A year or so ago I posted an analysis of the likely power output of the 2014
engines based on the mandated fuel flow limits. This can be found here and
needs reading again first.
http://rec.autos.sport.f1.narkive.com/YUJklIQk/the-2014-engine-a-technical-evaluation
So fuel flow peaks at 10,500 rpm at 100 kg/hr and below that it decreases in
a linear fashion according to the equation (rpm x 0.009) + 5.5 kg/hr. Power
at any rpm will be limited entirely by the BSFC (brake specific fuel
consumption) that can be achieved and there is obviously no data on that yet
for this new direct injection design but I made my own best guess of 0.43
lb/bhp/hr (262 grams/kWhr) and upon that surmised a peak power at 10,500 rpm
of 510 bhp. I could be way off on this but the general points that follow
won't alter. Indeed there is talk online of peak power closer to 600 bhp but
we'll see in due course if BSFC figures low enough to achieve this are even
remotely possible.
Above 10,500 rpm the power can't increase further because the fuel flow is
capped. In fact as frictional losses in the engine must increase as rpm
increases then crankshaft power should decrease somewhat. Below 10,500 rpm
BSFC should improve slightly and thus power per gram of fuel used should
rise a bit as revs drop.
The power curve can therefore be drawn as two straight lines, one rising
from low rpm to 10,500 rpm and then another almost horizontal line (sloping
downwards somewhat) from there to 15,000 rpm. If you want to draw this out
in a spreadsheet yourself my calculated data points are as follows:
7,000 rpm - 355 bhp
10,500 rpm - 510 bhp
15,000 rpm - 486 bhp
Join those three points with two straight lines and you have it.
Clearly this looks nothing like a conventional airflow limited power curve.
Regardless of the BSFC figures that the manufacturers achieve the general
shape of the curve will stay the same even if the actual bhp numbers are
higher. The remarkable thing that results from this curve shape is only
apparent once the full vehicle performance is simulated and that's what I've
now done.
Other things to note are that 8 gears will be allowed, minimum car weight
rises to 685 kg and that the ERS system will make 160 bhp available for up
to 33 seconds a lap. Twice the power and 5 times the duration of the current
KERS system. I've simulated the car performance both with and without ERS.
In either case, and regardless of gearing, the computer is adamant.
THERE IS NO POINT IN REVVING PAST 12,000 RPM BEFORE CHANGING GEAR!
Only in top gear will the engine want or need to go past 12,000 rpm in order
to achieve its top speed which will still be close to 200 mph on long
straights. In fact I calculate that top gear will need to be selected at
about 135 to 140 mph and from then on until 200 mph the driver has nothing
to do other than steer and brake and operate the ERS etc.
This will lead to a very strange driving experience and probably a similarly
strange viewing one. In the slow parts of the lap it will sound like the
drivers are short shifting, which indeed they will be, at about 12k rpm and
then finally on the straights the engines will howl right round to the 15k
redline and not want to change back down a gear until speed drops below 140
mph. At Silverstone for example the cars should be able to stay in top gear
without a change all the way from Woodcote, round Copse, Becketts and on to
Stowe which is over half a lap.
This will be utterly counter-intuitive to the drivers who are used to
revving to the red line in each gear before changing up as indeed are all of
us in any type of car being driven to the limit. I suspect no one other than
the teams, and maybe not all of those yet depending on how far they've got
with simulations will even be aware of this anomaly. You heard it here
first.
The other thing that becomes apparent is that the engines will not want or
need 8 gears. In fact a totally flat top end power curve like this is very
insensitive to gearing and could manage quite well on the current 7 gears or
even 6. We'll see if any teams opt to save weight and complexity with fewer
than the 8 gears allowed in the regs. I suspect the winning teams might well
do so.
Top gear is therefore going to take a real hammering because the cars will
spend so much time in it - way more than currently and will need to be made
stronger than the other gears. Let's see how many top gear failures plague
the start of the season. Engines will only exceed 12k rpm on long straights
so they should last for ages compared to the current 18k redline in every
gear.
I'm dying to see how long it takes people in the sport to realise any of
this or start commenting on it. Without access to a comprehensive vehicle
simulation program it would never be apparent. I doubt if the rule setters
had any clue their fuel flow limits would result in this strange behaviour.
--
Dave Baker