I have a gear question for tech folks. Given FIA guidelines for a max rpm of F1 engines, and given the power-to-weight ratio of the cars..with the aero surfaces for minimal wind resistance, I am looking at extreme top speed possibilities of a current F1 car, well beyond 200mph. Given that you can see the cars hold at a max rpm level on long straights, and that the cars stay around 200mph max, the FIA must have a final gear ratio rule in place...correct??

No, they don't. They only regulate the max rpm, not the gear ratios.

Top speed depends on the racetrack and how much aero package each car has...less aero, higher top speed.

Hmmm....well then I can't understand why a F1 team won't have a taller gear as a final ratio for more top end then? The current engine configurations produce mountains of torque, and the tallest gear in 6th or 7th could easily give the cars 30-50mph over other top end speed with current horse power/torque & areo packages... so why aren't taller gears as a final ratio used?

Hmmmmmm.........well............

1) F1 engines DO NOT produce mountains of torque, unless it is a very small mountain or you're speaking in relative terms (compared to what, I have no idea). An engine making 780 horsepower @ 18,000 rpm is also developing a whopping 233 ft lbs of torque at that rpm.

2) In order to get to a very tall 6th or 7th gear, one must accelerate from apex speed to a speed where a tall 6th and 7th can be engaged. F1, as all race cars are, are geared to get through the gears as quickly as possible over the length of the longest straightaway on the course, with small ratio adjustments made for specific crucial corners. What you are saying would make sense on an unlimited length run to terminal velocity, but has no bearing on the quickest way around a given course.

Yes..true at terminal rpm. I was approaching this more from the F1 gearbox getting through the gears..there is plenty of torque (maybe 400 ftlbs at say 10,000 rpm) to acquire the max rpm in a given-next gear. I still can't see at a track like Abu D. why a tall final gear is not used...the drivers sit at the terminal rpm forever on the straight there

Any engine has a range of RPM where it provides the best performance. That range can be moved around by the builders and tuners to suit the various tracks, but regardless, the transmission will be geared to provide shift points within that preferred range. To throw a faster ratio into high gear is going to force the engine to cover a wider rpm range for that gear and will probably hurt rather then help performance. Kinda like carrying a heavy load up a set of stairs and finding out that the top step is twice as high as the others. There are a ton of variables, but keeping the engine in it's optimum performance range is a big factor.
BTW, a year or 2 ago an F1 team, Honda I think, tried to set speed record for an F1 car at the Bonneville salt flats. I think they were shooting for 250 mph. For whatever reason, they didn't reach it.

cruzcntrl - 18 November 2009 08:43 PM

Yes..true at terminal rpm. I was approaching this more from the F1 gearbox getting through the gears..there is plenty of torque (maybe 400 ftlbs at say 10,000 rpm) to acquire the max rpm in a given-next gear. I still can't see at a track like Abu D. why a tall final gear is not used...the drivers sit at the terminal rpm forever on the straight there

1) I think you vastly overestimate the peak torque of an F1 engine and miss the mark on the rpm where that peak is reached. From atlasf1.autosport.com:

"Hi, everybody always wants to know about bhp of a Formula One car but what about the torque. Could you describe the torque curve of a Formula One car? Thank you. Tar."
Kurt: Current F1 engines produce somewhere between 250-290 lb-ft of torque with that figure peaking at around 14,500rpm. Expect bhp to peak around 3000rpm higher than the torque peak e.g. 17,500rpm, and the rev limiter to cut in a further 500-1000rpm higher than that. Sorry about the lb-ft, that is the way torque is expressed in F1, at least by the English-based teams.
http://atlasf1.autosport.com/2001/aug08/faq.html

2) If, indeed, "the drivers sit at the terminal rpm forever on the straight there" at Abu Dhabi, it is most likely because they have reached terminal velocity for that particular downforce arrangement. In other words, the engine cannot overcome any more drag and will accelerate no further. Keep in mind that aero forces (including drag) increase exponentially by a factor of two for a doubling of speed.

It is much more likely that they are still accelerating, even if at a very slow rate, at the end of that straight, although terminal velocity is certainly a possibility..

In many configurations F1 cars have a drag coefficient of nearly 1. I can see why the top speed/terminal velocity is limited.

Short answer, with their available horsepower, torque, frictional loses, & aero drag they cannot pull a taller gear. Ie., if they could upshift another gear the car would slow down.

Thanks everyone for answers... good info. The power to weight ratio is amazing in a F1 car, I guess I am really surprised STILL that they top out around 205mph and are without a taller gear. Production cars with far more weight (3-5times as much), worse power-to-weight ratios and worse areo designs are able to push through the air up to 220's.. the only reason I can see is the massive wall-dam of air the front tires create holding the car back. Otherwise, horsepower/torque to static weight comparisons are apples and oranges to high-end production cars, F1 cars being superior in every aspect.

Its the aero drag from the immense downforce (negative lift) limiting top speed. When the driver lifts at the end of the straight its like hes hitting the brakes, Ive numbers of around 1G coasting down from top speed.