I am trying to figure out what size fan i need to fit on the side panel of my case. I think i need a 92mm. There was previously a duct thing there but i feel a fan would be more useful. I have measured the duct and the space between the screws is 80mm. Are these normal fan measurements for a 92mm?

Are you serious?

it is definitely not an 80mm fan that fits as i have tried to fit one but it was too small. P.s I'm assuming you think it's obviously a 80mm.

Actually, I misunderstood the question & was wondering why you were asking when all you had to do was measure the fan? But after re-reading, I see that you don't have a fan, just the duct. Personally, I like the duct. It provides a fresh air source for the CPU cooling fan without adding any extra noise to the system. If you have enough room, you may be able to install the fan, then mount the duct onto the fan. Anyhow, here's the dimensions of a Vantec 92mm case fan...I believe all fans use the same mounting hole layout. It's listed as being 82.5mm between hole centers: http://www.vantecusa.com/pdf/td9238h.pdf

The duct was only really removed because it was positioned directly in fornt of a case fan at the back of my pc. All my fan seemed to be doin was to cool my duct.