how to prevent sudden jolt when shifting gears

[blink21me]

i'm not making it HARD for myself...
i'm making it EASIER for the thread-starter to understand..

and besides if sinabi kong "REV MATCHING lang yan" at naintindihan niya, hindi na siya dapat nagtanong in the first place.
hindi ko rin pala alam na may term na "rev matching"

Oh, ok,... I had just never heard of such term as "engine speed", "transmission speed", and "wheel speed" before, which made me think you're complicating things...

[rusem]

oooopsss, sorry I meant to say, "that is NOT true.... no gas is saved by shifting low..." Years ago I saw a thread in Team-Integra.net with charts, diagrams, numbers, etc, that monitored gas consumption in relation with driving in a certain rpm range ~ it proved that driving in the low end does not save you gas, in fact it eventually uses more gas, and that driving above 3,000 rpm consumes less gas on an ITR... I tried looking for that thread but couldn't find it...

ok, thanks... all this time since gas price skyrocketed, i was holding back in my driving... not anymore.

[wewoy_romero]

sorry, di ko naiintindihan yung mga rev matching, wheel speed, engine speed etc. lalo lang akong malilito hehe.

pero i'm doing what you guys suggested. slow release of the clutch and nawawala nga yung jolt.

question lang, if i slowly release the clutch, wouldn't this promote quicker wear of the clutch? nabasa ko kasi dito na parang 2 plates siya

http://auto.howstuffworks.com/clutch.htm


OT: talaga? i usually limit shifting to 2k rpm. parang sa lahat ng forums na nabasa ko, shifting at or below 2k rpm saves gas.

[XTO]

question lang, if i slowly release the clutch, wouldn't this promote quicker wear of the clutch? nabasa ko kasi dito na parang 2 plates siya

http://auto.howstuffworks.com/clutch.htm

tama kasi as long as naka-engaged ang clutch mo. re the two plates, it is
clutch disk itself and and pressure plate.

OT: talaga? i usually limit shifting to 2k rpm. parang sa lahat ng forums na nabasa ko, shifting at or below 2k rpm saves gas.

shifting lower than 2K rpm saves you more but depends sa engine capacity,
may mga engine na swabe pa rin even shifting at 1,5K rpm dapat 2K above.

[SpiritBeing]

clutch drop yata ang tawag dun kapag nag release ka ng clutch ng biglaan

[t_s_o_n_g]

Just my experience... you could really lower fuel consumption by shift gear at range of 1.5k to 2.5k rpms. I am driving from Manila to Calamba everyday. Before I usually change gear at 3k to 4k rpms. But this eat up lots of gas. Laging na ilaw yung fuel gauge pag-uwi ko to Manila na. Now I change my habit of changing gears to low rpms and I could really noticed na malaki yung na tipid sa gas. Kitang-kita sa fuel gauge ko. Pero yung na miss ko yung performance ng engine ko at 3k to 4k rpms. Sarap ng hataw. :-)

[ar_em18]

mga sirs, so ang adviseable rpm to shift gear is 2.5k-3k? tama po ba?

[spongee]

some stuffs that really do work for me:

1st..releasing the clutch gently BUT NOT slowly

2nd..i RELEASE the gas pedal when shifting gears then in syncrony stepping
on it before i release clutch fully..QUICK BUT SMOOTH just so i wont
compromise speed.
3rd..i DONT REV UP...i accelerate slowly and let the engine dictates me to
shift gears...i dont push the engine lalo na sa umaga when it's still cold.
4th..i think most females dont really give attention to rpms hehehe...
nadidistract lang ako pag tumitingin dun...I JUST FEEL MY ENGINE..
i just take note of my rpm pag erratic sha without me stepping on gas.

that's it...

[Yoda]

A lot of cars don't have tachs so sometimes it pays not to rely on them when it comes to shifting. Ewan ko lang kung standard na ito sa lahat ng mga latest models, hindi ko naman kayang bumili ng bagong modelo e. Just feel the engine. Don't let it lug and don't over rev.

[Syuryuken]

mga sirs, so ang adviseable rpm to shift gear is 2.5k-3k? tama po ba?

Depende pa rin sa engine. Sa akin bago mag 2,000 RPM shift na ko.

[chuaed]

Re: how to prevent sudden jolt when shifting gears

get an automatic

[puroy]

get an automatic

baka go back to automatic...:P

[rpm10]

Practice lang yan.ganyan din ako nung una.basta wag lang talaga biglang ire-release yung clutch.

Ewan ko lang kung totoo yung pag nag-shift ka sa 2k rpm tipid sa gas.ang alam ko kasi mas maaksaya yun sa gas kasi mahihirapan yung makina mo dahil na sa mataas na gear ka na, nasa 2k pa lang rpm mo.hindi match yung engine speed sa transmission speed.pero ako nag-shishift na ako at 2.5k-3k rpm.nag-shishift din ako sa redline paminsan-minsan hehehe.

Correct shifting:

1st gear = 0-20 kph
2nd gear = 20-40 kph
3rd gear = 40-60 kph
4th gear = 60-80 kph
5th gear = 80 kph-above

Yan ang magiging speed niyo kapag nag shift kayo every 3k rpm.try niyo.

[woohoo]

Practice lang yan.ganyan din ako nung una.basta wag lang talaga biglang ire-release yung clutch.

Ewan ko lang kung totoo yung pag nag-shift ka sa 2k rpm tipid sa gas.ang alam ko kasi mas maaksaya yun sa gas kasi mahihirapan yung makina mo dahil na sa mataas na gear ka na, nasa 2k pa lang rpm mo.hindi match yung engine speed sa transmission speed.pero ako nag-shishift na ako at 2.5k-3k rpm.nag-shishift din ako sa redline paminsan-minsan hehehe.

Correct shifting:

1st gear = 0-20 kph
2nd gear = 20-40 kph
3rd gear = 40-60 kph
4th gear = 60-80 kph
5th gear = 80 kph-above

Yan ang magiging speed niyo kapag nag shift kayo every 3k rpm.try niyo.

Hindi po applicable iyan sa lahat ng sasakyan. Magkakaiba ang gear ratios ng mga sasakyan.

[Alpha_One]

Practice lang yan.ganyan din ako nung una.basta wag lang talaga biglang ire-release yung clutch.

Ewan ko lang kung totoo yung pag nag-shift ka sa 2k rpm tipid sa gas.ang alam ko kasi mas maaksaya yun sa gas kasi mahihirapan yung makina mo dahil na sa mataas na gear ka na, nasa 2k pa lang rpm mo.hindi match yung engine speed sa transmission speed.pero ako nag-shishift na ako at 2.5k-3k rpm.nag-shishift din ako sa redline paminsan-minsan hehehe.

Correct shifting:

1st gear = 0-20 kph
2nd gear = 20-40 kph
3rd gear = 40-60 kph
4th gear = 60-80 kph
5th gear = 80 kph-above

Yan ang magiging speed niyo kapag nag shift kayo every 3k rpm.try niyo.

Errr... as the previous poster indicated this doesn't apply to all cars. Try this on a Toyota Revo and you'll be around 4k RPM before you get into top gear! Consult your manual for the recommended shift points.

Actually, at the same rate of acceleration less throttle at a lower gear (higher RPM) consumes more fuel than more throttle at a higher gear (lower RPM) - for two reasons:

1) Friction and rotational losses

As engine speed goes higher, the amount of energy spent to keep the engine turning around with all the rotating and reciprocating masses and parts sliding together becomes higher also. Ergo, at higher engine speeds the engine uses more of the fuel to keep itself running than at lower speeds. This is why lower RPMs are more efficient than higher RPMs.

2) Throttling losses

You can think of an internal combustion engine as a sort of an air pump, and with gasoline engines the less you press on the accelerator the more the throttle is blocking the intake to regulate power by preventing air and fuel from entering. Although there is less fuel being mixed due to less air being taken in, this blockage makes it harder for the engine to breathe. Consequently it takes more energy (which comes from fuel) to suck in fresh air from the intake. It sounds counter-intuitive, but the way gasoline engines work pressing more on the accelerator pedal is actually more efficient than easing off while accelerating (up to a point, more on that later).

Note that this does not necessarily apply to diesels. This is one reason (among others) why diesel engines - which are unthrottled - are more efficient than gasoline engines. At idle, where the throttle would be almost completely closed in a gas engine, diesels consume almost nothing in comparison. This is also why the engine braking effect is much more pronounced with gasoline engines especially when you immediately lift off the accelerator. Heck, the exhaust brake on bigger diesel engines use this same principle to introduce more engine braking, introducing pumping losses by blocking the exhaust.

Some gasoline engine designs, those with throttle-by-wire and variable valve timing actually take advantage of this during crusing. Instead of closing the throttle when the driver eases off the pedal, the car delays the closing of the intake valve to dump unused mixture back to the intake manifold instead, to be used at the next cycle. This minimizes the pumping losses during cruising when the throttle would be otherwise closed. Some BMW and Honda engines do this, and I believe the Atkinson (?) cycle hybrid gasoline engines too.

The most efficient way to accelerate a gas powered car is actually to use 70-80%* open throttle and work your way quickly through the gears, trying to keep the RPM low (1500-2500RPM). Though this loads the engine more at lower speeds, the frictional and pumping losses of the engine are optimised such that you're actually using less fuel to accelerate. When you get to top gear and at your desired cruising speed quickly back off the throttle and enjoy the drive.

Many (manual transmission, <=2k RPM shifting) drivers are actually not taking full advantage of the economy offered by the high gears giving low RPMs by, strangely enough, not using enough accelerator before getting to their cruising speed on the highway! Acceleration uses much fuel, and you want to get to cruising speed as quickly as possible, using the least amount of distance possible, at the most efficient operation of the engine as possible. Cruising uses minimal power (and consequently minimal fuel), hence the sooner you get to cruising, the longer the distance you spend doing so, and the more fuel you save. With the open throttle technique you also used the least amount of fuel to get the amount of kinetic energy for your cruising speed, at least with a gas powered car.

(Let me just qualify the last couple of paragraphs by stating that this only applies to M/Ts where the driver can tightly control the RPMs by shifting to higher gears sooner. A/Ts tend to downshift when you give it more throttle.)

Of course this doesn't work all the time - for example if you find yourself in top gear losing speed up a steep hill with the pedal to the floor - it would be wise to use common sense and downshift. Also don't go too low on the RPMs as to lug the engine, this is hard on your crank, and your oil pressure will drop to dangerously low levels increasing engine wear.

*Beyond a certain point the engine computer goes into "open-loop" mode, disregarding the input of the oxygen sensor in the exhaust, reducing the precision of the fuel delivery of the car which is bad for fuel economy. Many engines use extremely rich mixtures at wide open throttle also, in order to cool the engine in anticipation of high heat created by prolonged increased engine loading. Hence 70-80% is the most fuel efficient (per drop of fuel) point for most gas engines.

[tuwato]

^ depende din sa sasakyan. parang yung nakikita ko sa ibang sasakyan e hindi pa nakaka abante e shift na kaagad. siyempre wala pa bwelo at mahihirapan lalo yung makina. syempre pag nahirapan yung makina, mas malakas din paglaklak niya ng gasolina.

tsaka depende din kung diesel o gas. diesel kasi e torquey kaya di mo masyado kailangan ng bwelo. di gaya sa gasolina.

para di kumadyot, try mo mag double clutch para mag rev match and practice proper shifting.

[tuwato]

^ depende din sa sasakyan. parang yung nakikita ko sa ibang sasakyan e hindi pa nakaka abante e shift na kaagad. siyempre wala pa bwelo at mahihirapan lalo yung makina. syempre pag nahirapan yung makina, mas malakas din paglaklak niya ng gasolina.

tsaka depende din kung diesel o gas. diesel kasi e torquey kaya di mo masyado kailangan ng bwelo. di gaya sa gasolina.

para di kumadyot, try mo mag double clutch para mag rev match and practice proper shifting.