How many cars does a Formula One team build for each season?
How serious a crash can an F1 car take and still be repairable? What would a team do if they had a particularly grisly season and ran out of cars halfway through?
This is a difficult question to answer. The cars are very modular. The chassis is sort of the main part of a car, but in F1 the chassis is just a framework for other things to attach to.
The rules specify that the chassis and fuel tank must last the entire season. Engines and gearboxes must last 3 and 4 races, respectively.
Most of the components are rebuilt every race, except for a few parts that don’t see much wear, like seats and such.
Overall, most teams have at least one spare chassis, whereas the richer teams might have many. However, no team can have spare cars, and there is no testing allowed during the season. They are also very limited in where and how they can test in the off season – it has to be FIA approved.
This page gives a quick summary of the reliability rules, and the testing rules are available at the same site.
As far as how much work they put in on the cars over the season, I have heard that each engine takes about 80-150 hours to build, and gearboxes are about the same. Brakes might take 20-30 hours, and suspensions are probably about the same. Overall, there is a lot of work done on each car over the week(s) between races.
To answer the other part of your question, the damage a car can take is pretty amazing. The wheels and suspension are designed to break and crumple, as are the rear pieces that are connected to the gearbox. The engine and gearbox are also a structural part of the chassis. All of the body parts are just carbon fiber shells, easily replaced. A brand new car could probably be be assembled in a day or two from parts bolted onto a fresh chassis. But most crash damage is absorbed by the body pieces and the suspension members, and the chassis is rarely damaged, if ever damaged. I suppose if a driver was determined to really shunt his car every race, they might run low on fuel tanks and chassis. Building new ones would probably only take a week or so, though, given the money and manpower available.
But realistically, unless you see the car flip over, go end for end, or something equally dramatic (which is very rare), the damage is usually limited to the suspension and body pieces, and is quickly repaired. (You’ll often see them swapping wings out during a race, and it only takes a few seconds.)
Oh yes, I forgot: A chassis or fuel tank (and most other parts) can be replaced if they have suffered crash damage. There will be no penalty incurred.
Is there a race that has no restrictions? Baja? Mint400?
I’m not sure, but nothing major is unrestricted – series that have few restrictions end up going to the richest guy regardless of driving skill.
BTW, to clarify, the image of a chassis I posted is of a RC car, not a real one. But it’s nearly impossible to find a pic of an actual F1 chassis. The designs are highly secret. Nowadays, the chassis is a monocoque carbon fiber piece, not aluminum.
If the engine and gearbox are “part of the chassis”, how come they can be replaced every 3 or 4 races?
They are bolted onto the chassis. When they are installed they serve a structural function as well. For example, the rear suspension attaches directly to the gearbox, which is bolted onto the engine. Using the engine and gearbox as structural components saves a lot of weight.
Check out this PDF explaining it.
I think a fair number is more than two, less than fifteen. 
If you read some of the F1 team press releases they’ll often mention that driver X drove chassis Y. It takes a big hit to write off a monocoque (a la Kubica’s massive shunt at Montreal) but teams probably budget a particular monocoque to last four or five races. Now that no in season testing is going on, that should theoretically cut down the number of chassis required since there is no in-season “test team” anymore.
I’ve never heard this assertion; can you provide a reference? It would seem to be contradicted by the link you provide:
The phrase “spare cars are no longer allowed,” is that teams are no longer (as of 2008, I believe) allowed to have a third car, fully prepared and ready to race, in the garage at race meetings. They can (and do) have a chassis “back on the truck” that can be turned into a raceable car in a few hours.
Steve Matchett’s book Life in the Fast Lane gives a very detailed account of the 1994 F1 season from the perspective of a Benetton race team mechanic. I have read this book, but don’t have it with me - I believe Matchett says that Benetton made about 8-9 chassis for that season. Some get damaged beyond practical repair in crashes; others simply get “old” - after several races worth of use they flex noticeably more than when brand new - and get relegated to the test team.
With in-season testing all but banned in 2009 (very limited straight-line aero testing and new-driver work), there really is no test team to require a supply of cars; the number may well be less than that now. I’d be surprised if it was drastically less, but I don’t know anything definitive.
IIRC, every team has to supply one chassis to FIA for crash testing, in addition to the ones they actually use.
This jibes with my recollection, as well.
You’re correct. I was thinking of the proposed chassis rules for 2011, which limit the number of chassis changes.
A chassis on the truck is fine, but it can have almost no parts attached to it - engine, front suspension, bodywork, etc all make the pod into a car, rule 28.1.
Also, it looks like this year, the sporting regs just allow for 8 engines, which can be switched between races, instead of requiring consecutive uses.
Ah, neat - I hadn’t been aware of those upcoming (possible) changes. Thanks for the heads-up.