Tune pipe length

[Ray Sametz]

I'm doing a low budget restoration on old Twin rigger. 80 green head motors, Macs 1389 pipes with stock H-48 props. Need a good starting point for pipes, c/l of motor to fat part of pipe?????.......==={}

 

[julianconde]

11 1/4

 

[Ray Sametz]

11 1/4

Seems a little short J, boats on the heavy side.............==={}

 

[julianconde]

11 1/4 to 12 inches is what i used on my 15 year old roadrunner boat and every other one after that

 

[shoboat]

Ray,

Smaller propeller diameters will help with your heavy boat.

Less cup on the trailing edge as it just slows the RPM of the motors down.

If you want more pitch just add it in the leading edge or center of the blade.

Low budget and twin in the same sentence? LOL

11.5" on the pipes!

Have Fun Testing,

Mark

 

[BigChuck]

Ray

Use to run the Picco 80 boat on 11 3/4,long for some but I wanted throttle control. Props were 64mm 1667's and H-48.

Small Dia. but I was able to add pitch once I knew what the boat could pull.

 

[Ray Sametz]

Thanks for all the help men, need too find a set of short headers. B) .......==={}

 

[julianconde]

al hobbs has some headers you will like.

 

[Joe Warren]

11 1/2 after you get it sorted out. maybe 12 till you find the props it likes