To rev or not to rev?

[Mr Darcy]

Hi all

I have a newbie question.

My car is 2009 E250 with 84,500 on the clock. I drive like I'm driving 'Miss Daisy' (if anyone remembers that movie). I keep the revs pretty much at around 1500-1800; only passes 2000 in low gears when driving away quickly, and seldom passes 2500. I drive this way because I want to look after my car, and also because it's just a nicer, smoother driving experience for me. I have heard on numerous occasions, however, that an engine needs to be run at fairly high revs every now and again just to 'blow out the cobwebs' (so to speak), otherwise there may be issues in the future with 'things' clogging up etc.

Now, to the question:
Should I be doing this with my car? Is this not something that is more necessary for a high performance/racing engine?

Thanks in advance for your advice.

 

[malcolm E53 AMG]

Each to their own I suppose on this issue but I do like to raise the revs every now and then it does tend to clear some of the soot away even on modern diesels, what I would say is make sure the engine is up to operating temperature revving a cold engine is the worst thing you can do.

Regarding petrol the current generation of direct injection engines do benefit from using higher revs regularly as there is no petrol to wash over the valve seats and they tend to gum up with carbon deposits - same rule applies above with engine temperature

 

[Blobcat]

Get it fully warmed up then give it the berries, it will thank you for it in the long run (it’s also (almost legal) fun…)

 

[kotecki]

Each to their own I suppose on this issue but I do like to raise the revs every now and then it does tend to clear some of the soot away even on modern diesels, what I would say is make sure the engine is up to operating temperature revving a cold engine is the worst thing you can do.

Regarding petrol the current generation of direct injection engines do benefit from using higher revs regularly as there is no petrol to wash over the valve seats and they tend to gum up with carbon deposits - same rule applies above with engine temperature

I agree Malcolm and the joy of a diesel is we cannot over-rev the beast. With a manual gearbox, we can floor the throttle and as soon as the governor cuts in, the car will not rev any higher

Going up a steep hill will usually see a lot of diesel-powered cars chucking out a lot of black smoke as drivers change down as they climb. This is because the engine is possibly revving higher than the driver usually revs the engine and out comes all that soot. Better out than in

 

[Mr Darcy]

Thanks folks for the input so far

 

[Chrishazle]

I normally drive the C220Cdi fairly conservativly, but hitting a motorway slip road (or other suitable bit of road) with a tailgater, I do enjoy flooring the throttle and clearing the soot out of the system - right into tailgater's windscreen! The acceleration of the diesel also surprises and annoys them, it's rather good when you give it beans!!

 

[mioba]

Drive how the road conditions dictate. I am a rather sedate driver and not heavy footed.
I do massage my ego very seldom and floor it on an open road when it is empty.

Drive how you are comfortable

 

[sausage]

There was an article on Autocar.com this week called "40 things to do to make your car last for ever". One of them was to use the upper rev range now and again. For exactly the reasons listed above. Don't over do it though.

 

[Mr Darcy]

There was an article on Autocar.com this week called "40 things to do to make your car last for ever". One of them was to use the upper rev range now and again. For exactly the reasons listed above. Don't over do it though.

Thanks Sausage. I'll check that article out. . . . . and there's no chance of me overdoing it!

 

[Mr Darcy]

Get it fully warmed up then give it the berries, it will thank you for it in the long run (it’s also (almost legal) fun…)

Thanks Blobcat. Re warming up the engine, I'm verging on neurotic about making sure about that!

 

[Blobcat]

Thanks Blobcat. Re warming up the engine, I'm verging on neurotic about making sure about that!

There‘s about 14,000 reasons why I fully warm my 911 up…

 

[Tony Dyson]

Hi all

I have a newbie question.

My car is 2009 E250 with 84,500 on the clock. I drive like I'm driving 'Miss Daisy' (if anyone remembers that movie). I keep the revs pretty much at around 1500-1800; only passes 2000 in low gears when driving away quickly, and seldom passes 2500. I drive this way because I want to look after my car, and also because it's just a nicer, smoother driving experience for me. I have heard on numerous occasions, however, that an engine needs to be run at fairly high revs every now and again just to 'blow out the cobwebs' (so to speak), otherwise there may be issues in the future with 'things' clogging up etc.

Now, to the question:
Should I be doing this with my car? Is this not something that is more necessary for a high performance/racing engine?

Thanks in advance for your advice.

Well I don't normally drive as fast as you! But once started I never turn the engine off or work it hard until it has reached operating temperature and done a few miles at that. The car regenerates the DPF as regular as clockwork and in doing so runs an exhaust temperature from the exhaust manifold through the turbo, cat and the DPF of some 700°C for around 20 Mins and that's enough to make mild steel or glass glow cherry red! so I doubt much else is going to survive that treatment that a mad quick blast on a motorway is going to pick up, as that temperature is reached by the post ignition injection of diesel directly into the cylinder, you get all the benefits (if any) of giving your car a thrashing without actually having to thrash it once every 3-400 Miles! All that's missing is a blowout of the gunk in the EGR tracts but that won't be achieved by either method.

 

[Botus]

Hi all

I have a newbie question.

My car is 2009 E250 with 84,500 on the clock. I drive like I'm driving 'Miss Daisy' (if anyone remembers that movie). I keep the revs pretty much at around 1500-1800; only passes 2000 in low gears when driving away quickly, and seldom passes 2500. I drive this way because I want to look after my car, and also because it's just a nicer, smoother driving experience for me. I have heard on numerous occasions, however, that an engine needs to be run at fairly high revs every now and again just to 'blow out the cobwebs' (so to speak), otherwise there may be issues in the future with 'things' clogging up etc.

Now, to the question:
Should I be doing this with my car? Is this not something that is more necessary for a high performance/racing engine?

Thanks in advance for your advice.

if its a petrol engine'd car you are damaging it - once fully warmed up and running good oil they need exercising - driving slowly will lead to engine damage because the gunk isn't removed and the piston rings won't be sealing like they should

if its a tractor they too need exercising but you'll be closer to it....

the phase Italian tune up is actually quite sensible

 

[sausage]

Thanks Sausage. I'll check that article out. . . . . and there's no chance of me overdoing it!

Link: https://www.msn.com/en-gb/cars/ownership/40-easy-ways-to-make-your-car-last-forever/ss-AAOG849

I didn't think it a brilliant article, but does mention using the upper rev range.

 

[kotecki]

I was not going to say this because everyone here has given excellent advice but..

In another life, I was given a 1600cc non-turbo, diesel dog-van. I hated that useless vehicle with a passion and I guess, being honest, I was determined to blow that engine up. It was just hopeless and I swear the floor under the throttle had a dent where my size 13 boot was always trying to push that throttle through the floor. I had a very, very large area to cover which meant a great deal of high-speed driving but I ended up with that useless van for 120000 miles and that useless Ford diesel never missed a beat. Yes, it was regularly serviced, but by crikey those miles were all mostly hard-earned. The governor stopped the thing from over-revving and once the governor cut in that vehicle would not go any faster and you simply had to change gear.

What I am perhaps suggesting is that I very much doubt that you will do any damage by occasionally 'clearing the tubes' of soot. More chance of losing performance if you drive it like Granny Smith,

On the older Mercedes and again speaking from experience, driving the car without giving it the occasional burst of high revs will do no harm. We had both the S210 and S211 320Cdi, my wife was the sole driver, an excellent, safe driver but I will diplomatically suggest, not the fastest of drivers!

 

[Mr Darcy]

Well I don't normally drive as fast as you! But once started I never turn the engine off or work it hard until it has reached operating temperature and done a few miles at that. The car regenerates the DPF as regular as clockwork and in doing so runs an exhaust temperature from the exhaust manifold through the turbo, cat and the DPF of some 700°C for around 20 Mins and that's enough to make mild steel or glass glow cherry red! so I doubt much else is going to survive that treatment that a mad quick blast on a motorway is going to pick up, as that temperature is reached by the post ignition injection of diesel directly into the cylinder, you get all the benefits (if any) of giving your car a thrashing without actually having to thrash it once every 3-400 Miles! All that's missing is a blowout of the gunk in the EGR tracts but that won't be achieved by either method.

Thanks Tony. Why do you not turn the engine off until it's reached operating temp??

 

[Mr Darcy]

I was not going to say this because everyone here has given excellent advice but..

In another life, I was given a 1600cc non-turbo, diesel dog-van. I hated that useless vehicle with a passion and I guess, being honest, I was determined to blow that engine up. It was just hopeless and I swear the floor under the throttle had a dent where my size 13 boot was always trying to push that throttle through the floor. I had a very, very large area to cover which meant a great deal of high-speed driving but I ended up with that useless van for 120000 miles and that useless Ford diesel never missed a beat. Yes, it was regularly serviced, but by crikey those miles were all mostly hard-earned. The governor stopped the thing from over-revving and once the governor cut in that vehicle would not go any faster and you simply had to change gear.

What I am perhaps suggesting is that I very much doubt that you will do any damage by occasionally 'clearing the tubes' of soot. More chance of losing performance if you drive it like Granny Smith,

On the older Mercedes and again speaking from experience, driving the car without giving it the occasional burst of high revs will do no harm. We had both the S210 and S211 320Cdi, my wife was the sole driver, an excellent, safe driver but I will diplomatically suggest, not the fastest of drivers!

A very good point . . . . and a funny story!

In point of fact, there are uphill stretches of road where, in order to overtake for example, it's impossible not to 'give it some beans'.

There has been excellent advice given here. Thanks all

 

[Tony Dyson]

Thanks Tony. Why do you not turn the engine off until it's reached operating temp??

That is a very good question and one I'll briefly try to answer!

1, The first is it was advice given to me by a trusted diesel mechanic in the 1980's which I never contested!
2, Efficient combustion is only achieved when the engine is at full operating temp, inefficient combustion can result in unburnt diesel leaking through with the exhaust gasses, contaminating that path and past the piston rings into the engine oil
3, Engine oil needs to be brought up to an operating temp as well to inhibit the development of fuel and exhaust gas deposits into acids that will attack all the surfaces that will come into contact with the oil.
4, Condensation and/or water vapours in the fuel, oil and open spaces within the engine also have to be burnt off for efficiency and corrosion reasons.

I'm sure there will be contributions from others more informed than me on this subject...

 

[kotecki]

That is a very good question and one I'll briefly try to answer!

1, The first is it was advice given to me by a trusted diesel mechanic in the 1980's which I never contested!
2, Efficient combustion is only achieved when the engine is at full operating temp, inefficient combustion can result in unburnt diesel leaking through with the exhaust gasses, contaminating that path and past the piston rings into the engine oil
3, Engine oil needs to be brought up to an operating temp as well to inhibit the development of fuel and exhaust gas deposits into acids that will attack all the surfaces that will come into contact with the oil.
4, Condensation and/or water vapours in the fuel, oil and open spaces within the engine also have to be burnt off for efficiency and corrosion reasons.

I'm sure there will be contributions from others more informed than me on this subject...

I wish my diesel dog van had complied with what your are saying but please,. please do not think I am disagreeing with you. That van was destined to annoy me. The pesky engine never missed a heart beat and most of its miles were hard earned with the pedal to the metal, and the heel to the steel!! It warmed up with me thrashing the living daylights out of it and when we got to the destination, that engine was immediately switched off!! Cool down, what cool down. Lucky I never drove one of the Audi Quattro's. Their turbo would have cooked the vehicle the first time I would have been behind the wheel.

 

[Mr Darcy]

That is a very good question and one I'll briefly try to answer!

1, The first is it was advice given to me by a trusted diesel mechanic in the 1980's which I never contested!
2, Efficient combustion is only achieved when the engine is at full operating temp, inefficient combustion can result in unburnt diesel leaking through with the exhaust gasses, contaminating that path and past the piston rings into the engine oil
3, Engine oil needs to be brought up to an operating temp as well to inhibit the development of fuel and exhaust gas deposits into acids that will attack all the surfaces that will come into contact with the oil.
4, Condensation and/or water vapours in the fuel, oil and open spaces within the engine also have to be burnt off for efficiency and corrosion reasons.

I'm sure there will be contributions from others more informed than me on this subject...

This certainly very informative (especially since I know very little about detailed workings of an engine!).

Forgive me if I'm being a bit thick, but I still haven't understood why after starting the engine it is not to be turned until operating temperature is reached?