Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 26th August 2011, 11:03   #76
Senior - BHPian
 
sagarpadaki's Avatar
 
Join Date: May 2010
Location: Bengaluru
Posts: 2,632
Thanked: 1,256 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

THUMB RULE- Never redline a diesel engine.Its harmful to it in long run.

Morover there is not point in revving i20 diesel upto 3.5K or 4K.Because the max torque is between 1750-2800 RPM.So anything above that will just strain the engine and you wont get any more power out of it since its already out of the power band.

Keep the engine on the boil between 1800 and 3000 RPM and you will enjoy the push in the seat and the massive acceleration.This is more enjoyable in a diesel than redlining effect ,which is suitable in a petrol engine
sagarpadaki is offline   (1) Thanks Reply With Quote
Old 26th August 2011, 11:10   #77
Senior - BHPian
 
download2live's Avatar
 
Join Date: Feb 2010
Location: Bangalore
Posts: 1,103
Thanked: 387 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

Quote:
Originally Posted by Kimified View Post
I had gone on a longish drive last weekend and i noticed that i shift well beyond 2.5rpm and sometimes do it at 3.5k or even 4k rpm

So, Will this high revv usage of the engine reduce the lifetime or cause any unwanted problems at a later stage ? I have never red lined it (The red line is at 4.8k rpm) but just wanted to get this thing clarified.

PS : Mods. I searched for this kind of thread, did not find one. Please merge it with the right thread if needed. Thanks.
You should have taken Ford Fiesta Petrol 1.6.
As others have said. Do not redline the diesel engine if you want to make it last real long.
download2live is offline   (1) Thanks Reply With Quote
Old 26th August 2011, 11:13   #78
BHPian
 
Join Date: Jan 2009
Location: Hyderabad/Mysor
Posts: 155
Thanked: 58 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

I'm very interested to know myself.

I have a tata indica vista tdi and there's an annoying amount of turbo lag. Also, the torque is not very peaky. It makes at 135Nm at 2500rpm and 110.8Nm at 4500rpm (going by manufacturer's values). This means that upshifting before 4500rpm has no performance benefits as the gear multiplication of torque outweighs any benefits of being near the torque peak of the rpm band (except maybe a little earlier the 4-5th shift - which, being around 140kph, is rather pointless)

So, if i'm in a hurry, i tend to hold the gear till atleast 4500. I hold it a little higher during the 1-2 shift and the 2-3 shift as the ratio drop is so high and then the 3-4 shift at just over 4500 at 100kph.

The red line is at 4800 or 4900 rpm - atleast that's as high as the engine goes in 1st and the parallax error due to the central instrument pod and the tiny tach makes an accurate reading to get...ugh.

And if i shift consistently like this, my city fe drops from 14.5 to 11.5! And I've gotten variations in my highway fe from 15 all the way to 21.

So, am i killing my engine? If yes, what would i have to get replaced/fixed/checked up?
nukeblitz is offline   Reply With Quote
Old 26th August 2011, 11:26   #79
Senior - BHPian
 
Join Date: Apr 2008
Location: Dombivli
Posts: 2,626
Thanked: 1,191 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

As long as you are not redlining it, I doubt if simply high-revving an engine would cause it to fail. After all it's capable of running at 4k, so why not? It is obvious that you are impervious to the side-effects of high-revving the engine, such as the fuel efficiency (or the increased noise).
honeybee is offline   (1) Thanks Reply With Quote
Old 26th August 2011, 11:43   #80
Newbie
 
Join Date: Jul 2006
Location: Delhi
Posts: 19
Thanked: Once
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

It isn't a problem if your driving on a lounge rout especially. Just dont rev high on a cold engine. It takes the oil a couple of seconds to build up pressure and circulate through out. So it puts extra pressure on the cyldinal walls, valves, bearings, etc.
nvdisdesi is offline   (1) Thanks Reply With Quote
Old 26th August 2011, 11:46   #81
Team-BHP Support
 
Akshay1234's Avatar
 
Join Date: Dec 2006
Location: Mumbai
Posts: 9,759
Thanked: 6,665 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

There should not be any issues if you continue driving the way you do. All I can recommend is that you maintain the car well and keep the service intervals regular. if you do drive like this all the time, then shifting to synthetic oil is a good idea, try Mobil 1 Delvac 1, and change it about every 8 months. If you continue to use mineral oil then change every 4.5-5k kms. As long as you maintain the engine well high revving it will not cause any issues.
Akshay1234 is offline   (4) Thanks Reply With Quote
Old 26th August 2011, 11:53   #82
BHPian
 
Join Date: Jan 2009
Location: Hyderabad/Mysor
Posts: 155
Thanked: 58 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

@honeybee

I do hope you are right. I can't see why a manufacturer would want to design a high
revving engine if it's going to blow up if you rev it high. Actually i can't even see why manufacturers are going in for these large bore, short stroke high revving engines even when they are catering to non-enthusiasts as that compromises low rpm torque when they know low and mid range rpms are where 90% of cars spend 90% of their time.

Oh, and on my vista tdi, max power is made it 4500rpm and that holds till 4600rpm after which it drops of rapidly towards the 4900rpm redline. Pardon my ignorance, but why is it okay to shift at peak power point as long as i'm not redlining it? AFAIK, the only thing that happens at redline is the fuel cut off. So, if 4900rpm is going to damage my engine, 4500rpm shouldn't be much better right? Or am i missing something here?

About the fe - well, if i have to go fast, i should be able to pull all the 70horses that tata claims out of the engine, right?

About the noise - the tdi is noisy as it is but it absolutely roars when revved. Call me weird but i absolutely love the roar! :-D

@akshay1234

Thanks! I'll change it to synthetic oil when i service my car next. Wanted to do so earlier but the service station had all sorts of weird issues with me getting my own oil. But now that my car's out of the primary warranty period, i could do that.

Oh, are there any other specific things that i should look out for or need to be replaced more often? I don't consistently high rev the engine though. I have only two driving modes - minimum throttle mode for the best fe and high rev mode if i'm in a hurry and i spend a fair bit of time in both...

Last edited by nukeblitz : 26th August 2011 at 12:05.
nukeblitz is offline   Reply With Quote
Old 26th August 2011, 11:57   #83
BHPian
 
lucifer1881's Avatar
 
Join Date: Mar 2011
Location: Hyderabad
Posts: 290
Thanked: 710 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

Don't all cars come with rev limiters these days? The fuel cuts off much before the danger zone. The only way you can actually make the engine rev beyond a safe rpm is by downshifting to 1st when you are doing above 100 and using engine braking to slow down. As long as you don't engage in such stuff, you should be fine.
lucifer1881 is offline   Reply With Quote
Old 26th August 2011, 12:45   #84
BHPian
 
Reality's Avatar
 
Join Date: Feb 2005
Location: Mumbai
Posts: 39
Thanked: 7 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

Quote:
Originally Posted by lucifer1881 View Post
Don't all cars come with rev limiters these days? The fuel cuts off much before the danger zone. The only way you can actually make the engine rev beyond a safe rpm is by downshifting to 1st when you are doing above 100 and using engine braking to slow down. As long as you don't engage in such stuff, you should be fine.
Which car can you downshift into 1st at 100kmph?
Reality is offline   Reply With Quote
Old 26th August 2011, 12:46   #85
Distinguished - BHPian
 
phamilyman's Avatar
 
Join Date: Jul 2007
Location: Gurgaon
Posts: 5,601
Thanked: 3,451 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

There's no such issue from the gear changes the revs you mentioned!

Though you should've clearly taken a Fiesta petrol for that kinda running
phamilyman is offline   (1) Thanks Reply With Quote
Old 26th August 2011, 13:05   #86
Team-BHP Support
 
.anshuman's Avatar
 
Join Date: Dec 2004
Location: Good-Gaon
Posts: 7,708
Thanked: 8,929 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

Quote:
Originally Posted by Kimified View Post
I have a i20 Diesel which i have been using from the past 9 months. I absolutely love the engine. Being a diesel, Its still quite Rev happy.
i20's CRDi engine is a comparatively revv happy engine, i rate it as the best Diesel engine amongst all the hatchbacks we have here.


Quote:
So, Will this high revv usage of the engine reduce the lifetime or cause any unwanted problems at a later stage ? I have never red lined it (The red line is at 4.8k rpm) but just wanted to get this thing clarified.
Petrol or Diesel revving an engine hard constantly does increase the rate of wear and tear, except this there is no harm i see in revving an engine. i20's CRDi loves to be revved enjoy it, however the sweet spot for most Diesels is between 2-3k RPM where they make most torque.


Quote:
Originally Posted by sagarpadaki View Post
THUMB RULE- Never redline a diesel engine.Its harmful to it in long run.
Why only Diesels? Revving a Petrol also does increase rate of wear and tear.

Quote:
Morover there is not point in revving i20 diesel upto 3.5K or 4K.Because the max torque is between 1750-2800 RPM.So anything above that will just strain the engine and you wont get any more power out of it since its already out of the power band.
It's out of peak torque zone but is still in power zone, remember most Diesels make most power upwards of 4k RPM. I agree the best way to enjoy Diesels is to upshift early to keep it in peak torque zone.

Last edited by .anshuman : 26th August 2011 at 13:27. Reason: typo
.anshuman is offline   (1) Thanks Reply With Quote
Old 26th August 2011, 13:24   #87
Distinguished - BHPian
 
dhanushs's Avatar
 
Join Date: Oct 2009
Location: Bathery/BLR
Posts: 3,446
Thanked: 4,055 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

Quote:
Originally Posted by Kimified View Post
Now, Here is my Problem.
If its for the sheer fun of it, then the fun part of revvs in the i20 should not cause any issues.

Quote:
Originally Posted by .anshuman View Post
Why only Diesels? Revving a Petrol is also does increase rate of wear and tear.
Well, in the OP's case, there is no harm. But, if you consider wear and tear at similar redline for a diesel and a similar capacity petrol, IMO, the diesel will have more wear and tear. Reasons being: Heavier crankshaft, pistons and rods. Infact, I guess these are which prevent the diesel to revv high in the 1st place.
dhanushs is offline   (1) Thanks Reply With Quote
Old 26th August 2011, 13:45   #88
BHPian
 
Join Date: Jan 2009
Location: Hyderabad/Mysor
Posts: 155
Thanked: 58 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

Quote:
Originally Posted by .anshuman View Post
It's out of peak torque zone but is still in power zone, remember most Diesels make most power upwards of 4k RPM. I agree the best way to enjoy Diesels is to upshift early to keep it in peak torque zone.
I'll agree with you that might be the best way to enjoy a turbodiesel. But i don't think that would give the best acceleration. I'll give an example to explain why i think so.

I can't remember what the exact gear ratios are on the i20 crdi are but i'll take the first and second to be 3.42 and 1.95 and the final drive to be 4.4 (those are from my vista, but they should be fairly accurate for the i20 as it's the rpm drop that's important and, IIRC that's pretty close between these cars)

In first gear at 4000rpm, the engine is making 90ps of power. That means it's making around 160Nm of torque. Multiplying that by 3.42 and 4.4 to account for gear multiplication to get torque transmitted to wheels we get about 2400Nm (ignoring transmission losses of course).

If we shift to 2nd at this point, we fall to a shade below 2300rpm. At this rpm, we can assume that the engine is still making 220Nm. To get torque transmitted to wheels, we'll multiply it by 1.95 and 4.4. That gives us 1887.6Nm being transmitted to the wheels.

2400>1887.6 that means that upshifting at 4000rpm in first to second gear would still result in a major loss in power. Shifting early would be worse. So, from an acceleration point of view, it's mostly better to rev high than to shift early. Atleast that's what the math tells me. What do you people think?

Last edited by nukeblitz : 26th August 2011 at 14:08.
nukeblitz is offline   Reply With Quote
Old 26th August 2011, 14:13   #89
Team-BHP Support
 
.anshuman's Avatar
 
Join Date: Dec 2004
Location: Good-Gaon
Posts: 7,708
Thanked: 8,929 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

^^ For Max acceleration the engine will have to be revved till redline, upshifting early is obviously not recommended when max acceleration is required, for daily driving the sweet spot for most Diesels is 2-3k where the engine has more than enough grunt to accelerate hard yet deliver very good FE figures with lower wear and tear.
.anshuman is offline   Reply With Quote
Old 26th August 2011, 14:42   #90
BHPian
 
ghostrider's Avatar
 
Join Date: Jul 2008
Location: Bombay
Posts: 678
Thanked: 305 Times
Default Re: Does Revving the Engine consistently damage the engine on a longer run ?

Quote:
Originally Posted by sagarpadaki View Post
THUMB RULE- Never redline a diesel engine.Its harmful to it in long run.

Morover there is not point in revving i20 diesel upto 3.5K or 4K.Because the max torque is between 1750-2800 RPM.So anything above that will just strain the engine and you wont get any more power out of it since its already out of the power band.

Keep the engine on the boil between 1800 and 3000 RPM and you will enjoy the push in the seat and the massive acceleration.This is more enjoyable in a diesel than redlining effect ,which is suitable in a petrol engine
Sorry, wrong. You're confusing torque and BHP. The OP clearly gets his jollies from going as fast as he can do, and shifting at 3.5k or 4k is going to provide MUCH more acceleration than shifting at the revs you've mentioned. Just because an engine provides it's maximum torque within a particular rev-band, that doesnt mean there isn't more power to be had above that band.
ghostrider is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Is your kid as enthusiastic about cars as you!!! aryashiv1 Shifting gears 25 21st November 2013 15:24
Over revving MPFI Zen Engine( revv limiter doesnt cut at 6000 rpm!!) speedsatya Technical Stuff 4 30th October 2010 15:21
Ractive Tachometer 3.5'' does not cross 3000 RPM on Max Revv bugboy180 Modifications & Accessories 21 23rd January 2009 00:11
Are you an enthusiastic driver or a regular driver? mclaren1885 Shifting gears 51 27th November 2007 18:14
Over Enthusiastic Indica SLK Street Experiences 6 25th July 2004 14:25


All times are GMT +5.5. The time now is 05:54.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks