Thanks for the information. I'm going to look into it more . I may just get a set of mirage 3 blades and keep the bravo' incase or as spares. I was just figuring that formula would have done lots of testing when they designed the boat to get the correct prop.. thus why I would think the mirage 3 blade 23's would be best. Especially since they are just the stock factory 420's with around 60 hours on them.

Thank you.

For your info, I'm running 24 bravos repitched to 25 on a set of 420's in a Formula 292 SR-1. I get 5100-5200 rpm out of mine. 292's and 311's run almost the same speed so it's a fair comparison. IMO if you cannot spin the 24's your engine is tired or something is wrong with it.

Thank you for the input. I just got the boat last year and only had it out a couple times and every time it was full of fuel with 5-6 people in it and a couple pops. Never held it wide open for an extended period of time to see the peak speed I could get out of it but did get 50+ mph. It cruises at 40mph no problem at all. most of the time the boats going to have 4 plus people in it with coolers lots of fuel ect ect .. those are the conditions I want it to perform under.I cannot recall exactly but at the 48-50mph range I think the boat was reving about 4800 maybe less. Like I said before though it was not held wide open for an extended period of time. Sorry for my ignorance on the prop selection but I do not understand why formula would put a 3 blade 23" pitch prop on the boat to make it run 5200 rpm and around 65-68mph from the factory but a 4 blade 24" prop is supposed to pull the same rpm with the same motor? In my understanding 4 blades and more pitch = more load on motors due to more grip and forward movement per revolution. Is your boat loaded down when your getting 5200rpm?

Thank you.

not trying to be a smartass . but you are trimming up after getting on plane im sure .. after reading seems like you should have the power .. 420 s are a good engine .. good parts in those engines actually .. make good power .. just throwing it out there .. just make sure youre trimming up .. get that boat out of the water lol

if your running 4800 loaded with the 24s, your going to hate the 23 3blades with a load! Your getting your best cruise right now! The 3 blades will loose a few mph at cruise and a couple more with a load AND be harder to get on plane! Same pitch 3b vs 4b with same weight, the 4blade will when b/c she has more bite to hold the weight up.

IMO, you should keep the 24p b1s and enjoy your boat. trust me, I went the same direction, though different boats, but 3 - 4 blade comparison on straight bottom hulls will be the same.

Whats your goal? Cruise speed while loaded or wot while loaded. best cruise with decent top end or best top end and cruise rpms will go up several 100 at same speed.

Work your 24s to get best of both.

good luck

Have the same set up as you went through all that with 420's three different set ups ended up with bravo one 3 blades 25p work great great getting on plane and 51-5200 rpm great top end took a year lol. now going more hp need to step up to the 4 blades if you want to work something out let me know , thanks .

Tyler, I have a 1991 311 with the 502 Mags. Came from the factory with the 23 P Props. Would be willing to work a deal with you on your Bravo 4 blade props as I have been looking for those props lately. I can be reached at 402-201-3759.

Hello
Saw your post and I have a 311SR1 and located near London Ontario and boat near Bobcageon on Pigeon Lake.
Wondered what you ended up with props on your 311 to get optimum performance etc.
Did you stay with the Bravo 24-4 blades or go to a 3 blade prop?
What speeds are you reaching.
Thanks in advance.
Ron

I have a set of 22p 4 blade bravos I'd trade straight up

Pm sent