61 replies to this topic

[scarbs]

BMW Corporate Communications 22 September 2003 BMW Formula One engine development in facts and figures.

Link to full spec and images


Facts and figures:
Output of the BMW P83 is over 900 bhp.
Maximum engine speed is 19,200 rpm.
In a race, engine speed is limited to 19,000 rpm.
Idle speed is 4,000 rpm.

The engine weighs less than 90 kilograms.

The air intake volume is 1,995 cubic metres per hour.
Maximum piston acceleration is 10,000g.
Piston speed peaks at 40 metres per second and averages 25 metres per second.
Exhaust temperatures of up to 950 degrees are reached.
Maximum air temperature in the pneumatic system is 250 degrees.

It completes a distance of 500 kilometres before undergoing revision.
Total production of the BMW P83 is 200 units, ten of which the team takes to each race.
Before being phased out the engine will have received 1,388 upgrade modifications.
It comprises around 5,000 individual components, 1,000 of them different.

The ultra-high-speed 130R turn at Suzuka with its lateral load of 4g poses the greatest challenge to the oil system.
The BMW P83 endured the highest full-throttle proportion on the Monza circuit at 73 per cent per lap.
that 1,950 CAD drawings were made for this engine? Printed out and laid end to end, they would cover a distance of 1.3 kilometres.

[alexbiker]

Cheers Scarbs

300bhp per litre and 10 bhp per kilo. How do I get one of these for my Focus?

Alex

[scarbs]

Try searching the small ads in the Munich auto-trader or checking the garage of a certain Dr Mario Theissen. But, you might find the flames shooting out of the exhausts and through the bonnet on the overrun somewhat distracting...!

[desmo]

Thanks Craig!

Interesting indeed. I'm still looking for evidence of throttles or TPS pots, don't see them in those photos. Also note the Renaultesque twin FI rails and partitioned airbox tray. When I see an F1 engine on the test bed with it's inconel exhaust glowing yellow, I wonder if it will reach those sorts of temps installed in the car during a race. And how on earth do those Lambda and EGT sensors survive and give accurate data under those conditions? Wow.

[J. Edlund]

According to this info the bore and stroke of the BMW engine should be expected to be around 99 x 39 mm.

Since the color of the glowing exhaust is yellow, the temperature must be around 900-1000 degrees celsius or so. The thin inconel tubing are probably making it glow a little more compared to a cast manifold but anyway, the biggest question is probably how the exhaust valves can take that thermal load when the rpm peaks?

EDIT: missed that it stood that the peak temperature was 950 degrees

[Alexandros]

Hmmm interesting figures on the air intake volume (1995 cubic meters)..

18000 rpm (the average between say 17k and 19k as operating range) / 60 = 300 rotation per second. 300 rotations X approximately 1.5 liters of air (not considering fuel added in the cylinders) = 450 liters of air / second = 27.000 liters of air/minute (or 27 cubic meters) = 1620 cubic meters per hour..! That is around 375 cubic meters below the reported data. Which means that forced inductions provides these.. So the engine should be working at around 123% volumetric efficiency. Hmm..

(If any calculation is wrong feel free to point it out)

[Halfwitt]

Originally posted by Alexandros
Hmmm interesting figures on the air intake volume (1995 cubic meters)..

18000 rpm (the average between say 17k and 19k as operating range) / 60 = 300 rotation per second. 300 rotations X approximately 1.5 liters of air (not considering fuel added in the cylinders) = 450 liters of air / second = 27.000 liters of air/minute (or 27 cubic meters) = 1620 cubic meters per hour..! That is around 375 cubic meters below the reported data. Which means that forced inductions provides these.. So the engine should be working at around 123% volumetric efficiency. Hmm..

(If any calculation is wrong feel free to point it out)

I don't think 123% volumetric efficiency is out of the question. I assume that this calculation is based on engine speed at peak power (so probably nearer 18500rpm) , and at this point this engine will be working perfectly (or as well as it possibly can).

[robert dick]

I have the same problem with the efficiency :

Over 900 HP at 19200/min means 100 HP per litre for 6400/min, a rather surprising efficiency factor which is achieved in Formula 1 but nowhere else!

100 HP per litre at 8000/min is until the present day the usual efficiency in ALL atmospheric engines (including MotoGP) so that 720 HP at 19200/min (240 HP per litre at 19200/min) would be realistic (even too high considering the frictional losses at high speeds) for the BMW (and the Formula 1 competitors).

Has Formula 1 its own thermodynamic and chemical laws?
Have the dynamometers of the Formula 1 teams peculiar calibrations?
Is a high output in the direction of 1000 HP good for more publicity/sponsor money/image?

[alexbiker]

Has Formula 1 its own thermodynamic and chemical laws?

Or is the calculation you did inapplicable?

Seeing as these beasts are reputed to idle at 7000rpm, I doubt that they're producing 100bhp/litre down there in the rev range - either that or it takes 300 bhp to power the electrics and the hydraulics, plus the cams etc - that's 223 kW, which is more than most houses use.

I would argue that the volumetric efficiency and specific outputs are awful at low revs, as evidence by the cars' global lack of torque. Case in point - the limiting factor for a start is the lowest revs sustainable without stalling, which is around 13,000 rpm. And this is for a 600 kg car.

Your calculation assumes a linear power distribution, which racing engines just don't have. The power falls away massively either side of peak - drivers have complained that these are some of the peakiest engines they've driven.

Alex

[robert dick]

That the power distribution is not linear is evident : 100 HP per litre at 8000/min has to be understand as unit, the best possible value (+- a few percent) which can be achieved with an atmospheric engine.
In the case of the BMW we can fix this value at 200 HP per litre at 16000/min. But more is not possible, more is not contained in the fuel/air mixture. To achieve higher values we need a supercharger or different fuels.
The problem :
For an output of 900 HP, the BMW has to run at 24000/min (at least). At 19200/min an output of 900 HP is not contained in the fuel/air mixture. The “mixture turnover” at 19200/min is too low for 900 HP.

[cadwal]

Originally posted by robert dick
To achieve higher values we need a supercharger or different fuels.

Looking at the third picture from the top "something" is connected to the air intake. Might not that "something" simulate the effect of air being forced into the air intake at speed?

I am only an electrical engineer but I guess that having a higher than normal air pressure in the air intake would be able to cause "supercharging" effects?

[Vrba]

Originally posted by robert dick

In the case of the BMW we can fix this value at 200 HP per litre at 16000/min. But more is not possible, more is not contained in the fuel/air mixture. To achieve higher values we need a supercharger or different fuels.
The problem :
For an output of 900 HP, the BMW has to run at 24000/min (at least). At 19200/min an output of 900 HP is not contained in the fuel/air mixture. The “mixture turnover” at 19200/min is too low for 900 HP.

I don't agree. Efficency of common Otto engines (defined as power output/energy stored in the fuel consumed in one second, i.e. calorific value of the fuel) is usually at most 30-35%. Everything else is spent at various losses (thermal, mechanical).
Now, if we take a caloric value of gasoline as 45 kJ per gramme, we have the following calculation:
10 cilinders at 19,000 rpm suck the volume of each cylinder 1583 times per second, assuming the cylinders are fully charged with fresh mixture each time. It equals 0.475 cubic meters of air/fuel mixture per second (if an average air intake has the area of cca 150 square cm, it means that the speed of air entering the engine - assuming the car is not in motion - is 114 km/h)!
Now, if that 0.475 cubic metres of mixture contain 14 mass parts of air and 1 mass part of fuel (enabling all the fuel to burn), that means that cca 40 grammes of fuel enters the engine every second. It equals to 1800 kJ of latent energy per second and that equals 1800 kW of power on disposal. In other words, the fuel entering the 3000 cubic centimeter engine at 19,000 rpm contains the power of 1800 kW = 2448 HP. The engine manages to extract 900 HP as the useable power and that gives us the efficiency of 900/2448 = cca 37%, slightly higher than usual (not surprisingly).
Therefore, there's still much more enery stored in the fuel that today's technology is able to extract and 900 HP is nothing really strange.

Hrvoje

[robert dick]

A lot of test have been run with all forms of “airboxes” : They have no supercharging effect, the advantage being that the aspirated air is immobile.
The “something” above the intake is used on the bench and connected to the outside in order to provide enough air for the test (at the beginning of the eighties Renault tested the 1.5-litre turbo engine with no connection to the outside – suddenly the engine stalled, the air in the test room was used up).
Moreover articles 1.12 and 5.3.1 of the Formula 1 regulation outlaw any system increasing the pressure or decreasing the temperature of the aspirated air.

[michaelab]

Originally posted by cadwal
I am only an electrical engineer but I guess that having a higher than normal air pressure in the air intake would be able to cause "supercharging" effects?

It's well known that the shape of an F1 airbox provides a significant "ram" effect at high speed, effectively gentle supercharging.

Now, I'm no engineer and don't really follow all your calculations but, robert dick in particular, the fact that the top F1 engines (not just BMW) produce close to (or slightly above) 900hp at around 19,000rpm is well known and not for dispute. Your insinuation that the hp and rpm figures are invented for marketing/image reasons is very wide of the mark.

Michael.

[michaelab]

Originally posted by robert dick
A lot of test have been run with all forms of “airboxes” : They have no supercharging effect, the advantage being that the aspirated air is immobile.

Then why is it that the FIA in one year (1994 I think it was, after Senna's death) mandated that airboxes have a hole at the rear precisely to prevent the ram supercharging effect from working in a (crude) attempt to reduce engine power?

The rules about increasing air intake pressure are to outlaw forced induction systems like turbos and superchargers. I'm pretty sure they don't cover the design of static airboxes.

Michael.

[robert dick]

Originally posted by Vrba

...there's still much more enery stored in the fuel that today's technology is able to extract and 900 HP is nothing really strange.

Hrvoje

Of course I agree that more power is contained in the fuel itself .
But not in the engine using this fuel.
How is this quantum jump in efficiency realised?

[Racer Joe]

Originally posted by robert dick
That the power distribution is not linear is evident : 100 HP per litre at 8000/min has to be understand as unit, the best possible value (+- a few percent) which can be achieved with an atmospheric engine.
In the case of the BMW we can fix this value at 200 HP per litre at 16000/min. But more is not possible, more is not contained in the fuel/air mixture. To achieve higher values we need a supercharger or different fuels.
The problem :
For an output of 900 HP, the BMW has to run at 24000/min (at least). At 19200/min an output of 900 HP is not contained in the fuel/air mixture. The “mixture turnover?at 19200/min is too low for 900 HP.

Going by the way you are doing your calculations, let's look at a road car.

Honda S2000
2 litre engine. 240bhp. (Let's say it makes that @ 8000 rpm)

Extrapolate that to 19000rpm. 240/2/8000*3*19000=855bhp.

Well within range I say.

Obviously a lot of assumptions are made in this kind of calculations.

Let's say BMW makes 915 bhp at 19000rpm. That is 7% more horsepower. I think that is quite reasonable.

[robert dick]

Originally posted by michaelab

... the fact that the top F1 engines (not just BMW) produce close to (or slightly above) 900hp at around 19,000rpm is well known and not for dispute...
Michael.

Why not for dispute in this forum?
The problem is that the efficiency in question is only present in these current Formula 1 engines and nowhere else! And I am wondering why...

[Vrba]

Originally posted by robert dick


Of course I agree that more power is contained in the fuel itself .
But not in the engine using this fuel.
How is this quantum jump in efficiency realised?

But what quantum leap?
I didn't know about 100 HP per litre per 8000 rpm "rule" but according to my calculations (post no. 12), F1 engine is not much more efficient than usual Otto petrol engine. F1 constructors optimized everything they could for a special purpose, that's why those engines are more efficient than common ones but the difference is not significant.
The most efficient internal combustion engines are big two-stroke turbocharged Diesel ship engines. They rotate at the very low speed (60-100 rpm) and therefore have very small thermal losses (the charge doesn't take much of the heat to the exhaust) and mechanical losses. They achieve efficience of 60-65%, way higher than a F1 engine.

Hrvoje

[robert dick]

The Honda S 2000 example is good.
Honda gives 237 HP at 8300/min, 118.5 HP per litre at 8300/min.
Transferred into the BMW this would give 822 HP at 19200/min so that we come nearer the 900 HP mark. But we are still away and we have forgotten the frictional losses.
Is the Formula 1 fuel good for the further increase in efficiency?

= = = = =

In my eyes an efficiency jump from 35 % to 37 % = jump of nearly 6 % (under the same conditions) is a quantum jump.

[Vrba]

Originally posted by robert dick

In my eyes an efficiency jump from 35 % to 37 % = jump of nearly 6 % (under the same conditions) is a quantum jump.

Hardly so. If that's so, then all car engines would have had the same fuel consumption (within a few percent) and it's not the case. Formula 1 uses better materials, higher quality control and tighter tolerances than road engines. Those factors in itself should be enough to account for a significant raise in efficiency.

Hrvoje

[robert dick]

Back to the Honda 2000S which has the maximum torque (= best efficiency) at 7500/min producing 230 HP, or 115 HP per litre at 7500/min.
Again transferred into the BMW we have 885 HP at 19200/min. Assuming that the quality of the BMW Formula 1 engine and the fuel are better, 900 HP should be possible.

I am beginning to be convinced.

Thanks for your patience!

[cadwal]

Originally posted by robert dick
A lot of test have been run with all forms of “airboxes” : They have no supercharging effect, the
advantage being that the aspirated air is immobile.

Ah, I never considered that reason for having an airbox. It is nice to always learn something new.

The “something” above the intake is used on the bench and connected to the outside in order to
provide enough air for the test (at the beginning of the eighties Renault tested the 1.5-litre turbo
engine with no connection to the outside – suddenly the engine stalled, the air in the test room
was used up).

Yes, I did consider that. Diesel engines on submarines is the perfect example. I just did not find
any good reason to connect that contraption directly to the air intake, it would have been simpler
just pushing a resonable amount of air into the room itself.

Moreover articles 1.12 and 5.3.1 of the Formula 1 regulation outlaw any system increasing the
pressure or decreasing the temperature of the aspirated air.

Article 5.3.1 talks about temperature, but article 1.12:

1.12 Supercharging :
Increasing the weight of the charge of the fuel/air mixture in the
combustion chamber (over the weight induced by normal
atmospheric pressure, ram effect and dynamic effects in the
intake and/or exhaust system) by any means whatsoever. The
injection of fuel under pressure is not considered to be
supercharging.

definitely mentions effects caused by the air intake as NOT counting towards supercharging.
It then goes on to say that injecting fuel under pressure is ok as well.

For this to explain Alexandros observations the pressure in the intake would have to be 23%
above normal on average. (reservations for possible math errors here )

It might also explain the efficiency deviations Vrba calculates. They can just push more fuel into the
cylinders than he allows for instead of being more efficient. There has to be a limit to the useful
pressure yes, but it probably is higher than 1 atm.

Article 5.3.2, about not putting nitro, eter or something like that in the air, looks like a major
loophole to me, but there are probably all sorts of reasons why you cannot make your "engine
sump gases" contain anything useful.

[JwS]

I don't know if the ram effect is included in the quoted HP figures, that is an interesting point to consider, but there definitely is an effect. Many current sport bikes use the ram effect to get a few percent more HP, and when you are making around 900HP a few percent makes a difference. In addition, an F1 car going 200mph with that big intake up there in the breeze is definitely going to have the potential to produce more pressure than the production bike systems.
In addition, cylinder filling of over 100% (supercharging) is possible using intake tuning etc, and F1 cars do use variable intake horns (for some reason, I wonder why??).
So the efficiency does not have to be all that fantastic, in fact at the high engine speeds I would think it would get worse.
JwS

[michaelab]

JwS - I'm pretty sure that variable intake (and exhaust) geometries are banned in F1.

Michael.

[sannik]

Engine weights:

If the new BMW engine weighs less than 90 kilograms, how does that compare to the rest of the Formula One engines, Ferrari, Renault, BAR, Toyota,etc...?

And...

How does engine weight impact on an F1 car's driveablity?

Any thoughts???

[J. Edlund]

A VE of around 120% sounds about right, but I do believe this is without ram effects, so in other words, only with the use of induction wave ram or whatever type of cylinder charging they use.

Efficiency is highest at peak torque, after that it is dropping. Maximum efficiency is reached with full or close to full throttle (with or without throttles) and is probably around 30% at peak power. The efficiency should be expected to be a little lower compared to a modern "normal" engine due to the high cooling areas per cylinder volume (caused by an extremly oversquare cylinder), and the less thas ideal combustion chamber design as well as higher friction losses.

[Greg Locock]

Interesting.

In my opinion the real answer is in a mixture of three of the posts.

Firstly ram air. Max benefit is 1/2*rho*v^2, so at 200 mph that is 1/2*1.2*(200*1600/3600)^2, or about 5%, compared with taking air at the stream velocity.

Next VE is very high at 123% as worked out by someone else. The way this is given (as an airflow)makes me think that it includes any ram air contribution, if you think about it. So the 'true' VE is 118%, great but not unheard of.

Third vrba has done a very handy calculation showing the expected power out per m^3/s of air flow in, but he took a VE of 100% and static air pressure, and I think he might have omitted the air density.

Add all these up and from a 3 litre engine at 105% ram air, 19000 rpm, 118% VE, 45 kJ/g and 14:1 a/f ratio with air at 1.2 kg/m^3 has a calorific power input of
3*10^-3*1.05*19000/60/2*1.18*1.2*45*10^6/14/1000

=2270 kW or 3088 hp.

So the overall efficiency falls to 900/3088, or 29%.

Which is not an unusual figure for an engine that is tuned for efficiency without regards for emissions. A Toyota Prius (which meets Euro IV emissions) manages 32% for instance. If the ram air is a separate effect then you can even reduce that to 27.5%.

There was an old Fiat ad produced during the 1970's energy crisis. It said "Engines don't drink, they breathe".

[robert dick]

Just for comparison :
2.5-litre Climax FPF/1960 : 243 HP at 6800/min = 14.2 HP per litre at 1000/min (= in principle nothing else than the mean pressure)
1.5-litre Ferrari 158/1964 : 210 at 11000 = 12.7
3-litre Matra MS9/1968 : 395 at 10500 = 12.6
3-litre BRM P142/1969 : 418 at 9800 = 14.1
3-litre Cosworth DFV/1970 : 450 at 10500 = 14.2
3-litre Ferrari 312B/1974 : 490 at 12400 = 13.2
3-litre Alfa Romeo/1975 : 515 at 12400 = 13.8

3-litre BMW/2003 : 900 at 19200 = 15.6

[PPatrik :: LKF]

Honda S2000 is good for example. 240 bhp/ ~8000...

You can think what is better in an F1 engine?

the air filter is more efficient, the engine usually won't do more than 1000 km even with revision. so they don't need to keep out all of the dirt. the air intake system don't have such long and narrow intake pipes and whatsoever like a road car does.

they can open the intake and the exhaust valves at the same times (pls forgive me, my english you know... ) so the fuel can go directly out. with a catalysator on your car you can't do this...

the exhaust system: it doesn't have any muffler nor catalysator, far more efficient than a road car's.

the fuel: sure they have some hard rules about it nowadays but it can bring you yet more some percent of power.

IIRC a Saxo Kit-Car had around 225 bhp with a 1.6 litre engine. And it's highest rev was around 9500.

Now they have the cheaper Super 1600, 207 bhp / 8500 RPM (and Saxo is the only S1600 to have four 34 mm air intake restrictors which will be outlawed in 2002.)

so i think it surely can do 200 bhp / 8000 rpm without that restriction. and it's a 1.6, so as follow your line a 3.0 can do 375 bhp / 8000 RPM and can do 890 at 19000 rpm

[scarbs]

I can't dispute the efficiency equations stated here, but heres a few snippets I've picked up that answer a few comments in this thread.

Luca Marmorini (Toyota) told me he would have thought an engine spinning at 19,000 should produce more horserpower than the ~900 Williams quoted last year, he suggested the 2002 P82 BMW engine might not be as efficient as beleived..!

Inlet tuning makes use of both Ram effect from the airbox inlet and the accoustics effects of the inlet waves. these combine to allow increased efficiency.

Engine outpput (IIRC from Mario Iliens PDF at the top of the forum) is based on the net of two parameter FMEP and BMEP, BMEP being the theoretical maximum output and FMEP being the frictionalpumping losses. Aside from configuration changes BMEP is almost a constant, while design and material developments can reduce FMEP, so this is a major area where F1 engines gain over production units, with production based materials, part-life and tolerances. (please correct me on this one if you have read the PDF recently)

Variable inlet lengths are allowed in F1 and are used, the inlets (bell mounths) move up and down via stepper motors. Variabel length exhausts are not allowed.

Engine weight is a non specific figure, what is included in the engine? oil, coolant ancillaries. I doubt the BMW is the lightest engine on the grid, I know the target figure is between 90-100Kgs from a chassis designers point of view (geoff Willis's to be exact) so that weight is probably inclusive of all the bits reqiured to be contained within or around the engine. less than that and stiffness becomes an issue and at that the engines weight is already around same as the ballast added to the car.

The CofG height is bigger issue than the ultimate low weight, the manufacturers are waisting the heads to dramatic proportions, the Cosworth CR4 (an oldish engine, right?) has water jackets shrunk around the bores and combustion chmaber to the point the hemi-spherical chamber and inlets port stacks shapes are visible externally..! Cam covers are wrapped tight around the cam shafts, no big block shape heads in F1.

Excess Engine weight is a factor, Jacques villenueve mentioned in the BAR Indy press release that drivers with heavy engines (Honda...?) will struggle in the corners where braking and direction chnages are reqiured simultaneously.

[JwS]

The S2000 is not a bad model, but motorcycle engines are probably closer. The good 600 cc engines are spinning up to 15000 rpm, and outputs are up around 120 hp. So at a 3.0L level, that would be 600 hp at 15000, sounds fairly close. Of course there is more involved than just scaling up the engine to get 3.0L, it is much easier to build a smaller displacement engine that can handle those revs. (you can buy a .049 cubic inch engine that spins 30000rpm for 50 bucks....)
Alot of the difference in efficiency is in the basic construction of the engine, they are less limited in port design. They can afford to spend a week cutting and shaping ports and stuff in an f1 engine where a S2000 or bike engine is as cast. The same thing goes for every part of the engine. In production things have to pretty much go together without fiddling, in F1 you can afford to spend time on the little details.
JwS

[karlth]

"In its final development stage, the P83 engine weighs 90kg and endures 19,300 revs per minute."
BMW-Motorsport.com

[desmo]

The following is a brief excerpt from the SAE paper alluded to by Craig above (unfortunately not freely available on the web) 2002-01-3359 "Demands on F1 Engines and Subsequent Development Strategies" authored by Hans Alten and Mario Ilien of Ilmor. The second equation does not show properly in this excerpt unfortunately. Anyone interested in this thread would probably find the paper an informative read.


The maximum specific torque output of an internal
combustion engine is driven by the following key values:
• Maximum volumetric efficiency
• Optimised combustion process
• Minimized friction losses

The maximum specific power performance is specified
by the factor TORQUE x RPM.
To deliver a competitive race engine, the highest power
output is necessary, but low overall weight, a low centre
of gravity, durability and low fuel consumption have to be
considered as well.

BASIC THERMODYNAMICS:
The effective engine power output is defined by the
following terms:
PE [kW] = BMEP x VOL x n / 1200
where the brake mean effective pressure is
BMEP = IMEP – FMEP.

The indicated mean effective pressure IMEP can be
divided into two sub events during the entire cycle period
of 720 deg CRA:
dV p
V
IMEP IMEP IMEP P H 1 ∫ ⋅ ⋅ 



 = + = (3)
IMEPH ……………………High-pressure-MEP, -180 - 180° CRA
IMEPEX = IMEPEX + IMEPIN……Pumping-MEP, 180° - 540°
CRA
p……..…………………….…………………..In-cylinder pressure
PE……..…………………….…………………….Power (effective)
V……..…………………….…………………..…..Cylinder volume
CRA……..…………………….……………….…..…..Crank Angle
The friction mean effective pressure FMEP in equation
(2) contains all losses due to internal friction and all
auxiliary drives. This data is related to the mean piston
speed and is significantly lower in comparison to
common road engines. On the other hand, even with
extremely short stroke lengths, today’s F1 engines
exceed mean piston velocities of 27m/s. This limit
defines the size of the bore - the engine has to have a
bore diameter of at least 90 to 92 mm.
To predict an IMEP and/or a number for the volumetric
efficiency at rated speed, an absolute friction value has
to be predicted. In a simple assumption a FMEP from
common road engines can be taken into account,
running with approx. 18m/s mean piston speed at 6000
to 6500 rpm. This leads to a simplified equation to
calculate the friction losses as function of the mean
piston speed vP:
FMEP = 0.3 + 0.04*(vP)1.3 (4)
These basic equations and assumptions are a good
starting point to work out some key dimensions of an F1-
race engine, which has to run with a volumetric
efficiency of at least 116% at 17000rpm to achieve a
power output of nearly 800hp.

[robert dick]

According to Hans Alten and Mario Ilien “The friction mean effective pressure FMEP in equation (2) contains all losses due to internal friction and all auxiliary drives. This data is related to the mean piston speed and is significantly lower in comparison to common road engines.”

This means that frictional losses which are not proportional to the engine speed are/could be the reason for “an efficiency of at least 116 %”. Between the lines can be read that some mechanical/dynamic effects within the crankshaft/piston system (using an extreme bore/stroke ratio) reduce the generated forces on the bearings and cylinder walls and are responsible for these relatively low losses.

On the other hand we still have the MotoGP engines, for example the Ducati which delivers 220 HP at 16000/min (= engine speed of best efficiency, the engine being able to reach 18000/min) or 13.75 HP per litre and 1000/min, in comparison to the BMW’s 15.6 (this value being nothing else than the “bmep” of the Alten/Ilien paper expressed in a different unit). Obviously in the MotoGP engines we still have the usual losses.

[JwS]

I don't think any of the MotoGP engines are at this point as fully developed as the top F1 engines, and they may also be tuned to give a wider power band to improve rideability.
JwS

[dc21]

Here's some more figures for you to chew over:

With a 24mm air intake a 2.0l F3 engine produces about 160bhp @ 6000rpm
With a 26mm air intake the same engine produces about 200bhp @ 7000rpm

These are high compression engines with what should be standard crank, rods, and pistons. The fuel is standard pump fuel.

A 3.0l Judd BV (maybe EV) produces 500bhp @12000rpm (I think).
A 3.0l Cosworth HB produces similar figures.
A 100cc 2-stroke can produce between 30 and 35bhp @ 19000rpm with a 24mm carb.

As a generally rule of thumb you should knock about 50bhp off the figures quoted in F1, there is a degree of hyping that goes on. Also, at higher ranges I would be unsure as to the accuracy of a dyno.

Dave

[Alexandros]

We're taking the horsepower output of S2000 to compare it to F1 but we forget that this is NOT the optimum horsepower value that can be taken out of this engine, where in F1 it is. In an old Autospeed article (autospeed.com is a subscriber based e-zine) they had achieved a bit over 300 hp in a Honda S2000 from ECU replacement with an aftermarket ECU, an intake duct to the airbox and a new exhaust. They found out that the exhaust was the most restrictive part.

And from other magazines I've read, a gain of around 4% was dynoed in a S2000 with Shell V-Power Racing 99+. A racing lubricant would also provide at least 3-4% better top end hp as it does in any high-revving engine.

Anyway if we combined all these, it means that we'd have around ~325 hp out of a 2lt NA engine with peripheral modifications !!! (162.5 hp/liter)

I really wonder what would happen if we used F1 fuel and increased this engine's compression from 11 to 13 or do other "heavy" mods... Perhaps we could see 400 hp. (200 hp/liter). Perhaps it's not unlikely, since non-variable timing engines like those used in 1.6lt NA kit cars (like the Saxo mentioned above) usually produce around 210-220 hp IIRC, which is around 137.5hp/liter...

So I take the prior calculation that Racer Joe did: 240/2/8000*3*19000=855bhp and apply the new number.. 325/2/8000*3*19000=1157 hp and 1170 for 19200 rpm. Hmmm... there must be quite a lot frictional losses up there...

[Dynojet]

Robert Dick

You are making a mathematical mistake here: power is already a product of engine speed (Power = torque vs rpm), so you cannot say a thing like "200 hp per liter rpm/min ". At every RPM you will get a different figure of BHP/Liter, with the peak at the peak power rpm.

I haven't readden the whole topic (not patient today) but I may answer your questions:

1. Power is a function of speed, so the way to increase power output is by increasing engine speed by shortening the stroke. Thus the 19k plus rpm marks of today. As far the specific power is just the peak power divided by the displacement, it increases also.

2. Volumetric efficiency over 100 % is possible in aspirated engines. You can anchieve this by some means: More "open" camshat, ie with more duration and overlap; use the pressure waves on air box; using the ram air effect, with the airbox increasing air pressure; use of richer air/fuel mixture, so fuel latent heat is used to increase the air density (this explains why the injectors are placed so far from the ports).

3. The thermal efficiency of racing engines are usually not high, so a figure under 30 % is probable. This is caused by the greater friction losses from higher rpm's and the somewhat rich mixture.

[jdowns]

2c's worth:

My ZX-12R has approx 190hp from a 1.2l @ 10,500rpm (176 at rear wheels, 190 at engine is a guess by the guy running the dyno).

= 860HP with 3l, 19,000rpm.

Stock is 176hp at 10,500 at engine = 796hp @ 19,000rpm, 3l.

Engineers from Kawasaki say they get around 12hp from the air ram at 320km/h = 7% over the stock 176hp.

If you add the 12hp to 190, 202hp, you get 913hp @ 19,000, 3l. Even stock (12+176=188) gives 850.

Only mods are new exhaust and air filter. Standard ECU, injectors, plugs, etc.. F1 must have advantages in them.

PS. Heaps good fun in a 215kg bike ;)

[schuy]

Jdowns- Good to hear you own a ZX-12R.
I hope it's the pre-2003 version, before they limited them to 300kph.

It's one hairy bike innit?

Liran.

[jdowns]

Yep, 2002. Already been about 330km/h, but since the speedo only goes to 280, I had to guess from the tacho. I hear the Australian version isn't going to be speed limited. The Euro version (so I've heard) has been limited for a while now.

Affectionaly known as the Anti-Christ.

[schuy]

Originally posted by jdowns

Affectionaly known as the Anti-Christ.

Cool.
Don't you find it though a tad too heavy in corners when compared to it's rivals?

[jdowns]

Yes, even with performance tyres it can't carry the same speed through corners as the thoroughbreds (I take it to Eastern Creek race track occasionally), but I doubt I'd be able to use the extra handling anyway - I've only been riding for a year - and as Wayne Gardner said 'Anyone can go fast in a straight line' - and I have the best production bike ever built for going fast in a straight line!;) Most HP, best acceleration and highest top speed of any proddie bike ever built. Besides, I'm a few pounds over my fighting weight, and probably wouldn't get the best out of a smaller bike anyway... There's nothing like coming onto the straight behind someone who's bought a big name sports bike like an R1 or a Hyabusa, AND STOMPING ON THEM!!! Of course, the R1 normally re-takes me through turn 1...

Now look what you've made me go and do - rambling off topic... Sorry group. Still, there aren't too many other ways we plebs will ever see >220mph. Street-legal to boot (mostly).

[Patrice L'Rodent]

Since when will a 'mostly standard' version of the big Kwacka do >220mph?
PDR

[jdowns]

I have a video here ("Return of the Mach" by 'Fast Bikes TV') where they take a Blackbird, Hyabusa and a ZX-12 through Europe. Quote of the video (the video is on the 'busa rider's helmet, where you can see the speedo) "210mph on the hyabusa speedo, and the ZX is walking away in the distance". It's gotta be doing at least 215.

The pipe and air filter on mine added about 17hp (10%). Dunno about the gearing (but the stock gearing apparently is good for 215), but that's easilly changed. Biggest challenge is finding the road - and the balls...

I've done about 206 (330km/h), and it was still pulling pretty good.

220 was just a guess. I'll tell the world if I ever max it out ;)

Jordan.

[Patrice L'Rodent]

Whatever.

[Halfwitt]

Ooh, if it says it on a speedo it must be right

I calibrated a digital push-bike speedo and fitted it to my trusty steed. Keeping up with my mate on a GSXR750 (1996 model), I showed 148mph max. He swears he was doing just the high side of 175mph. He looked hurt when I suggested Suzuki hadn't made one that went that fast yet.

Production speedometers are about as believable as Mr. Blair.

I'd be pretty surprised if any stock bike with a pipe and filter did a genuine 200mph, never mind 215 or 220

[schuy]

Cool.

Just watch out mate.

[LandOfSnow]

A Blackbird showed about 300km/h at speedo... measured speed 253km/h,
a Volvo T6: 235km/h at speedo... 193km/h measured.