Hey guys, I want to add a smoke system to my SHowtime 90 w/ saito 1.25. I bought the sullivan skywriter smoke pump and the instructions say you have to buy a special smoke muffler. Can't the muffler that came with the saito be modified with a threaded hole and a nipple similar to the one used for fuel tank pressure? If so where do you suggest I drill the hole? thanks for the help!!

The added nipple should go as close to the cyclinder as possible. So that the somke oil is in the muffler and getting heated the longest possible time.

So it is possible then! Should the nipple go in the header portion right next to the engine? (not the muffler itself)

try to lacate the nipple at a low pressure area (remember: at greater speed less pressure.) vernulli theory. don't install it in the wide part of the muffler this will make it easier for the pump to deliver the oil. and try ti put it the closer to the cilinder as possible. here is a link to get you started. http://www.greathobbies.com/technical/tech_smoke_1.php

I just finished setting up an O.S. 1.20 pumped with a Slimline.

The O.S. comes with a muffler which is predrilled ( ostensibly for the non-pumped version of the engine ) at the point where the muffler begins to widen out just past the threads.

This was close enough to the threads that I elected to try it this way.

It's worked just great, especially since the stock muffler also has a hard baffle like structure in the metal that helps keep the oil in the muffler a bit longer.

So I did not have to drill anything, I merely removed the existing screw.

Here is what I got out of OS 90.

my ys does that to vsustko

Did you really need the pre-heater?

I see that you used the same tap point I am using. I have not put in the coils as you've done, but I am running a 1.20.

I probaly could have gotten away without the pre-heat, but then hotter it is then more it smokes. Also, it helps smoking up a storm when you are running low throttle. This model was very overpowered and I liked using smoke while hovering so it helped at lower throttle settings.

Be careful not to over-preheated. if you wrap to much coil around the muffler it will act as a radiator and cool the muffler body and a cooler muffler means less smoke!

Very good point rzarikian!

thanks guys. I have it all installed and I have one more question: According the the SKYWRITER instructions you should just let the vent tube dangle but I was wondering if I should run it to the muffler for pressure?

if you're using a pump it will probably relieve some works from it while its working but once you close the valve everything will tend to "pressurize" and oil flow will probably be inconsistent. I don't see why bother. actually I think it whould be better now that I thought it through... if you use the pump alone it has to fight and overcome the muffler's prussure to be able to inject the oil to the muffler. BUT if you connect a line from the tank to the muffler the that will balance the pressure in the system. the pressure (lets call it #1) coming from the muffler equals the pressure #2 so now instead of the pump having to fight pressure and push the oil through now it just needs to push the oil since it has the same amount of pressure coming from the muffler to the tank and virtually elimimating pressure to to the pump and making flow MORE consistent!! Hope you understand and helps!!

Pro2K:

No you DO NOT need this with the Skywriter.

The pump primes itself quite nicely and the flow is quite good.