Hey, I was thinking about puting one of those new air foils in that claim to increase HP by about 10. Is this HP claim really true? And where is the stock air foil located in the intake? I have an '89 Camaro IROC-Z 5.7L TPI. Thanks. -89IRO

 

i dont know if it really gives you 10 hp, but it smoothes out airflow. it should have instructions with it when you buy one. they are placed between the throttle blades on the throttle body itself. i dont know how much you are paying, but i shopped around and found one from an individual selling it in the package for 20 bux. good luck!! it is a good investment in my opinion.

 

89IRO,
If you can't find one for a good price, I could make one for you. Email me if interested and we'll discuss particulars.

 

Don't waste your money!

 

i bought one from tpis i believe.. easy mod, its worth 45 dollars in my book..

 

So was that air foil you installed worth the $45? How much HP/Torque increase did you get out of it? Oh, and where is the stupid thing located anyways? Is it in the actual metal body of the throttle body? -89IRO

 

i felt a little better throttle response! they say it works and adds a couple horses and torque, i dont have a dyno to prove it though. take your air cleaner assembly off you will see the front of the throttle body and it has two opening in it, inbetween is a flat spot the air foil goes there.. smoothes the air out better..

 

I didn't really notice much of a difference after putting it in,but I figure for the price I paid,its still worth it...
Apparently the more you modify your intake,the more useful it becomes..

 

I did some calculations just out of curiosity. The space between the two 48mm butterfly valves, by my calculation, is almost 1/2 the total area of the throttlebody at that point. Each 48mm valve uses 25% of the available area. Also, the coefficient of drag (Cd) for a flat plate is 1.0, but for an indented space like between the valves Cd can be closer to 2.0. A well shaped airfoil resembling a rocket nose cone can have a Cd<<0.1, though most are about 0.4 to 0.6.
Another thing I found is that at max RPM, the airflow through the intake is something like 167 mph, and at this speed, the air hits that "flat" space with a pressure of nearly 1/2 pound of backpressure, or drag, on each square inch, or around 5 psi total. With an airfoil, the resulting backpressure is only a fraction of that. It sounds to me like a gizmo that can actually work, at least in principle, even if not giving all the extra HP it is claimed to give.

 

on that hot 383 they test parts on it may add 10 hp through the 48mm tb. figure that 383 probably needs a 52mm tb anyway. but on a stock 350 you wont see much except in your mental dyno. you know where your brain says i feel a difference even if there isnt one.

but if you are going to buy 1 the tpis looks like the best, i personally have a slp but the fit isnt as close as the tpis is. the slp was dirt cheap though compared to the tpis. but remember the airfoil isnt like a prom where they at least change afew things.

 

About our "mental dynos", I agree. There's something satisfying about having a new part to play with. We all like the feeling that we're getting something a little extra. Money is tight for me these days and the airfoil looked simple in design so I saved $$ and made my own. I don't know how much it's helping, but I'm sure it's not hurting anything.