Re: Top speed of your sunbird??
Hey guys I think myself and maybe two other people in America have a 1996 sunbird neptune. I say this because well, try finding any info on this boat! Anyway, it's working out great for me and my family, we're having loads of fun tubing, fishing ,and skiing.
On to the question at hand.
I have a Sunbird Neptune 181 dc with a 90 hp Evinrude and a 14x17 aluminum prop. I'm getting 32 mph on my best days and around 28 mph average. Problem is, I'm only getting around 4200-4500 rpm wot depending on the load.
I just found a used stainless steel prop on Ebay in good shape and at a good price and I'm hoping and praying it's just what I need.
The new prop is a 13 3/8 x 12.
Now going with the math I've been reading from all the prop matching articles every degree of pitch results in 150-200 rpm gain/loss. So 5 degrees of pitch loss should equal 750-1000 rpm gain at wot.
I know the prop is a bit smaller diameter but I also understand that the stainless steel should be stronger and therefore result in a little bit less of rpm gain.
I'm looking for better hole shot to give my skiers a better chance of getting out of the water.
I'll try and report back and maybe the other 1 or 2 Sunbird Neptune owners can use this info for comparison!