I just called K & N to find out if their replacement filter for the stock air box on the L would flow enough air for my truck that is now running 15 lbs. of boost thanks to Apten. I feel like a fool. Even though I trust Sal completely I really thought he was full of ***** about me needing a aftermarket filter if running above 12 lbs. of boost. The guy at K & N said at 15 lbs of boost you need 1051 CFM's available to the Supercharger. The K & N replacement panel filter only flows, brand new.......are you ready for this....562 CFM! I guess I'm in the market for a filter. How about this for some good info?


Jerry

 

Sometime it helps to be doubtful, you are prompted to do research. Anyway thanks for the info

 

Total cfm is NOT the whole picture either!

The greater the filtering surface area the less velocity per open cell. Which = better filtration on a oiled type of filter.

Just get the biggest conical sheped one you can.

Rich

 

Straight from the horses mouth is always the best source.

But I've been told that trucks run faster with the stock airbox

 

Gator,

I have read that also but I think that was before we started increasing boost. Either that or he wants you to try it when he races you.

Jerry

 

Stock or stock with a little added boost is better with a stock airbox. The air is cooler. 15psi you are better off with a cone filter.

 

I am researching this.......

 

I don't supose he mentioned what a stock box and filter flows at 8# did he?

 

http://www.gnttype.org/techarea/turbo/turboflow.html


less fuel = less power
more fuel= more power= the need to increase air volume by more filter surface which will increase density, air speed and keep air "on tap" for combustion.

I'll use a 15" cone

 

other trivia info from K&N website: (knfilters.com)

- "Will NOT Void Vehicle Warranty"
- "Customer modification of the standard airbox - removing the cover, drilling holes into the side or top will have a drastic effect on smooth carburetion."
- "Can an engine get too much airflow?
No, an engine can only take in a fixed volume of air depending on the engine’s size. The more restriction that an air intake system (filter, air box, and tubing) causes, the greater the potential is for power and mileage degradation. "
- "Should I install the largest K&N filter that will fit in my race vehicle?
If an existing K&N filter is large enough to provide negligible restriction, a larger than required filter will not affect the amount of air an engine can take in, however, it will lengthen the filter’s service interval. A longer service interval can be an important factor when racing in dusty, dirty environments."

I don't think anyone will debate that fact the K&N flows 35-50% more air than stock filters
... http://www.knfilters.com/facts.htm#STOCK

but either the person you talked to typo'd the 1051, or the stock panel filter only flows around 350-400CFM? (or both?) and quoted the panel filter CFM not cone filter... and don't forget other restrictions besides the filter (filter box, hoses, ducts, etc)...
I went with cone filter

 

V(cu.ft./min) = n(lbs/min) x 10.73 x T(deg R)
(29 x P(psia))

hehe

 

Wouldn't you run rich on a dyno if you were starving for air? The tune sets the a/f, but wouldn't you see some affect on a/f on the dyno?

 

If it was all about CFM of air into the motor, we'd run air pre-heaters..

Remember that a colder air mixture actually has less CFM for the same amount of power since air decreases in density extremely quickly with an increase in temperature...

So what was they're measuring criteria? Temperature?

That's why you use lbs/min of air.... Since a mass of air has equal power producing oxygen whether that lb of air takes up 6 ft^3 or 6000 ft^3....

Just something to keep in mine.. Plus what was the pressure differential between each side of the filter when they tested it??

 

I don't know how he came up with those numbers but he wanted to know the cubic inches, red line RPM, and lbs. of boost. I'm thinking of calling him tomorrow and asking for the formula.


Jerry

 

Here is a thread from last year with some formulas. Here is another.