^^ yea, what he said.

 

punching it wont show any flex or buckle. revving it from neutral to high rpm will make it flix and buckle by going high vacuum to low vacuum. i've witnessed a fast 102mm flex and buckle like crazy and it's a $800 intake.

 

Intersting. Yea, I wouldn't have expect a FAST to flex. They appears solid also.

 

Check some videos out on YouTube. Pretty crazy to see how much they actually flex.

 

I'll do that.

 

Still photos have been added to the first post.

 

My factory truck intake without any mods flexed probably 1/2-1" in the middle when going from high vac to low vac.

 

Wow, thats crazy. That explains the posts that are in the intake then. I was thinking about removing them, maybe I won't. I've heard people saying thats what they remove in the LS2 intake when they port it. The posts inside the intake that go from bottom to top.

I searched "LS1 fast intake flex" and a few other ways of wording that on youtube last night and didn't find anything. I must be wording it wrong.

 

Doing some easy math lets say the surface area of the outside of the intake is 18"x6" (just guessing sitting at work), thats 108in^2. Idle vacuum is usually 7psi (50kpa) or so with a daily driver type cam, so thats 108*7=756lb trying to crush the intake.

On hard decel, manifold vacuum drops down to 20-30kpa, so 3.5psi, 180*(14.7-3.5)=1210lb.

 

Holy crap! Never saw it that way. wow!

BTW you just gave away your job description Mr Engineer....