2014 Gear ratios and Final Drives

[wuzak]

Don't forget that the mguk will be delivering power to the mguh to spooling the turbo under braking, which will not go to the ES. Realistically the mguk needs to harvest more then 2MJ to get everything out of a normal lap. The mgu-h will barely contribute anything to the ES. Perhaps a very tiny bit just when braking starts. In a perfect world you want the mgu-h not take anything from the ES, either relying on exhaust gasses or the mguk to spool the turbo, and the mguk harvesting enough to get 2MJ plus enough energy to let the mguh spool the turbo (to negate turbo lag when getting back on the power).

The MGU-H starts harvesting just at soon as the turbo reaches maximum boost.

I think the MGU-H will be harvesting power before full boost. Assuming full boost coincides with the maximum fuel flow rate and 10,500rpm.

There may be situations coming off corners where the MGU-H is harvesting power but the chassis can't take it (traction limited). So, if the car is below, say, 150km/h the MGU-H sends energy to the ES, but above that it sticks it straight onto the MGU-K. They may even choose to blend the transition over 20-30km/h, during which some is sent to the ES and some to the MGU-K.

[Tommy Cookers]

...... Realistically the mguk needs to harvest more then 2MJ to get everything out of a normal lap ....

..... There may be situations coming off corners where the MGU-H is harvesting power but the chassis can't take it (traction limited). So, if the car is below, say, 150km/h the MGU-H sends energy to the ES, but above that it sticks it straight onto the MGU-K. They may even choose to blend the transition over 20-30km/h, during which some is sent to the ES and some to the MGU-K.

often when braking is finished (or before) there is more fuel available via the rpm rule than the driver wants to power the wheels
this fuel can be used for generation (to storage) by the mgu-k, simply by engine running to include generation torque
(this has been done for the last 5+ years with KERS, as 'over-run push' )

Adrian Newey said races will be dominated by fuel quantity more than rate, maybe he believes otherwise and intends the above
within whatever constraints the mapping rules present to this (AFAIK the maps are circuit-specific, so there's not a big problem)

it would alleviate turbof1's problem of limited mgu-k recovery
and it is a relatively efficient way of turning fuel into energy
and so surely it's benefits must be more than alternatives such as weight saving by eg loading less than 100 kg of fuel
whose proponents presumably intend to load 90 kg or 80 kg or, by their 'logic' ...... perhaps 1 kg ?

[Pieoter]

They could just be running a 7speed box?

It would be lighter and help with balance. Aslong as the rev drop between gears keeps the revs above 10.5k it won't see a performance drop

[Richard]

A 7 speed box, or even just 7 gears in an 8 speed box would be illegal. My understanding of the rules is that they have to run the same 8 gears at every race, with one option to change huge ratios during the season. Any unused gears would be ballast.

[bonjon1979]

This quote:

"By the way there are rumors that Mercedes is running with only seven gears, indeed during the practice start it seems that drivers are using the 2nd gear, this could suggest that AMG did longer gear ratios, planning to not use the 8th gear, this could explain the sudden drop in rpm during braking and the delay in changing gear during the first phase of acceleration unlike Ferrari and Renault."

from here: http://thejudge13.com/2014/02/24/f1-for ... melbourne/

Any idea of why they would do this? What performance gains?

Presumably, this means they're going for 8th gear being the Monza/Spa gear.

No, I think it's saying they're not using first gear. Maybe it's for weight saving, ie they have a tiny first gear they never use. could it have a fuel efficiency advantage?

[Alexgtt]

This quote:

"By the way there are rumors that Mercedes is running with only seven gears, indeed during the practice start it seems that drivers are using the 2nd gear, this could suggest that AMG did longer gear ratios, planning to not use the 8th gear, this could explain the sudden drop in rpm during braking and the delay in changing gear during the first phase of acceleration unlike Ferrari and Renault."

from here: http://thejudge13.com/2014/02/24/f1-for ... melbourne/

Any idea of why they would do this? What performance gains?

Presumably, this means they're going for 8th gear being the Monza/Spa gear.

No, I think it's saying they're not using first gear. Maybe it's for weight saving, ie they have a tiny first gear they never use. could it have a fuel efficiency advantage?

I think it's more likely they have chosen their ratios to use 1-7 for some tracks, 2-8 for some and 1-8 for others, just switching software to suit.

[diego.liv]

Couldn't it be like bonjon1979 is saying? Skipping the 1st-very-short-gear could
-save a bit of fuel
-less spinning, hence less rear temperature/damage/degradation

If they are confident of the whole package they have, why not starting in 2nd gear?

[theWPTformula]

First gear is incredibly small anyway so starting in second is a plausible idea. They were in third (sometimes fourth) gear in the Dry Sac hairpin at Jerez such is the torque available to them this year. Considering that the W05 is on a bit of a diet, weight saving by using a tiny first gear is also my hunch.

[Owen.C93]

You can go small radius but the thickness of the gear is defined by a minimum value. Or at least it always used to be.

[smlbstcbr]

I thought it was written on the Rules that a 1st gear is mandatory and is also mandatory to use it until 100 kph are reached. Is that true?

[Per]

There is even a minimum weight for gears:

9.6.3 No forward gear ratio pair may be:
a) Less than 12mm wide when measured across the gear tooth at the root diameter or any point 1mm above or below the root diameter. Above this area each side of the gear teeth may be chamfered by a maximum of 10 ̊. In addition, a chamfer or radius not exceeding 2.0mm may be applied to the sides and the tip of the teeth.

b) Less than 85mm between centres.

c) Less than 600g in weight (excluding any integral shaft or collar). If an integral shaft or collar is to be excluded the mass of this may be shown by calculation assuming the gear to be 12mm wide and the shaft geometry to be the same as that where slide on gears are used.


I think it's a normal thing not to use all gears in Bahrain, as there will be more tracks with slower corners and/or higher top speeds. Also check the testing topic, someone posted telemetry from Caterham and they were only using 6 gears in that lap.

[Per]

I thought it was written on the Rules that a 1st gear is mandatory and is also mandatory to use it until 100 kph are reached. Is that true?

I can't imagine that. There is a rule though that says you can only shift once before reaching 80 km/h at the race start. Actually I don't know why this rule exists (why would anyone want to shift more than once before reaching 80?).

[smlbstcbr]

I thought it was written on the Rules that a 1st gear is mandatory and is also mandatory to use it until 100 kph are reached. Is that true?

I can't imagine that. There is a rule though that says you can only shift once before reaching 80 km/h at the race start. Actually I don't know why this rule exists (why would anyone want to shift more than once before reaching 80?).

Thanks for the clarification.

[vtr]

I did some quick calcs on another forum, based on Brembo braking data provided to me by another member.

(...)

Even on this very basic analysis, you can see that the cars will struggle to recover 2MJ from braking, and some tracks won't even allow half of that.

Do you think they could maybe recover more energy by reducing the engine braking in favour of the MGU-K? It might not be much, but we can barely hear the downshifting on this years videos, and it seems they are letting the revs go way down. 120k is very little braking power anyway, so it might make a difference in the harvesting power.

For comparison, here is telemetry from Caterham-Renault of a lap of Spa. You can see that, even braking for la Source or the Bus Stop, the engine does not go below 12k pretty much, and most downshifts send the engine up almost to 15-16k.
(on a different note, check out the massive lateral g's the cars achieve at the middle part of Eau Rouge, Pouhon and Blanchimont )



I have not seen the Brembo data however, I don't know if it disproves this little idea.

The caterham track previews link (for last year), with telemetry! http://www.caterhamf1.com/seasons/race-previews

[rscsr]

But would they ditch the first gear?
If there is to much torque on the wheel, why not make the first gear longer to make it useable and have more gears to accelerate faster?