We expect to see Red Bull Racing, McLaren and Ferrari at the pointy end of the Formula 1 practice time sheets, and so it has been today at Spa. But they never have it all to themselves, so who are the interlopers this weekend?

Sauber has been constantly improving all season, and this morning Kamui Kobayashi set the 8th fastest time, and his team mate Pedro de la Rosa did the same this afternoon.

The other men shoving their noses into the top 8 were Robert Kubica (3rd in P1, 4th in P2) and Adrian Sutil (5th in P1, 2nd in P2).

That’s by no means uncommon for Kubica, and his rookie Renault team mate Vitaly Petrov improved from 17th this morning to 11th this afternoon. It’ll be disappointing if Petrov doesn’t keep his drive for at least another year.

It’s different over at Force India. Giancarlo Fisichella nearly won the race last year, and though there have been changes to the car since then, it still seems to like a low downforce track. Then there’s Sutil, who’s been pretty consistent this season, but more importantly is a noted regenmeister – and the weather in Belgium has been more than a little damp. A good combination, then.

Which leaves us with Sutil’s team mate Vitantonio Liuzzi, who managed 15th and 16th fastest times in today’s sessions. So far this year he’s amassed 12 points; Sutil has 35. Liuzzi isn’t a rookie. And Force India have given Paul di Resta regular runs in practice sessions this year. It doesn’t look good, does it?

Back to this weekend, Alonso topped both practice sessions today. But I wouldn’t be surprised to see Sutil and Kubica on the podium if it’s an extreme wet race. Let’s hope so, eh?