If I am printing a large flat object with no overhangs, would it be better to turn off my cooling fans to help avoid warping? Or will no cooling fans somehow affect the performance of the printer?
Depends on the material you are using. ABS is very prone to warping whereas PLA is not so much.
I usually keep the fan off for the first several layers to make sure that they lay flat and then kick it on so you still get the benefits of using a fan but your part still sticks. I also print with a brim for additional adhesion.
@Ernesto_Martinez Its pla. Last time I tried somthing this large it had lots of warping, so if I turn off fans, will it help?
If there are no bridges, overhangs, or small layers you shouldn’t notice any negative effects by turning your part cooling fan off.
I have great success with cooling and glue stick and a good brim touching the part
PLA shouldn’t warp though. Do you have a heated bed?
@Adam_Steinmark yes I do, its set to 60c
What brand PLA? I find 55-65 works for all the brands I’ve tried.
@Matthew_Del_Rosso it might help, but you might have something larger than your fan causing that warping. Try blocking any source of large air flow in the room (open windows, doors, or fan/Air con).
@Ernesto_Martinez will do, erd time trying to print it xD
3rd*
@Matthew_Del_Rosso When I’m printing PLA I heat the bed to 60C (just above the glass temp for PLA) for only the first few layers or 0.5mm in height and then drop it down to 45C (just below the glass temp). It is warm enough for the part to not crack off the bed but cool enough to be solid and not warp when upper layers cool. I never get warped edges. I get a much better surface quality especially over sparse infill when I have the cooling fans on. I only turn them off for the very first layer so it sticks really well to the bed.
Example:
https://plus.google.com/u/0/113930448883604105560/posts/is6L8h81cYh
@Jeff_Parish I cranked mine to 70c (the max I can do with my current psu) and It did just fine! Tho I dud have to keep it on the bed for a good 20min b4 I could pry it off, it was very soft
@Matthew_Del_Rosso Glad that worked for you. Depending on the construction of your bed you might need a higher temperature read. I let the objects cool to at least 40C or below and then pop them off the bed. That way they don’t bend from being too warm.
What is it you are printing this time around?
@Jeff_Parish Im currently designing and printing a caridge system for my prometheuse system.
Ahhh, now your other post makes more sense. 
Yes, you would want that to be nice and flat.