stinger size reduction in the ops 3280 pipe.

[tmunn]

Guys ,

I heard of some guys making mods to their OPS 3280 pipe by reducing stinger size with brass tubing.

Is this correct and would their be any benifit if only using 35% nitro due to cost and unavailability.

I run the CMB .21 valvola and the 3280 at 8.5" in my SS 21 and a smaller (x438)prop due to lower nitro.

I have it working pretty well and have the blow over issues cured.

Just curious about the pipe issue now.

Thanks

Terry

 

[Terry Keeley]

If the stinger is much over 5/16" (0.312") you'll mostly loose bottom end and the motor will run colder than optimum, taking a little top away too. When you choke the stinger down you need to lean the main needle 'cause the pipe puts out more pressure...

 

[tmunn]

Terry,

Mine is exatly 5/16" or 0.312 a 5/16 drill or a 5/16" brass tubing will fit right in the stinger.

Would there be any benifit to reduce it or sleeve it down if so how do you guys do it.

Thanks

 

[Terry Keeley]

I've tryed the next size down (9/32" or 0.281") but was hard pressed to tell the difference once I re-adjusted the needle.

Try it, just take some brass tubing & locktite or JB weld it in place, you can flare the end or solder a small bit of the nest sized tube over it if you're worried about it getting in the pipe.

Let us know what you find!

 

[Chris Wood]

Guys ,
I heard of some guys making mods to their OPS 3280 pipe by reducing stinger size with brass tubing.

Is this correct and would their be any benifit if only using 35% nitro due to cost and unavailability.

I run the CMB .21 valvola and the 3280 at 8.5" in my SS 21 and a smaller (x438)prop due to lower nitro.

I have it working pretty well and have the blow over issues cured.

Just curious about the pipe issue now.

Thanks

Terry

Terry,

My sport boat i run the stock stinger.. 3280 pipe and I see no need to reduce it for my situation.. I run 8 1/8 and a 1440 prop, now with lower nitro i am not sure, as i run 70%.. I do know i am not a fan of alot of back pressure specialy in a cowled boat.

chris