formula 311 sr1 rpm
#1
Thread Starter
Registered
Joined: Mar 2013
Posts: 27
Likes: 0
hey guys..i purchased a 1988 311 recently..the props i believe are prob stock..23p bravo..i have the 365 hp which are around 400hp a piece with the little work that have done to them..on gps i hit 68mph at 5200 rpm...is that to high of an rpm for these motors? should i go higher in pitch? the boat planes out awesome and cruises really well also...any input would be great..thanks!!
#6
Registered

Joined: Mar 2008
Posts: 315
Likes: 2
From: Kissimmee, Florida
I had a 1990 292 sR1 with 365's and I had both 23" pitch and 25" pitch props. I went up to 25" pitch and had the same speed at a little lower RPM, $1,000.00 down the drain. If you don't have aftermarket exhaust, I would save the $1,200.00 and put towards stainless marine exhaust or some other aftermarket system. Also, the 25's will probably hurt your hole shot a little.
#8
Registered

Joined: May 2009
Posts: 3,895
Likes: 124
From: Chicago, IL; Onekama, MI
Something doesn't seem right. Bravo 23 (really 22) props @ 5200 rpms with a top speed of 68 equals 6% slip, which is not possible. A slip number of 11-13% would be more realistic which would give you a top speed of 64 mph. What have you done to you engines over stock?
#9
Well, they don't make odd numbered Bravo props so he likely has 24's and that gets the numbers a little closer. If you are turning 5200 light then you are almost perfect, put people, a cooler, and fuel in and that will drop down to 4900-5000,
#10
Thread Starter
Registered
Joined: Mar 2013
Posts: 27
Likes: 0
guy i bought it from said diff pistons and cam in motors..said each motor was 400 hp..i lied about props they're quicksilver not bravo and def 23p..i had a half tank of gas 5 adults 3 kidsand against the currant on river rpm gauge on boat said 5200 and gps said 67.9...gonna stay withwhats on it..seems pretty dialed in on taking off cruising and topend



