Author Topic: Venturi Question (Read 919 times)

Joe Messinger · « **on:** February 25, 2007, 11:01:19 AM »

Hello,

I've recently made several venturis for some of my engines. I haven't had a chance to try them yet due to the weather. There's a good deal of information available regarding the size of the venturi opening for various engines but I've not found much about other aspects of venturi design.

Is there an optimum length from the spray bar to the top of the venturi? How about the inside taper from the top to the spray bar?

Looking at several differant engines, there doesn't seem to be any "standard" configurations. Maybe it really doesn't matter or isn't an important factor in engine performance?

Anyone have any thoughts or recommendations?

Thanks to all.

Joe

Dick Fowler · « **Reply #1 on:** February 25, 2007, 03:21:34 PM »

With regard to spraybar/needle location, I like them to be close to on plane with the centerline of the tank. As far as shape is concerned, at least with stunt motors where we aren't trying to squeeze every last bit of UMMPH, I think you got it right. It doesn't matters a whole lot. Cross sectional area does matter though. There has to be some acceleration and minimum velocity of the air thru the "venturi" to have fuel pushed through the spraybar/needle valve assy.

People jam all kinds of stuff in venturi to change the area looking for a good run. Sticks, tubing and such. Seen more than one plane flow all season with the "popsicle stick" mod.

Bob Reeves · « **Reply #2 on:** February 25, 2007, 04:11:24 PM »

I agree with Dick, might be a best design but don't think it much matters with our engines. My experience with sticking screws through the side to choke the intake down seems to enforce this line of thinking.

Bill Little · « **Reply #3 on:** February 25, 2007, 05:18:04 PM »

I have noticed on the engines I have seen that Big Art Adimisin worked on that he likes a longer than normal venturi/restrictor stack that tapers internally. He told me it is to inhance fuel draw..........

Bill <><

Author Topic: Venturi Question (Read 919 times)

Joe Messinger

Venturi Question

Dick Fowler

Re: Venturi Question

Bob Reeves

Re: Venturi Question

Bill Little

Re: Venturi Question