I race a 04 pontiac sunfire on dirt tracks. was wondering if it would be a good idea to remove front sway bar to get more grip?

More grip at which end? Do you have a rear bar? J's have understeer built in, and taking out the front bar may or may not help you depending on what you want to do.

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front. no rear bar. open differential though. i was told to take it off with a open differential because when you go into the corner the pressure pushes down on RF causes LF to come up or off ground even to get more grip in the front

The sway bar's purpose is to keep both wheels at the end of the car both on the ground. Taking off your front bar will allow the inside wheel to come up easier, regardless of what type of diff you're running. With a solid axle RWD car, that theory would hold true, but not FWD independent. You could add a rear bar, which will cause the rear to "lose" grip, but it wouldn't necessarily tighten up the front end. It would be a good idea if you want to be able to have some snap oversteer, especially on dirt.

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problem im having is the tracks that im racing at are rough and high banked 3/8s. meaning when all that pressure is applied to the RF either going into or coming out of the corner it makes the LF come up off the ground almost, so im thinking taking it out will help it. pretty much a trial and error sort of deal but thanks for the advise