Pipe Length?

[Martin Lovsund]

Guys , where should I start with pipe length for a CMB 45 purple head , OPS 67 pipe and 1655 prop on a RR Extreme. I was running the new Cooper pipe at 9.25" but will be testing with the the OPS tomorrow for comparison.

Thanks

 

[John Knight]

About 9.5" to start with and may have to go in or out .25 to .5". May also have to reduce the prop size as well to get the engine to unload enough to find the sweet spot for the pipe.

Have you reduced the stinger size on the OPS 67 pipe? You need to.

 

[Terry Keeley]

About 9.5" to start with and may have to go in or out .25 to .5". May also have to reduce the prop size as well to get the engine to unload enough to find the sweet spot for the pipe.
Have you reduced the stinger size on the OPS 67 pipe? You need to.

Yup.

 

[Martin Lovsund]

Thanks guys , I have not reduced the stinger yet. What ID is working? I have the next three smaller ID sizes of tubing cut. I was thinking of starting two sizes smaller. Is that about right?

Martin

 

[Terry Keeley]

Thanks guys , I have not reduced the stinger yet. What ID is working? I have the next three smaller ID sizes of tubing cut. I was thinking of starting two sizes smaller. Is that about right?

Martin

3/8" I/D is what i run.

 

[gooycheese]

Hi all,

When you are reducing stinger size are you JB welding a tube in or how are you attaching it? Approximately how long are you make the 3/8 id reducer?

Thanks Paul

Are you also running an aftermarket muffler? If so what type/make?

 

[Ray Sametz]

Paul, the reducer is the lenght of the stinger. on a rigger green loctite works for me, let it dry good. Stinger muffler is tricky, sometimes it causes enough back pressure so you dont need reducer. Testing only way to find out. Ray B) B)

 

[Martin Lovsund]

Thanks Terry. Paul I use red loctite 272 and haven't had a problem with it holding yet. I am running the new Cooper mufflers on my nitro pipes.

Martin

 

[Don Ferrette]

Paul, the reducer is the lenght of the stinger. on a rigger green loctite works for me, let it dry good. Stinger muffler is tricky, sometimes it causes enough back pressure so you dont need reducer. Testing only way to find out. Ray B) B)

When I ran that combo of the CMB45 with the OPS67 pipe I used a RumRacing (Lenny Blake) stinger muffler with no reduction in stinger i.d. and it worked great. Another thing to try is an internal stinger set up, Terry might be able to chime in on that set up on this pipe. B)

 

[aaron alberico]

Martin.

i would start your pipe length at 9-1\2 and work your way down,

as i run the ops 45 nitro pipe on cmb45hr with 1657 prop at around 8-3\4 to 9in..

and the speed speaks for itself

regards Aaron

 

[shoboat]

Aaron,

I am with you on the OPS 45 Nitro pipe at 8 1/2", it turns up real well

on a Picco Bluehead with a 1457 @ 4.50" of cup. If anyone wants to sell

their 45 OPS Nitro pipes, I will be happy to buy them from you.

Thanks,

Mark Sholund