Where's the magic pipe that just runs?

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Okay, here's a question, give me a logical answer that I can understand, maybe something from first hand or second hand experience, be offended, get bent, say you don't know, tell me you were thinking the same exact thing, whatever, but try and give some serious input. I'm not looking for "They can just go buy a 100% rtr toy kit boat and I'm not trying to offend anyone, but:

It seems common these days that not just Andy's pipes (I choose that name first because there is a current post that you might recognize) as well as the other well known inboard pipe brands including the O/B pipes all need some sort of modification to get them to run right? I've got to say that seems frustrating?

 

I guess now I feel comfortable changing pipes and trying new ones, longer shorter, fatter slimer and not worrying about not just going to the lake to play. But it wasn't always the case. For example I had a Rossi T4 O/B engine on a Lawless lower end with a Rossi "J" pipe. Me and my friends, who by the way are good racers, couldn't get this this set up to run for me. We tried everything but I didn't know that if I did a mod to the pipe it would solve my problem. Izitbrokeyet? told me about the .250 stinger to solve the problem. Most common advice I got "that pipe sucks, get another one" I got an Irwin but was told "no, not that Irwin, the queit Irwin" then I heard, try an Aerotech, a Garcia.......... :wacko: :wacko: :wacko: WOW, very overwhelming but I was determined to get this damn expensive motor to run.

 

But, what happens for the recreational boater who just wants go to the lake and run. He buys a $400 engine and $80 pipe and finds that it needs something else?? What he might ask??? Can he just figure it out?? Have to have someone tell him?? Or surf the web and hope he finds a post dealing with he's problem?? Even the lone boat magazine doesn't always discuss things like this.

 

I remember the first boat I sold. It had a .61 Rossi and an old airplane pipe. The thing could run like a gas boat, none stop and forever. Now a days that isn't always the case.

 

What's your guys take or experience? Anyone else notice that?

 

Signed,

Puzzled in Pacifica

 

[Don Ferrette]

It all boils down to one thing Big Daddy.......SPEED. All these mods we keep talking about are found trying to maximize that particular pipes performance and, .....well...... it's just the way it is. Kinda like modifying a motor to get more out of it. Plus there is no magic combo as every set up is different. Different hulls, motors, weight, fuel, altitude it's run at, on & on............

 

[Bob Kensill]

The problem with most pipes on the market(there are several that are right) is that they are made for a range of engine/hull/fuel/glowplug combinations. That's why the pipes are adjustable in length. If you have a specific application in mind,maybe someone here can give you some guidance. I build pipes for outboards and know some of the requirements for some engines. There are too many variables to make a "fit all" pipe.

 

[Mike G]

For me that was half the appeal of going Gas.

 

[John Knight]

Mike,

You have a valid point but I have seen many a gas guy doing the same as the nitro guys with their pipes. And their needles too. Real advantage is that gas is less sensitive to temp/humid/air density than nitro (disregarding the costs as well). But the power and smell of nitro is worth it! Real challenge is to find the best combination and then stick with it. The necessary changes are small once you have found it. True with gas as well.

 

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Don,

I took that into consideration, all makess hulls, motors pipes etc play by a different rule...

Let me play DEVIL's advocate: I go buy a CMB .67 Purple head. Bobby tells me "go w/the CMB pipe, the slim or fat pipe will work just fine. At $200 dollars each I figured I'd buy two. Bought one slim and one fat pipe. Now the first motor I ran, MOTOR A would not run with the Fat pipe, odd isn't it? :wacko: I tried the slim pipe and set it right at 11 1/2 like the Fat pipe and it hauled booty. Now, Motor B on the other hand would not run with the slim pipe but ran with the fat pipe. Same length, same hull, same fuel, same plug different pipe. Bizarre ain't it?

Krapnova, what type of O/B pipes do you make? any pictures of one?

 

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Mike and John,

That makes sense. I've never seen gas guys fooling with their pipes. So why is it easier for the gas to make a smooth tranisition?? W/nitro it's cut the length, extend the length, don't over cool it, cool it, zip tie-it, get a high temp coupler, blow out a coupler, add a silencer, drill holes in it, reduce the stinger........and-on-and-on-and-on.

This is like Saddathra trying to fing Nirvana....LOL :lol: :lol:

 

[TimD]

The problem with most pipes on the market(there are several that are right) is that they are made for a range of engine/hull/fuel/glowplug combinations. That's why the pipes are adjustable in length. If you have a specific application in mind,maybe someone here can give you some guidance. I build pipes for outboards and know some of the requirements for some engines. There are too many variables to make a "fit all" pipe.

I agree with Bob,

Too many variables. The MAC's inboard pipes seem to be a good compromise pipe and work in most applications - but working and working well are 2 different things.

We have beeen driven to a point with racing that the pipe just working isn't enough anymore. No other bolt on part will give as much potential for a power increase than a pipe -and those of us who get the pipe to really work will make more power.

Mike - it will happen in gas eventually! hehehehe

 

[Rules]

Krpnova gave you the correct answer. If you can't get the results you want using the available pipes, you need to build. What you need is a pipe builder/racer that will build a specific pipe for a particular motor/hull for outstanding performance. This means selecting the front cone, mid section, rear cone, stinger, diameter, etc, that will really work. Then combine the dimensions and arrive at a good design. Things were real easy when the only engines were K&B, Rossi, and Picco. Outboard pipes are particularly difficult since the gas temperature is not what all the design formulas tell you it should be. I found the correct temperature by trial and error. Long pipes are easy to cobble, so get out your hacksaw and start experimenting. Buy up a basketfull of $5-10 pipes to get the cones and use the formulas, or the aplet on the web if you can find it. Play with the stinger diameter to get the correct temps each time you change the design. Once one person finds the right design, you can copy it. Get together and assign one engine/hull combo to each team to avoid effort duplication. Just wait a few years, the GAS guys will reach the power plateau and need revised pipes to keep the top dogs winning. The only other options the average racer has, besides building his own pipe is to try all the pipes he can get his hands on, starting with the aluminum pipes that MAC makes. These are cheap, and plenty. Have fun !!!!

John in Huntsville

 

[Mike T.]

The gas guys play with pipes too when they want that last 5-8 mph they think they should be getting. I went gas tuning with John Finch the other day and saw him do just that. His nitro experience was showing, and paying off big time. He tried them all and settled on one very available pipe combo that anyone can buy, no modifications, set at just the right length. It made a nice difference, and had a killer sound, too. I'd tell you what it is but then we'd have to terminate you. You're right though, the gas boats keep their edge pretty well once you find the sweet spot.

 

[Don Ferrette]

Hey Mike-

And that was part 2 of gas pipe tuning. We tried a bunch of stuff the weekend prior that you couldn't join us. B)

 

[Mike G]

Hey Mike, since you said widely available I will guess that it was not an M&D pipe! :lol: I can tell you a story from the M&D pipe camp though, first ones were fixed, second gen adjustable, guess where the "sweet spot" is to run the adjustables????? The same length as the fix ones! :lol: :lol: :lol:

Tell me what boat and motor and I will give you a guess on the pipe.

Nice thing on Gassers is even if your out they still run, nothing more fustrating to a newbie than running a nitro boat that just won't come up on pipe. Been there did that. :blink:

 

[Mike T.]

Yes they do still run well enough to sometimes discourage experimentation. Then when you see it work right, you see the light.

Don, we made a water-cooled o-ring coupler and JB welded it onto Joe's Mac quiet pipe and it ran pretty well and was oh so quiet. Still need to find the sweet spot on that one though, if there is one. His cat ran very well for the first time out.

 

[Don Ferrette]

Yes they do still run well enough to sometimes discourage experimentation. Then when you see it work right, you see the light.
Don, we made a water-cooled o-ring coupler and JB welded it onto Joe's Mac quiet pipe and it ran pretty well and was oh so quiet. Still need to find the sweet spot on that one though, if there is one. His cat ran very well for the first time out.

I knew those Mac 15cc quiet pipes would be a good gas pipe!

 

[Mike T.]

Midwest sells one like that with the o-ring coupler welded on. Mine gives about an inch of length adjustment before the end of the header hits the front end of the pipe inside the coupler. And it allowed us to press a header into service that was cut too short for the other pipes we have. Funny what we'll do to save money sometimes.

 

[Mike G]

OK, now 0 band, 1" band or 2" band, I have seen them all?

 

[AndyBrown]

Don's first line really answers the question. Everyone wants more SPEED.

It's not really a pipe problem.

It is an engine design problem. Not bad engine design, but engine design born out of everyone's need for more SPEED.

Because of this, today's engines are less tolorent to pipe variables along with several other outside influences.

In the "old" days when engine design was more conservative, pipes and other variables were less critical. But at that time .60 to .90 riggers were only heat racing at 60 to 65 mph. These days we are racing in the 70's,80's and even 90's and much more reliably I must add.

With todays knowlege we could slow everything down 15 - 20 mph and it would be so easy......... and BORING. We Always get bored when we're not fighting for the next level. That's why it will always be Difficult and Frustrating for New and Seasoned boaters alike.

I have a big box of old pipes that I save, because what did'nt work on on last years set up might work on this years set up.

 

[[email protected]]

Rules,

welcome to the board! I like your idea. What I need is a learning curb on the "how to" going about making my own pipe. To shape and join them together.

Andy,

Your right, this all comes down to wanting more speed. That's why I sold my first boat. Yeah it ran, ran forever but it was slow and boring.

However, pipes can be expensive. I like the ideas, and it's actually what I've been doing, buying up the $5-$10 pipes to stock up. Pipe experimenting however can make for a long and tedious day at the lake. Especially for a guy like me that get just a few days at the pond. Those are days that I must really get everything done. Sometimes the thought of just testing pipes don't cut it.

I guess it seems frustrating when you got a boat running great but maybe you can get more.

 

[AndyBrown]

Those $5-10 pipes are great. Many times I cut them up and stick them back together with parts from other pipes. I've got lots of little "Frankenstine" pipes around here.

The ever popular CMB 67-80 (Big Belly pipe) was a "Frankestine". 1 MACS cone, 1 OPS cone, and 2 cones I cut from 2 1/2" bar stock (what a job).

At the time of testing (1994) it ran exactly the same on the Picco 67 as the Stock Picco pipe. So into the "scrap" box it went. Later it was tested on a CMB 67 Evo. Best pipe that engine ever had. Sent it to CMB and they have been producing it ever since.

Once you've had enough experince with all that cutting and trying and have read everything ever written about pipes. You will be able to draw a pipe and know almost exactly what it's going to do before it's ever built.

Every AB and Brown pipe that I have come out with in the last 4 years was drawn on paper and committed to a full production run with out ever testing a prototype.

All have worked as I anticapated.

I do think there is a certain amount of "seat of the pants", "black art" involved as I have yet to find one book or one formula that gives the complete answer.

Happy testing!

 

[Rules]

For those that are interested, the Java Tuned pipe aplet is at: www.mh-aerotools/de

(If your browser can't find it, then type "tuned pipe" and see if mh-aerotools shows up, if still no go, then use another browser)

You will have to download a few items, but these only took me a few minutes. This is a site you can use to verify a new pipe design, and also to reverse engineer any tuned pipe to see what it will do. BUT, like I mentioned it assumes a few items, which are temperature based, so the resultant will be skewed a bit, but will give you valuable info. I have used it dozens of times. You will need to convert from degrees kelvin, but thats easy. You can plug your existing pipe dimensions into the aplet by moving the sliders until the dimensions are correct on the drawing. This will give you the tuned RPM that your pipe was designed for. Then you can change the header length and see the new RPM. You can calculate the correct pipe length for the pipe shown, as related to model boating measurements. There is a wealth of other info on the site you might find valuable. John in Huntsville