switch from aluminum to ss

[spazzer]

I want to switch from my aluminum prop to a ss prop. The one i have now is 14.25x23p and pushes my boat (a nitro 180 f/s with a 175 rude ) at 53mph on the gps at 5200rpms. The ss prop iam looking at is 13.75x24p both are 3 blade. What will be the difference between the two as far as performance? I believe the max rpm is 5600 on my motor. Any input would be great.

 

[SparkieBoat]

Re: switch from aluminum to ss

why are you wanting to go up in pitch?? 5200 RPM at top end is slightly low..I would shoot for 5500. maybe a 21 or 22 pitch would be what I would go with.

 

[spazzer]

Re: switch from aluminum to ss

Maybe i should of stated that i wasn't at wot on that run. My bad. Basically i want to do is put a ss prop on and thats one i can get for a good price. Should i just stay with the same pitch and dia? Also i heard that a 4 blade prop is better, less vibration but have to drop by 1 pitch for that. Is this true? Thanks.

 

[SparkieBoat]

Re: switch from aluminum to ss

4 blades will give you better hole shot but less top end..and i have heard less vibration but I have never been able to tell the difference. what is your RPM at WOT?? Diameter will make slight difference but not much, pitch is most important.

 

[spazzer]

Re: switch from aluminum to ss

Its at 5550. Just wondered if the smaller dia would increase the rpms even though the bigger pitch would drop them. Kinda like a cat and mouse game i guess.

 

[SparkieBoat]

Re: switch from aluminum to ss

roughly you gain about 50 RPM per inch in DIA drop and about 200 RPM per pitch drop..reverse is true also. but this is just a rule of thumb because different manufacturers props all run different. 5500 is my target RPMs for most motors. you should be ok with the prop you mentioned if you want to try it..maybe lose 150 rpms or so.

 

[spazzer]

Re: switch from aluminum to ss

Excellent. Thankyou very much for your help. Thats close enough for me on thr rpms.