Yo guys, I need a little help and maybe you can point me in the right direction. I need to hook up with someone who knows about fluid dynamics and venturis. The mental image I have of the perfect person would be a little nerdy MIT student who is pumped on oddball designs and knows their way around CAD modeling, and a working knowledge of 2-stroke motors would be plus. I have a decent understanding of the physics involved but have no one to bounce ideas off of, nor do I personally have the resources nor mentality to beat my head against the wall with trial and error.
I want to add a scoop to my 2-stroke and grab some free HP in the form of RAM-air. The complication I am running into is the shape of the scoop and the proper carb to run. The round-slide, 39mm Mikuni I have been using meters fuel based on the volume and speed moving through the venturi. If I successfully force air into the intake I will be increasing the mass of the airflow but not the speed and volume and thus will create a lean mix at high speeds. My solution is to get a CV carb, but what carb? I was thinking about running the same CV some dudes run on ironheads: 40mm keihin. They are easy to find and use, but where I need help is in the making of a scoop. The rendering is easy, I can make it, but the shape cannot be arbitrary. I can calculate the opening based on my engine's needs and the speed I am hoping for, but the shape is key and I don't know enough about gas dynamics to make it proper. To complicate things, I have very limited space, an odd motor and would like to integrate an air box based on a Helmholtz resonator. What's more, from what I understand about scoops, the openings are often too small until i reach the projected speed and beyond that they drag; sweet. I'm not sure how or where i can make compromises.
Anyways, I welcome any and all input, but this may be a bit too involved for anyone to enter pro bono on, and I am working my way through a stack of books. Thanks for getting back to me.
Send any good ideas to ride@ftwco.com
I want to add a scoop to my 2-stroke and grab some free HP in the form of RAM-air. The complication I am running into is the shape of the scoop and the proper carb to run. The round-slide, 39mm Mikuni I have been using meters fuel based on the volume and speed moving through the venturi. If I successfully force air into the intake I will be increasing the mass of the airflow but not the speed and volume and thus will create a lean mix at high speeds. My solution is to get a CV carb, but what carb? I was thinking about running the same CV some dudes run on ironheads: 40mm keihin. They are easy to find and use, but where I need help is in the making of a scoop. The rendering is easy, I can make it, but the shape cannot be arbitrary. I can calculate the opening based on my engine's needs and the speed I am hoping for, but the shape is key and I don't know enough about gas dynamics to make it proper. To complicate things, I have very limited space, an odd motor and would like to integrate an air box based on a Helmholtz resonator. What's more, from what I understand about scoops, the openings are often too small until i reach the projected speed and beyond that they drag; sweet. I'm not sure how or where i can make compromises.
Anyways, I welcome any and all input, but this may be a bit too involved for anyone to enter pro bono on, and I am working my way through a stack of books. Thanks for getting back to me.
Send any good ideas to ride@ftwco.com