Care to expand a bit more?

I know what the venturi effect is but I'm not quite sure what you mean by the venturi effect makes these things work.

 

OK... since you know how the venturi effect works then take the venturi pipe and cut it in half and that's your horn constricting airflow to speed up that big chunk of air that your cylinders are demanding.

 

Yah I agree with you on that. The way it is right now, the air doesn't really speed up since its a pretty constant flow area. Its almost like, whatever it gets at the entrance is what it'll end up with. With the horns in place, the taper allows the pressure to the converted into velocity.

I was also calculating the entrance losses with the horns vs without.

http://www.engineeringtoolbox.com/minor-lo...ings-d_208.html

From rough calculations, I found out that there is an extra 100Pa drop in pressure just from not having the horns.

 

horn sizes are critical when tuning.... air velocity, density, volume are all key components of ITB tuning. so if you dont have horns, of course it will affect the tune.


here are my smaller horns, smal short horns for topend peak



and this is my normal.. midrange horns.



im working on a longer horns right now... theyre angled since we dont have enough room to extend the horn longer without angling it.

 

Lovin it!

 

^ so what are your impressions on the different lengths?

huge difference in performance?
what does the butt dyno tell you?

 

what exactly what i said earlier.... short is topend, at wot... no lowend power (butt dyno)

my normal one is midrange...

if i make that longer length, that will give me more lowend

 

Thats reassuring. Right now, my overall runner length is REALLY short. If I were to guess, I'd say about 8".

That's exactly what I'm feeling, NO low end power at all...

We'll see what happens when I add an extra 4" to that runner length.

 

Anyone run ITB's with Hondata?

 

bump for a good thread, also curious as to how everyones ITB setups are treating them.