I'm in the early stages of testing a smoke system on a 2.4 Brison on a Sig Extra. I was running an on-the-ground test today which resulted in a question or two.

I've got a Perry pump running off the crankcase. When the engine idled, it seemed like the smoke was good and white, but when I revved the rpms, the smoke seemed to thin a lot. I've adjusted the amount of the smoke oil with the needle valve and that helped a little, but at high rpms it didn't EVER get as nice and white as it did at idle.

Ideas? Is is possible that at high rpms the crankcase pulse becomes more like a constant pressure and the pump doesn't oscillate like it does at idle - just a thought. I'll keep testing.

Thanks!

First: I dont have a smoke system so this is just a guess.

Could it be the extra airflow from the propellor "diluting" your smoke. A thick cloud of smoke is all dandy untill you blow a big fan at it.

Hey there, Joe -

Yeah... it could be. As I was revving it, I thought it could be that too, but it looked so diluted compared to other smokers I've seen that I somewhat ruled that out... but in the end, that may be the case. At high rpms, it almost looked like a 2-cycle exhaust that is too rich - rather than an actual smoke system. At the lows, it was a nice dense white puff. Since the pump is running off the crankcase pressure, I was hoping that it would keep in proportion the amount that would be required by having the pump speed increase as the pressure cycle speed increased. But... still experimenting.

Thanks for the note!

-shaun

The amount of smoke fluid is critical to performance, you may actually have too much fluid flow. I have never used the Perry but I have used electric pumps.