Tuned pipes

[Sean Bowf]

I built my first RC boat about 25-30 years ago. It was a Dumas Lil Rascal rigger. I kept this boat through 20 years in the military, and then a couple years ago decided I wanted to get it going again.

To keep a long story short, I went through a couple motors, and wound up with a .12 CVR in the boat. A friend told me about mousse can mufflers...so I built one, and this is what I had:



In the second video, I was WOT the whole time in the beginning of the video, I guess it finally built up enough heat in the engine and took off.

Anyhow, my point...I have not seen as dramatic a change with any other engine/pipe. I own two CMBs now, and have had numerous .18 engines in mine and my kids RTRs. I think the closest increase I have seen when the engine actually hits the pipe, is the cooper pipes. I had an old .45 pipe on my CMB 45HR, and when I could get it to hit the tune on the pipe, it was pretty much out of control.

I guess what really brought this to mind was that I have been playing with different pipes on the .18 engines (Q18, MACS 3.5, Cooper QHP, stock, AB short .21 pipe) and have not hit as dramatic a change as I did when I put that pipe on the .12 CVR. I run a .18 CVRM in my mod RTR (which I have pretty much handed over to my kid). I have not found a pipe that had such a dramatic change in the boat. The pipes do show a change...stock AQ engine in a stock miss vegas hull goes from about 32.5 to about 35 MPH when a MACS pipe is swapped in for the stock one.

What am I missing?? Is it just that there is not a decent pipe for this size of engine (the .18 engines)?? I have tried a couple different headers on the rear exhaust and the side exhaust engine. I have tuned the pipe to the point where it goes slower if I go longer or short, so I am in the right spot for the pipe....I just don't see the change like I did on the old rigger...

Sean

 

[tnrcboatracer]

The pipe is only 1 part of the picture. If the motor is not timed for using a pipe, you will have only marginal results. Do you know the timing of your .18 motor?

 

[Sean Bowf]

The pipe is only 1 part of the picture. If the motor is not timed for using a pipe, you will have only marginal results. Do you know the timing of your .18 motor?

I don't know the timing numbers on the CVRM, but it is a stock engine (stock timing). The .18 CVRM has the same parts inside the engine, as the car .18 CVR engine. So...I figured comparing the .12 CVR, to the .18 CVRM, that they would both be built (timed, etc) similarly.

Most recently, I have been fooling with a .18 GO engine, and again, it is a stock engine, and I don't know the timing on it.

Sean

 

[M@MRacing]

You can have the best engine and pipe but if your boat set up isnt right it wont go any where

 

[opio]

You can have the best engine and pipe but if your boat set up isnt right it wont go any where

I am the king of that statement.............. :blink: