Airfoil is proven useless. A lot of guys start with 1.6 ratio rockers, adjustable fuel pressure regulator and underdrive pulleys. All are low buck and not real complicated. 
Air foil
Instructor
Joined: Aug 2009
Posts: 218
Likes: 5
From: OR
How to install the "Air Foil".
Apply a liberal amount of Crisco to the air foil.
Drop your drawers down around your ankles.
Bend forward so as to position your torso at a 45 degree angle to your legs.
Pick up the air foil with your right hand using the thumb and fore finger.
Reach around behind and slide air foil into fundamental orifice.
It will add just as much power installed here as it will under the hood of a Vette.
Apply a liberal amount of Crisco to the air foil.
Drop your drawers down around your ankles.
Bend forward so as to position your torso at a 45 degree angle to your legs.
Pick up the air foil with your right hand using the thumb and fore finger.
Reach around behind and slide air foil into fundamental orifice.
It will add just as much power installed here as it will under the hood of a Vette.
Last edited by John Holmes; Sep 3, 2009 at 04:06 PM. Reason: grammar
Race Director
Joined: Jun 2004
Posts: 13,957
Likes: 706
From: WI
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
Airfoils only really work at high speeds, fundamentally it is a sound principal, but at normal driving speeds the air is not comimg in fast enough for them to be effective.
If you drive at Nascar speeds, then you will see a gain, but you might see a hp or 2 gain at highway speeds and I doubt you would see any time difference at a track, as you are only at high speeds for a few seconds. Unless you have a 8-9 sec car.
If you drive at Nascar speeds, then you will see a gain, but you might see a hp or 2 gain at highway speeds and I doubt you would see any time difference at a track, as you are only at high speeds for a few seconds. Unless you have a 8-9 sec car.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
I agree they don't do much, but they do some.
I put one on an 87 4+3 along with flowmaster mufflers. There was enough change that it caused some stumble or surge at normal speeds. I took off the air foil and the problem went away.
I later changed proms to an SLP one and then it was fine with the airfoil.
I never really noticed an increase in performance, but before the chip change I noticed a problem, therefore I do think they do something. My guess was that the change in flow put it outside the mapping of the stock prom.
Bottom line, they don't do much.
I put one on an 87 4+3 along with flowmaster mufflers. There was enough change that it caused some stumble or surge at normal speeds. I took off the air foil and the problem went away.
I later changed proms to an SLP one and then it was fine with the airfoil.
I never really noticed an increase in performance, but before the chip change I noticed a problem, therefore I do think they do something. My guess was that the change in flow put it outside the mapping of the stock prom.
Bottom line, they don't do much.
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Pro
Joined: Mar 1999
Posts: 678
Likes: 0
From: Oslo, Norway
HI I have an 85 4+3 z 51.
If everyone complaining about no gain they should read about the preconditions for it. If everything as plenum runners, manifold and heads are modified so that the only limiting entity is the throttlebody one will gain using throttlebody. The more limiting entities there are the less gain you will see.
On stock engine it is not very much but the air is etter distributed throughthe throttle body. So it is more a psychological mean on stock 86 engineor TPI engines
If everyone complaining about no gain they should read about the preconditions for it. If everything as plenum runners, manifold and heads are modified so that the only limiting entity is the throttlebody one will gain using throttlebody. The more limiting entities there are the less gain you will see.
On stock engine it is not very much but the air is etter distributed throughthe throttle body. So it is more a psychological mean on stock 86 engineor TPI engines
Instructor
Joined: Aug 2009
Posts: 218
Likes: 5
From: OR
hi i have an 85 4+3 z 51.
If everyone complaining about no gain they should read about the preconditions for it. If everything as plenum runners, manifold and heads are modified so that the only limiting entity is the throttlebody one will gain using throttlebody. The more limiting entities there are the less gain you will see.
On stock engine it is not very much but the air is etter distributed throughthe throttle body. So it is more a psychological mean on stock 86 engineor tpi engines
If everyone complaining about no gain they should read about the preconditions for it. If everything as plenum runners, manifold and heads are modified so that the only limiting entity is the throttlebody one will gain using throttlebody. The more limiting entities there are the less gain you will see.
On stock engine it is not very much but the air is etter distributed throughthe throttle body. So it is more a psychological mean on stock 86 engineor tpi engines
Burning Brakes
Joined: May 2007
Posts: 829
Likes: 0
From: San Francisco CA
I put one on my 86 TPI IROC, It went from not being able light the tires w/o it to being able to get a decent burn out from a stab of the throttle.Over all it wont add much till the the plenum is opened up to unblock the throttle body opening but it helps a little.
cost me $20K
, hope that tells you something
Team Owner
Joined: Aug 2005
Posts: 34,988
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From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
funny a noob's first post about the stupid airfoil. I dont think a new member would waist his time on that. Another case of a looser (likely to be a C5 owner) looking for attention.
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
Now, in response to the OP's question, if you do a search on this subject, you will find tons of responses. In essence, it's a waste of money.
Team Owner
Joined: Aug 2005
Posts: 34,988
Likes: 515
From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
A long time ago, but not far far away, a forum member recorded the difference on a dynomometer, with and without an air foil. I recall that only at the highest rpm did he observe 8 ft-lb of torque and 3 hp increase. At lower rpm, there was no difference.