68 replies to this topic

[SlowDrivr]

Anyone want to discuss the technical side of F1? Anyone actually work in the motorsports industry that knows stuff like this?

I'd be interested in engine, suspension, and aerodynamics, whatever. Details (even guesses) about how one engine can have 100hp more than another, what fails what an engine blows up (I've heard the engine manf. like to keep that secret), etc.

Here's a couple tidbits I've read:
1) F1 cars today use the same size calipers and rotors on the front and rear. Reason is there's so little weight transfer you don't need the fronts to be larger.

2) The Stewart engine weighs under 100kg. The Mercedes engine develops over 820hp and revs to over 17500 rpm.

[Schumi Fan]

All these figures are mostly guesses, because the F1 teams don't really want to divulge any info that might benefit other teams... I think that if they gave out their HP numbers, their aerodyamic efficiency would become evident (eg. if Stewart said that they have 20 HP more than Ferrari, yet they are slower in race trim, that would ruin team/driver morale).

I found it interesting that F1 engines produce about 235(?) LB-FT of torque (or is that Newton-meters?), yet they accelerate so fast...

[DangerMouse]

Schumi Horsepower = Torque(lbs/ft) * Revs, (not exact equation but that's how it works) you don’t need big torque figures to make big horsepower just lots of revs.

[Schumi Fan]

I aggree, but torque is inversely proportional to power at any RPM, so an engine optimised for peak horsepower will lack torque, especially at low RPMs. What I found interesting was that the engines, off the start, rev at about 6-10K, and then build up from there. That is roughly 1/2 of the max RPM, so the torque figures must be very low, much less than the max 235 or so. To get a car off the start so fast with so little torque is impressive.

But then again, I might be mistaken...

[ket]

I think today's top engine will rev close to 20,000rpm. Last year's Ferrari engine already surpassed the 800hp mark. It is quite amazing how reliable their engine has been consider the kind of mechanical stress it endures. When engine output figure are quoted I wonder if it refers to the output at the dynometer or at the wheel. I believe having the most powerful engine doesn't necessary mean that you will have the highest output at the wheel. Things likes gearing and rotating mass of the transmission all comes into play as well. This is the area where the Macs probably have a significant edge over the Ferraris.

[Zoe]

Concerning engine revs, isn't there a method to measure the revs it actually does by measuring the frequency of its exhaust noise?

With respect to the torque of an F1 engine, there is always the issue of "driveability", which simply describes how the torque is "spread" over the revs range. There is little use in an engine with an incredibly hich peak power that is only available at peak revs. I remember that the Renault engine was rarely the best in terms of peak horse power, but it featured a good torque bandwidth so it was more easy to drive than a on-off engine (I think the Yamaha was one of the latter).

Zoe

[Duane]

Usually an engine will hit it's peak torque much further down the rev range than for peak horsepower. One would think that about mid range on the rev band is about the area where peak torque wiuld come in? Maybe.....???

[JHH]

So with the Mercedes or the Ferrari (or even the Supertech), where in the rev range does the motor hit optimum torque and/or peak horsepower? Do you think the drivers need to run the revs in excess of 14K in order to get the powerplant "up on the cam" as they used to say? I guess I'm wanting to know whether the newer F1 racing motors tend to be the on-off types like the older versions.

Also, who makes the Supertech motor? Is it a Williams venture or is it just a rebranded version of a Mechachrome or something?

I think any of the HP figures you read about are measured off the dyno. I'm guessing that once the motor makes it into the chassis, the teams prob. give up on figuring hp and measure factors more related to drivability.

Here's an interesting comparison of bhp outputs over the last couple decades.

1961 Ferrari non turbo V6, 1.5Litres - 190 bhp
1970 Ford non turbo V8, 3 Litres - 510 bhp
1986 Honda Turbo, 1.5 Litres - 1,200 bhp
1993 Renault non turbo V10, 3.5 Litres - 750 bhp
1995 Renault non turbo V10, 3 Litres - 700 bhp

Interesting how the turbo had so much grunt in qualifying trim but the modern cars are lapping faster due to advances in suspension and chassis design.

I also have to wonder whether FIA will move to drop displacement requirements now that motors are approaching 800 hp under the 3.0 liter formula.

pondering...

James Harold



------------------
" I have no interest in any ship that does not sail fast, for I intend
to go in harm's way." Captain J. P. Jones, US Navy - January 16, 1777

[Schumi Fan]

JHH, from what I know, the Supertec is the old (1996?) Renault engine that is branded as Supertec/Meccachrome/Playlife. It's a works deal, with Flavio Briatore in charge.

About the displacement, I read somewhere that the FIA will not drop the displacement to under 3 liter, because F3000 has a 2.5 liter restriction (I believe), and they don't want to bring F1 down to the level of a lower series.

[Megatron]

The Supertec is a continuation/update of the engine Renault designed in 1996 that was raced their last year in F1 in 1997.

After Renault offically pulled out of F1 at the end of 1997, they continued to supply customer engines via their technical partner Mecachrome (who actually designed some of the first Renualt engines). Mecachromes job was to tune and service the engines.

These previously free engines now carry a price tag of $21 Million a year.

The engines devlopement was slowed way down to basically nothing in 1998.

Then Flavio Breitore started Supertec, and took control of the Renault engines. The engine is still way behind in devolopment and is rumored to be between 50 HP and 70 HP down to Mercedes, Mugen, Ford and Ferrari.

The rumors are that if Renault does come back, then they might take control of Supertec and then give reasonable updates to the Supertec users.

The Playlife is the Supertec V10. They call it Playlife because that is owned by Rocco Benneton, owner of the team.

Also, during the turbo era, the two strongest engines were rumored to be the BMW W4 and the Renault V6.

BMW were rumored to bring an engine to the German GP in 1985 that had around 1400 BHP in quailifying trim, while Senna's Loutus Renault had nearly 1500 BHP.


------------------
Death through Tyranny - Megatron



[This message has been edited by Megatron (edited 07-30-1999).]

[tak]

Great thread. As far as peaky motors are concerned, keep in mind that all the cars have 6 or 7 speed close ratio gearboxes--the engines need less than a 2000 RPM wide powerband. Of course, coming off slow corners in 1st or 2nd gear is always an issue, as the cars are traction limited, not power limited. Expect 1st gear on an F1 car to stretch to approx 100 kph. If the track in question has a 300 kph top speed, then each successive gear in a six speed box only needs to cover 40kph (a bit oversimplified). There is a great magazine out of the UK called "Race Car Engineering", that talks about alot of the technical issues without going into engineering terms. If you've had 1 semester of university physics, you should understand 95% of what they write.
Another great book for basic technical knowledge is the "Automotive Handbook" published by Bosch. It has a 10 page section giving simple equations calculating combustion pressures, engine torque, piston velocities, engine output, etc.

Traditional problems with high revving engines (and F1 motors deal with all of these) include:
1)Strength of materials--especialy connecting rods and valvetrain. At 18,000 RPM the acceleration that pistons and valves suffer is ferocious. Crankshafts also try to fly apart from the centrifugal force. Engine components face a strength/weight tradeoff.
2) Oiling. Almost all engine bearings are "journal" bearings, using a thin film of oil to keep metal surfaces from touching.
3) Heat transfer away from the piston. Most of the heat is transferred away from the piston through the piston rings into the cylinder bore, and from oil sprayed onto the bottom of the piston. Higher rpm requires smaller piston rings, allowing less heat transfer. Additionally, the faster you spin an engine, the harder it is to keep oil in contact with the bottom side of the piston...

[IndyIan]

Does anyone remember one of the years when schumacher was at benneton and his
transmission go stuck in 5th gear? It was after his last pitstop and after
a few laps to adjust he was lapping only a second or two of his race pace.
In that race having a wide power band was very important.
tak,
I think you would find most of the successful engines in F1 have a fairly wide power band,
even though it is possible with 6 or 7 gears to have a narrower stronger power band.
You never hear the cars high rpm in the middle of tight or medium speed corners
because the throttle response is too touchy up there. Say a driver is half way
around a 140 kph corner and is starting to dail on all the power he can get
down to the ground (150hp lets say) without wheel spin. He doesn't want the
engine up at 14000 rpm because 150 hp is 1/8th throttle and a slight bump could
make his foot hit the gas slightly harder to 2/8 throttle(say 300hp at 14000rpm)
and then he sliding sideways and might have to let off. It would be better to be
at lower rpm where 1/2 throttle is 150hp and 3/4 is 200hp which means the driver
can be less precise with throttle position and still get out of the corner quickly.
My buddy and I used to have dirt bikes. He had a 125cc screamer and I had a fairly
mellow 200cc. Riding the 125 it was very difficult to get consistent exit speeds
out of tight corners because it would bog or spin and slide out. My 200 was much
easier because I had a wider powerband and better response at lower rpm.

Also, an other problem with high revving engines is that they are ineffecient,
spraying and pumping the oil around actually begins to use up a significant amount
of the engines horsepower(maybe 20% at 16000 rpm) this horsepower goes into heat which make the engine less powerful.

Mercedes used a special lower rpm engine at the last Indy 500 that the CART cars
ran. I think the rule at Indy was if the engine didn't have over head cams you could use
more boost. Without ohc they couldn't rev as high but with extra boost they could
make as much (or more) hp as the rest of the cars but their big advantage was that
they used less fuel because the engines were more effiecient, less weight, less
pitstops. I think they won but I know they did well.

[Megatron]

The engine in 1994 at Indy won the race easily. Fittapaldi had nearly a lap lead on everyone when he crashed, then Unser Jr blew off a young JV.

That engine is actually (some say) one reason for the CART/IRL spilt.

------------------
Death through Tyranny - Megatron

[Yelnats]

The issue of how an F1 car can be so impressive off the line with so little torque comes down to gear ratios.

An engine that produces it's torque at high RPM can use a higher gear ratio in the transmision to multiply the torque delivered to the rear wheels. So a F1 engine reving to 18,000 can easily out torgue a Viper V10 at the rear wheels. It can use about 3 times as high a gear ratio for a given road speed to multiply the 235 ft lb to effectivly 700 ft lb, well over the approximatly 500 ft lb of the Vipers 8 litre engine.

[This message has been edited by Yelnats (edited 07-30-1999).]

[tak]

IndyIan-
You are right about not taking a corner at max RPM. Typically, gearing is chosen to maximize acceleration out of a corner. Ideally, the engine will reach redline at the same time the car reaches the exit berm. As soon as the driver straightens the wheel, he is shifting to the next gear. This gives the fastest launch onto the straights, without upsetting the car by shifting in the middle of a corner. Carrol Smith's "Tune to Win" describes the process of selecting gear ratio's--it's good reading!
The example of MS (at estoril I think) is a paradoxical example. Yes the Ford engine that year had a wider power band than the v10's or v12's. It's real strength however, was driveability--small changes in throttle position gave predictable, repeatable changes in power delivery. This enabled MS to carry as much speed around the corners as his tires would allow, he could get on the gas early and progressivly without upsetting the handling of the car. The good driveability of the engine allowed him feed on power gently, and keep the rear wheels within their traction limits. Whenever you hear drivers talking about "engine mapping" today, this is trying to improve the driveability of the engine.
A somewhat more telling example of engine driveability involves Mclaren Honda between 88 and 89 seasons.
After the 88 Suzuka GP, Prost and Senna stayed in Japan to try the new normally aspirated Honda engines. In the turbo cars, the boost lag was so bad they had to roll on the throttle a few tenths of a second before they wanted power, and power would build as the turbos spooled up. The first morning of the test, much of Honda's brass got to watch the two best drivers in the world suffer repeated spins and off's. The power delivery of the normally aspirated motors was immediate, and the drivers had to learn to "wait" until they needed the power before rolling on the gas!

[HartleyHare]

F3000 cars all have 3 litre engines. Hence the name.

The reason F1 engines are so revvy yet remain so tractable is down to sophisticated control of induction, fuelling and valve timing. Now that all are electronically controlled the engine can be optimised for all rev/load conditions within the mechanical constraints of a very short stroke engine.

In the search for power, control of frictional and mechanical losses at high revs, and maintaining a good burn at those revs are the key. Given the current state of the art, a V12 would seem a wise move. Perhaps that is one reason why teams are trying to build the lightest possble car (except Benetton! ballast is a useful tool, but perhaps it is a first step to accomodating a heavier motor. Ilmor/Mercedes V12 next year? I'd love to see a bit of variety....

I was very amused to read recent suggestions that F1 regs ought to ban 12 cylinder engines's in order to save money. Save money? An exotic V10 is no cheaper, is it? A new design is necessary every two or three years already - evolutions will not cut it after that (witness the struggle of the redoubtable Renault/Mecachrome/Supertec). So why not a new 12 cylinder job rather than the neverending succession of blimmin' V10's?

And the idea of saving money is anathema in F1 anyway - if they don't spend it on the engine it will go elsewhere. Restrictive regulations only serve to maintain the status quo - miniscule refinement of existing technology is very expensive, so it is almost impossible for small teams to bridge the gap to the big teams: they can't afford the wind-tunnel time, plethora of new parts (most of which are rejected) or track time. But freer rules might allow an innovative team to steal a march. And even if the advantage was fairly short lived, it would add a bit of spice.

I'd just like to see a modern day Colin Chapman. And a modern day Lotus F1 team. Unlikely in the commercially dominated, motor manufacturer friendly F1 of today.

Sigh....

[PDA]

HH - to expand a little on your comments for the sake of clarity.

Induction path length is variable, i.e. the inlet "trumpets" are of variable length.
Valve timing is variable, allowing gentler cam profiles at lower revs, therefore making the engine more flexible.
Fuel injection and ignition timing electronically controlled to enhance drivability i.e. widen the power band. the mapping can also be "tuned" to the style of one driver or another.
Really clever mapping can detect that the engine is increasing its revs faster than it should be given the known performance parameters of the car (i.e. the wheels are spinning or the clutch is slipping) and then modulate the spark or fuel feed. This is not allowed by F1 rules, and the engine mapping software must be examined by FIA software engineers to (try to) prevent cheating.

The torque and power of an engine at any particular revs are ultimately determined by how well the cylinders are filled with fuel/air mixture (the reason for the variable inlet stacks and the variable valve timing) and how well the mixture is burned (engine mapping - control of the spark process).

I am assuming the variable valve timing, because there is no way of seeing its presence in an engine, and as pointed out above, the manufacturers are very reluctant to give out specifications, so most if not all of the "data" we see reported in the magazines is speculation.

Honda have claimed in the past that their VTEC variable valve timing for road cars was a direct result of their involvement in F1 racing. This would imply that Honda at least uses variable valve timing.

Re costs and V12s. I would suggest that when Ferrari, Ford etc bring out a "new" engine, it is really a development of what they already have rather than a truly new engine. If, say, Honda came in next year with a truly new V12, and it proved substantially better than the V10s, then the others would have to follow suit, and incur massive development costs. Some people in the sport reckon it is expensive enough as it is without this threat. It is the same with chassis rules. If a change was made from grooved to slicks, together with a major change in aerodynamic rules (banning diffusers e.g.) then totally new cars will have to be designed. Again, the less well sponsored teams will suffer the most. This is an argument for stability in chassis rules.

[HartleyHare]

What cam profiles? They have pneumatically operated valves these days - infinitely varible logical cams, I suppose.

I disagree about rule restrictions helping the little teams. The more it is an exercise in refining the same basic formula, the more the big budgets, unlimited testing (even though this is meant to be restricted) and 24/7 windtunnels will win the day. A more broad base of rules would allow a smaller team to explore different avenues and possibly gain a brief advantage. Otherwise they have no chance at all.

And it would be more interesting.

[Incal]

Another query. I read somewhere that the centre of gravity in a F1 car shifts under heavy braking from just behind the driver to just over the front wheels. That is impressive stopping power. Is this one reason the turnin speed to the corner can be so high? How does this braking ability compare to the early F1 years given that the top speed has not changed that much? I know that the downforce is much greater, but does the braking speed also help?

[HartleyHare]

The braking effort these days is massively stronger than in 'the old days'. This is helped by terrible aerodynamic drag (honest!), carbon brakes and modern, slick tyres. Doh! We're back to retro treaded tyres now, aren't we? Next it will be wire wheels and drum brakes.....

[HartleyHare]

And the speed at which a turn can be taken is mainly determined by downforce. The shift in the weight distribution is just a result of the stunning deceleration. In fact the pitch chance it causes upsets aerodynamic balance into turns. The virtual elimination of which was why the old active-suspension cars were able to corner so hard.

[PDA]

HH - the pneumatic operation in the valve gear is a replacement for the steel valve springs which we mortals have to use. The valve opening is still controlled by a camshaft. the pneumatic part is used for closing the valves only.

The massive reduction in braking distance since, say, 1969, has been brought about by a number of factors.
1 use of Carbon discs and pads.
2 massively improved efficiency of the tyres.
3 high drag of high downforce wing settings
4 When braking from high speed, the high downforce contributes.

Of these, the tyres are probably the biggest factor. If F1 went back to slicks, without reducing section size, braking distances would reduce even further.

[Christiaan]

where the hell were you guys when I asked for Pacman to set up a technical Forum?

Shall we bother him again ? I know I would want one, what say the rest of you?

[SlowDrivr]

Another good magazine with technical stuff in it is RaceTech. That's where I got the HP estimates from the beginning of this year.

I think saying that the center of gravity shifts is misleading, since the CG is a function of how much weight is where and has nothing to do with acceleration.

I didn't know F1 engines used variable inlet lengths. They must be fairly short considering they need to work at 18krpm (or whatever it is). Like a 2-3 inches?

Anyone know if a partial vacuum is kept inside the crankcase to lower losses from pushing air back and forth in there?

In the turbo era, what was the rumoured maximum hp in race trim? I have a book, "The Formula 1 Turbo Era" by Alan Henry, that lists 900hp as the highest for a race engine.

Tak- I would be very happy waiting a few tenths of a second for a 1000+hp turbo engine to spool up F1 drivers are so impatient!

[SlowDrivr]

Anyone have details on how the pneumatic valvetrain works? I've never seen a picture of it. It uses compressed air to help close it? Is the compressed by a pump on the engine or is it a valve assembly that is compressed when its made and sealed?

[Yelnats]

Anyone know the status of eliptical pictons , ceramic coated combustion chambers and composite connecting rods? I understand these were banned by the FIA or general aggreement quite some time ago. I don't know if ceramics have been included in this ban also or if they have made an appearance in piston coatings yet?

Eliptical Pistons are fiendishly difficult to manufactiure with rings and combustion chambers to suit but offer reduced engine length and accomodate larger valves.

Composite (carbon or Boron fibre) have huge theoretical weight and strength advantages but are sensitive to heat and go hand in hand with ceramic pistons which reduce heat transmission to the piston.

Ceramic coatings in the combustion chambers can reduce loss of heat into the walls and pistons, thus increasing the expansion of the gasses and pressure on the piston for better gas milage and more horsepower.

Expensive as F1 is now I pressume it would become even more so if these technologies were introduced though I have no inside information as to whether they have already made an appearance.

[PDA]

F1 rules, article 5.1.4 - "Maximum number of cylinders is 12 and the normal section of each cylinder must be circular."

5.1.5 ".. no more than 5 valves per cylinder"

5.1.1 Only 4 stroke engines with reciprocating pistons are permitted.

5.2 Nothing other than the engine is permitted to provide drive (i.e. no regenerative capacitance discharge devices)

5.4 engine materials
1 basic structure of crankshaft and camshafts must be made from steel or cast iron
2 Pistons, cylinder heads and cylinder blocks may not be composite structures which use carbon or aramid fibre reinforcement

I read this as allowing exotic (ceramic) coatings for pistons and combustion chambers. Also no restriction on valve material or connecting rod material.

The engines run pretty hot. The fluid cooling system may be pressurised to 3.5 bar

Pneumatic valves. These are charged up with compressed air before use and are not supposed to leak. In the Brazilian GP, Irvine was called in for a late pit stop. The reason given by ferrari was that they needed to recharge the valve system as the pressure was getting low. I have never seen drawings of Pn valve springs, but they have been around for a while, having been introduced to F1 by Renault. It is these that allow such high revs. Metal springs would be at their limits, although, CART engines rev pretty high (16Krpm??) and must use metal valve springs.

Variable inlet stacks - no idea how long they are, as you never see an engine with the cover off. Operation of the system is by hydraulic pressure, and control by the ems.

I note with some amazement that article 5.4 disallows variable length exhaust systems!

[SalutGilles]

Well, I'd get ready for the wail of V-12's again. The current Ferrari engine produces 820 BHP at 18,000 rpms. I read that they reckon 19,500 rpm, and 860 BHP will be on tap right out of the box with the V12. Ferrari would have a definate advantage with the V12, even if Honda is ready with theirs, because the Ferrari 048v is the only engine in F1 to utilize both direct and indirect injection, depending on engine speed. This would give the V12 far more drivability than a regular V12. Torque would also be improved, and the Ferrari would be the class of the field.

The Supertec doesn't have to suck, if someone wanted to do development work with it. it would need a lot, but remember that the Mercedes started out in the back of a leyton house in 1991, my point being, F1 is about evolution, rather than revolution. Trouble is, with each passing day, I'm becoming more and more coinvinced that Flavio is in F1 for the chicks.

Here's what I've come to figure about engine output:

Illmor: 835
Ferrari:825
Ford:815-820
Mugen Honda:815
Pugeot: 810
Petronas:800
Ford customer: 770
Supertec: 760-765
Arrows: 765

that's what I've gathered from various sources, but I'm sure it's far from spot-on, given than mum's the word about power from the companies. Any additions/changes?

[JHH]

Turbo Basics:

CART uses a turbo-charged formula. Do the Hondas/Mercs/Fords/Toyotas they use in CART suffer the same turbo lag as the F1 cars used to?

Normally aspirated race cars always seem to have that big air intake up on the engine cowling. Turbo cars don’t have the air intake. Why is that? Doesn’t the 2650cc CART unit require air just like the 3000cc F1 motor?

Back in the days of the 1500cc/4500cc engine formula, they used to refer to the “blown” cars as supercharged. Is there any difference between supercharging and turbo charging?

Thanks… James Harold


------------------
" I have no interest in any ship that does not sail fast, for I intend
to go in harm's way." Captain J. P. Jones, US Navy - January 16, 1777

[SalutGilles]

JHH, the air intake on the F1 cars shoves teh air at the engine, which serves to mildly compress the air, boosting output, if ever so slightly. CART engines, with the turbo boost, have no need for this, and therfore the drag created by the huge intake would not be overcome by any advantage. The engine gets just as much air, but in a more aerodynamically efficient package.

[tony]

Hi,

Here are the answers to some questions people have had in this discussion.

Someone said that horsepower and torque were inversely proportional. This is not true. In fact the relationship between the two is a derivative. For those who know calculus:

Power = d(torque)/dt where t is time.

What is true is that frequently an engine will produce it's peak torque at a lower RPM than it's peak horsepower. The relationship between torque and horsepower is similar to that of acceleration(a) and velocity(v). a=dv/dt

Torque determines the wheel's angular acceleration(degrees per second per second). There is a direct linear relationship between angular acceleration of the wheels and the linear acceleration of the car. Torque = (moment of inertia of a wheel) x (angular acceleration). Thus torque determines how quickly the car accelerates in a straight line(meters/sec/sec or mph/sec). Since horsepower = d(torque)/dt, it is a measure of how quickly the torque is changing with time and thus how quickly the acceleration is changing with time. The rate at which acceleration changes with time does not have a technical name but many people refer to it as "the jerk" Horespower governs how much "jerk" the car has. Oh yea the moment of inertia is a quantity related to the mass and mass distubution of a wheel. The easier way to think about all this is to assume that through friction between the tire and the ground the torque supplied to the wheel produces a force on the car which pushes it. Then you get the more familiar Newton's second law,
Force = Mass X acceleration

Summary:

Horsepower determines how large the change in acceleration with time is("the jerk"

Torque determines how large the acceleration is.

Lastly, the reason why F1 cars can leave from a dead stop reasonably well is because the 1st gear is extremely low, and also simply beacause they are light(Large torque to to weight ratio = good acceleration)

[SlowDrivr]

Re: CART & turbo lag
Any turbo engine has turbo lag. There's a basic tradeoff with big turbo=big horsepower but it takes longer to get spinning fast so you get more lag. That's what we mortals have to deal with in street cars.

There are ways around this. CART uses ball-bearing turbos, which spin easier than the conventional turbos used in street cars. Also, I think CART can use a shift w/o lift system, which keeps WOT during shifting, which keeps the turbo spinning so no lag. There's also a anti-lag system used in rallying that help keeps the turbo spinning.

Re: Engine air scoops.
I think the air inlet on Champ cars is farther back on the top sides of the car, just in front of the rear wheels. I don't know why they don't use a scoop on top of the car.

Re: supercharging vs. turbo.
This can be a little confusing, since sometimes people use supercharging to mean any kind of forced induction, supercharger, turbo, whatever.

A supercharger is a compressor driven by the engine. A turbo(charger) is a compressor driven by turbine which is driven by exhaust gases. A supercharger has no lag but generates more heat for the same pressure than a turbo does.

[HartleyHare]

I thought supercharger was the generic term for forced induction: early turbos were called turbo-superchargers. The convention these days is that supercharger means mechanical just because 'turbo' is not mentioned, but this can cause confusion, as you rightly say.

The power outputs quoted earlier are pure speculation and tend to give a slightly misleading idea of engine performance. Peak power is important but delivery, response and peak revs are pretty important too, especially as most tracks are dominated by 2nd/3rd gear corners these days.

For the same reason aerodynamic efficiency has slightly less importance than it used to be and mechanical performance has more.

[tak]

A couple of items-
On horsepower vs torque. Tony, please check your source! The relationship between horsepower and torque is:
HP = (Torque * RPM)/ 5250. It is best described as the rate torque is delivered, not the rate it changes. For example, a mythical F1 car that makes 250 ft*lbs of torque at 17,000 RPM gives 810 HP. A street car with 250 ft*lbs of torque at 5000RPM only makes 238 HP.
For the more techno minded, consider some simple unit conversions. According the "Bosch Automotive Handbook" (or any physics book) 1 HP = 746 kW. Recall that 1 watt = 1 joule/sec = 1 N*m/s. Reconfirming that Horsepower is the rate of torque delivery--ie, the number of Newton*meters delivered per second.

On the pneumatic valves, the "air" supply is a bottle of compressed nitrogen (I think at around 2000 PSI (136 Bar). I have no idea what the actual working pressure in the system is--I would assume they allow for some leakage.

On turbo lag of CART vs F1, remember that in 88 the F1 cars were allowed 2.5 bar (36.7 psi). In 87, they could run 4 bar (58.8 psi), and before that it was unlimited (I read BMW used 5.5 bar (81 PSI) in qualifying. In comparison, Cart cars run (I think) about 0.5 Bar (7.4 PSI). Cart cars have very little lag because they make very little pressure. If anyone can quote the current CART rule, I'll do the conversion to BAR and psi.

[SlowDrivr]

CART currently allows 1.35 bar of manifold pressure, or just over 5 psi.

That's a good point though, with that little boost turbo lag isn't as bad as it was with the F1 turbo cars. Since CART is so competative though every little bit gets squeezed out of them....

[PDA]

CART rule is 40 inches of Mercury, or as stated, about 1.35 bar.

I presume that lag is minimised by dumping raw fuel into the turbocharger on the overun to keep the blades spinning.

[SlowDrivr]

In regards to V12s- Even if someone develops one and it makes more hp, I would think there are some trade-offs involved. Certainly reliability would be compromised for awhile. I seem to remember reading that V12's should have increased fuel consumption (I don't know why...anyone know? More friction from more cylinders?).

My point is that even if a V12 is developed, that doesn't necessarily mean the V10 will be a big handicap.

[Zoe]

Engineering means finding the right compromise for a given task (looking for the ideal solution would be science). Trade-offs between an 8, 10 or 12 cyclinder engine are (1) size and weight, (2) max. revs and power, (3) fuel consumption, (4) internal friction, (5) heat generated by engine. What else?

In my humble opinion a trade-off chart would look like:

1 2 3 4 5
---+---+---+---+---+---
8 | ++| - | + | + | +
10 | + | o | o | o | o
12 | o | + | - | - | -

Depending on how you weigh the different aspects, you'll get the best compromise. Horsepower obviously is rated very important, thus the trend towards a V12. The drawbacks of such an engine seem to be able to be mastered now.

When Ford was racing its V8, one of the biggest advantages was the fuel consumption. When refueling was introduced (94?) this advantage was quickly neutralised, so they concentrated on a V10 instead.

Comments anyone (I'd like to learn something new!)

Zoe

[Christiaan]

A 3l V12 was almost impossible 5 years ago because it would rev too high because of the shorter stroke and smaller cylinders. This would make the stresses on the materials very very high and the demands on the lubricants also very high. It also follows that the engine would thirst very easily.

I guess now with advent of Al/Be alloys and carbon lubrication it is possible to make a V12. If the current engines peak at 18 000rpm then by speculation a V12 could peak as high as 20 000rpm. That makes it very hard to guarantee the reliability of the engine. A design theory widely used today suggests that a rotating shaft has a 50% chance of failing beyond 6 000 000 revs, from pure fatigue. This gives the engine a useful life of 5hrs, which is far too short if you include bench inspection testing, pre race testing ,qualifying , and finally the full race. Unfortunately failure from fatigue is not an exact science and that is why you still get broken driveshafts in F1.

[Johnny]

Tak & Tony,
Good information, and good work, but I believe there is more than one equation for torque depending on the application and conditions and that is where the confusion is. Don't ask me which is which, its been 13 years at least.

Supercharging: Different from turbocharging because supercharging involves the use of the combustion gases to increase mechanical power whereas turbocharging involves the compression of intake gases to increase chemical power (the reaction). This is oversimplified, but in a basic way, this is correct. There is a bigger power lag with supercharging than turbocharging, because the power must come post ignition for supercharging, whereas power for turbocharging is at ignition.

tak, I think you brought up an interesting point about the exit rpm of a corner, and its relation to gear ratio and power.
At the 98 Canadian GP, I was in the Casino hairpin area towards the end of the race. ALL the drivers were changing gear at the apex of the hairpin, except Michael Schumacher and his Ferrari, who changed gears upon straightening the wheel.
That means? He was the only driver to use 2nd gear around the corner, whereas everone else used 1st and shifted up 1/2 way through?
I wonder how Ferrari decided the best gearbox for the race. It was definitely a unique choice.

He won.

[DangerMouse]

Johnny ?

Turbochargers and Superchargers do the same job, positively pressurising the engine's intake increasing the density of the air or fuel/air mixture (depending on whether the fuel is added up or downstream of the xxxxxcharger), The only difference is one is run mechanically (supercharger) and the other pneumatically via a turbine driven by the expelled exhaust gases.

Mechanical loses usually mean than once you are above 5-6 PSI turbochargers are more efficient than superchargers, they also cushion the piston on the exhaust stroke (by nature of restricting the outbound exhaust gas) meaning less mechanical stress on the reciprocating parts of the engine - although the thermal loads of the more powerful engine obviously outweigh this!

[tony]

To Tak and all,

My source for the equation I gave relating torque and horsepower was a webpage whose URL I have forgotten. I got out my old physics text book and discovered that the URL and thus my statements were wrong. The reason it is wrong is actually very subtle and interesting.

Whoever made the URL knew the following(I'm copying this from a physics text):

Power = d(Work)/dt

Work has the same units as torque. Those units are a product of a force and a distance(ie ft x lb or N x m). However even though they have the same units they measure different quantities. The difference is that one of the products is a scalar product(Work) and the other is a vector product or sometimes called a cross product(torque). The author of the URL assumed that since they have the same units that power is just
d(torque)/dt. Which is, as I discovered wrong. Here is a derviation of the correct equation.

An infinitismal element of work, d(Work), delivered to a rigid body is given by:

d(Work) = Torque x d(theta), where theta is the the angle by which the wheel has rotated. Also keep in mind that theta or angle is unitless. Now as I stated above
d(Work)/dt is the power, thus
power = Torque x d(theta)/dt.
But d(theta)/dt is the angular speed of the object which can be measured in degrees per second, radians per second or the all familiar revolutions per minute(RPM). Now we all agree,

Power = Torque x (angular speed). If you use radians per second to measure angular speed, Newton x meters to measure the torque and Watts to measure the power then the equation is exact as it stands. If you use the units of horsepower, RPMs and lb-ft you would need to look up the conversation between RPM and rad/sec, horsepower and watts, and lb-ft and newton-meters. Thus I agree now that:

Horsepower = (some number) x torque x RPM.

Thanks to all for paying attention and catching that error. Sorry to all I confused.

One interesting thing is that the derivative of d(torque)/dt does indeed have units of power, so what does that quanitiy measure?

[NeuralSkiOil]

I´d like to add one interesting point of view to engine specs...

Mika Salo is a driver, who´s had a change to compare three -99 F1 cars: Arrows (winter testing), Bar-Supertec & Ferrari. He commented in finnish press that Supertec was by far the most powerful engine he had ever sat in front of. When he told about his first impressions of Ferrari, he said that the power difference to Supertec engine was NOT so big! Instead, it was the CAR that made the difference, its driveablility and tuneability and the way the car responded to changes made when setting up differently.

That sounds VERY interesting to me, and it also supports my theory that the Ferrari engine power is over-hyped.

-NSO-

[Johnny]

Dangermouse,

Oops, thanks for the correction. I reversed the action of the turbo vs. supercharging. Of course, your explanation is correct. This forum has provided some great discussion on the technical merits of F1 and powerplants in general.

Is there an aerodynamicist in the house to comment on changes to the Ferrari front wing in this season alone? It looks like they have a new one every other race.

[HartleyHare]

Or perhaps, Neural, it shows that the Supertec is not so bad: it is just fitted to duff cars.

And didn't Salo mention something about the difficulties in managing the workload of switches and setting in the cockpit? What wonderful technical marvels does the current Ferrari sport?

[PDA]

C - Al/BE alloys will be banned for 2000, so they will have to find another way of reducing block weight.

Fuel consumption - all other things being equal, which they never are, fuel consumption is approximately proportional to piston area. A 12 cyclinder engine will usually have more piston area than an 8 or 10. It generates more power because it burns more fuel. Some of the "extra" power is lost to additional friction, and it must overcome the additional weight of the rotating parts. The overall increased weight is a concern, but because most of the cars are now well below the minimum weight, a 12 probably would not suffer by being above the 600 K minimum. There would be less opportunity to trim the car by moving ballast around, leading in part to a slight increase in height of the centre of gravity, which would adversely effect handling. However, if you have an extra 50 hp, then the problems are overcome.

[SlowDrivr]

This is a guess, but could the other part of the d(work)/dt equation be the power used to accelerate the rotating masses? When we talk about hp its used to describe the ability to accelerate the car forward, same for dyno measurements. But the engine also has to work to just to spin itself and the drivetrain faster, but this power is usually neglected because to measure it you have to know the interia of the drivetrain and engine, which you don't (and it changes depending on what gear you're in).

On another subject, in one of the other folders about small F1 teams, someone mentioned a W12 engine. What's that? Two crankshafts with 2 sets of 3 cylinders each? Uhh... why?

[F1razor]

Check this out: (this reportedly comes from an insider at Mercedes)

Curb weight/fueled w/150lb driver: CART 1910 lb / F1 McLaren 1300 lb

HorsePower: CART 985+/- F1 McL 915+/-

These figures are relative to the tuning. The engineers may detune or ???addtune??? relative to need (ie qualifying, wet conditions (you want less hp-generally not always)

The F-1 Mercedes is far and away a much more advanced engine. Impossibly, it is designed to last for exactly 1.5 races(approx 250 miles), and then it is 'german toast'.
In terms of relative performance, after having asked someone, here's how they compare. From 0-200 mph, F1 Mercedes is a SR-71, and the CART Mercedes is a passenger jet.

At 200 mph+ CART Mercedes is the Concorde, and F1 Mercedes is a Cessna. On any road course (possible exception, a circuit like Hockenheim), F1 Mercedes would be totally untouchable by CART Mercedes.
Short Ovals (1.5 miles or less): Advantage F1

Large Ovals (2.0 miles or more): Advantage CART note-Large Ovals with sharp cornering (ie INDY, RIO) may be quite competetive.

Grip / Aero: Grip massive F1 advantge / Aero in a word..DIFFUSER!

Comparisons here involve quizing a friend at Reynard. Reynard not only builds CART chassis but also is the BAR constructor in F-1.

No real numbers for you, all I recieved were "yesses / no's and doesn't even come close's. The only area where the CART car has a decided advantage in aerodynamics is in the 200mph plus area, because he referred to the fact that it not only 'naturally' produces less downforce, but also less drag. The F-1 cars recquire the excessive drag to retain control under acceration due to the grooved tires, in addition it will slow quicker when power is lifted for a corner.
This drag is brilliantly engineered in strategic ways, craftily usurping the FIA's ban on a curved underbody (ie CART's underwing) He said the CART underwing does not have a large effect until that 200 mph speed range.

[JHH]

Do not know about the W12 but it reminds me of reading about one of the weirdest GP racers, the Alfa Bi-motore from 1934.

The car had one engine in the front (normal position) and one in the rear. The driver sat on the gearbox in the middle of the vehicle. Total displacement was 6.4 liters and the thing supposedly could do 200mph.

According to A. Pritchard “the handling was so bad as to scare the most courageous of drivers and the cars had such a voracious appetite for tyres that pit stops ruined any chance of winning”.

Is a W12 just two V6s bolted together? I dunno but it certainly isn’t stranger than a GP car with two motors. Unless it has, say, six wheels ;)

Regards… James Harold


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" I have no interest in any ship that does not sail fast, for I intend
to go in harm's way." Captain J. P. Jones, US Navy - January 16, 1777

[Pit Babe]

Oh, my aching head...

Wow, you folks are serious! This is a great discussion. I will need to read through the postings again before contributing for although I am a technician, I am not a bona fide mechanical engineer. I'll be back when the Excedrin kicks in. But I couldn't leave without mentioning how wonderful it is to find thought and reason regarding F1, not just endless streams of "So-and-so sucks!" and similar babbling.

Incidentally, www.gtf1.com is a nifty tech site, in case anyone is looking for one.


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PB ;-)