Fact or Fiction - The Italian Tune-Up

[Ron99]

Drive Blind said:

I also believe there's a benefit to giving the brakes a good work out too.

I agree.
As mentioned earlier, my wife drives fairly gently and one of my wife's cars which is used only about once per week will need a major brake overhaul for next MoT due to corrosion/pitting/scoring of the discs rather than wear, probably resulting from insufficient use of the brakes.

[andy43]

Ron99 said:

.
I wonder whether sometimes a car which doesn't make many long journeys spends most of its time with the alternator charging the battery and the drag of the alternator on the engine is noticeable on cars with smaller engines.
After a good blast the battery may be fully charged and the alternator disengages from the engine, making the engine feel smoother and more responsive.

Certainly in my Viva (1-litre, naturally aspirated) I can feel when the alternator is engaged - it feels rougher, more sluggish and slightly worse mpg.
,

Edited by Ron99 on Friday 23 August 23:56

That’s unlikely as afaik alternators don't have clutches, although drag charging a flat battery could make a difference.

Italian tuneup could in theory knacker an engine that’s not been revved for years. The piston rings wear the bores where they contact the cylinder walls. This creates a lip at TDC. Then at high revs the pistons get further up those bores than before, due to rod stretch. The con rods stretch slightly more at higher revs due to higher forces meaning the piston rings then hit the previously unworn part of the bores, hitting the ‘step’ left by low revs use, meaning the rings wear quicker and result in oil usage. Honest

[steveo3002]

yeah im always carefull to not rev the pistons too far up the bores ffs

[Ron99]

andy43 said:

That’s unlikely as afaik alternators don't have clutches, although drag charging a flat battery could make a difference.

Italian tuneup could in theory knacker an engine that’s not been revved for years. The piston rings wear the bores where they contact the cylinder walls. This creates a lip at TDC. Then at high revs the pistons get further up those bores than before, due to rod stretch. The con rods stretch slightly more at higher revs due to higher forces meaning the piston rings then hit the previously unworn part of the bores, hitting the ‘step’ left by low revs use, meaning the rings wear quicker and result in oil usage. Honest

Well, something 'comes on' occasionally (maybe about as often as a DPF regen in a diesel) and causes a noticeable increase in the 12v socket voltage regardless of engine rpms (although the voltage increase is less at idle/low rpms than when cruising) and at the same time causing drag on the engine. What else could it be?

Incidentally, although it's a 'town car' it is not used much for town driving; it spends a lot of time making ~1hr journeys often on back roads at medium speeds so it's likely to have more than ample opportunity for battery charging.

[Garvin]

Ron99 said:

I think it makes a difference to smoother running, better response and better mpg. Many people have used the Italian tune up to get through a previously failed MoT emissions test.

I wonder whether sometimes a car which doesn't make many long journeys spends most of its time with the alternator charging the battery and the drag of the alternator on the engine is noticeable on cars with smaller engines.
After a good blast the battery may be fully charged and the alternator disengages from the engine, making the engine feel smoother and more responsive.

Certainly in my Viva (1-litre, naturally aspirated) I can feel when the alternator is engaged - it feels rougher, more sluggish and slightly worse mpg.
By chance I have a 12v multisocket in the car for various gadgets and the socket has four LEDs which light up in sequence to show the approximate voltage of the electrical system so I have been able to repeatedly confirm that the sluggish episodes coincide with battery charging,

Edited by Ron99 on Friday 23 August 23:56

Alternator disengaging? If you can feel the difference in drag from an alternator charging/not charging then your Viva really does need an Italian tune up!

[Garvin]

Ron99 said:

Well, something 'comes on' occasionally (maybe about as often as a DPF regen in a diesel) and causes a noticeable increase in the 12v socket voltage regardless of engine rpms (although the voltage increase is less at idle/low rpms than when cruising) and at the same time causing drag on the engine. What else could it be?

I suspect you have the optional air conditioning fitted in which case it is the compressor, which does have a clutch, cutting in and out. The ‘drag’ of the compressor is much more than an alternator ‘on charge’ and the vibrations/noise can be felt/heard when it cuts in and will effect fuel consumption. For a weedy Vauxhall 1.0 litre engine the reduction in performance might well be noticeable

[Ron99]

Garvin said:

Alternator disengaging? If you can feel the difference in drag from an alternator charging/not charging then your Viva really does need an Italian tune up!

Like most 1-litre 3-cyl town cars, it is gutless at low rpms but goes reasonably well once it reaches the power band 4500-6500rpm. I think its mapping is torque-limited below 3000rpm to help with emissions and/or to prevent damage from lugging.

At 1500-2000rpm it probably only has about 15-20hp available at the crank, much of which would be consumed by drivetrain losses and running the drives to water pump, oil pump, cams etc (maybe aircon). By my reckoning, the drag losses from its alternator is probably about 2hp.

So starting with 15-20hp, take away several hp for drivetrain loss, pumps, cam drives etc, it's not hard to believe that taking another 2hp away from what remains might be noticeable.
Giving it an Italian tune-up probably makes it feel better because the higher rpms mean the alternator charges the battery and de-couples sooner.

Also bear in mind that I cover a lot of miles in the car (it's insured for 30k miles this year), so I'm very familiar with it and probably notice small things more than someone who only does a few k miles mostly popping to the shops a couple of times a week

[Ron99]

Garvin said:

I suspect you have the optional air conditioning fitted in which case it is the compressor, which does have a clutch, cutting in and out. The ‘drag’ of the compressor is much more than an alternator ‘on charge’ and the vibrations/noise can be felt/heard when it cuts in and will effect fuel consumption. For a weedy Vauxhall 1.0 litre engine the reduction in performance might well be noticeable

Yes, it is the A/C version but I can still feel the alternator drag when the A/C is off (and there are the LEDs on the 12v adapter which coincide with sluggishness).

With both A/C and alternator on it's really sluggish and often needs prolonged holding on to lower gears to keep up with traffic, and for cruising needs a gear lower than normal.

In some instances when climbing fairly steep hills (countryside hills, not motorway hills) it can get to a point where it can't do more than 40-odd mph because 1st gear is too short but it can't pull 3rd gear.

[andy43]

Ron99 said:

Garvin said:

I suspect you have the optional air conditioning fitted in which case it is the compressor, which does have a clutch, cutting in and out. The ‘drag’ of the compressor is much more than an alternator ‘on charge’ and the vibrations/noise can be felt/heard when it cuts in and will effect fuel consumption. For a weedy Vauxhall 1.0 litre engine the reduction in performance might well be noticeable

Yes, it is the A/C version but I can still feel the alternator drag when the A/C is off (and there are the LEDs on the 12v adapter which coincide with sluggishness).

With both A/C and alternator on it's really sluggish and often needs prolonged holding on to lower gears to keep up with traffic, and for cruising needs a gear lower than normal.

In some instances when climbing fairly steep hills it can get to a point where it can't do more than 40-odd mph because 1st gear is too short but it can't pull 3rd gear.

Does it go any faster when you unplug your phone charger?

[Ron99]

andy43 said:

Does it go any faster when you unplug your phone charger?

No, switching in-car gadgets off (satnav etc) doesn't cause the LEDs indicating the voltage to go out. Plugging in a device which needs charging also doesn't necessarily cause the voltage to increase.

I think there are just times every couple of hundred miles when the battery needs a charge and the alternator comes on which causes a drag on the engine until the battery is fully charged.

Switching on the headlamps usually causes the voltage LEDs to indicate 14-14.5V (alternator is on), and switching off the headlamps at the end of a journey usually causes the LEDs to immediately go out and indicate 12.5V.

[TurboRob]

Cars that spend a lot of their time low speed stop/start or on their warm-up cycle definitely benefit from a regular thrashing, as said.

Italian tune-up to pass emissions test is usually a result of getting the cats/DPFs hot and any residuals burnt off them.

Italian tune-up making a city car feel more eager is decoking of the piston-rings, valves seats/stems/recesses and exhaust ports/manifold.

[Garvin]

Ron99 said:

Garvin said:

I suspect you have the optional air conditioning fitted in which case it is the compressor, which does have a clutch, cutting in and out. The ‘drag’ of the compressor is much more than an alternator ‘on charge’ and the vibrations/noise can be felt/heard when it cuts in and will effect fuel consumption. For a weedy Vauxhall 1.0 litre engine the reduction in performance might well be noticeable

Yes, it is the A/C version but I can still feel the alternator drag when the A/C is off (and there are the LEDs on the 12v adapter which coincide with sluggishness).

With both A/C and alternator on it's really sluggish and often needs prolonged holding on to lower gears to keep up with traffic, and for cruising needs a gear lower than normal.

In some instances when climbing fairly steep hills (countryside hills, not motorway hills) it can get to a point where it can't do more than 40-odd mph because 1st gear is too short but it can't pull 3rd gear.

I just had a look at alternators for Vivas and, surprise, surprise, they come with clutch pulleys - well you learn something new every day!

[andy43]

Garvin said:

Ron99 said:

Garvin said:

I suspect you have the optional air conditioning fitted in which case it is the compressor, which does have a clutch, cutting in and out. The ‘drag’ of the compressor is much more than an alternator ‘on charge’ and the vibrations/noise can be felt/heard when it cuts in and will effect fuel consumption. For a weedy Vauxhall 1.0 litre engine the reduction in performance might well be noticeable

Yes, it is the A/C version but I can still feel the alternator drag when the A/C is off (and there are the LEDs on the 12v adapter which coincide with sluggishness).

With both A/C and alternator on it's really sluggish and often needs prolonged holding on to lower gears to keep up with traffic, and for cruising needs a gear lower than normal.

In some instances when climbing fairly steep hills (countryside hills, not motorway hills) it can get to a point where it can't do more than 40-odd mph because 1st gear is too short but it can't pull 3rd gear.

I just had a look at alternators for Vivas and, surprise, surprise, they come with clutch pulleys - well you learn something new every day!

You made me look! Well there you go, had no idea that was a thing. I sit corrected. Freewheeling clutch allows alternator to spin on overrun. Added complexity to save the planet presumably.
https://www.gatestechzone.com/en/problem-diagnosis...

[Ron99]

Garvin said:

I just had a look at alternators for Vivas and, surprise, surprise, they come with clutch pulleys - well you learn something new every day!

It probably helps the emissions test figures.

The car starts the official test with a fully charged battery and uses minimal electrical power during the test (no use of radio, wipers, lights, electric steering etc) so the alternator wouldn't need to latch onto the engine, saving a few mpg.

[anonymous-user]

Please, please make sure you fully extend your engine often!

Modern engines are designed and tested to be used, they even do a test where the engine is started on a engine dyno, taken to peak power, and left there, for 180 hours straight !! (That's 7 and a half days continuous to save you working it out)

Running at high rpm and load beds rings, heats the oil (boils water / condensate out of the oil), burns off soot and carbon, brings the CAT and DPF to operating temperature, fully excercises things like fuel pumps and injectors, allows cams and valve control systems to switch / phase, helps clear EGR systems, allows turbos to shed soot and have their boost control system exercised (which can seize through non use) It even does things like cycle O ring seals so that they get lubricated dynamically (helps them stay flexible and hence seal.


So, warm up your car carefully, (at least 15min of gentle driving, using increasing revs and load) and then THRASH it!

[anonymous-user]

steveo3002 said:

yeah im always carefull to not rev the pistons too far up the bores ffs

you may scoff but this is (or rather was) a genuine issue. Cars driven at low revs wear a sharp edged step in the bore at the top where the ring reversal occurs. At high revs, that position is further up the bore (due to component stretch, component thermal expansion and reduced oil film thrickness), which can mean the ring colides suddenly with that step, leading to ring scuff, or even ring or piston land failure!

(i say "was" because these days with metal sprayed bores (ie not basic iron bores) the days of having "steps" in the bore are long gone at any mileage.....)

[anonymous-user]

Ron99 said:

Garvin said:

I just had a look at alternators for Vivas and, surprise, surprise, they come with clutch pulleys - well you learn something new every day!

It probably helps the emissions test figures.

The car starts the official test with a fully charged battery and uses minimal electrical power during the test (no use of radio, wipers, lights, electric steering etc) so the alternator wouldn't need to latch onto the engine, saving a few mpg.

The one-way clutch is to releave the FEAD (Front End Auxilary Drive, or what used to be called the "Fan Belt" when it actually drove a physical fan....) belt from torsional vibration loads driven by the rotatonal inertia of the alternator as referenced to the crank (typically around 3:1 ratio). It also of cause removes any critical harmonic vibrational node from the alternator too as the torque can only be applied in a positive direction.

The alternator output is controlled electronically by varying the field winding (the current pushed through the claw pole rotor), these days generally that control signal comes from the engine ECU, so it can include battery management and regen functionality

[Red 4]

I seem to recall that I read somewhere that modern cars have "learning" ECUs.

Drive with a bit of urgency, the ECU learns your driving style and the engine may become a bit more responsive.

Could all be BS or my imagination of course. I'm sure the PH gurus will put me right if I'm wrong.

[anonymous-user]

Red 4 said:

I seem to recall that I read somewhere that modern cars have "learning" ECUs.

Drive with a bit of urgency, the ECU learns your driving style and the engine may become a bit more responsive.

Could all be BS or my imagination of course. I'm sure the PH gurus will put me right if I'm wrong.

Very much the case, especially with turbo charged engines! On a turbo engine, you don't want the turbo doing work (ie creating boost pressure) that is then "wasted" across the throttle, because that reduces fuel economy. But for sporty driving, having lots of 'Pre throttle boost' is good because it gives faster throttle response. With modern electronically controlled turbo's, the ECU can choose how much pre throttle boost to run, so when you put the car in sports mode, or drive more agressively, the ecu will move to maps that maximise response at the expense of a worse fuel economy. The same is true for other control parameters such as EGR flow, cam phasing, and oil and water pump demands etc.

These days, even if you have selected "sport" if you drive gently the ecu will actually slowly revert to "economy" settings!

[Pothole]

Certainly seemed to work on the current shed. It had done about 90000 miles in the hands of an older couple around Bournemouth/Poole and felt pretty sluggish when I picked it up. After a good thrash back to Cannock it was far more perky the next morning.