If i rev to 3.5krpm when pickup, is it bad ?

[Jchuacl]

I do 1-2-3-6. 8)

 

Typically I rev 5k for 1-2-3, and daily I rev to 8+k at least once when exiting into expressway.

 

And I thought I was weird to do 1-2-3-5.

 

[GoodCar]

Engine is designed to rev, so occasionally rev a bit to clear carbon is ok.

 

The other day friend ask me look after his 2.5L car for 2 days, can really feel the different between 2L and 2.5L.

 

The 2.5L rev a bit only pick up very fast, most of the time running between 1 to 2k rpm.

my 2L for normal driving rev between 1 to 3k rpm.

[GoodCar]

3.5K???

 

Redline is only 6.5K typical.

 

Can't be too bad what. It's considered normal. In fact, it's healthy for engine and gearbox.

 

I tried 5.5K from 1st to 2nd gear occassionally. No problem. Change ATF every year.

 

Autobox is normally killed by HEAT (frequently caught in slow moving traffic).

 

Engine is normally killed by under-revving (constantly driving/changing gear at low engine speed). Very few people can stand the sound and vibration at constant engine speed of >5K at prolonged period. Chances of wrecking an engine at too low rpm is higher than wrecking it at high rpm.

 

3.5K is also the rpm where the torque peaks for most engines.

 

Dun worry.

 

 

I always get caught in traffic Jam, should I change the ATF at a tigther schedule?

[Demodan]

3500rpm wor....becareful of vtec opening....500rpm more or so, depending on model and u be on ur way to vtec heaven

[Happily1986]

I feel that if you want to ensure optimal pickup you should go check out your car's engine torque curve. From standing, pickup depends on torque. In other words, you want the shove from the car's engine to be maximum. That is if you want the best possible pick up.

 

Nowadays alot of cars are designed to have the torque curve kick in at low revs e.g. 2.2k rpm. You would want the torque curve to know where the peak torque kicks in. For example, for the new generation Altis, it kicks in at 2.8k rpm. Basically if i rev to 3.5k rpm, it is wasted since max is only 140Nm of torque. i rev more but still the max is 140Nm.

 

Another thing is transmission efficiency. Unless yours is a semi auto using a dry clutch, i think most bread and butter autos are using hydraulics to transmit power in the transmission. I find that when i rev bloody high e.g. 4k~5k rpm vs 2.8k rpm, there is no practical difference. I feel that it is due to the formation of eddy currents within the transmission that causes transmission losses. Intuitively, if you suddenly rev sky high, the tendency to have eddy currents and the amount of hydraulic turbulence should be higher.

 

In other words, rev to whatever rpm your car's peak torque comes in. No point revving more than that.

[Happily1986]

Engine is designed to rev, so occasionally rev a bit to clear carbon is ok.

 

The other day friend ask me look after his 2.5L car for 2 days, can really feel the different between 2L and 2.5L.

 

The 2.5L rev a bit only pick up very fast, most of the time running between 1 to 2k rpm.

my 2L for normal driving rev between 1 to 3k rpm.

 

Reminds me of what fellow forummer Soya mentioned. Something along the lines of anything below 2.4 NA is underpowered.

 

I remember when i first started driving. WOW 1500cc in the G9 corolla seems powerful enough liao. Then during the holidays i drove a Grandis 2.4, rev like nobody's business. Feel the car was very underpowered. From then on, the G9 felt underpowered. And the current Altis felt lagi underpowered. [bigcry]

[Zippaboy]

Reminds me of what fellow forummer Soya mentioned. Something along the lines of anything below 2.4 NA is underpowered.

 

I remember when i first started driving. WOW 1500cc in the G9 corolla seems powerful enough liao. Then during the holidays i drove a Grandis 2.4, rev like nobody's business. Feel the car was very underpowered. From then on, the G9 felt underpowered. And the current Altis felt lagi underpowered. [bigcry]

 

after riding a 1000cc sportbikes, almost every car feels slow to me.

 

180bhp for 160+kg.

[Perc2161]

3.5K is nothing for the engine and transmission. If your engine and transmission can spoil because of the 3.5K RPM, then you should sue the manufacturer for making flawed products.

[Friendstar]

Reminds me of what fellow forummer Soya mentioned. Something along the lines of anything below 2.4 NA is underpowered.

 

I remember when i first started driving. WOW 1500cc in the G9 corolla seems powerful enough liao. Then during the holidays i drove a Grandis 2.4, rev like nobody's business. Feel the car was very underpowered. From then on, the G9 felt underpowered. And the current Altis felt lagi underpowered. [bigcry]

 

 

eh .... 2.4 grandis no power one, even though its a 2.4

 

cos of the MPV weight la and the engineering design

[Throttle2]

Find that the auto car slow in pickup, so either slowly let it pick up speed at 2krpm or rev harder to 3.5krpm where it change to next 2 gear

is it bad for engine, transmission in the long run?

 

 

erm, why is it bad?

i rev 3 - 4rpm just about every gear on a normal basis.

 

sweet...............

 

[Throttle2]

after riding a 1000cc sportbikes, almost every car feels slow to me.

 

180bhp for 160+kg.

 

 

yeah, but no basis for comparison although people like to compare 2 and 4 wheels all the time.

[Desmondtwb]

I feel that if you want to ensure optimal pickup you should go check out your car's engine torque curve. From standing, pickup depends on torque. In other words, you want the shove from the car's engine to be maximum. That is if you want the best possible pick up.

 

Nowadays alot of cars are designed to have the torque curve kick in at low revs e.g. 2.2k rpm. You would want the torque curve to know where the peak torque kicks in. For example, for the new generation Altis, it kicks in at 2.8k rpm. Basically if i rev to 3.5k rpm, it is wasted since max is only 140Nm of torque. i rev more but still the max is 140Nm.

 

Another thing is transmission efficiency. Unless yours is a semi auto using a dry clutch, i think most bread and butter autos are using hydraulics to transmit power in the transmission. I find that when i rev bloody high e.g. 4k~5k rpm vs 2.8k rpm, there is no practical difference. I feel that it is due to the formation of eddy currents within the transmission that causes transmission losses. Intuitively, if you suddenly rev sky high, the tendency to have eddy currents and the amount of hydraulic turbulence should be higher.

 

In other words, rev to whatever rpm your car's peak torque comes in. No point revving more than that.

 

Bro, from official specs the Altis seems to be at it's peak torque at 4.4k rpm.

 

Power 109bhp at 6000rpm

Torque 145Nm at 4400rpm

 

When you based max torque at 2.8k, is it based on feel or some sort of calculation?

I'm new at such car terms so can only rely on the official specs.

Please enlighten me :)

[Scion]

if u are too cautious, then dun rev too much in a 36degC hot day loh

[sly]

[Cerano]

Bro, from official specs the Altis seems to be at it's peak torque at 4.4k rpm.

 

Power 109bhp at 6000rpm

Torque 145Nm at 4400rpm

 

When you based max torque at 2.8k, is it based on feel or some sort of calculation?

I'm new at such car terms so can only rely on the official specs.

Please enlighten me :)

 

specs or dyno chart bro

[Ladykillerz]

rev 3.5k rpm is okay.

pro: faster

con: fuel

 

=p

[Krado]

3500rpm wor....becareful of vtec opening....500rpm more or so, depending on model and u be on ur way to vtec heaven

 

Huh? VTEC heaven? Can't feel the VTEC in my car at all, it lacks the VTEC "kick".

 

Maybe that's why my engine is classified as VTEC-E....... VTEC-Exhausted...

[Demodan]

not all vtec are created equal dude

http://en.wikipedia.org/wiki/VTEC#VTEC-E

[Happily1986]

Bro, from official specs the Altis seems to be at it's peak torque at 4.4k rpm.

 

Power 109bhp at 6000rpm

Torque 145Nm at 4400rpm

 

When you based max torque at 2.8k, is it based on feel or some sort of calculation?

I'm new at such car terms so can only rely on the official specs.

Please enlighten me :)

 

 

Oops paiseh, i am not sure how this value of 2800 rpm got planted in my head. But anyway i put the torque curve of the altis here.

 

 

i still maintain that even though acceleration is a function of engine power i.e. BHP/WHP, the thing that gets you moving from standby is torque. The torque is this shove you get when you floor the accelerator. And if your car is heavy e.g. > 1,100kg, the more important this "torque" plays in its role to get the car to move i.e. torque affects pickup.

 

By right in theory, i see the torque curve as attached, i should by right maintain at 4400rpm in order to get the max 140Nm of torque.

 

But actually there are other factors affecting pickup too which i have not mentioned. For example gear ratio. gear ratio can be thought as the ratio in size between your wheel and your gear. By right it should be the ratio between the number of "teeth" of two gears in comparison. But hey, the larger the wheel, the greater the number of teeth it would have so i think my rough analogy still counts.

 

But anyway the ratio is between your wheel and an imaginary "gear" since i think most gearboxes should be using interplanetary gears. Anyway cutting to the chase, the problem is when your gearbox has a tall or wide gear ratio for all your gears. That is, for a 4 speed auto, you have a specific gear ratio for every gear i.e. 1, 2, 3 and 4. If your gear ratio, you will observe the needle on the odometer drop alot when the auto gearbox shift up. But if your gear ratio is short, the drop is not that much. Short gear ratios are supposed to be better for acceleration. But sadly your gear ratios are fixed unless your car is on CVT.

 

Anyway i talk so much about gear ratio but essentially gear ratio is a factor affecting your pickup and there is nothing you can do about it haha except the peak torque stuff.

 

Hi everyone, what i wrote is my understanding and impression of how stuff works. if i am wrong in any sense just kindly point out. please dont flame.

Edited May 1, 2010 by Happily1986