what are some things that give you horse power in a car. And how much...
 

...horse power does it give you?

the engine gives you horse power!the way it is tuned alters the horsepower slightlyhow much depends on the engine capacity and its design

That all depends on what kind of car you have, what kind and size engine you have, how many miles are on the car, what kind of transmission you have...etc...etc...etc. try offering up some basic information about your car so people here in Y! Answers can better and more accurately answer your question. I'm sorry my answer is vague but your question is vague as well.

the parts you can add to your car depends on what type of car you have. also with more HP u use more gas and want more money. look up preformance parts for your car like cool air intake, new filters, new plugs, all your oiles are good, and check your tiere pressers. if you do a search on teh web for you car and year u might be able to find what other people have done.

sometimes a vehicle isnt underpowered as much as it is overweight .Heavy seats,heavy wheels and tires,spare tire and jack etc... once these parts are scrutinized for replacement [in my case parts i just never replaced i.e. back seats] the amount of added h.p. variers as consideration for replacement after market parts weights need calculaterd. but ill tell you this; i felt major responsiveness just from ...weight loss. next is mid grade gas and up no regular fuel. this will be debated by some but i believe this like i believe we need oxygen to survive , details as to why this is fact ? Are long and boring therefore im going to get to what i believe to be the best h.p. helper and its not the ecu.Its a cold air intake sytem.engines power is dependent on how much cold air can be shoved into said engine,and cold air is superior as it contains more of what is needed i.e. oxygen molecules.in addition, a heat shield gasket to aid the process .last perhaps if cost is not a consideration and if you have a death wish a turbo kit /supercharging.n2o ecu recalibration. and if the later 3 are your cup of sugar i advise you upgrade the breaks as you are going to have to reconsider how your going to stop the thing.i cant tell you your tot. increase but hertes mine for a guide. subtracting two rear seats switch to michelin xts from wranglers drop stock rims for 5zigan blacks racing,235 60 17,no jack,spare [thats what AAA is for] 1 Aem cold air intake,mid grade fuel.all these variables applied to a stock 3500 lb. honda element i dropped down to 3200 approx lbs. and starting out with 166 hps increased top 220.with a increased 20 to 30 with ecu. i could get a quarter ml time in under 14 seconds. its allready been doccumented by those who are way way ahead of me.hope i helped