There have been a few threads on the Evolution 36 and in particular it's venturi and fuel delivery system. Admitidly it is a weak spot on a better then most people have given it credit  for engine.
 I'd wanted to convert one for awhile and called around and of course called Jim Lee. He had already done it and was happy with it. His venturi and  one of Randy's NVA's properly sleeved for the conversion.So for viewing pleasure, here is how a properly converted Evolution 36 should look like.
My thanks to Jim  Lee and Randy Smith for this conversion.


Dennis

Dennis-

How did this work out?  Looks really good.  I got a venturi for the Evo 36 that had a through hole in it from Jim and it worked really well.  I also have put a OS part #21181902 1A,15 NVA in the stock small venturi and it also works really well.  The remote didn't work for me, but the plane had a weak nose.

I really like my Evo.  I got three venturis from Jim.  I never had time try the large one.  The smallest .280 venturi really turns a 10-5 at a fat four cycle at around 10,000.  With the biggest venturi he sent I think it will proably turn an 11 1/4-4 really well, which is people are using an the 46 LA.  This engine seems more powerful than the Brodak 40 even though it's a bit heavier.

I agree that this engine is better than people think.  Parts are really cheap too.  Don't ask me how i know this.

Thanks, Dennis!

Since I have not seen the "stock" set up, I am not aware of what has been changed.   

Big Bear

Hi Bill, stock set-up is standard remote-NV configuration that you see on OS LA engines and others.

Thanks, Pete.  AS I thought about it, I kinda pictured that scenario.

Dennis, is the venturi you are using a "sprinkler"?

Bill

Hey Dennis, have you gotten any flite time on your conversion yet was wondering how it was working. T.J.

Does this have multiple holes all the way around the venturie for fuel to sprinkle out (sprinkler)  or does it have 1 hole for the fuel to come out of (true venturie) ?

     A venturi can have either single or multiple fuel inlets and still be "true".

    Brett

They also work much much better with 1 hole, rather than the many holes around the perimeter, I know this from test after test after test on several motors.

Randy

True enough ,But not a sprinkler, as it has been known for decades in Model engines, this came mainly from the 360 degree holes of the Super Tiger sprinkler venturie.
If it has 1 hole it isn't a sprinkler

Regards
Randy

Randy, It is not the tiger 360 type but a single point. As Brett said it is still a true sprinkler. I can't remember the id of the venturi right now and thats pretty bad seeing as I did 2 of them.I'll check and get back. They run perfectly with a 2/2 break and when broken in are not bad on fuel. I have an additional engine fitted with an Irvine venturi with a banjo type NVA that also runs well. It has a slightly smaller hole and delivers really well controlled power. The spray bar used with Jim Lee's venturi has to be sleeved to fit the oversized holes for the cinch bolt. The venturi unlike most  has a relatively small hole in it. Proper alignment is required for the 3 pieces but easy to do. Hopefully the next shipment will have these conversions done. This will make the engine fully capable out of the box.

True enough ,But not a sprinkler, as it has been known for decades in Model engines, this came mainly from the 360 degree holes of the Super Tiger sprinkler venturie.
If it has 1 hole it isn't a sprinkler

Regards
Randy

aka - Annular Discharge    ...which is the most efficient form of a booster venturi in a carburetor.

aka - Annular Discharge    ...which is the most efficient form of a booster venturi in a carburetor.

Which is apples compared to oranges, we don't run carburetors, nor do we have booster venturies inside of venturies, and if we did there would still be 1 main feed to the inside booster venturie.
Although this would make for a very interesting exercise to make a venturie with a booster inside of it.  Someone needs to take on that chore and report back to us

There were many downsides to the Super Tiger Sprinkler venturie
1 was the machined step halfway down, this worked but not nearly as well as a real , or conventional venturie made with the  proper angles
2 was the very tiny holes you needed to keep the fuel from dribbling..if the holes are made larger the fuel does not come out of the multiple holes very well, same thing happens if you make a main hole way too large.  The same thing happens when people drill out true venturies into straight tubes...they loose the fuel feed pressure and the fuel will dribble out of the side.
3 The tiny holes needed to use in the sprinkler would stop up much much easier than 1 larger hole, especially if you used castor fuel.
4  Super Tiger used, and you needed a complete ditch cut all the way around the outside of the venturie for the fuel to flow all the way around in order to feed the 360 degree holes, this got mix with air near the end of the tank and caused many engines to surge and cut on and off, you can fix this by blocking off that area and using only 1 or 2 holes close to the fuel feed (spray bar), this would stop the surging caused by the air bubbles. You could then jb weld or turn a 3/4 moon shaped piece to fill the ditch in the ST venturie.
The st venturie was better after this mod, you could use 2 holes if wanted in this configuration and you could also just use a smaller slit to connect the 2 feed holes, if you wanted to use 2, if this was used it is best to center the 2 holes between the sprat bar feed hole.

We made many adjustable venturies with 3 and 4 feedholes similar to the sprinkler one, but they were differant because they had a much smaller area inside to feed the holes with fuel. These worked OK  but did not work better than a standard true venturie.

Regards
Randy