Drive ratio/prop combo
 

I have a 91 32 fountain
Took a gps out last night.
78mph @ 4500 rpms 27p hydromotives
80mph @ 5000 rpms 25p mirages
I think I have 1.36 drives, and I want to get to 85mph. What props should I try next. Are 1.50 drives better for my application?

Re: Drive ratio/prop combo
 

Jryan
You Need To Be Sure First About The Drive Ratio Before You Make Any Changes. What I Always Advise Is That A Naturally Aspirated Engine Use A 1.5 Ratio Because Generraly Will Not Make Over 700 Ft Lbs Of Torque And 1.36 For Big Hp Appliactions.you Can Check The Drive Ratio By Marking The Input Shaft And The Output Shaft Then Turn The Input 1 Full Turn As Precisely As Possible And The Output Shaft Will Turn 1.5 Or 1.36 The Difference Is Noticible.good Luck Laz Mesa

Re: Drive ratio/prop combo
 

Jryan
You Need To Be Sure First About The Drive Ratio Before You Make Any Changes. What I Always Advise Is That A Naturally Aspirated Engine Use A 1.5 Ratio Because Generally Will Not Make Over 700 Ft Lbs Of Torque And 1.36 For Big Hp Applications.you Can Check The Drive Ratio By Marking The Input Shaft And The Output Shaft Then Turn The Input 1 Full Turn As Precisely As Possible And The Output Shaft Will Turn 1.5 Or 1.36 The Difference Is Noticeable.good Luck Laz Mesa

Re: Drive ratio/prop combo
 

Thanks Mesa
Ive been told that you can take off the top cap and count the teeth also. I'll check it out this weekend.