|Remarkable finding re 2104 engines||Dave Baker||1/14/13 8:14 AM|
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.
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
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
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
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
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
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.
|Re: Remarkable finding re 2104 engines||a425couple||1/14/13 9:14 AM|
"Dave Baker" <Nu...@null.com> wrote in message...
>A year or so ago I posted an analysis ---
(big snip of good stuff)
> I'm dying to see how long it takes people in the sport to realise any ofInteresting. (Indeed = "counter-intuitive")
Thank you for posting it.
|Re: Remarkable finding re 2104 engines||News||1/14/13 9:17 AM|
As you pointed out in your prescient analysis a long while ago (which I
did recall), this follows directly from the 2014-spec fuel flow taper,
the only issue being at what point on each engine/chassis the efficiency
and power output are overwhelmed by internal friction, pumping losses
and induced drag, net output curve rolls over, and car hits the drag
rise. A bit top fuel dragster-ish.
|Re: Remarkable finding re 2104 engines||AC||1/14/13 12:06 PM|
Im my Alan Davis role, why not gear it to reach top speed at 10k rpm?
Why go through the extra revs at all?
|Re: Remarkable finding re 2104 engines||alan||1/14/13 12:19 PM|
Remember that the object of the exercise is to change gears so as to
maximize the area under the rmp/horsepower curve. So if power above 10K
only falls off slowly, you still want to operate in that regime rather
than below 10K where it falls off more quickly.
Vancouver, British Columbia
"If you raise the ceiling four feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect if you
sit in the bottom of that cupboard."
|Re: Remarkable finding re 2104 engines||Noj||1/14/13 12:20 PM|
Dave Baker wrote ...
Why am I thinking of go-carts and chainsaws?
I reckon the engine makers will have sussed out much, if not all, of
what you've discovered. If they pass that info onto the non-factory
teams is another matter.
|Re: Remarkable finding re 2104 engines||AC||1/14/13 1:03 PM|
Ok, so the point being that you can keep going up the revs as long as
the power there is higher than the power available at lower revs if you
go up a gear? So even though its less power at those +10k revs, its
still better than the power at lower revs? Is that it?
|Re: Remarkable finding re 2104 engines||Dave Baker||1/14/13 1:48 PM|
Ok, I need to amend the above slightly. It's a most unusual power curve to
optimise the gearing for and the program had been trying to tell me
something I was not spotting. You don't need to use the revs between 12k and
15k at all, even in top gear. I'd already input a default 15k rev limit
simply because that's what the engines are allowed to rev to and I'd worked
out the top gear ratio to give 200 mph at 15k before entering the other gear
It's more simple than that. You gear it for 200 mph (or whatever the drag
coefficient will let the car run to) at 12k in top, ignore the extra 3000
rpm and change gear at 12k in every gear as before. The engine never goes
above 12k rpm at any time. The 15k rpm limit is academic.
|Re: Remarkable finding re 2104 engines||alan||1/14/13 4:05 PM|
> >> Im my Alan Davis role, why not gear it to reach top speed at 10k rpm?Basically.
Horsepower combines the torque and RPM into a single number that
reflects (less frictional and some other driveline losses) how much
torque you can deliver at the wheels. X torque at y RPM is equal to x/2
torque at 2y rpm. So when you shift up, you do so because the HP at the
high RPM now matches the HP at the RPM you'll have in the next higher
The short of it is that you don't shift AT the power peak, you shift
AROUND the power peak; maximizing the power delivered at all times. If
you've got a curve that ramps up at a high rate to peak power at
10,000rpm, and then that ramps down only very slowly, your going to
maximize total power by shifting well beyond 10,000.
|Re: Remarkable finding re 2104 engines||alan||1/14/13 4:08 PM|
In article <kd1ugc$db7$1...@speranza.aioe.org>,
What is the horsepower you calculate for 12k?
What is the horsepower you calculate at the new RPM after each upshift?
Imagine for a moment that the curve above 10K stayed perfectly flat.
You'd want to run it right to the rev limit and then only let the revs
drop back to 10K (if that's possible with an 8 ratio gearbox, that is).
|Re: Remarkable finding re 2104 engines||Bobster||1/14/13 7:08 PM|
On Jan 14, 11:48 pm, "Dave Baker" <N...@null.com> wrote:
> It's more simple than that. You gear it for 200 mph (or whatever the dragBut the drag coefficient will change with DRS, so you'll go a bit past
12k and not have to worry about hitting the rev limiter.
Interesting thing I read somewhere is that with the life of these
engines they'll be usable at Le Mans.
|Re: Remarkable finding re 2104 engines||Mark Jackson||1/15/13 4:37 AM|
On 1/14/2013 7:05 PM, Alan Baker wrote:
>> Ok, so the point being that you can keep going up the revs as long asYears ago I saw (in /Road & Track/ I think) a graph of torque at the
driven wheels versus road speed - separate curve for each gear. The
curves overlap (low gear peaks at low speed, higher gears peak at higher
speeds but lower torque values) and one shifts up when the curve for the
current gear crosses the curve for the next. This is also the point
where HP in the two gears are equal.
Note that with a CVT (not allowed under the F1 regulations) one would
run the engine continuously *at* peak power.
Mark Jackson - http://www.alumni.caltech.edu/~mjackson
Education is what survives when what has been learnt has
been forgotten. - B. F. Skinner
|Re: Remarkable finding re 2104 engines||Dave Baker||1/15/13 5:27 AM|
"Alan Baker" <alang...@telus.net> wrote in message
> Questions?You can interpolate from the data I supplied but clearly just a bit less
than the 510 bhp peak at 10.5k.
>Obviously exactly the same bhp as before the change if acceleration is to be
>Not quite, and this is what the computer had been trying to tell me and I'd
been too stupid to appreciate despite having written articles on the very
same phenomenon many times in the past. If the bhp curve goes perfectly flat
i.e. 510 bhp everywhere from 10,500 rpm to 15,000 rpm then "at a given
speed" it makes no difference whereabouts on that bhp line you are because
the torque at the wheels will always be the same once gearing has been
factored in. So you still ideally change up a gear to drop the rpm in the
new gear back to 10,500 rpm i.e. at about 12k to 12.5k which maintains a
constant 510 bhp but uses as few revs as possible. Better for BSFC and
better for engine life.
Lowering the gearing and revving out to 15k won't actually make the car any
quicker. It will just use more revs to maintain the same 510 bhp.
|Re: Remarkable finding re 2104 engines||Dave Baker||1/15/13 5:28 AM|
> Horsepower combines the torque and RPM into a single number thatAlmost. Horsepower combines the torque and RPM "and gearing" into a single
|Re: Remarkable finding re 2104 engines||Mower Man||1/15/13 2:49 PM|
Shame we won't be here to see it. In 2104 I doubt there'll be F1 anyway. :-)
'Fashion is a form of ugliness so intolerable that we have to alter it
every six months.'
|Re: Remarkable finding re 2104 engines||Dave Baker||1/15/13 3:17 PM|
> The other thing that becomes apparent is that the engines will not want orMy friend at McLaren has pointed out that the 8 gears are mandatory and
indeed the ratios for the whole season must be nominated and fixed before
the first event of the season. For 2104 only you are allowed to change the
nominated ratios once during the year. Technical Regs rule 9.6.
So whether at Monza or Monaco you're stuck with one set of ratios that are
going to have to cover a massive range of top speeds and corner speeds. The
availability of at least 2,500 of unused rpm capability between say the
normal 12,500 rpm change point and the redline at 15k will therefore come in
handy and might be part of an overall plan by the FIA rule setters although
I don't usually expect them to be that smart judging by past performance.
So probably 7th will be the normal top gear for slow and medium speed
circuits and 8th will be reserved for fast circuits.
|Re: Remarkable finding re 2104 engines||Bobster||1/15/13 7:31 PM|
On Jan 16, 1:17 am, "Dave Baker" <N...@null.com> wrote:
> My friend at McLaren has pointed out that the 8 gears are mandatory andWell the regulations published on the FIA web site say different.
9.6 Gear ratios :
9.6.1 The maximum number of forward gear ratios is 7.
9.6.2 The maximum number of numerical change gear ratio pairs a
competitor has available to him during a Championship season is 30.
All such gear ratio pairs must be declared to the FIA technical
delegate at or before the first Event of the Championship.
Those are the regs as published early last month.
I keep on seeing comment on F1 sites that seems at odd with the
published regs. James Allen ran a report that said with a single,
central exhaust outlet diffuser blowing is going to be made difficult.
Thing is the regs allow for TWO exhaust outlets, once each side of the
car's centre line.
Either the regs published in the public domain are not what is being
made available to the teams and certain people in the media, or people
aren't reading them properly.
|Re: Remarkable finding re 2104 engines||Bobster||1/15/13 7:45 PM|
On Jan 16, 5:31 am, Bobster <megap...@gmail.com> wrote:Forgot the URL. Many appy polly loggies
Latest downloadable copy is at
|Re: Remarkable finding re 2104 engines||alan||1/15/13 7:46 PM|
Bobster <mega...@gmail.com> wrote:And those aren't the regs for 2014...
...because these are:
|Re: Remarkable finding re 2104 engines||Bobster||1/15/13 9:37 PM|
On Jan 16, 5:46 am, Alan Baker <alangba...@telus.net> wrote:
> In article
>Yes. Which is what I thought I was working from. Anyhoo... got that
one wrong. Please erase my post from your memories, folks, and let
normal service resume.