Are high RPMs bad for a turbo diesel?

Sobanek

My mother's complaining about me reving the diesel high (3500-4000rpm) before the gear change. Is it true that this will destroy the engine?..

Vicxas

I thought you had to rev the car high enough in TDI's? As they'res fook all power low revs.

Sobanek

Vicxas wrote: »

I thought you had to rev the car high enough in TDI's? As they'res fook all power low revs.

It's a TDCI (Ford, Peugeot, Volvo) engine. The car is a Volvo V50.

Mr. Manager

On my 1.9 TDI it's in the red at 5,000 RPM. Change gears at 2,000.

Plenty of power in the low revs

Henry Ford III

She's got a point O.P.

Depending on the capacity - 1.6 or 2.0 - there's little benefit changing up after peak torque. Infact you should feel the power dropping off.

EPM

I find little reason to rev above 3.5k even for overtaking. The power in mine drops after just over 4k so there's no point going higher. I do redline it every so often to clear the cobwebs out as I usually change just over 2.5k.

There's no need to stress a part when it's not giving anything back tbh.

Sobanek

Henry Ford III wrote: »

She's got a point O.P.

Depending on the capacity - 1.6 or 2.0 - there's little benefit changing up after peak torque. Infact you should feel the power dropping off.

2.0 D. 136 HP

flash1080

Diesels - high torque at low rpm, low torque at high rpm

No point in revving the shít out of it.

unkel

You need to shift up when the next gear would be in the maximum torque range. For a typical modern common rail diesel, this would be around the 1600-1800rpm range. So that means shifting up when you're doing not much more than 2500rpm

If you're block shifting (from 1st to 3rd or from 2nd to 4th, etc.) you might leave it a little later

Try it out for yourself after you looked up your torque curve online!

Vicxas

Vicxas wrote: »

I thought you had to rev the car high enough in TDI's? As they'res fook all power low revs.

Sweet Jesus that's one of the worst posts ever in here :pac:
'tis the opposite

vectra

Sobanek wrote: »

My mother's complaining about me reving the diesel high (3500-4000rpm) before the gear change. Is it true that this will destroy the engine?..

I would say constantly bringing any engine ( Petrol or diesel) to max revs befroe gearchange will do damage eventually.
Premature wear

TestTransmission

EPM wrote: »

I find little reason to rev above 3.5k even for overtaking. The power in mine drops after just over 4k so there's no point going higher. I do redline it every so often to clear the cobwebs out as I usually change just over 2.5k.

There's no need to stress a part when it's not giving anything back tbh.

God,it must be horrible to drive a diesel

dev100

Your mum sounds like a great woman. listen to her wisdom:)

You must screaming the poor engine. Less revving uses less diesel:)
Is your car lacking power that you need to rev that high?

dev100

TestTransmission wrote: »

God,it must be horrible to drive a diesel

Hop into a 320D older types had 150bhp newer ones even more
or a golf tdi 150bhp take either for a test drive. You wont find it a horrible experience:)

Well that is unless you a real petrol head with a high performance car then i bow to ya

unkel

TestTransmission wrote: »

God,it must be horrible to drive a diesel

In a petrol on the other hand - shifting up near the red line generally gives the best performance

JJJJNR

Actually changing gear on Diesels while revs are low is supposed to cause a lot of stress on the DMF, not sure how true it is but it make sense with all the failures around.

TestTransmission

dev100 wrote: »

or a golf tdi 150bhp take either for a test drive. You wont find it a horrible experience:)

ah lad,come on.

:pac::pac::pac::pac:

TDI POWER!!!!

EPM

TestTransmission wrote: »

God,it must be horrible to drive a diesel

What are you like since you got a rice cart:D

Only when you want to drive on. It's def not the same with a diesel unless for short blasts out of corners. For everyday motorway driving that I do it's the perfect tool.

tossy

TestTransmission wrote: »

God,it must be horrible to drive a diesel

Its a dirty dirty experience alright,no amount of hours curled up in a ball whimpering on the shower floor ever makes the hurt less!

GTE

I have always read topics like this end with the consensus that you shouldnt and you have no need to.

The engines are not meant to really like high reving but also lose the real meaningful power before then anyway.

My useable range is 1900 to about 3000. By 3000 revs and I shift up I think I am past 1900 so its fairly easy for me to always be in the power, I admit I dont have a crazy amount it despite my awe inspiring badge.
I dont see what people say about being in the right gear at the right time with diesels, its driving haha. Its only in roundabouts that i could see a careful thought being made on what gear to be in.

Anyway, red lining is pointless in a diesel in my opinion but as someone has already said, giving it a bit of consistent higher revs (not redline IMO) is good for the engine once in a while to get cobwebs out. Soot on the turbo vanes and the EGR valve for example. No need to know much about them but basically during use soot can stick to parts of the system and higher consistent revs can raise the temps in the engine system and burn the soot away. Perfectly fine.

My old driving conditions saw me doing a lot of regional and N road stuff and the turbo never really being used fully. So, changing at about 2000 all the time. On the motorway my particular car is at 3000rpm and the turbo is well whistling so its fine now.

I dont think going mad up the gears and ending up at 2000rpm in top gear is any good to clear the cobwebs. I would go up the gears normally but end up a gear lower then normal at higher consistent revs.

rs8

harder the better!!!!

bigroad

Diesels can go to their limiter and stay there as long as they want there is no harm done they are made this way with max revs 4500 or 5000 .tractors ,boat engine and older transits to name but a few .For the previous posters please read up on engines before posting silly comments from car mags .To the op drive a diesel the way you feel happy and enjoy no harm done .by the way i am a diesel mechanic.

^^^ surely as a diesel mechanic you can appreciate that there is no point in reving a diesel outside of the power band though?

bigroad

I agree about the power band ,but if a driver is overtaking and is in say 3rd gear at 3000rpm and does not hav time to wait for the 4th gear power band it is better to keep going to 4000 and pull in keep their on the steering wheel and indicator .job done .2000 revs is where the turbo is but older diesels did not have this power band so it was a case of drive it as hard as possible.vw 1.6 diesel was well able for revs and got smoother after 2500.

Very true, my ole E250 nasp had no power band at all really.

dr.fuzzenstein

Had a Focus TDDI with variable valve timing.
Completely gutless below 1800 rpm and lost all power above 4000.
So usable rev range was 2000-4000.
My current TDCI has pull from just above 1200 rpm and seems to pull all the way to the red line. Much better power band.
But really no point in revving it beyond 4000 anyway, there will be enough pull in the next gear.
And mostly change at 2500 rpm.
Diesels suit lazy driving based on torque, rather than pure revs like a petrol.
The GF drives an MX5, which burbles along nicely up to 4000, but rev it beyond and Mr Hyde comes out, screaming all the way to the red line. Fuuuuun!
Goes to show when she drives my car. trip computer tells me she gets 42-44 mpg, while I get 50-52, so revving it will guzzle juice with no real return.

bigroad

In the end of the day the power band stoke band might be gone at 3000 maybe 3500 but if you keep your foot on the floor the car will still be accelarate up to the limeter ,maybe not quiet as fast as before but it will still go.

Henry Ford III

dr.fuzzenstein wrote: »

Had a Focus TDDI with variable valve timing...

Wasn't Ti-vct a petrol engine thing only?

Senna

Might not be the case with these new diesel engines, but with the older ones i was always found it good to take them for a good hard spin (rev up to red line) every so often.

crosstownk

As stated in many earlier posts, on a modern TD changing at approx 2,000rpm is optimum for most driving conditions. Yes it may clog the DPF but they're designed to clog. A regen cycle will have to be done at some stage. There's no point in redlining a TD as torque drops off rapidly.

PaulKK

Personally, I drive my diesel in this fashion:

Normal driving, change up at approx 2k/2.5k rpm.

Brisk driving, change up at 3k/3.5k rpm.

Sometimes for overtaking and to clean out the cobwebs I'll bring her up to 4k, but its pointless going any further.

teednab-el

Slightly off topic but I hate the way they rev the sh*t out of diesel cars at the NCT centre. What exactly are they looking for, surely emissions can be detected at lower RPMs? I had a nct mechanic an a*shole rev my car about 4 times at max revs for a minute each time and I didnt even recognise my own car engine. It sounded very bad for a car that I keep very well. So wrong.

Sobanek

teednab-el wrote: »

Slightly off topic but I hate the way they rev the sh*t out of diesel cars at the NCT centre. What exactly are they looking for, surely emissions can be detected a t looer RPMs? I had a nct mechanic (a*shole) rev my car about 4 times at max revs for a minute each time and I didnt even recognise my own car engine. It sounded very bad for a car that I keep very well. So wrong.

I felt the same when the V50 was passing its first NCT.

R.O.R

I think there is a better chance of the emissions being lower the higher the engine temperature, so if it's not looking good at low revs the NCT guys will rev the balls off the engine to raise the temperature to give it a better chance of passing.

teednab-el

teednab-el wrote: »

Slightly off topic but I hate the way they rev the sh*t out of diesel cars at the NCT centre. What exactly are they looking for, surely emissions can be detected a t looer RPMs? I had a nct mechanic (a*shole) rev my car about 4 times at max revs for a minute each time and I didnt even recognise my own car engine. It sounded very bad for a car that I keep very well. So wrong.

R.O.R wrote: »

I think there is a better chance of the emissions being lower the higher the engine temperature, so if it's not looking good at low revs the NCT guys will rev the balls off the engine to raise the temperature to give it a better chance of passing.

The test states to being the diesel to the red line or rev limit whatever the term is. With a diesel the higher the revs the more smoke. Hardly the NCT staff's fault that they have to test the diesels this way.

Petrol cars are at idle and at 3000rpm ish iirc.

Mar4ix

my new vw polo i was unable rev more then 1.5 k., while parked.

keithclancy

The Volvo V50 2.0D Engines Turbo only kicks in at 1800 RPM and tops off at about 3200RPM.

I change at about 3000 driving briskly and about 2200 - 2500 driving to save fuel.

Depends on the engine really, but generally I'd change 3/4s of the way through the Turbo band.

Its what your used to I think, personally I think whatever is best for the job, i.e. 1.0Litre Petrol for around the City and a 2.0D for long distance.

Couldn't afford to run a Petrol, low road tax but 1.78 / liter, at 40,000km / year thats allot

snowman707

if you have yo look at the rev counter to a drive any vehicle you may as well return to the L plates

the rpm will depend on the circumstances, I find most small diesel engines are happy about 2500 rpm, larger ( tractors with different ratio gearboxes etc) about 1800 rpm , a 'happy ' engine will last longer and is far more fuel efficient


4000 rpm changing gear is idiotic

EPM

Mar4ix wrote: »

my new vw polo i was unable rev more then 1.5 k., while parked.

Yeah, 3k revs on mine and it wont go any higher.

keithclancy

snowman707 wrote: »

if you have yo look at the rev counter to a drive any vehicle you may as well return to the L plates

Handy to know so you have a reference point for what sounds like high revs.

Otherwise your just guessing

I.E. changing at 16000 - 17000 RPM on a 250CC inline 4 would be normal
Getting a 125CC two stroke moving requires about 8000 RPM.
A 1.9 TDI will take off without any throttle at 900-1000RPM
A 1 liter petrol requires around 2000 - 2500 to take off.

If none of them had rev counters and it was your first time driving it you wouldn't have a clue (especially with 2 stroke engines, sound like their going to blow up)

ThisRegard

Just as a matter of interest, what's the thinking behind dropping the clutch and revving just before changing gear in a modern car with a modern gearbox ? I understand it may be a throwback to older gearboxes but why do some young lads still do it who probably have never driven an older car, is it the sound they like ?

ShiresV2

ThisRegard wrote: »

Just as a matter of interest, what's the thinking behind dropping the clutch and revving just before changing gear in a modern car with a modern gearbox ? I understand it may be a throwback to older gearboxes but why do some young lads still do it who probably have never driven an older car, is it the sound they like ?

It's called rev-matching gear changes and you do it when going down the box. Makes for a smoother trip. Google it.

ThisRegard

I know what it is but with modern synchromesh there's no need for it or double clutching.

alanmc

keithclancy wrote: »

Handy to know so you have a reference point for what sounds like high revs.

Otherwise your just guessing

I.E. changing at 16000 - 17000 RPM on a 250CC inline 4 would be normal
Getting a 125CC two stroke moving requires about 8000 RPM.
A 1.9 TDI will take off without any throttle at 900-1000RPM
A 1 liter petrol requires around 2000 - 2500 to take off.

If none of them had rev counters and it was your first time driving it you wouldn't have a clue (especially with 2 stroke engines, sound like their going to blow up)

My first few cars didn't have rev counters.

Matt Simis

crosstownk wrote: »

As stated in many earlier posts, on a modern TD changing at approx 2,000rpm is optimum for most driving conditions. Yes it may clog the DPF but they're designed to clog. A regen cycle will have to be done at some stage. There's no point in redlining a TD as torque drops off rapidly.

Um, I find it hard to believe that changing gear at 2000RPM is "optimum" for anything other than saving fuel.
For fast driving you should change gear at 2/3 the max RPM for a diesel in my experience. On a 2.4JTD engine thats about 3800rpm, but its a lot less suck ass than more diesels.


The problem with changing low down on diesels wasnt clogging the DPF, it was causing excessive vibrations (on an already chuggy engine) to rapidly accelerate wear on the DMF (not DPF). Just cos you can change gear low doesnt in anyway mean you should.

Thatnastyboy

I dunno about those dirty muck burners,

but

I change gear at 9200rpm :P

Seriously though, the power range in a diesel is very short, but with huge amounts of torque. Wherever the power is, use that rev range.. simples.

I read a very good article explaining it all a while back ill try dig it out.

The article basically said, that if it was possible to get a diesel to make proper power efficiently and stay stable at high rpms, they would trounce any petrol engine..

But they can't, and won't!

ShiresV2

ThisRegard wrote: »

I know what it is but with modern synchromesh there's no need for it or double clutching.

It's not directly related to concepts like to synchromesh and double declutching. See here:

http://tinyurl.com/67k7qbs

MetzgerMeister

dev100 wrote: »

Well that is unless you a real petrol head with a high performance car then i bow to ya

He is

You may take a bow

keithclancy

alanmc wrote: »

My first few cars didn't have rev counters.

Of course ... then its trial and error, rev counter can be handy though.

I hopped on an Aprilia RS125 Extrema, stalled it about 7 or 8 times before I got it to even move

ThisRegard

ShiresV2 wrote: »

It's not directly related to concepts like to synchromesh and double declutching. See here:

http://tinyurl.com/67k7qbs

As I said, I know what it is, but on modern cars whilst just driving around changing gear at the appropriate time there's no need for it, unless you're into traffic light gran prix.

TestTransmission

einheisserschre wrote: »

dev100 wrote: »

Well that is unless you a real petrol head with a high performance car then i bow to ya

He is

You may take a bow

Lol,I luv you too