[nukeblitz]

I just can't help but notice that the vast majority of people don't use the rpm band over 4000. 4000 is a little high in the city but is rarely hit in overtaking maneuvers on the highway. Even, a lot the "fast" drivers don't.

The reason for this is that a lot of people shift when the engine sounds "bad" or "loud". Or have learnt in a tacholess car and use the speedo to shift.

So, IMO, low-range is important for the city, mid-range for the highway and high-range for the enthusiast. That also means that the vast majority will feel only low end and mid range grunt. If i were a manufacturer, i would try to design an engine with as much low and mid torque as possible at the expense of the top. I might even have a lower rev limit. It won't go down well with us non-enthusiasts but it'll certainly impress the regular joe.

The reason i even brought this up is that i have recently driven a honda city and the low end was just sad. I was on the highway and fe didn't matter. So, what do i do, i keep the revs between 3k and 5k. And ofcourse, the rest of the people in the car wanted to know how fast i was going and if i wanted to blow the engine. It took me a while to calm them down and explain stuff.
Now, all that got me wondering. There were other drivers in the car, and they probably haven't seen the wrong ride of 4k rpm. That means that they'll never be able to take advantage any free revving engine like the honda's with the peak torque being produced very late. Peak torque being produced very late is awesome as you'll be keep your engine in it's power band but useless for the regular joe.

So, why are manufacturers continuing to focus on that? The number of engines producing peak torque early is very low. I find that strange. Is it just the numbers you can advertise? Wouldn't having powerful low and midranges make the average customer feel that the car in question has more "pickup"? Sure, that'll mean that, on paper might produce less power than your competitor's...but that'll improve drivability and more people are looking for drivability rather than flat out acceleration, right? Sure, that'll definitely be bad news for most of us, but i find it interesting nonetheless.

Example. Fiat's old school 1.2l 8valve petrol engine makes a peak power of only 65bhp and a peak torque of only 96Nm. That's very low by today's standards. But it makes the peak torque at a lowly 2500 rpm. Which makes it perfectly drivable even though it's no scorcher. Now if same was made at 4500 rpm, i'd say it'd be very difficult to drive even though it'll be a litte better for raw acceleration. On the other end of scale, honda's 1.5 and 1.8 engines. Most of us know how pull all the horses out of them and they are brilliant for drags but won't the ugly low end put off a customer? (it normally doesn't cuz it's honda and customers don't case, but with new entrants coming in, it might soon)

[JustCause]

Originally Posted by nukeblitz

I just can't help but notice that the vast majority of people don't use the rpm band over 4000.............

>4K RPM is mostly useless for regular driving. A lot also depend on the engine characteristics too. A recent case in example is the Alto-800 V/S the Alto K10. While the K-Series motors have to be revved to extract the power, the humble 800cc is quite brilliant when it comes to pottering about in high gear.

Rev any of these engines above 3.5K & there is a profound Roar which passengers might equate with rash driving. Many long-term owner-drivers don't realize the importance of changing gear according to the immediate need. I have seen self proclaimed 'expert drivers' making an overtaking maneuver in 5th gear rather than downshifting to 4th, making minutes of what could've been seconds.

IIRC the OHC was offered in vanilla engine & the V-TEC version, & both were on sale simultaneously. So, an average Joe could opt for the vanilla version & save some cash while the one who seeks spirited driving could opt for the Hi-rev V-TEC.

And Hondas do have problems climbing higher gradients due to their low torque at low RPM. Even the Accord 2.4/Civic with so much power can't climb up to a hill resort & has to be revved at half clutch while the Maruti Esteem chugs away to glory almost effortlessly.

[srikanthns]

Couple this with the wrong tutoring given to you in the driving school, ie, shift to the higher gears at the earliest opportunity, so taught by gurus in the name of increasing FE! And most of the driving schools will have cars with no tachometer too. I myself learnt driving on the wrong side of forties and I was taught like the above only. SO the low end torque is the one needed for folks in city driving and the above 4k is really useless for most of city driving and about 50% of driving population (forgive my generalization, could not resist)

[DicKy]

It's not only the high sounding engine.
Mostly it is the FE bit that makes most drivers drive like that including myself.Part due to FE concerns and part due to the engine not run-in yet at that time.
I have never revved the engine sportingly and still continues to up shift early as possible and to chug along in a higher gear,even though my dad keeps on saying it does more harm to the engine in the long run.
On the other hand when my dad returns from abroad on vacation,he drives the car revving the engine to just when a sporty gnarling sound comes in and then shifts upwards. In short performance efficiency.
Well,as he is used to driving in Saudi Arabia ,he is more concerned about engine longevity than FE.
Another thing is many driver's are too lazy to down shift and want the engine to do the chugging.

[LNK]

Alright, here's a mildly related question I have. I'd posted it elsewhere but no response.

If an engine is not revved high for a long time, say for years, does the engine lose its potential by an amount? Like, if the car's always been driven around at <3.5k rpm, will it be an issue if all of a sudden I push it and maintain it at 4.5k or higher? In short, do engines get lazy like humans?

Originally Posted by JustCause

>
IIRC the OHC was offered in vanilla engine & the V-TEC version, & both were on sale simultaneously. So, an average Joe could opt for the vanilla version & save some cash while the one who seeks spirited driving could opt for the Hi-rev V-TEC.

I disagree with this specific comparison. The non vtec version is fun to drive too, very! Unless by "vanilla" you mean the smaller engine (1.3 in case of OHC) which is still an unfair comparison. That being said, the cars 1.5 and 1.3 were targeted at different audience. Not the 1.5 Vtec and 1.5 exi, in my humble opinion.

[nukeblitz]

Exactly, in the city low end torque is god. Even on the highway, it's midrange that's used by most people. Very few people use the high end even on the highways. Now we know that revving to the redline (post run in, ofcourse) is usually the way to go to extract the most out of the engine and even if we don't do it all the time, situations like overtaking with incoming traffic might call for something like that and we wouldn't be afraid to do so.

I didn't comment on fe considerations and about diesel mills.
So, here goes.

1. FE - most of us consider this at all times. And that's often a good reason not to race around redlining the engine. But consider this, in an emergency situation like the highway situation described above, we know there still a whole lot more left in the gear, and we would be ready to use it. And even if that's just an exception, it shows >4k is not useless to us. Still tho, apart from this small crosssection of people, most people still don't go that far.
There's a fairly amusing misconception that "high gear = higher speed" somewhat true, but still very amusing :-D

2. Diesels
>4k is usually pointless in a diesel as in most turbodiesels, torque drops off very rapidly after peak power is reached. Depending on the gear ratios, it's often smarter to shift up at that point as even the torque multiplier effect of lower gears doesn't compensate for the loss in power.
Even with that out of the way, 3k is what most people limit themselves to. I attribute this to diesels being noisier.
However, being in the proper gear is far more important for a diesel than for a petrol as the power band is much smaller. But doing so rewards you so much, especially on the highway.
Turbocharged engines (not just diesels) have an inherently powerful midrange which i feel is far more practical on a highway - it makes overtaking a breeze. And yet, i see people cruising at 60 in 5th in a diesel n pressing on the gas and trying to get past.


I'll go a little OFFTOPIC and share a little story to demonstrate this.
I was on the bang-hyd highway recently. I was in my vista tdi and i ran into this dzire petrol guy. Since the highway was mostly empty, the only way to keep yourself awake was some entertaining tandem driving. And well, it came down to a drag on a straight just for the kicks. It started at like 50kmph with both of up in third (am sure about the dzire too, only way it could have worked). My trusty vista actually kept up with the superior engine, even gaining a small lead till we hit 100 where my third gear ran out..but his didn't and he was gone. Sure, granted, if he started in 2nd instead of third, i wouldn't have had a chance, but anyway, getting back on topic, 50 to 100 km/hr is the most important overtaking speed on a highway. And the point of the story is that by being in the right gear i was able to keep with a petrol car with an undisputably better engine. In other words, shifting right in even a weak diesel would make even highway maneuvers a piece of cake, which most people don't and it turns into a case of "will he make it or will he not make it".

So, what would i do if i was a manufacturer? I'd put a smaller turbo, reduce lag, and try and reach max power by 3500 rpm. Most people don't care about what's after that anyway.

[gemithomas]

You should drive a FIAT 1.6 Engine to know what it really feels to be at >4K RPM.

I'm sure you'll never settle for anything less

[nukeblitz]

Actually, i take my trusty vista tdi all the way to 4500 rpm more often than i should.

If i had a palio 1.6...well, i'm pretty sure i won't be spending much time below 3k - not to mention i probably won't be eating much either cuz feeding the car would suddenly become a lot more important. Lol :-D

[rajushank84]

Originally Posted by nukeblitz

So, what would i do if i was a manufacturer? I'd put a smaller turbo, reduce lag, and try and reach max power by 3500 rpm. Most people don't care about what's after that anyway.

You just described Ford's TDCi engine. It is the perfect thing for the city, and is good on highways too up to 120kmph. After that, progress is slow.

Polo's diesel engine also feels very similar.

[1100D]

I find the 4k rpm of my new diesel vehicle pretty disturbing.

Infact even my old Fiat sees more RPM than that on regular driving.

Short shifting has FE benefits maybe, but then just saying bye-bye to the irritating traffic is also important.

What fun remains when you wait infinitely for speed to build up while overtaking a smoke belching cabbie driving at low speed high gear. Down shift, accelerate fast, and continue it to ensure that the offending vehicle does not come to trouble you for sometime, then get back to your low rpm driving.

According to me, one needs consistent torque across the rev range, low, medium or high.

[dr.dre]

SX4 1.6L feels at home around 4k rpm and in 5th gear one would be crusing at 100-120km/h, but then its so very difficult to maintain those revs on our roads. The power curve is ideal for most european speed limits.

[vinaydas]

4k+ for diesel engines are pointless as you are out of the power band.
But it is completely different for petrols. Drive a palio at 4k+ and you can hear the engine Roar with life.
The same goes for the Japs.

[AVR]

Originally Posted by LNK

If an engine is not revved high for a long time, say for years, does the engine lose its potential by an amount? Like, if the car's always been driven around at <3.5k rpm, will it be an issue if all of a sudden I push it and maintain it at 4.5k or higher? In short, do engines get lazy like humans?

I read somewhere that its advisable to rev it hard every few weeks just to keep the engine in good shape. Google "Italian tuneup"

Cheers,
Adi

[vivekgk]

I completely agree that most drivers don't rev the engine above 4K unless they're in a hurry. Recently, I was told by someone who works at Indus that the customers weren't fond of the new WagonR as it had 'no pulling'. Now this sounded weird to me, until I realized that those guys probably weren't bringing the car into its powerband, ever!

On the contrary, Alto K10 is considered peppy because it is auch a light car, and does fine even with the low torque that it makes at lower rpms.

[DicKy]

Originally Posted by AVR

I read somewhere that its advisable to rev it hard every few weeks just to keep the engine in good shape. Google "Italian tuneup"

Cheers,
Adi

Looked up at wikipedia.
Looks like my WagonR deserves it as it's being used sparingly and that too at low speeds.
Also read in a ' car maintenance ' that came with an old ACI that one had to make the car stretch it's legs once in a while.
But one doubt 'gurus'- does mpfi engines need this treatment?