engine RPM with 25 mirage plus
 

Hello,
I have had three different engines in my boat between 25 to 75 hp different. I'm unable to turn the engine over 5k, the engine is a 500hp with a stardard bravo 1 with a 1:5 ratio . The engine has no rev. limiter has good fuel pressure and spark. The timing is set at 34 degrees with a holley 950 Hp which is about a 800cfm. Is this the proper Rpm the engine should be turning or should it be alot more. Jp

What is you prop depth. That maybe keeping your rpms down. It does on mine. Could be hull design, etc.,. My vote is prop depth if more than 5"

What boat do you have and what is your speed GPS? How deep is your propshaft centerline? I run a 25p and at 5K I am hitting about 70-71MPH. I am still a tad overproped, I am hitting 5200RPM but would like to be around 5400. Before I raised my x dim up 3" I could only hit 4900-5000. I think with a 500HP you should be around 5400 for your peak.

I am running 25P Mirage's (not +'s) at 5000-5100 rpm, engines are 502 carbed at 425hp, a bit overproped for them should run 5400rpm. Gives me 74MPH at 5000rpm GPS.

What kind of boat do you have?

i have kinda got the same thing..... i am running around 570hp. just found out that my 24 bravo 1 is labbed. ( i always wondered why it is so thin) i can turn it 5500 rpms with me and my girlfireind in it and have had it up to 5700 with just me in it and LOW fuel. Anyways. i have gone 74 with the bravo 1 and i have a mirage plus 25 that is new. i cannot turn it above 4900 with 2 people in it. soooo im gonna get a 23 worked on. i need to be running 54-5600 rpm for my peak power. the mirage is good but it is holdimg me back. the mirage performs better overall. it carries the bow well and planes more level. the bravo 1 sends my bow sky high when im planing. but i have a porpouse at around 50mph. overall i am stoked with its performance. i even got 72 with 5 people downriver on gps with the b1. also keep in mind that my boat is like a poker run edition. the cuddy is stripped and has nothing in it. i can get the bow up there and get on top of the water.

if i were you i would try a 23 mirage plus. gain 400rpm. its not about having a big number on the side of the prop. you just go faster with the right prop.

Fixx
 

22 classic?

read your plugs,,,a jet change is good for a few hunderd rmps.. on my x i pulled 2 jet sizes out of each corner and picked up 300 rpm's

The boat is a 22ft. Donzi Classic the drive is very deep in the water. The spark plugs look fine, the prop has never had any work on it all stock drive and prop. Jeff

Before you do anything, check the accuracy of your tach against a shop tach.