Air Intake Design ?'s Velocity Stack Placement, Etc.

[deiloohay]

Looking to design an air intake for my 2.4L cyl car. Figuring this engine is looking for max 600cfm around redline.

I've seen many different designs for intakes, and not been able to find very much info on design. I have seen the "short ram" design, big tube, open filter, some interesting stuff from where the filter is still in a chamber, cold air intakes, and then this interesting item:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=8003061815

Can anyone clear up the use and benefits of a velocity stack? and perhaps where to place one in the intake?

Do these devices smooth out airflow? Do they have a logorithmic taper?

If you are designing an intake for efficiency (maybe get some perfomance as a side effect, but dont mind trading a little efficiency for noise) is the goal just to have the air intake resistance minimized, or are there other considerations?

 

[GregLocock]

"this interesting item:"

snake oil

If you look at intake systems that are designed for efficiency at one speed, what do you see?

no filter

no funny shapes

one tuned length

reasonably shaped trumpet. (and I bet you can't tell the difference ona dyno between one reasonable shape and another, I expect evelrod has data)

For a realistic system you might want to consider cylinder to cylinder coupling, but I bet at one speed you'd be better off without it.







Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[evelrod]

You know, everytime I think that I have seen it all, someone comes up with another scheme to get your hard earned cash. Oh well, I guess that if your gullable enough to buy these "trick" items, you deserve what you get. If they marketed it as a so called "cold air intake" system, without all the BS, I might give them more latitude. As I see it, IMNSHO, they are preying on the ignorance and gullibility of a significant portion of the automotive enthusiast market.

Yeah, I have a bunch of stuff on the velocity stacks for Weber carbs...nothing you can't get from the little pamphlet that Weber puts out. If you really want to get an insight into stack shapes and length v. performance, check out the tuner books for SU carbs...those little darlings are a lot more critical to shape because of their inherant fuel "stand off" at speed.
The only reason I did tests on my own was because I'm kinda "anal"...in this case, re. "shape", the books were right on.

Rod