How important is or to what degree does the intake tract design effect the output of a high HP(500 +) NA motor. For example with the LT1 unless you go with a custom set up or a Trans Am ram air set up your stuck with the 90 degree bend. Is this design a restriction? If not than why did GM decide to go with the straight ahead design of the LS1? Just got to thinking after reading some of the threads in LT1 tech that were talking about the supporting components needed to realize a high cfm value actually seen by the heads. How can a cooky design CAI like a Moroso or K&N flow enough air when they are such odd shapes?

 

Intake design is very important. The diameter, length, contour
and all other aspects are critical to squeezing power out of the motor.

First off, I would imagine getting cold air into the motor is priority.
Having an intake design which allows cold air with the shortest
path through a heat source is a key factor.

Bends aren't so bad as long as they are smooth. A direct shot
is best, but that isn't always possible.

The output power of the motor really isn't an issue; this would
apply to any motor.

Engines of extreme output are probably banking on timed pulses
which are tuned via runner lengths and volumes according to
engine operating ranges and valve timing.

The shape of the tube is important, but from what I've read, the
cross sectional area is one of the major criteria for flow. The FIPK
kits from K&N are flat and wide as opposed to circular.

The area and volume of flow is equal or greater than that of a stock
LT1 intake.

A shot in the dark tells me the deliberate shape will also straighten
air flow, and/or accelerate air flow as it passes into a narrow
path...sort of like a venturi?

The MAF screens are also said to remove eddy currents from the
intake tract before it enters the plenum.

This 'myth' has been tossed around for a while, but nobody has
stepped up with solid evidence. I tend to believe that a turbulent
fluid passing through the screen will straighten out, just as it would
flowing through an air filter.

 

The K&N CAI will flow in excess of 1300cfm.The cork in this system is the small filter that comes with it,it flows 700cfm.AFAIK 1300 is the biggest TB you can buy so a K&N should do fine.
The cross section area and length do quite a bit toward shaping the air and get it headed to the piston.The length will differ from engine to engine depending on your tuning pressures.It isn't one size fits all.The plentum volume figures into the mix also.You have to have enough,but as with runner length you have to fit it under the hood.

Some of the figures I have seen for plentum volume are BIG CID

 

Good info guys.

What about an intake design like this...(found this on a search).

http://community.webshots.com/photo/...18796895NXIcpX

http://community.webshots.com/photo/...18797672jBxXUn

http://community.webshots.com/photo/...20934904drNCHV

 

A bit GETTO,don't you think?

 

Without a doubt, functionally though?

 

Probably not any more so than a neat CAI.If you are trying to make 500+ to the tire you will look for air intake help anywhere,but this wouldn't be MY first choice.
I have done a lot of research on this,and into making my own.(going for 700FWHP on pump gas) For the time being I will use the K&N and their 1400cfm filter mounted in the fender.It will fit,but I have no front bumper and modified plastic in that area(I have a plastic welder)I also reshaped the end of the K&N tube to move it to the rear of the hole to allow for the 14"filter.Looks pretty good but I would advise taking the front clip off to do it.They make a 12"cone filter also that flows1200cfm.But don't know if it will work with the bumper in.

 

This is an interesting discussion being that I personally will have some freedom in my choice of intake design once I get SStrokerAce's intake.

1racerdude your talking about some big filter's here. Any idea on what the two puny SLP CAI filters flow? Thats what Im running now, that's may have to change...

http://www.slponline.com/view_produc...&SHOWEMAIL=Off

 

Are these the standard K&N cone filter that is 6-7" long and has a 4" opening?If it is they flow 700cfm.Cain't tell the size in the picture.

Ain't that a nice intake Bret's got.Will be one hell of a set up to make all the HP a body could stand.I got a sneak prevew when it was being built.I may have wrung it out for him if I hadn't already had Wilson do one for me.

 

Oh that intake is a beauty. I got a sneak preview from start to finish also, looks so nice I dont want to get it dirty.

I think the length's are maybe 5" or so. The openings for each filter are small, maybe 2" in diameter each. Ill check for sure tommorow. Thinking quickly they are realtively close to a campbells soup can in size.

 

Well, the intake system does it's thing from the filter to the piston so it sounds like those filters are a cork in the system.I thought about building a CIA like that with bigger tubing and 2 of the 700cfm(6-7") filters in the fender of this '94 but it seemed like less work with the 1x14" until I got to doing it(lazy)That plastic is not easy to make it do what you want.

 

If this is the filter(k&n 7inch) I am running with my solid intake and vortech is it a restriction since the blower flows 1000cfm? Or does it really matter with forced induction.

Slightly off the topic... I been reading on maxima.org about how ram air is worthless, more specifically, its just another CAI. I believe different, If TA's were equal with the same hardware would one with a Ram Air hood be faster, if so, what would have to be done to make it faster, i.e, sealed box, different lid? I dont think that the different exahust was worth all 20hp.

 

Yes you have a restriction.If your blower is trying to suck 1000cfm and the filter only flows 700cfm then the blower is not at full potential.It is a little different with a blower but any restriction will limit it's output.
IMO ram air is effective,but not through the hood.It should come from the outer quarter of the lower front clip were air pressure is at speed is the greatest,and be ducted to the TB.Parking light hole??

 

To add further to the RAM Air discussion:

Ram Air is more functional as a cold air intake and efficient beacuse
of the straighter path from the outside world to the engine.

I've seen dyno curves of Grand Prix (GT and GTP) with and without
the Ram Air GTX hood. There was a slight variance of a couple of
horsepower, but nobody could attribute that small increase to the
hood design.

On top of that, Ram Air on a dyno is sort of pointless because the
car isn't moving.

The more interesting facts came with track times and speeds between
these cars as well as a graph of manifold pressure as the car
accelerated down the track.

I don't recall exact times/speeds/or MAP, but I know it wasn't
in excess of a couple MPH and a tenth averaged out between
the tests.

You'll find it interesting to know that Ram Air hoods don't work
as well as you might think until the car is moving at excessive
speeds.

The engine is sucking up quite a bit of air to begin with. In order
to pressurize the intake plenum with enough reserve air, the car
must be moving at high speeds. Some numbers I've heard are
100+ MPH.

Not very effective for street use, but will grab some power on the
track.

 

Yes 700cfm... but at what pressure drop?

-Mindgame