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In the broad spectrum of cars, there's higher end models with sport-focused engines. Examples would be an BMW M3, and even more so Ferraris and Koenigseggs etc. Apparently they're more fussy, in that new cars need a careful run in, special oil, etc.

Given that they often have a huge swathe of torque, you can get away with minimal throttle and low RPMs for conservative road driving. Question is, is this ok?

I've heard that these cars "need" to be driven hard occasionally, i.e. an "Italian tune-up" and all that. Granted, there's the ulterior motive of actually using the car to its full potential. One owner wrote on a forum that after taking his BMW M5 to the track, the exhaust pipe was nicely cleaned out and it was a smoother drive on the way back.

Along with clearing out carbon build up from low temperature and low airflow usage, another issue might be optimal RPM for piston and head life. An engine might be so optimised for performance at 8,000 RPM, that driving it at 1,500 RPM long term, though very doable, could result in extra engine wear.

Is there any truth in that? Perhaps there are certain sports cars that do need this "Italian" treatment?

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2 Answers 2

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DISCLAIMER: This is one of those questions where you are going to get a ton of opinion and speculation, and my reply will have some of that in it as well.

I think there is a lot of myth out there about what cars actually need to maintain them as they are and should be. For instance, your comment about the M5 owner. The entire statement is about seat of the pants performance check. It could be that the driver was very excited, still hyped on adrenalin, and it felt better to him because he felt better. On the other hand there is some basis of truth, depending on the driving habits of the individual involved.

It is good for any vehicle to be driven for an extended period of time. If the engine and components are not given a chance to warm up thoroughly, you'll find that carbon build-up and moisture will be left behind where you really don't want it to occur (in the oil and crank case most notably). Does this mean you need to once in a while drive the performance vehicle like a raped banshee to "clean the carbon out"? Not at all. If the car is ran up to operating temperature on a regular basis (a minimum of once a month) and driven for a good set of miles (30+), you should have no issue with the car other than normal maintenance and should expect the vehicle to perform when you want it to perform.

Even if it were true, what would be the maintenance interval and specifications for an "Italian Tuneup"? Do you roast the rear tires once a month? Twice a month? Is driving at 150mph what needs to happen? And for how long? What should you do to achieve this "blowing out the carbon" and getting your high performance sports car to a proper tune? I hope you see the problem with this, because there isn't any correct answer. It all comes from seat of the pants tuning, which isn't accurate, to say the least. People will tell you this must be done so as to give themselves a reason to drive their vehicle to the extreme of their vehicle's ability. This is one of the two reasons to have bought the vehicle in the first place (the other reason is for the bragging rights). Something you'll find, though, is owners of these higher performance vehicles are not content with "normal driving". It is way too easy and exhibits way too much fun to be able to drive such a car at the performance level it was designed. This is the reason you purchase something like this in the first place. Most owners of such vehicles will give it the Italian Tuneup on a regular basis, just because they can.

What it boils down to is this: Give me some empirical evidence an "Italian Tuneup" is needed to maintain the proper running of a vehicle and I'll believe it. Until then, I'll stick with what I know, which is, proper maintenance and regular driving is all you need and the vehicle, no matter what vehicle, will be just fine.

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Good answer. I guess the uncertainty lies around the "operating temperature". Yes you have the cooling system temp, though for a given cooling system temp my understanding is that you could have a significant range of temps of the engine internals. I think it's possible that the engineers could design an engine for which the proper operating temperature, for internal carbon buildup prevention, is actually quite hot due to "spirited driving". I'm still learning about mechanics, but would that be reasonable? –  andrewb Jun 2 at 0:02
    
Spirited driving should not increase the combustion temperatures appreciably on normally aspirated engines. Forced induction engines (turbo or blown) may increase combustion temps, but only if driven exceptionally hard for a long period of time. Combustion temps are controlled if for the only reason so as to keep NOx emissions lower, which is a by-product of high exhaust temps. This would be a design limitation, an intentional means by which to reduce or eliminate this. Not a perfect answer, but it is what it is. –  Paulster2 Jun 2 at 0:19
    
Ah right, so would that mean that harder driving doesn't require the radiator (fan) to work significantly harder? –  andrewb Jun 2 at 22:21
    
Depending on what you mean by harder driving (speed v. auto cross, for instance). At a certain speed (35mph I believe?) the fan becomes moot because the air moving over the radiator exceeds what the fan can move. Again, manufactures usually engineer more than enough cooling capacity into their cars. Only when a vehicle is modified or when parts start to fail (such as the radiator becoming clogged) might it come into play. –  Paulster2 Jun 2 at 23:15
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@andrewb ... It seems to me that fuel is primarily carbon based. If you have carbon build up it's because the engine is running in a rich condition. If the vehicle is tuned correctly, you shouldn't see these issues. Tuning includes the exhaust as well as what's in the computer. Seems to me who ever is doing the tuning for such a vehicle needs to go back to basics and do some work. If a V8 can support 1200 rwhp with a dual 3" exhaust without carbon build-up, I'm sure a GT-R v6 can manage with a single 3" exhaust and easily make the 600hp at the engine, but that is conjecture on my part. –  Paulster2 Jun 3 at 10:29

As asked, the question is highly subjective, and Paulster2 provides sound reasoning that makes it amply clear why.

In an effort to remain objective, I will stick with the example of the BMW M5 (which I own).


The source of the Italian tune-up myth pertaining to the E39 M5 is easily explained.

Every car has its quirks and design flaws and the M5 is no exception. The relevant design flaw in the S62 pertains to the secondary air tracts in the cylinder heads. These tracts are designed to reduce cold-start emissions by delivering extra air to the exhaust in order to help eliminate unburnt hydrocarbons and carbon monoxide. Over several years, unburnt hydrocarbons accumulate in these poorly designed tracts (a.k.a "carbon build-up"), clogging them and rendering the secondary air system ineffective.

The carbon build-up has two impacts:

  • It triggers a Check Engine Light/engine code

  • It worsens cold-start emissions (and makes the engine a lot noisier at startup)

In most cases, the former is more of a concern than the latter due to road permit regulations and owners' annoyance.

To delay the onset of this issue, the owners on some forums suggest to drive "spiritedly" from time to time to clear out these secondary air tracts. Since most people don't need a second invitation to drive such a car like they stole it, the notion of driving the M5 hard as preventive maintenance easily gained traction.

This particular issue has negligible impact on the S62's performance and life.


Carbon build-up aside, is it better for the engine run at max RPM than 1,500 RPM?

No. At least not in terms of longevity.

This is because most components in modern-day engines are designed to endure a certain number of cycles before failing. Running the engine at higher RPM reduces the time needed to achieve reach failure.

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Great post. I would suggest a Seafoam treatment on an M5 would be of more use than the "Italian Tuneup" ... –  Paulster2 Jun 1 at 14:35
    
@Paulster2 : What I understood from the forums is that even Seafoam has had limited success. I can post up some images of nasty carbon build-up when I get back home. –  Zaid Jun 1 at 15:01
    
If done correctly, Seafoam works wonders, but I'm not a BMW guy, so I will leave that commentary to your expertise. –  Paulster2 Jun 1 at 17:18
    
@Paulster2 : This is a thread showing the extreme carbon build-up in the S62. –  Zaid Jun 1 at 19:26
    
That is way beyond what an "Italian Tuneup" is going to clean up. That's just nasty. Hopefully BMW has figured it out and the newer engines don't have this problem. –  Paulster2 Jun 1 at 20:23

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