Is my impeller to conservative ???

« **on:** May 08, 2011, 06:24:27 PM »

Had my jet rebuilt this winter and decided to stay with a "A" impeller . I figured my BBF around 450-500 Hp .....Well after all the little bugs were worked out I run at 4300 RPM at full throttle around 65-68 MPH . That RPM seems bit high . But it runs so great with no cavitation issues and has a great holeshot . I just dont want to trash the motor ,because I love to mash it . Thanks

« **Reply #1 on:** May 08, 2011, 06:34:21 PM »

Is your tach accurate and working properly? Have to ask, that RPM seems kinda low for the HP you are claiming.

« **Reply #2 on:** May 08, 2011, 06:41:31 PM »

Quote from: gregb on May 08, 2011, 06:34:21 PM

Is your tach accurate and working properly? Have to ask, that RPM seems kinda low for the HP you are claiming.

x2

« **Reply #3 on:** May 08, 2011, 06:43:05 PM »

Sounds to me like its set up perfectly. My tunnel at 4300rpm was right at 71mph, so mid 60's out of what I guessing is a v-hull sounds really good. As for 4300rpm if the motor is build descent (good rod bolts,proper clearances, balanced properly....ect.) I think your in good shape. But with a larger Imp. A+ or AA will pull RPM down and probably lose top speed.

« **Reply #4 on:** May 08, 2011, 06:54:06 PM »

I believe my tach is fine ..... Let me give you some more info . The boat is a 22 Mini Day cruiser , Has 460 with, 10.5.1 compression, Roller rockers , Comp Cam XM296HR , Weiand Stealth Intake , Holley 750 double pumper Vaccuum secondary .And runs Harmann long bolt logs ...... I thought 450 was pretty conservative guess for that build . Well I wont screw with success ...So I will run it . Thanks

« **Reply #5 on:** May 08, 2011, 06:59:34 PM »

charger, that makes even less sense since it is a 22foot boat, that speed and rpm dont match for that size boat.

that motor should pull an A impellor 5k

« **Reply #6 on:** May 08, 2011, 07:10:18 PM »

Well I will check my tach first and then check my jetting again ......

« **Reply #7 on:** May 08, 2011, 07:11:55 PM »

Quote from: gregb on May 08, 2011, 06:34:21 PM

Is your tach accurate and working properly? Have to ask, that RPM seems kinda low for the HP you are claiming.

Xs 3 450 to 500 HP=4900 rpms =an "A' Impeller ....

79charger

Is my impeller to conservative ???

gregb

Re: Is my impeller to conservative ???

Ralph Brunt

Re: Is my impeller to conservative ???

Dirty Air

Re: Is my impeller to conservative ???

79charger

Re: Is my impeller to conservative ???

Ralph Brunt

Re: Is my impeller to conservative ???

79charger

Re: Is my impeller to conservative ???

jet boat performance

Re: Is my impeller to conservative ???