Noob question here.

I see all sorts of performance parts for sale. Air filters alone claiming increases of 35-50 horsepower.

Why doesn't the factory equip the car with these items? 35-50 horsepower for relatively tiny increase in sticker price. Seems like a no brainer.

What am I missing here?

 

They aren't really putting down those numbers.
Rule of thumb: If it seems too good to be true, it probably is.

The other trick you'll see places pull is the "Gain ____ hp". They don't ever say it's at the top end. Say something claims 10 hp gain. It might be at 1100 rpm..suddenly you have 110 hp instead of 100 at that rpm, and it adds nothing to the top end over all power at all.

 

I've been told some of these products have dyno sheets that prove these increases?

 

dyno tests can be manipulated. your not gonna get 35-50 horsepower changing an air filter. more like 5. there are alot of BULL**** claims out there (infact most gains listed are bull**** claims or atleast dont tell you the whole truth).

and most of the time they say gain UP TO XX horsepower with this product. that could mean ANYTHING. that could be their expected max gains, that could be the gains you get on a fully built supercharged motor already pushing 500+ hp and is bottlenecked by whatever your replacing.

the turbonator does not add 35 horsepower, in most cases is causes damage to the motor. an electric supercharger is not going to give you 50rwhp, infact it usually lowers HP because it clogs up your intake.

 

Yeah its all false advertising with a K&N filter you might get 3-5 HP or 5-8 If its a cold air intake. Not to mention alittle better gas milage. Another thing that companys aredoing is they say that certain parts will improve your M.P.G(Fuel Economy) ThatsFalse. Some do But its not something big. They do this cause of todays gas prices