8 replies to this topic

[karlth]

A friend mine asked me why F1 teams didn't use Variomatic gearboxes? He himself thought it was because of strength issues, i.e the belt would break easily.

... 'Variomatic' transmission originally developed by DAF. It relied on centrifugal forces throwing out bob-weights within a pulley assembly and the whole lot was driven by drivebelts. It was considered to be over complicated and impractical. But in reality it was a brilliant idea as it enable the car to virtually 'free-wheel' at higher speeds therefore, saving fuel.

Anyone know why?

[Garagiste]

Variomatic = CVT and therefore specifically banned by the regs.

[karlth]

Originally posted by Garagiste
Variomatic = CVT and therefore specifically banned by the regs.

OK, thanks for the info. Then it is probably only Ferrari who are researching it.

[Chewbacca]

According to ancient AtlasF1 myth - Williams had a system in operation at some point. It was banned shortly thereafter.

[MCH]

Williams developed a CVT transmission together with the Dutch company VDT. David Coulthard ran a test with a Williams f1 car fitted with the transmission late 1993, even though they knew it was going to be banned for the 1994 season.

To my knowledge the test was a succes (nothing broke) and the performance was pretty good.

[desmo]

Peter Wright from his book Formula 1 Technology on the Williams CVT experiment:

"Step-less gear ratio changing permits the engine to operate within a narrow rpm band, or even at a discrete rpm, instead of requiring an operating band of approximately 200 rpm. The engine designer can then tune the engine for that rpm, avoiding any compromises in intake and exhaust lengths or valve timing, The increase in available power (the integral of power throughout a cycle of accelerating through the speed range) must outweigh any loss in efficiency or increase in weight.

"Williams started research into CVTs in the late 70s, initially with a system based on the Perbury system. At the time, Williams was developing the Cosworth DFV and was seeking ways to achieve a power advantage over other DFV users. The Perbury proved to be too heavy and was encumbered with IPR problems. Some years previously, Van Doorne had raced a F3 version of it's rubber belt and cone CVT, based on a system sold in DAF road cars. It was reasonably competitive but unable to take the power of an F1 engine. Williams decided to work with Van Doorne to develop a steel belt version, suitable for F1. The issues of engine starting, engaging drive, reverse, and the hydraulic and electronic control integration with the engine all had to be solved. The gearbox was mounted in a Williams FW15, powered by a specially tuned Renault 3.5l engine, weighed 6 kg more than the six-speed one it replaced and was approx 93% efficient compared to 96% for the spur gear variant. This appeared in testing in 1993 but was banned as part of a package of control system regulations, at the end of the year, before it's performance advantages could be demonstrated. History does not relate whether the ban was the result of the fear of having to develop competing systems, when Williams had been working on the principle for so long, or the thought of 24 F1 cars, all with their engines continuously at peak rpm."

It seems entirely possible to me that if the CVT ban hadn't been instituted by the FIA, that CVTs well might have become de rigeur for F1, and we might all be used to the sound of a CVT powertrain as we might be all driving around in peppier, more fuel efficient CVT vehicles ourselves as a result of the technical cachet of F1 driving road car development faster than it turned out to happen.

Banning advanced technologies in F1 can IMO result in the delaying of implementation of those same advancements in street cars.

[Bluehair]

Absolutely!!! I have anticipated seeing a CVT for longer than magnetic valve actuation! I think that the FIA should have at least allowed the thing to see a race or two before they banned it. It seems to me that with the dopler effect, traction control, and multiple cars on the track, there would still be enough sound variation to keep our attention. The sound couldn't possibly be as dull as that of an oval track race could it?

[Marco94]

Ferrari has also tested an earlier version of the CVT at the end of the 1970's. But is was discontinued because the turbo engine offered much larger rewards.

[Catalina Park]

Jack Brabham also ran a CVT car in the 60's and the problems were never properly solved (Like having to left foot brake to keep the CVT wound up but with the electronics of the 90's they may have solved these.
But like the Lotus 88 because it was banned before it proved itself, we will never know!