Has anybody used a TPIS throttle body ?http://www.jegs.com/cgi-bin/ncommerc...34&prmenbr=361 I'll get one if it really is worth 12 hp, that stuff adds up

 

More realistically, half of that. I lie awake every night trying to figure out how they managed to get that infamous figure of 12hp from an airfoil. Still can't figure it out.

Robert

 

?? but i know i have 1 i need to get ride of. i got a 58mm T.b. and i only used it for about a month and have no use 4 the air foil now.

 

They got that much by using it on a larger engine Ill bet.

 

The theory of operation is valid and straightforward, but the calculations are tough. You really need the proper equipment to make your own measurements of HP and CFM. I saved about $50 by making my own airfoil. All I can say is it's smoothing the airflow, I'm sure, but in normal driving, I can't tell it's there.

 

It's only 60$, I might as well buy it. Don't forget, in their commercials, K&N claims to give you like 30- 50 hp over stock, it's those figures that give ricers such phony horsepower. maybe on a ghetto 60's Big block that has the origional filter on it "Yeah, I run 12's with just K&N, 5 inch muffler and prolong on my civic HX" not

 

**** I can make those air foils easily, I got three of them sitting in my garage. The difficult part is making the hardware to make it stay in place, which is mostly just for ease of installation.

 

Rezinn,
I had no easy way to secure the airfoil in the manner it was meant to be, but my airfoil is a snug fit in its space so I used a little silicone glue on the top and bottom to hold it in place. Because the glue stays flexible I can pull the airfoil out easily. The glue, being rubbery, does not flake like other glues which get hard when cured. I've been using it for maybe 2 months now and haven't seen a hint of problems.
What did you make your airfoils out of?

 

I made an airfoil with epoxy putty. Why pay more...

 

I made a mold and I form jbweld into airfoils. I have some thin hex bolts that fit into the airfoil and a nut type thing that attaches inside the throttle body to snug it into place.

 

I tried epoxy putty but something didn't go right so I scrapped it. The next one I made from polymer clay from the hobby shop. It stays soft till you bake it. To get a good fit I had to do a partial bake to make it set-up enough that I could handle it w/o denting it. I was concerned about a piece possibly cracking off with all the thermal cycling and flying righht into the engine so I covered the fully cured airfoil with fiberglass cloth then "painted" epoxy glue over the cloth. Now it has a very smooth surface and it can crack all it wants, the fiberglass prevents it from coming apart. I cycled it several times between the oven and freezer to see what would happen and it didn't crack. I'm currently trying to estimate the reduction in backpressure resulting from covering the center of the throttlebody with the low drag airfoil.

 

Ed & Rezinn,
I'm just curious, how large did you make the opening in the airfoil for idle air to pass through? Where did you locate the hole? None of the photos I've seen show the size and placement in detail. My idle air hole is about 1/2" in diam and is located at the bottom of the airfoil, where the narrow vertical part widens to a horizontal direction. Later I added another hole ~3/16" diam near the top of the vertical section. I just guessed at a size that would allow enough air for idling. I imagine you pretty much copied the apparent size and shape from photos. By coincidence something unrelated was making my check engine light come on intermittantly while I was making the airfoil so I kept thinking it wasn't getting quite enough air going through these holes. That's why I have 2 holes and one is relatively large. I suspect I could shrink & reposition the holes and cut down on the drag even more.

I'm also experimenting with a baffle in the intake air duct in front of the airfoil which will partially streamline the airflow even sooner and reduce large scale turbulence. This should allow the air to flow more directly into the throttlebody without as much side-to-side mixing like might occur in the large open volume in front of the airfoil. So far it's all working like it's supposed to it seems.

 

Simple. They measure it's "before and after" on a seriously built eninge that has a bone stock 48mm TB and then install it. At that point, the engine is being starved for air that ANYTHING will be a major improvement if it removes the restriction.

Do the same thing on a bone stock engine, the HP difference becomes negligible because there are so many restrictions to power.

 

This is what I'm gonna add to this thread...

If you add up all the HP that each bolt on gives you:
Headers = 20hp
Chip = 20hp (advertised)
K&N = 25hp (advertised)
Airfoil = 12hp (advertised)
Pulleys = 10hp
etc, etc, etc

If you were to buy all of the bolt ons and put them all on and add up all of the power that they give you.... your car would have approximatley 1200hp on stock heads and cam.

 

i dont know about an airfoil, but after putting 150 dollars worth of chinese letters on my car it goes alot faster now. i guess the material they are made out of somehow smoothes out airflow on my fenders and such. they are definitley worth the money.

 

On a N/A application I don't see it helping that much, but prolly a little.

On a blown TPI application, It helps tremendously.. I mean look at where the positively charged air would be hitting without one, causing turbulance, back pressure, etc.

-- Joe

 

Do any of you guys who make your own TB airfoils offer them for sale ??

 

Well, nobody's ever asked before. I'm willing to make one for you (if your Throttlebody is the same size and construction as mine.) I have an '89 T/A w/305 tpi, BTW. I found that I could make it a tight fit and then fine tune the fit by filing down high spots. Send me an email if you're interested and we can discuss details.
Jim.

 

I can answer this! I called TPIS years ago and asked how they measure this. So I asked did you measure "peak HP" or did you measure "the area under the graph". The answer back was area under the graph. So take a 0-5000 RPM graph and overlay the two with and without airfoil. The shaded area between the two graphs is 12 hp. So at any given point, peak power may only increase a fraction.

Not the best way to market a product, but it is correct in the statement. Just should have some clarification.

Mark.

 

I don't think anyone can have a job in marketing and not know how to twist the truth to their advantage. Lawyers are often consulted on these matters too, to make sure the claims are just legal enough.