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i noticed during qualifying in monaco those rough engine noise are back on lower throttle input. before they were using exhaust to blow diffuser and enhance downforce after double diffuser were banned and now it seems this trick is back. are they deactivating cylinders and those deactivated cylinder used to create power pulses and blow the rear wing or all cylinders are throttled that way instead of typically relying on fuel or air volume control? stratergy around creating more downforce or even maybe some sort of traction improvement?

Powerslide wrote: ↑

27 May 2017, 19:48

i noticed during qualifying in monaco those rough engine noise are back on lower throttle input. before they were using exhaust to blow diffuser and enhance downforce after double diffuser were banned and now it seems this trick is back. are they deactivating cylinders and those deactivated cylinder used to create power pulses and blow the rear wing or all cylinders are throttled that way instead of typically relying on fuel or air volume control? stratergy around creating more downforce or even maybe some sort of traction improvement?

They continued to use cylinder deactivation at low loads for the current era.

Honda is the most obvious one.

I imagine it is more the characteristics of the track showing this off as opposed to a change in strategies.

what would be the targeted intent of such a state of tune

The highest fuel efficiency point for any given cylinder is approximately 10,500 rpm and 3 or 4 bar MAP. If then want 50% power the most efficient way to do it is run 50% of the cylinders at 10,500 rpm and 3 or 4 bar MAP. Obviously this operates on a sliding scale but the point is - throttling 6 cylinders to a much lower load to produce a reduced output will use a lot more fuel than cylinder skipping.

Powerslide wrote: ↑

16 Jun 2017, 23:42

what would be the targeted intent of such a state of tune

Blow the turbo, used as kind of antilag. Keep the turbine spinning with cold air from the deactivated cilinder, maybe even hot blowing with the active ones (use a late ignition timing) and it will mix with the cold air from the inactive cilinders.

Monaco doesn't have much good braking points to charge with the mgu-k, maybe they need to save some energy from preventing mgu-h to spool up the turbo.

I can't imagine that it takes much energy from the total supply to keep the turbo spooled up with MGU.

[quote=gruntguru]
The highest fuel efficiency point for any given cylinder is approximately 10,500 rpm and 3 or 4 bar MAP. If then want 50% power the most efficient way to do it is run 50% of the cylinders at 10,500 rpm and 3 or 4 bar MAP. Obviously this operates on a sliding scale but the point is - throttling 6 cylinders to a much lower load to produce a reduced output will use a lot more fuel than cylinder skipping.[/quote]

this seems poor reasoning
it's wrong to exclude running in a higher gear (to keep the throttles open and the revs well below 10500 rpm)
and afaik nobody runs eg 50% modulated displacement at or near 10500

bizarrely eg 10500 allows 100 kg/hr fuel rate even running only 3 cylinders
so something weird giving a lot of exhaust energy would be possible (specially valuable with low K-recovery circuits/cars)
whereas dropping the revs drops the permissible fuel rate of course

NL_Fer wrote: ↑

20 Jun 2017, 17:35

Powerslide wrote: ↑

16 Jun 2017, 23:42

what would be the targeted intent of such a state of tune

Blow the turbo, used as kind of antilag. Keep the turbine spinning with cold air from the deactivated cilinder, maybe even hot blowing with the active ones (use a late ignition timing) and it will mix with the cold air from the inactive cilinders.

Monaco doesn't have much good braking points to charge with the mgu-k, maybe they need to save some energy from preventing mgu-h to spool up the turbo.

yes anti lag, they use the anti lag system in formula one even when the cars were naturally aspirated. the thing is, they used it to blow the diffuser instead to produce downforce. could this be the case as well but getting two birds with one dance? blow the turbo and aero element? maybe thats why they got that small wing element around the exhaust exit. what about cylinder deactivation during mild engine loads to improve fuel economy so that they can run the car on lighter load of fuel?

Powerslide wrote: ↑

08 Jul 2017, 01:11

NL_Fer wrote: ↑

20 Jun 2017, 17:35

Powerslide wrote: ↑

16 Jun 2017, 23:42

what would be the targeted intent of such a state of tune

Blow the turbo, used as kind of antilag. Keep the turbine spinning with cold air from the deactivated cilinder, maybe even hot blowing with the active ones (use a late ignition timing) and it will mix with the cold air from the inactive cilinders.

Monaco doesn't have much good braking points to charge with the mgu-k, maybe they need to save some energy from preventing mgu-h to spool up the turbo.

yes anti lag, they use the anti lag system in formula one even when the cars were naturally aspirated. the thing is, they used it to blow the diffuser instead to produce downforce. could this be the case as well but getting two birds with one dance? blow the turbo and aero element? maybe thats why they got that small wing element around the exhaust exit. what about cylinder deactivation during mild engine loads to improve fuel economy so that they can run the car on lighter load of fuel?

Right, exactly the same function, but with the single exhaust, diffuser/cloanda should not be possible anymore.

Could it be that they are cold blowing the cilinders to gain some extra cooling capacity in slow sections? It seems to me that the sound is most pronounced on the Honda engine which is the most critical one.

Edax wrote: ↑

09 Jul 2017, 13:53

Could it be that they are cold blowing the cilinders to gain some extra cooling capacity in slow sections? It seems to me that the sound is most pronounced on the Honda engine which is the most critical one.

they actually run the engines hot. well they use to i dont know in this turbo era they still do or not but i dont think they are cooling the cylinders.

reasons are probably cylinder deactivation for better fuel economy so they could beat the fuel flow regulations *someone educate me on this if im wrong here) or most likely going back to increases exhaust pulses to blow rear wing elements