Hat Nozzle Question

I Was Reading A Article About Fuel Systems It Said The Hat Nozzles Should Be Aerated Type And The Port Nozzles Should Be Non Aerated I Have Never Heard Of This Before Have I Missed Something Somewhere ?????? I Have Allways Ran The Non Aerated In The Hat I Learn Something New Everyday Thanks Jamie

 

it wont idle very well without aerated nozzles in the hat. or should i say at all. ..LOL THE the motor idles by sucking air through the holes in the nozzle pulling fuel with it just as a carb would.

 

do you understand what an aerated nozzel body is jamie? just look for the little hole on it. thats all it is.

 

Oh is that why some drill holes in the injector blades?? dah,,

 

Oh I thought the holes in the injector blades were to allow sufficient air to bleed through for idle mixture? Instead of using only the blade/bore clearance which would frost shut????

 

Thanks Bruce And Mark I Know What A Aerated Nozzle Is But I Thought The Idle Was Set With Blade Clearance Opening? Am I Wrong To Think About This In This Way Thanks Jamie

 

you still have to have blade clearence to idle ,but the aerated nozzel bodies help to atomize the fuel better going into the hat at an idle. it has nothing to do with drilling holes in the injector blades. there is no need to drill holes in the blades on a roots blower aplication either. usually somewhere around a 8 to 12 thousanths gap and aproximatly 78 percent will let a roots idle around 1800 rpm. no tricks ,bells or whistles. most people don't realize the motors idle on the hat only, and the pressure is so low at an idle you need aerated nozzles for atomization at the low pressure.

 

We run the blades as tight as we can get them without sticking, then we use bleed holes to adjust our idle. also doing it this way in conjuction with the barrel you can control your head temp much better in different conditions we dont like the head temp much over 170 on the starting line.

 

I had always thought that the aerated nozzles were also to keep the blower from actually sucking the fuel out of the nozzles which would keep the barrel valve from controlling idle fuel flow. That is why they are aerated and the port nozzles aren't. Positive pressure below the blower and negative pressure above.

 

When using aerated nozzles in the hat, isn't there a chance that under full load, the alcohol would be spraying out of the air bleed holes in the nozzles, since with the butterflies full open, there is very few vacuum in the hat, and the fuel pressure is quite high at that moment?

We don't use any aerated nozzles in our hat (PSI blower), but I do remember we had that problem before when we ran an normally aspirated engine with a tunnel ram...

Erwin

 

That is what I thought also...