Are high RPMs bad for a turbo diesel?

Sobanek · 13-07-2011 07:52PM #1

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 · 13-07-2011 07:55PM

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

Sobanek · 13-07-2011 07:57PM

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 · 13-07-2011 07:57PM

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 · 13-07-2011 08:29PM

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 · 13-07-2011 08:37PM

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 · 13-07-2011 08:37PM

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 · 13-07-2011 09:34PM

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

No point in revving the shít out of it.

unkel · 13-07-2011 09:49PM

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!

13-07-2011 09:51PM

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 · 13-07-2011 09:53PM

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 · 13-07-2011 09:54PM

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 · 13-07-2011 09:56PM

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 · 13-07-2011 10:01PM

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 · 13-07-2011 10:02PM

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 · 13-07-2011 10:11PM

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 · 13-07-2011 10:13PM

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 · 13-07-2011 10:13PM

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 · 13-07-2011 10:20PM

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 · 13-07-2011 10:24PM

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 · 13-07-2011 10:38PM

harder the better!!!!

bigroad · 13-07-2011 10:52PM

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.

13-07-2011 10:56PM

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

bigroad · 13-07-2011 11:10PM

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.

13-07-2011 11:17PM

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

dr.fuzzenstein · 13-07-2011 11:28PM

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 · 13-07-2011 11:37PM

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 · 13-07-2011 11:44PM

dr.fuzzenstein wrote: »

Had a Focus TDDI with variable valve timing...

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

Senna · 13-07-2011 11:45PM

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 · 13-07-2011 11:59PM

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 · 14-07-2011 12:13AM

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.

Are high RPMs bad for a turbo diesel?

Comments