30 replies to this topic

[tom]

how many thousand revs per minute does an f1 car do , my little motor bike doesn't like being reved higher than 7 thousand .

does any of you know what the f1 cars go up to?

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irvine = w@nker


[This message has been edited by tom (edited 02-01-2000).]

[Jonathan]

17,000 RPM +

(Many are likely to be even faster this year)

[Daemon]

I heard talk of the new Mercedes being able to rev up to 20,000rpm...

[Ray Bell]

The Cosworth V8 passed 12,000 back in about 1980 - with pneumatic valve 'springs' coming in about 1985 there has been a constant increase since.

[Bogwoppit]

No idea of the limits of an F1 engine - my poor little Fiat red-lines at 6,000 RPM!

------------------
Boggy.

*FIAT - Fix It Again Tomorrow* (If you're lucky!)

*Member - Stratford-upon-Avon IAM Group*

[awill4x4]

Last years guesstimate appears to range from 16500 to 18000 depending on engine manufacturer.
regards awill.

[Ray Bell]

Bogwoppit -
Don't feel so bad about your cousin to a Ferrari, after all Ford stands for:
Fabricators Of Rusty Derelicts.
Peugeot, on the other hand, have:
Powerful Engines Useful Gears Over Every Terrain.
SAAB shows that Swedes Are All Bull****

[Damop]

Wow Tom, your bike must be a classic to rev that low (or a Harley). Current sport bikes will rev to 12,000 rpm plus. My SiR redlines at 8,000 rpm, and the S2000 redlines at 8,900 rpm. The revs on street machines are climbing all the time. As for F1, I believe the top teams were getting 18,000 rpm or so. As someone mentioned above, they could be approaching 20,000 rpm this year. ChampCars will rev to about 16,000 to 16,000 rpm this year. Heck, even dinosaurs like NASTYCAR can get upwards of 9,000 rpm out of a low-tech pushrod motor.

[Bogwoppit]

Thanks Ray - I feel better about my little Fiend already, and fords are not match for it anyway.. (Apart from the Cossies!)

;)

------------------
Boggy.

*FIAT - Fix It Again Tomorrow* (If you're lucky!)

*Member - Stratford-upon-Avon IAM Group*

[Penulis]

20,000 RPM? Wow! That means that the pistons move up and down at 330 times per second!

Even my digital stopwatch is not that fast! Some engineering..!

[Megatron]

As stated, The new Benz suppoesdly goes around 20,000 RPM's. The rumor is that they have passed this "magic mark" and that is responsbile for the odd sound of the engine.

I have heard that the Ford is pretty close to the Mercedes.

The Honda turbo went around 12,000 RPM's.

The 1994 Ford Cosworth was the first to pass 15,000 PRM's.

[pa]

Actually, 20,000 divided by 60 (seconds) divided by 10 (cylinders) = 33.333 cycles per second...

[nhbrian]

Each piston moves up and down once per RPM, so Penulis is right (333 1/3 up/downs per second).

[Damop]

Pa - the number of cylinders is irrelevant - they don't take turns for each rotation of the crank. The motor could have 1 cylinder or 100. The piston will go through it's full travel (i.e. back to it's starting position) 333 1/3 times per second.

[desmo]

I don't know what the state of the art is nowadays, but in the 70s we had a device called an oscilloscope that would tell one very easily what max rpms were from a good sound sample. I doubt if teams would be coy about it as it's so easy to check. The exhaust broadcasts the answer. I had an '65 MB 220SE that redlined at 7000! Maybe not that amazing for a 2.2 litre six, but still Mercedes isn't afraid to let 'em spin.

[This message has been edited by desmo (edited 02-02-2000).]

[Damop]

It would have to be a very good sound sample, and it would have to be able to detect individual pusles from the engine, I would imagine. You would also need to know the firing order of the engine, etc. Flying by the seat of my pants here. Considering the impact of different intake and exhaust systems on an engine's note, I would predict it would be damn near impossible to do it accurately. You would need some data to calibrate it to the particular car.

[DangerMouse]

I don't think current F1 engines are limited by revs par se since the into of pnuematics to close valves, Brian Hart had an engine on the bench reliably doing 20,000 RPM years ago, the problem is, once you are past a certain engine speed usually around 17,000RPM power drops off dramatically due to the tiny amount of time to "fill" the cylinder with air at those revs, hence the interest all of a sudden in V12s again, their smaller cylinders (at the given 3 Litre capacity) would have meant they fill more quickly enabling VE to be maintained at higher revs meaning torque curve would not have dropped off so quickly.

As V12s are now banned anyway, the emphasis will be back to controlling the opening and closing of the valves by a non linear method (ie lose the camshaft!) This way you could run a huge overlap of valve timing at high RPM without sacrificing driveability lower down the rev band, this of course means that banning V12s will make engine development MORE expensive in the long run and as usual the FIA don't know their arse from their elbow.

Obviously supercharging of any sort means that valve overlap isn't a problem but of course this is also banned, I think Ferrari and Stewart's Exhaust system is a substitute. The positioning of the exhausts and the air flow across the exit venturis causes a negative pressure in the exhaust system causing a kind of forced extraction of the exhaust gases improving scavenging.

Prost have missed this completely assuming Ferrari and Stewart have done this merely to improve top end power by nature of the shorter exhaust systems, as their exhaust system doesn't seem to have the sort of aerodynamic properties as the Stewarts and Ferrari's, BTW I've not read this 'forced extraction' theory anywhere, it is completely a theory or mine! I bet time proves me right! (cocky sod! )

As a side bar current Yamaha R6 road bikes redline at 14,500 and happily rev past 15,000RPM totally reliably, as I said I don't think the valve train bounce is what is limiting revs in F1 today - efficiency at these revs is.

[baddog]

I vaguely remember hearing something about forced extraction exhausts being illegal? or maybe it was just a dream... Im going to inwestigate

Shaun

[f1speed]

Dangermouse, you are on the right track, even simple headers are designed for the velocity of the gases to create a low pressure area in the valve area that not only helps in the removal of gas around the exhaust valves, but since the exhaust and intake valves are open at the same time(briefly) the design of the exhaust helps fuel into the engine as well. If anyone finds out how they are working those valves, I would sure like to know because it looks like something powerful enough to open and close the valves as fast as would be nescessary would be too heavy for the reported light weight of the engine. Just oppinion but I'm beginning to suspect they might have found a loophole in the rules and gone two stroke on us.

[desmo]

Great post Dangermouse. As an ex-karter we of course used exhaust resonance to aid in cylinder scavaging i.e. expansion chambers. I realise that the principles are quite different in a 4 stroke, but I always thought that a similar principle might apply. Packaging in an F1 would of course preclude large volume exhaust systems such as are used in a 2 stroke. Any good info on the web about the fluid dynamics of 4 stroke exhaust systems? BTW Christiaan, good call moving this thread to Tech forum!

[This message has been edited by desmo (edited 02-02-2000).]

[DangerMouse]

Shaun, I believe it's a grey area, forced induction is banned (specifically supercharging of any sort) although "ram air" systems are legal and are a form of supercharging!

The regs say...
"5.1.3 Supercharging is forbidden."
Supercharging is defined as... "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."

"the dynamic effects of the intake and/or exhaust system" clause would seem to me that it is specifically *allowing* forced extraction!

f1speed & desmo, yup two stoke tuners have taken advantage of "pulse tuning" for years, 4 stroke designers have been well aware of it's properties too, the problem being that pulse tuning only works within a certain range of frequencies, it will always mean as deficit in another part of the rev range unless you can artificially alter the length or volume of the exhaust system depending on revs (like the Yamaha EXUP and power valve systems on their four and two strokes.)

However variable exhaust length systems are banned in F1, so Ferrari had the brainwave of having an exhaust with a wide outlet so reducing back reflected sound waves and hence nullifying the pulse tuning effect, meaning the engine is tractable everywhere, and running these wide apertures at right angles to air flow in such a way that a forced extraction effect will occur in the exhaust system with no loss of tractability anywhere in the rev range.

Simple, effective, brilliant!

[This message has been edited by DangerMouse (edited 02-03-2000).]

[desmo]

Yes, the increase in output we saw from expansion chambers was narrow. At MOST 4Krpm in an engine with a 18Krpm limit. However, the upside was so large that we still got down the track significantly faster with them in spite of the peaky powerband and only one gear. We could see noticable differences in performance by altering the distance betwen the exhaust port and the diverging cone as little as 5mm. Every track had it's particular optimal length for each engine. They banned variable length exhausts on us as well. One could spread the boost over a much wider rev range with them. I have learned great respect for the subtleties of exhaust tuning.

[Christiaan]

Dangermouse, as far as your forced induction goes, that technique has been used on two generations of engines on the M5. It is also used on the Mclaren F1. The principle is basically creating an interrupted path for the exhaust which creates a stationary pressure wave in the exhaust pipe. The trick is that the pressure wave must be travelling outwards during both the induction stroke and exhaust stroke, but with some phase difference. This means that during induction the action of the wave should be such that a vacuum is created near the an exhaust valve wich will remain open during induction, thus the wave will force in more air than normal.

The problem of course is that the charactoristics of the stationary wave are dependant on path length, and engine frequency. Furthermore, the waves will only be produced at integer multiples of a path length and engine frequency relationship. I have heard of variable length exhausts to counter this effect, but the problem is they have to be able to vary length 100% in phase with the engine frequency. I am not sure if such a system is allowed in F1.

Then comes the question? If Ferrari provide the Sauber engine, and engine that uses forced induction, why then does Sauber have the rear diffusor setup? check out the engine hereand check out a picture of the car here

[desmo]

Christiaan,
What's with the dead links in your post? If you saved the images to your hard drive perhaps you could put them up on this site's server for us.

[Christiaan]

Okay, I downloaded the photo onto another site. here is the Sauber, but now I have notives that they do have the same exhaust as Ferrari. i wish you could have seen the photo of the engine...the exhaust was pointing do downwards! This means that there must be a very sharp interrupt in the exhaust path. Damn those Sauber IT guys for rearranging their site



[This message has been edited by Christiaan (edited 02-04-2000).]

[DangerMouse]

Christiaan, there is a huge difference between using reflected sound waves to cause negative pressure at certain revs and altering the effective exhaust length or volume aka BMW to running the whole exhaust system with negative pressure causing forced extraction.

If you look at the Sauber/Ferrari exhaust you'll notice the shape of the "tailpipe" is very large and elongated, this will massively reduce the "pulse tuning" effect you has described dispersing sound waves rather than reflecting them, the only logical reason I can think of for that shape is for it to cause negative pressure in the exhaust system and thus forced extraction, which is an entirely different kettle of fish to tuning engine via exhaust length or volume like the (venos?) System used in M5s and McLaren F1s.

BTW the first production 4 a stroke vehicle to use some kind of exhaust system to optimise pulse tuning timing for two rev ranges is Yamaha on the FZR1000 Exup back in the late eighties, what BMW have done is old news!

PS You are correct in thinking variable length exhaust systems are banned in F1.

[IndyIan]

All this talk about exhaust tuning got me thinking.

Has any engine been designed to use exhaust pulse energy to force more air into the the intake? Sort of like turbocharging without the turbine.

I have no idea how this might be done and I'm sure the plumbing of the engine would be complex.

Maybe the exhaust of one cylinder could compress the intake of the next cylinder in the firing order.

Maybe I should be a F1 engine designer?

[Christiaan]

DM, understood, but the shape might only be because the exhaust is desiged for a certain exit angle, and thus that lobe shape.

[Ray Bell]

Indy Fan - I'm sure if you did it they's soon work out a way to ban it as forced induction. But don't give up dreaming, once all these things they use were just bright ideas.

[davo]

IndyIan

Yes is the answer. Ferrari had a supercharger which even with very good drawings and lots of explanation seems to be too close to a perpetual motion machine to actually work. I can remember puzzling over it for days without success.

It had a crank driven barrel with flexible walled cambers around the circumfrence. The exhaust was introduced to one chamber, and expanded the flexible pouch pushing out the inlet air from the adjacent chambers.

It doesn't take alot of energy to drive as the barrel is simply being spun to achieve a kind of porting. It would seem to have huge heat gain problems in concept.

Ferrari ditched it alegedly do to shaft breakage problems on the SC. This seems preposterous as that is a simple solution and if cranks, and drive shafts can be made to live...
...it just seems odd.

I think it was actually raced at least once, and I think I have more than exhausted my knowledge of it.

[IndyIan]

Davo,
Is there any place on the web where I can look at Ferrari's system?
Thanks