"Ginagalit ang makina?"

**ebbfolls** · December 12th, 2004 08:25 AM

One does not need to look up the torque band data of a particular engine to drive the car properly. One only needs to have a seat of the pants feel for how the engine pulls as it revs through the rpm band.

Different engines are designed to produce maximum torque at different points in the rpm band. This depends on the application for which the engine is designed. For a sports car, the ideal engine would be something light yet capable of producing much power for its weight. For an industrial load hauler, on the other hand, the ideal engine should be one that does not need to be revved hard to be able to pull its cargo. As such, a sports car will best benefit from an engine that can rev high and produce its maximum torque at higher revs, while a diesel-powered people mover is best fitted with a low revving engine that will produce most of its torque in the lower rpm.

Of course, overall gearing (transmission gear ratio, differential gear ratio, and tire size) play an important role in the driveability of the vehicle. But an engine's torque curve is determined by the design of its intake and exhaust plumbing, and the profile of its cam. This is why you hear about "variable valve timing" and "variable intake plenum". This are methods/techniques used by engineers to make the engine as efficient at high and low rpm.

**Bogeyman** · December 12th, 2004 05:55 PM

Originally posted by OTEP
As posted earlier, the Mitsubishi 4d56 makes peak torque at around 2500 rpm.

You can use that as your shift point. Or if lightly loaded lang and you do not need much power, you can shift earlier.

That's exactly how I do it. Dahil dalawa lang kami ni misis sa byahe most of the time, I shift at 2000rpm. If there are two additional passengers on the second row seats, I shift at 2500rpm.

**quiksie** · December 18th, 2004 05:21 PM

Nakakatipid ba ng gas if you're always on neutral> Example is pag mabilis na speed mo ssa hi-way, neutral mo, pero nacalculate mo na yun speed mo and braking distance. Also pag slight downhill. Tapos engine brakes. Kasi dati ko pa ito ginagawa hindi ko lang alam kung nakatulong magsave ng gas. Minsan ko na rin lang galitin makina ko para makatipid sa gas, masama ba pag hindi mo ginagalit ang diesel engine.Mas magastos ba din sa gas pag nagengine brake ka?

**pink_cadillac** · December 18th, 2004 10:33 PM

4D56's shift well within 1500 to 2000 rpm. Whether its the turbo or non-turbo version torque peaks at 2000 rpm.

**jonvic** · December 19th, 2004 12:45 AM

Originally Posted by Ungas

Premature shifting with sufficient engine power for the upper gear can minimize fuel consumption. But inreturn, you alter your injection pump's timing slowly. You will feel its adjustment after 30k kms or more.

I am a newbie with diesel engines and I am not sure if I am guilty of this as I usually shift gears on the lower revs. I would just like to know how complicated is the process of adjusting the injection pump's timing. Like how long it will take and how much will be the cost.

Cheers!

**ebbfolls** · December 19th, 2004 12:51 AM

Originally Posted by quiksie

Nakakatipid ba ng gas if you're always on neutral> Example is pag mabilis na speed mo ssa hi-way, neutral mo, pero nacalculate mo na yun speed mo and braking distance. Also pag slight downhill. Tapos engine brakes. Kasi dati ko pa ito ginagawa hindi ko lang alam kung nakatulong magsave ng gas. Minsan ko na rin lang galitin makina ko para makatipid sa gas, masama ba pag hindi mo ginagalit ang diesel engine.Mas magastos ba din sa gas pag nagengine brake ka?

Unlike a gas fuel injected engine, you can save some fuel if you do not use engine braking. The reason being is that a diesel is constantly using fuel as long as it is running, except for C/R diesels which, I believe, behave like gas fuel injected engines. If your load is not that much, and if the incline is not that long, you can use the brakes alone to slow or stop the vehicle, provided you have disc brakes that are in good working order. Otherwise, you should not take chances in overheating the brakes by using the engine to help slow down your vehicle.

**JAYarc** · December 19th, 2004 02:00 AM

oo nga sa diesel just use ur brake and engine to slow down/stop, para makatipid just cruise at lower RPM as you can, unlike sa gas na paramakatipid lower RPM and smooth and lite trottle opening..tapuz smooth engine brake on downhill can save fuel due to vacuum effect on manifold.. >>hehe

**ebbfolls** · December 19th, 2004 05:06 AM

Originally Posted by JAYarc

oo nga sa diesel just use ur brake and engine to slow down/stop, para makatipid just cruise at lower RPM as you can, unlike sa gas na paramakatipid lower RPM and smooth and lite trottle opening..tapuz smooth engine brake on downhill can save fuel due to vacuum effect on manifold.. >>hehe

alright! hehehe.

**Ungas** · December 20th, 2004 08:28 PM

Originally Posted by jonvic

I am a newbie with diesel engines and I am not sure if I am guilty of this as I usually shift gears on the lower revs. I would just like to know how complicated is the process of adjusting the injection pump's timing. Like how long it will take and how much will be the cost.

Cheers!

Shifting prematurely with enough power to sustain higher gears are safe. What is not safe is when you force to shift prematurely where the engine vibrates excessively. Or run on higher gear after slowing down that the momentum is almost off.

**jojo_mouth2** · December 20th, 2004 09:23 PM

i have L200 wd 4d56 (dont have tacometer), i shift gear just a little above the "critical rpm" (when the engine shakes/vibrates) in order to attain 10-12km/L on city driving.