[Frank Lee]

That's pretty much the deal. Aero wasn't much (any?) of a design factor in the '60s and yes for that old stuff there was such a thing as aero-induced misbehavior at highway speeds which was noticeable because it magnified the instabilities built in to many '60s suspension systems (especially tires which were nowhere near as stable as today's designs).

Corvairs are very light in the front. Most of the instability comes from having a Cg that's BEHIND the Cp (Center of Pressure); the analogy for that is to visualize firing an arrow backwards. Old RACING VW Beetles could become airborne due to lift... at 140+ mph. As a current owner of an old Beetle, an old Microbus, an old Corvair, and Tempos too, I can comment first hand on their handling characteristics. What's astonishing on the rear-engined vehicles is the simple addition of a little weight up front- evidently enough to get the Cg ahead of the Cp- boy they calm right down even in crosswinds. I believe that to be a far greater factor in stability than lift. BTW I've taken Vairs up to 100 mph and lived to tell about it- it wasn't that bad.

But I think we are talking about Tempos and similar stuff, likely from the '80s to now. The Cg/aero/lift/stability issues have been addressed by the factory boys, who really aren't as dumb as the guys at Modified Magazine or Autospeed would have you believe.

I've read that Tempos went through almost 1000 detail design changes in the wind tunnel for drag/lift tweaking.

FWD cars now are very stable. The Cg is well ahead of the Cp and not only that, even heavily loaded they don't get a rear weight bias unless REALLY loaded or overloaded. The Cg doesn't vary wildly from the empty to the loaded condition like it does in the old rear-engine cars- a Corvair is like two completely different cars when comparing trunk empty vs trunk full, while in a Tempo empty vs full is scarcely noticeable. Heck, in a Vair you can tell the handling difference between a full and empty gas tank (it's in the front). The only way a Tempo will be anywhere close to catching air is going off a ramp. If we say 75 mph is likely the top legal speed, the dreaded lift still only amounts to a tiny percentage of the weight of the car UNLIKE the examples frequently found in racing oriented aero articles. Increased speed rapidly increases aero effects.

If we could find the Cl for Tempos we could calculate a good estimate for the lbs of lift the cars experience at various speeds. My WAG is yes of course there's some lift but it's probably something like 20 lbs which for our non-racing purposes = nothing. Consider that the Tempo front wheels probably have 1000 lbs on em each.

Tempo/Topaz seem to suffer sagging rear springs as they age. I've read about that and seen it in other cars anyway- none of mine are or ever were like that. If the rear is dragging and the nose is in the air and it's going 75 mph I can see where things could start to get "floaty". But then a car in that condition probably also has worn out struts, worn out suspension bushings, worn out tires that are half-flat, 200 lbs of junk in the trunk, and a driver that possibly isn't in the top percentile. I wouldn't be surprised to see that whole mess in the ditch either. I have personally experienced the effects of worn-out suspension components and they are an order of magnitude more important for handling than aero at <75 mph. Many people like to disrespect Tempo suspension design but the part of the story they often leave out is they are complaining about a worn-out old hunk of crap. When Tempo suspensions are in good working order I find they have very good handling characteristics.

So yeah if you want to make yourself useful find the Cl values for Tempos... or even anything similar.