While there are a lot of variables, an F1 car will produce a downforce equivalent to its own weight at about 130kph. In theory, if it could reach a ceiling at this speed it should be able to drive upside down without falling.

there are tons of variables here to be considered, the nature of the airflow in the tunnel, how the suspension and tires gain traction on the ceiling, if hes going in a straight line or if hes wobbling.... case in point hereif the tunnel has a circular interior and he can simply just drive around the walls of the tunnel without being impeded, the it is possible for him to "orbit" the exterior of the tunnel as long as he keeps his angular momentum high enough , soo therefore he would have to be rotating about the tunnel walls at a rate of a 15 rpm around the tunnel wall, in which case his forward momentum can be 0 kph.... if the tunnel is 10 meteres wide , his speed he would have to be moving along the walls is an unimpressive 27 kph to be driving along the walls ( provided hes facing the walls directly), therefore he cud be driving along that seam tunnel at 180 and stick to the walls , as long as his wheels are tilted atleast at an angle of 9 degrees left or right...for full upside down car travel , the downward force the aerodynamics excert must be greater than the weight of the car, else the car would simply fall off the roof, it needs to be around x2 the weight of the car in order to maintain traction( the upwards resulting force = weight of the car) if this was your only agenda , you would create  a car whose aim is to maximize downtrust at the expense of cornerbility and top end speednice q though

I am a very keen follower of formula one and although it may be possible for the car to generate the equivalent force required to do this, the tires would probably not be able to generate sufficient heat and therefore grip to be able to do this as the required speed may not be possible. Also, being a tunnel the level of downforce created is a factor as if the environment is similar to being indoors then a formula one car would not have a significant advantage over any car in terms of being able to apply the power that the standard F1-type engine can deliver. There are quite a few variables that would need to be considered but ultimately for greatest probability of success it would require significant speed upon entering the tunnel for any realistic chance.

Commentators often say that drivers need strong necks because they pull 5G on bends, where the bend speed is as slow as 80mph/120kph. A standard car tyre can do around 1G under braking, so I would expect an F1 tyre to be maybe twice as sticky - it is still rubber on tarmac. So you might think that an F1 car gets 1G gravity plus 1.5G aerodynamic downforce at 120kph.

Similar forces should apply whatever orientation or direction the car is going in.

So, if you have a 90 degree curved ramp (with a big enough radius) at the foot of a skyscraper, an F1 car should be able to drive at the building on the street level, go up the curve of the ramp, and drive straight up into the sky!

In that orientation, the car needs 1G driving force to maintain its initial vertical speed against gravity, and (with sticky F1 tyres on glass) only about 1G of horizontal "downforce" to give it traction on the building.

I just know somebody (Richard Hammond ?) is going to try this now. See the question about "Sky Diving Anvil Hanging" to see what happens at the top of the building!

I recently saw a bit on Top Gear showing them looping a standard small car (once) around inside a 10 foot diameter steel storm drain, and it didn't look faked. It only needed about 25mph. There are also "wall of death" travelling shows, inside spheres as well as cylinders. But of course these are done with inertia, not aerodynamics.