare" kehtay hain - iss ke barr akss agar umoodi harkat ka fasla piston ke kull qatr se zyada ho tau aisay engine ko oversquare ke ism se pehchana jaata hai.

oversquare engine mein taaqat zyada paida nahin hotee kum chakar pe kyunke piston apni umoodi hudd pe zyada der therta nahin hai ke uss waqt uss ko poori dehen ki taaqat ka saamna ho - iss ke ilawa aisay engine ki piston ko crank se munsalik karne ki dandee bhi kum qadd ki hotee hain - yeh kum qadd ki dandee ki waja se crank pahiya pe chota ya kum moment arm ka asr hot hai jiss se kam natieejatun taaqat miltee hai.

aisay engine ka faida ye hota hai ke iss ki zindagi khaasi lambee hoti hai kyunke piston ki kull bahisaab raftaar kum rehtee hai banisbat crank ke pahiye se jiss ka nateeja kum vibration (please help me here with correct word) aur piston ki golaee barqrar rehna kyunke iss ko eik tarfa dhakka nahin lagta.

I had a meetha paan and thought this up - kaisa?

shukreeya aab samhaj aa gaya @Xulifiqar

[imrananr]

this is already in #42 , explain it in URDU please

Over square engine: iss terha kay engine main cylinder bore ka size piston stroke (TDC sey BDC) sey ziyada hota hai. Matlab cylinder bore ka diameter piston ke length of stroke sey ziyada hota hai. (Small connecting rod length but big diameter of piston)

Under square engine: iss terha kay engine main cylinder ka bore ya phir diameter length of stroke sey kam hota hai. (Long connecting rod length making stroke longer than size of piston head ).

[syncview]

pistun ke umoodi harkat ka kul fasla agar uss ke qatr se kam ho tau aisay engine ko "oversquare" kehtay hain - iss ke barr akss agar umoodi harkat ka fasla piston ke kull qatr se zyada ho tau aisay engine ko oversquare ke ism se pehchana jaata hai.

oversquare engine mein taaqat zyada paida nahin hotee kum chakar pe kyunke piston apni umoodi hudd pe zyada der therta nahin hai ke uss waqt uss ko poori dehen ki taaqat ka saamna ho - iss ke ilawa aisay engine ki piston ko crank se munsalik karne ki dandee bhi kum qadd ki hotee hain - yeh kum qadd ki dandee ki waja se crank pahiya pe chota ya kum moment arm ka asr hot hai jiss se kam natieejatun taaqat miltee hai.

aisay engine ka faida ye hota hai ke iss ki zindagi khaasi lambee hoti hai kyunke piston ki kull bahisaab raftaar kum rehtee hai banisbat crank ke pahiye se jiss ka nateeja kum vibration (please help me here with correct word) aur piston ki golaee barqrar rehna kyunke iss ko eik tarfa dhakka nahin lagta.

I had a meetha paan and thought this up - kaisa?

I'm wondering what if it was a khushboo wala paan. . . . . . . . . . . . . .

[argtr65]

pistun ke umoodi harkat ka kul fasla agar uss ke qatr se kam ho tau aisay engine ko "oversquare" kehtay hain - iss ke barr akss agar umoodi harkat ka fasla piston ke kull qatr se zyada ho tau aisay engine ko oversquare ke ism se pehchana jaata hai.

oversquare engine mein taaqat zyada paida nahin hotee kum chakar pe kyunke piston apni umoodi hudd pe zyada der therta nahin hai ke uss waqt uss ko poori dehen ki taaqat ka saamna ho - iss ke ilawa aisay engine ki piston ko crank se munsalik karne ki dandee bhi kum qadd ki hotee hain - yeh kum qadd ki dandee ki waja se crank pahiya pe chota ya kum moment arm ka asr hot hai jiss se kam natieejatun taaqat miltee hai.

aisay engine ka faida ye hota hai ke iss ki zindagi khaasi lambee hoti hai kyunke piston ki kull bahisaab raftaar kum rehtee hai banisbat crank ke pahiye se jiss ka nateeja kum vibration (please help me here with correct word) aur piston ki golaee barqrar rehna kyunke iss ko eik tarfa dhakka nahin lagta.

I had a meetha paan and thought this up - kaisa?

Irteaush;)

[autotranny]

this is highly dependant on the engine and the stall speed of the torque converter.

OK thanks. so the engine in questions is of SE saloon 2005. Don't know about the stall speed though.

[waqasjamil]

Auto is more fuel efficient if compared to the same cc car

[Xulfiqar]

Auto is more fuel efficient if compared to the same cc car

If you consider auto to be more fuel efficient, I would really want to know what are you referring to when you say "auto"

[Xulfiqar]

Auto is more fuel efficient if compared to the same cc car

your car's engine cannot idle smoothly at anything below 800 rpm, adjusting it lower will also cause the the transmission pump to slow down, its a pretty useless exercise.

[Driver41]

pistun ke umoodi harkat ka kul fasla agar uss ke qatr se kam ho tau aisay engine ko "oversquare" kehtay hain - iss ke barr akss agar umoodi harkat ka fasla piston ke kull qatr se zyada ho tau aisay engine ko undersquare ke ism se pehchana jaata hai.

oversquare engine mein taaqat zyada paida nahin hotee kum chakar pe kyunke piston apni umoodi hudd pe zyada der therta nahin hai ke uss waqt uss ko poori dehen ki taaqat ka saamna ho - iss ke ilawa aisay engine ki piston ko crank se munsalik karne ki dandee bhi kum qadd ki hotee hain - yeh kum qadd ki dandee ki waja se crank pahiya pe chota ya kum moment arm ka asr hot hai jiss se kam natieejatun taaqat miltee hai.

aisay engine ka faida ye hota hai ke iss ki zindagi khaasi lambee hoti hai kyunke piston ki kull bahisaab raftaar kum rehtee hai banisbat crank ke pahiye se jiss ka nateeja kum vibration (please help me here with correct word) aur piston ki golaee barqrar rehna kyunke iss ko eik tarfa dhakka nahin lagta.

I had a meetha paan and thought this up - kaisa?

Boht he ala xulfiqar bhai Signed in just to appreciate ur comment!

[muradi]

Auto is more fuel efficient if compared to the same cc car

depends totally on driving style bro, but in reality manual is much fuel efficient than Auto

[imrananr]

depends totally on driving style bro, but in reality manual is much fuel efficient than Auto

Your right Murad, but we will call it slight difference with manual being more fuel efficient.
I the torque converter taking up some part of the kinetic energy for the fluid to keep the system running I guess.

[Proverbial_Slang]

Boht he ala xulfiqar bhai Signed in just to appreciate ur comment!

pistun ke umoodi harkat ka kul fasla agar uss ke qatr se kam ho tau aisay engine ko "oversquare" kehtay hain - iss ke barr akss agar umoodi harkat ka fasla piston ke kull qatr se zyada ho tau aisay engine ko undersquare ke ism se pehchana jaata hai.

oversquare engine mein taaqat zyada paida nahin hotee kum chakar pe kyunke piston apni umoodi hudd pe zyada der therta nahin hai ke uss waqt uss ko poori dehen ki taaqat ka saamna ho - iss ke ilawa aisay engine ki piston ko crank se munsalik karne ki dandee bhi kum qadd ki hotee hain - yeh kum qadd ki dandee ki waja se crank pahiya pe chota ya kum moment arm ka asr hot hai jiss se kam natieejatun taaqat miltee hai.

aisay engine ka faida ye hota hai ke iss ki zindagi khaasi lambee hoti hai kyunke piston ki kull bahisaab raftaar kum rehtee hai banisbat crank ke pahiye se jiss ka nateeja kum vibration (please help me here with correct word) aur piston ki golaee barqrar rehna kyunke iss ko eik tarfa dhakka nahin lagta.

I had a meetha paan and thought this up - kaisa?

Epic!!!

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