hey guys, im helping my friend jet his trailblazer. its stock but i told him that if we take off the airbox lid and jet it to make up for the extra air comming in it will add more power.
so not being familiar with the jet sizes, and how much to go up taking off the lid, i think that a 130 main and like a 42 pilot should be good. but maybe a 48 pilot? im just not sure so if you guys could give me the correct jet sizes i would appreciate it

 

You should only have to change the main if anything best thing to do is start rich and do a plug check, note witha k&n you do not have to re-jet but by removing the lid you might have to.

 

Well, if you had a pipe you would need a 145 or 155 main. I would start at a 130 and go down from there. You're definently right about taking the lid off and re-jetting, that should give it a little more life.

 

no dont start with a 130 main beings a 130 main is stock.

 

130 main is stock? My 2001 250 came stock with a 95-no kidding! Actually i should have said 130 and go up one notch on the needle.