3 replies to this topic

[Pingguest]

Throughout motorsport history the cars generating most downforce were the IMSA GTP cars. For example, the Nissan P35 created up to 9,000 lbs/4,500 kg of downforce at 200 mph/320 kph. That's almost twice what the current breed of Formula 1 cars generate!

Those incredible loads caused massive g-forces, I suppose. How did the drivers cope those forces? Nowadays Formula 1 drivers sometimes complain about their neck. In the early 1980s Formula 1 drivers even complained about feasibility. Was the physical (dis)comfort never an issue during the IMSA GTP era? If it was, how did IMSA (tried to) resolve this issue?

Could anyone help me out with this one?

Thanks in advance.

[Frank S]

My thinker sometimes shows a little disjointedness these days, but if the very high downforces generated in straight-line travel are greater than those during change-of-direction behavior, wouldn't their influence on driver comfort be less? Cornering forces at high-G do make for physical stress on the driver, but they are not in the same grotesque range as the straight-line forces, which are effective on the car itself and not on the driver, eh?

[fester82]

I believe some of the early problems were how stiff the suspensions had to be to cope with the downforce levels. Vision was a problem due to the vibration. Chapman, at Lotus, was trying to get around that with his double-suspension idea. I'm not sure how the IMSA cars dealt with the stiffness problems.

[Dan333SP]

They might have had higher absolute numbers than nearly anything before or since, but the cars still had tires that are primitive by modern standards. Having spoken to some drivers of historic GTPs, they say that the ride is rough because of the stiff suspensions but nothing spectacular. The diesel prototypes today actually corner with greater force than the GTP cars, as they have less downforce but they also have more efficient aero packages so they carry more speed into the corners and the better tires of today allow them to stick with force that is 2nd only to F1 cars. There's a reason most of the best prototype guys have recent F1 experience, the cornering and acceleration of 908s and R15s is nearly equal with F1 cars of about 10 years ago. The only place they really lose time is under braking, when the weight becomes an issue.