A DIFFERENT APPROACH TO A PIPED OUTBOARD

[topfuel443]

Hey Guys, I was really bored the other night and I had an Idea. I had an extra irwin header for my OS outboard, and a extra Brown .21 pipe laying in my box. I decided that since I liked the Brown pipe so much on my rigger and Andy doesnt make one for an outboard, I would make my own. I cut the header right at the mounting plate and re welded it so it would stick straight out the back of the engine. I then cu the pipe short enough to where it was the correct length and fashioned it to the header, and made some bracketry to support the pipe. It only changed my CG by 3% so I added about 1/2 once to the front to get it back where it was.

In my past topfuel dragbike racing experiences we always made the best horsepower/torque when the intake and exhaust flow was straight in and straight out. The aftermarket outboard pipes have alot of direction changes in them, am I wrong in my theory??? are there any disadvantages to placing the pipe this way? I will have the boat on the water this weekend to see if I made a mistake or not. I will post pics tonight to give you guys a better Idea of what it looks like.

If im not mistaken, this was the way they used to do it in the past.....Jerry, Grim, do you guys have any experience with this?? (Jerry, Grim said that you were the errrrr....."most experienced with the way it was back in the day" ;D It would probably have been around the same time you bought all those acient radio box boots....LOL

(mike didnt really say that 8))

~ James

 

[Jerry Dunlap]

James,

The Magic Muffler/Pipe stuck straight out from the back of the motor and it worked well. I ran an O.S. Max 21 with a straight back muffler on my A Outboard Mono at last summer's NAMBA Nats. I pulled the pipe upwards somewhat to get it out of the prop wash.

JD

 

[topfuel443]

Yeah, i hear you about the prop wash, I had to do a little changing and raise it up after I thought about it. Seems like it might work as long as I can keep other boats from running up the back of me.

 

[topfuel443]

Does anyone know of any other pics I can look at with this setup?

 

[TomMoorehouse]

 

[TomMoorehouse]

 

[TomMoorehouse]

 

[TomMoorehouse]

 

[RonD]

I tried that on a tunnel of mine back in 1990. I replaced my then current 'Magic' pipe with it. The one thing that I had to do was reinforce the transom because of the extra vibration. Even though I did not think that I had added that much more weight the extra length did cause my transom to crack. It did however give me a great deal of hp gain. But because I did'nt like the extra care it took to maintain it I replaced it with a "J" pipe. That set up however was the fastest that my boat has run.

Best of luck,

Ron

 

[topfuel443]

That set up however was the fastest that my boat has run.

Best of luck,

Ron

Thats what i like to hear!!

Sounds promising, This hull seems to have a pretty strong transom, have to wait and see how it holds up tough. Thanks for the reply.

 

[TimD]

Have done it that way and have also used a 180 degree header and had the pipe pointing up in the air. I couldn't get the boat to handle as well with those setup's. The further the pipe is from the transom the worse the handling became (especially if you ran across some ripples in the water - it got real upset). The other drama was the pipes being hit with propwash, and the huge stresses on the pipe mount.

I now use a CF curved pipe and it does not suffer from any of those issues.