3 blade vs 4 blade

[Gsteve]

I have a 21' baja witha 490 hp 502 and am currently trying a pile of props. I notice in mosy mag tests the boats all turn a 4 blade , but so far all the 3 blades I've tried have been 2-4 mph faster than the 4's. Whats up with that? Also I have heard of a new 4 blade merc called a rev-4 anyone heard of it of what its is supposed to do?
Thanks Gsteve

[Trash]

Nearly all 3 blades will run faster on the top end than a 4 blade. Not always, but nearly so. The 4 blades will most likely give you better all around performance than a three blade. Adding that fourth blade increases total blade area which helps with load/power distribution which is good for holeshot and holding during turns (less ventilation) along with a slightly more efficient midrange. The down side is the added drag which diminishes top end somewhat. Fine tuning (blue printing or "lab finishing") a 4 blade can sometimes bring the speeds up as well. Bottom line is to try props until you find something that suits you best.

[sheikman]

Hey.. just a word of caution, I purchase a Revolution 4 blade...very pricy but midrange and whole shot did increase. Remember, your RPM will drop around 100-150 rpm. Make sure you compensate with the correct pitch.

[sheikman]

Hey.. just a word of caution, I purchase a Revolution 4 blade...very pricy but midrange and whole shot did increase. Remember, your RPM will drop around 100-150 rpm. Make sure you compensate with the correct pitch.