How to I replicate a "dirty" F1 car?

I am will begin working on the Tamiya McLaren mp4/8 Ford soon and I would like to make it look like it has been raced. Noticably somewhat dirty around the nose and other leading edges. In the past I have been unable to get the paint to splatter thinly enough on there to look realistic. Any suggestions?

This all started when I saw a pic of Senna's car from a 93 race in which his car had many tiny specs and a slightly dirty look to it.

I've heard people arbrush a light brown on the car, but other than that im not sure.

Try using the Tamiya Weathering Compounds, look great, come in white, black and different browns and soon available in gun metal, orange rust and silver. They do pens for thick, or powders for thiner work. Wash off very easily with a bit of water if it looks no good, even when dry. When dry, it is still possible to smudge, but it does go pretty solid. See http://www.tamiyausa.com/articles/feature.php?article-id=133 for directions. Finished result if done with loads http://www.tamiyausa.com/articles/ln/133/images/WRX.jpg

For an F1 car, don't put as many layers on, to get the desired effect. Watch the movies, they show how you build up the amount until you think it looks good enough

I would use black pastels for brake dust, and a light tanish brown around the exhaust outlets, and use a tooth brush with some flat black paint and flick it onto the car to simulate rubber build up.

If you go the paint and airbrush route, thin it way more than you think you should, and if you paint the car with lacquers, use acryl for the weathering. Then, when spraying the dirty, add several thin layers. When you think you need one or two more layers, stop! It's easy to add more if after you walk away and come back it doesn't look right, but it's really hard to take it away.

Check out this build from Bil Attridge's website. If you click on the "Building Specifications" link, it gives you some info how he did it...

http://members.shaw.ca/bil_attridge/Gallery/LeMans/index.htm