how much horsepower can i get out of a d15? Just all motor...no turbo or nitrous

 

honestly, not much... there's an easy (though expensive) 30-40 horses (random number range off the top of my head... it's probably fairly accurate though) to be gained with naturally aspirated motors... after that, you're spending thousands of dollars for one or two horses. I'd say turbo the d15 or swap it to a b- or an h-series... d-series engines aren't really great n/a motors.

 

look into "bisi" they are all about all motor sohc hondas and make then damn quick