This post is cut and pasted from another forum,but is raises some interesting questions regarding the NACA duct and its effectiveness,any comments?
Induction systems...
Author Message
Speedracer XTC
Stage III User
While I was taking a break and reading some funny posts on the VCA site, I came across this one
Quote:
"Hot Air Induction Systems" for Show-Vipers.
--Turns a NACA duct into the worlds fastest bugcatcher.
--Turns the valley of the V-10 into the Valley Of The Bugs.
--Pressurizes underhood at speed, creating lift.
--Bends and compresses the air at the elbow.
--Evacuates hot air from behind the fan shroud, making the fan even more efficient. Unfortunately, that hot air goes WHERE?
Way too funny... I would love to know where this info comes from. We all know that Porsches kill bugs fast, but the NACA duct is a bugcatcher, ? I want to know how many people have actually found bugs IN their airbox from driving their Viper at speed.
First off... where do you figure you are going to get MORE air INTO the NACA from? Did you think to read ANY of the posts made YEARS ago proving that the NACA duct was truly ineffective as an induction tract at high speeds? Does anyone wonder WHY the factory and Oreca GTS-R Vipers DO NOT have NACA ducts on the hood?? Air flows OUT of the NACA duct at any speed over 75+ mph!! Do the test yourself. Tape some yarn on the hood of your Viper. Use 2-4" strips of yarn around the NACA and hood vents. Watch how they blow straight UP at the NACA duct as high pressure air is LEAVING the duct from under the hood.
Again, I will state this for those to read the truth. Airboxes HELP only in the fact that they allow more air to flow to the throttle bodies. Stock airboxes are a joke in that only 30% of the airfilter is used. Wanna see? Open your airbox and hold your airfilter to the light. You will see a small portion just where the outlet is to the throttle body is dirty. Wonder why??? Maybe because that is the only part that is getting any airflow. The Hennessey box and a few other modified ones use 100% of the area behind the filter and that is why they make power.
Want more power and do not have the $1200.00 for the carbon fiber box? Then use a carbon fiber or aluminum 3" tubing with a large filter. Sure you are going to get a little hot air from the radiator, maybe not as much as you could get by reading all the crap xxxx could sell you, but still some hot air. What you will get is unrestricted airflow ahead of the throttle bodies and this relates directly to MORE POWER!! Do like I did... Make your own carbon fiber tubes, buy two filters and have the entire thing done for less than $200.00!! This setup made 20HP to the rear wheels over using just K&N filters.
Still want to be cheap, but have a good looking set-up? Go to Autozone and buy TWO of those rice looking Honda intake pipes with the mesh screen filters for $29.95!! Cut the pipe and bevel the edges with a small file. The silicon hose is the perfect size to mate the Viper throttle body to a 3" inlet, and they even come in RED, BLUE, YELLOW, BLACK, & GREEN!!!
Check out the pic below and see for yourself. This "All Show" Viper goes 10.20's on Radials and 11-teens on Motor with no internal mods!!! Show that!! Don't get ripped off!! Get Informed!!
