Originally Posted by NeverLateInMyNineTwoEight

Do you mean on public roads, or on the track?

If people are going beyond 120 or so on public highways, or even beyond 100 or so from time to time - wow. I must be a slow poke.

On the track, no problem - that is assuming your car is prepped, and the driver has had some DE under their belt.

For my purposes, up to 100 is about my limit on wide open, great visibility, no one else around highways. I think I've topped out around 120 or so in my '85 once on a public highway.

So, for me, I don't believe the wing delete would be an issue on my S4. Now if I was going to hit the track, it would be a different story. The wing would go back on, just because I wouldn't want to take any chances at those speeds.

Originally Posted by docmirror

Well lets see if I can confuse folks a bit more. The Wing is a good thing, if it's used for high speed stability. By that I mean speeds above 140 or so.

Originally Posted by docmirror

Well lets see if I can confuse folks a bit more. The Wing is a good thing, if it's used for high speed stability. By that I mean speeds above 140 or so. Below that, on the roads we have in the US the Wing won't make much difference either way, on or off. As I mentioned, aerodynamic drag increases at the square of the velocity. Thankfully, other aerodynamic forces like lift operate the same way. That means an increase from 130 to 150MPH means a great deal in terms of aerodynamic instability.

This area is what pilots and flight engineers call the edge of the envelope. You can be tootling along just fine at 120-130, then punch it up to 150 and things will feel kinda funky. Then punch it up into the 160 range and things will definantly feel squirelly. The 928, like most production GTs could handle the lift generated up through the 140MPH range which was the limit of the OBs. then, as engines increased, and top potential speeds increased, Horst und Viktor had to re-engineer the aerodynamic package to deal with the higher speeds. Even though they were only about 10-15MPH higher, it was just enough for the incremental effects of the lift to rear it's ugly head - or tail so to speak.
.....

this is why I said the car is pretty safe sans Wing at speeds up to around 140-ish, cause that's what the OBs were capable of sans Wing. That doesn't mean that there isn't detrimental effects from no Wing, it just means that the effects are manageable.

So here's a cookbook for you. OB, no Wing no belly pan: limit your top speed to around 140. Spoiler cars: Limit your speed to around 155. Big wing, belly pan, fender skirt treatment limit to 175. If you take stuff off your car, limit your top speeds to those of the next lower rated car.

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Originally Posted by NeverLateInMyNineTwoEight

Do you mean on public roads, ... ...
If people are going beyond 120 or so on public highways, or even beyond 100 or so from time to time - wow. I must be a slow poke. ...For my purposes, up to 100 is about my limit on wide open, great visibility, no one else around highways. I think I've topped out around 120 or so in my '85 once on a public highway. ....

Originally Posted by Ron_H

I have been in a 928S with belly pan, spoiler and rear spoiler at 160ish and it was as stable as a rock....for a relatively long period of continuous time. Must have been the air or the inclination of the sun relative to some other planet or what ever gobblygook reason. But it was dead solid.

Originally Posted by dr bob

The good news is that most well-designed planes (and probably the cars) have enough forgiveness at design speeds to "recover" on their own if you let them. Overcorrecton at higher speeds is generally worse than no correction, since the effects of the 'correction' are amplified and the effects of the 'problem' are not. It takes a very gentle touch at high speeds; more can quickly be trouble. Generally, the car will save me if I let it.