tuned pipe question

[anthony_marquart]

If you can fins one the AB parabolic pipe has worked real well for me.. Still trying to get my S pipe to work.. maybe my new boat, being lighter, will like it better. I'm running 65%,.. starting see the narrow set-up window with the 65% I think..

 

[shoboat]

Tony,

I think the carbon pipes are the way to go, but you have to tune

for them. I think they run the motor hotter and make the charge

coming back to the exhaust port faster. They can two or three

stage when set up right. Most cannot get them to run the best

because they want to pull too much propeller. Remember: RPM = Speed.

What length do you have your S-pipe set at? 7&7/8"?

I remember back quite a few years ago SPP did some S-pipe designs.

These still work very well on my engines. Ian is correct about the shape

of the ports being efficent. Ports and pipes have a lot of different combinations

that work well together, you just need to figure out what works best for your

set up.

Thanks For Reading,

Mark Sholund

 

[Ian Inverarity]

I personally dont see the difference between a single port or 3 port exhaust. Especially when the newer stuff has an "eye brow" on each side of the exhaust anyhow, instead of the 2 satellite ports... They are probably not all that far apart as far as port area I wouldnt think... But then again, Im no engine guru either. So I could be completely off base.

Rodney,

Its not only about total port area, it is the distribution of the area. The sub exhaust layout does allow a wider port than a single port configuration. The wider port can allow more power at higher RPM. At the cost of torque. This doesnt suit some people, it suits me, but not Chris for example. It also affects the pipe designs that work best.

 

[RodneyPierce]

Ian, thanks very much my friend for the explanation!!!

 

[Mike Larson]

I've run carbons forever.... TD21, MS21, and a pair of muffled longer versions I cant number.... I'm currently using Cooper "S"... basically along Mark's lines, the carbons have to be HOT to stage consistently, seem to be finite on the sweet spot, ( test and test).... all on 3 port Bulifant engines for years.... and they run great once you find harmony...... engine dynamics vary... you never know..... All around general for a platform start and further finite tuning would have me on the 3280, and normally does for a short time..... aint the fun of it about testing and perfecting most weeks anyway?..... they'll all work.... find what your particular engine dynamically likes..... and test them.... Mike

 

[shoboat]

Mike,

I have found the stinger diameters the biggest single

Item that is very important on the carbon pipes.

Have Fun Testing And Learning More,

Mark Sholund