Air Intake and Flow Modification Poll

A lot of Jeepers have Opinions on Air Intake and Flow Modification. Especially when used offroading. There are many systems used. What do you use and why do you feel it is a better system than most. Function is important here. Trail capability extremely important. Physics, Engineering, Fab Work, 4x4 Shop Talk, Back Yard Mechanic, Junk Yard Dog solutions are all welcome. Logical and Constructive Criticism please.

In your post please state your choice or choices, explain why or why not, and please give details of how this modification can be fabbed up. A combination system is allowed in the poll by choosing 2 or more choices.

If I have missed a type of Air Intake and Flow Modification, please feel free to Post Up. I could only poll up to 13 choices.

This subject is as important as a rear suspension modification or any other modification as without Air Intake and Flow, no one would be going anywhere.


Thanks

Caps put aside... I'm bored with them now. LOL


If Auto Makers think the cowl is a good dry place to draw air for the cabin then why not for the engine? If you plan on going through water deeper than your hood than obviously it's not the best choice.

There is a high pressure area at the base of the windshield. Cowl hoods like those on late '60's Z28s were used to make more horsepower. The old cowl induction hoods used raised center sections that ran back to the base of the windshield. Instead of having the opening on the front of the hood scoop, it was on the back. A cowl hood scoop was to direct cool air by picking it up from deflecting it off the windshield.

Many cowl scoops are not set up correctly. If you study the various configurations and placement you will see that many are too far from the glass to catch the air and let the scoop do it's job. 90% of them are installed wrong
in that most are too far away from the glass to catch any clean air deflected from the glass. You see some that are not even within a foot of their windsheilds. If done correctly the cowl hood flows with the vehicle no matter what make or model. I think 4 to 6 inches is desired but I am sure glass angle plays a big part. There's a good chance if improperly positioned it could also cause a negative effect stopping any flow of air.

When a intake can pull its air from the relatively high pressure area at the base of the windshield, a cowl cold air intake can provide a very mild passive supercharging effect and possibly a few more horsepower. IMHO

My modification is a Cowl Induction Scoop and Tubing from the rear of the scoop to a Canister Air Filter tubed to a 62mm Throttle Body attatched to a '99+ Intake Mainifold. I increased the diameter of the tubing, which allows increased flow and utilized a high-flow, high-filtering air filter.

My Cowl Induction Scoop.




Cowl Induction Scoop in Action Going From 0 to 15 MPH








Cowl Action on the Freeway

Here are some more shots on the freeway..







This last shot is a 3rd gear pull building up to about 9psi.. Notice the paper is all the way back! LOL!!




Cowl hoods DO FLOW AIR into the engine. IMHO

You should add snorkel as an option...

stroker was definitely my best flow mod
that and the 63mm throttle body, with cold air K&N with prefilter <-- my answer.
to qualify it more, i am going to move the intake to the "cold" side of the engine compartment, right now, it sits in the old airbox location, right next to the toasty warm header

a real cowl hood gives the hot air a place to escape, making the engine run cooler. a cooler engine makes more hp.

What type of 4x4ing are we talking about because intakes are def not one size fits all.

For rock crawling, get a cold air. It wont matter too much since there isnt much for your engine to breath in.
On the other hand, if you plan on doing mud bogging/submarine. Then get a snorkel, you dont want to suck in mud or water.

Since cost was not presented as a factor I voted for the supercharger. Now, I don't think there is a bolt on supercharger kit for our Jeeps but it can be done with modification. I would use the Lysholm style twin screw supercharger because it is a very efficient design and it doesn't raise the intake air charge temp nearly as much as a turbo or centrifugal supercharger. Another reason I chose this one is that it produces boost on a very linear curve right off idle. This is great for low end torque which is what we need for crawling. If set up properly and driven conservatively it can also improve fuel economy. If I had the money I would definitely go this route. Now given that I am po', I'll just use a cold air intake setup.

I have a home brew cold air and like it...but I'll definately have to do some modding before it see's offroad use (so it doesn't suck in water). It does work great on the street though, offroad though I got the idea from a fellow naxja member (fubar_xj) how moving the intake back and into a "cold air" raises your ability to submerge in water (as it's further away from any hole or water access point).

~Scott

ericsxj.com has the best possible configuration I can think of. EZ cheap and sweet cold air and snorkel possibilities. on the list

A Cold Air Intake is a device used to bring lower temperature air into a car's internal-combustion engine, to increase engine power and efficiency.

Standard air intake systems tend to be very restrictive, in order to eliminate engine noise. All cold air intakes operate on the principle of increasing the amount of oxygen available for combustion with fuel. Because cooler air has a higher density (greater mass per unit volume), cold air intakes generally work by introducing cooler air from outside the hot engine bay.

Some strategies used in designing cold-air intakes are:

* increasing the diameter of the air intake, allowing increased airflow.
* smoothing the interior of the intake to reduce air resistance.
* providing a more direct route to the air intake.
* tuning the length of the intake to provide maximum airflow at certain engine speeds (RPM).
* using a more efficient, less restricting air filter.
* cold air provides more oxygen for the engine to burn.

Disadvantages

* hydrolock - The intake is lower, and more likely to introduce water into the engine when fording streams or flooded roads. Hydrolock generally does not occur unless the filter is fully submerged in water."Bypass filters" can be purchased which prevent any water of any kind from entering the engine.

To combat hydrolock my cold air intake is not a short ram-air intake (as most cold air intakes) pulling air from the front of the vehicle. Rather, it is used in conjunction with my Cowl Induction Scoop.

As air pressure off the windshield enters the cowl to cool the engine bay, air is also forced into a large diameter tube 2 inches behind the lip of the cowl into a canister with a large conical filter. Water flows down and into the stock cowl below the windshield and not into the intake tubing.

I do admit, it was Gojeep's that gave me the ideas to do it much like his. However, my cowl is taller, my intake hose has a much wider opening, my canister is a tad smaller, and I use a large conical air filter.

Thank you Gojeep for this writeup. http://www.go.jeep-xj.info/HowtoAirFilter.htm

[size=+1]Gojeep's Setup[/size]

ToxinNH said:

You should add snorkel as an option...

Click to expand...

x2

Sorry, folks. I can only have up to 13 choices and I did not use Snorkel as a choice because of the Different Configurations one could incorporate. Rather than list at least 4 of the configurations, I chose to allow people to vote for more than one item on the poll to sum up the their system.

Example: Myself: Cowl Induction Scoop (rear opening scoop) and Cold-Air Intake (air flow from outside the engine bay)

If you wish, Post Up what you have and so forth.

Hope this helps.

I didnt vote. need Snorkel as option

IH8EPA said:

What type of 4x4ing are we talking about because intakes are def not one size fits all.

For rock crawling, get a cold air. It wont matter too much since there isnt much for your engine to breath in.
On the other hand, if you plan on doing mud bogging/submarine. Then get a snorkel, you dont want to suck in mud or water.

Click to expand...

I agree. There are so many Variables and a Poll can only go so far.

I live in Florida. Lots of sand, mud, and swamp. However, I do travel northward and crawl from time to time when visiting family.

Everyone, please feel free to Post Up what you would use for a given offroad environment and maybe why.

LostSoul said:

I didnt vote. need Snorkel as option

Click to expand...

Sorry, I am unable to go back and Edit the Poll and add Snorkel as a choice. I wanted to delete Ram Air Hood and add Snorkel as so many requested, however, I can not see how I can do it.

I will PM a Mod and see if they are able to do it. Until it is changed or not, the Poll will have to stay as is.

Sorry

The best intake mod for SLOW SPEED offing is HOOD VENTS.
With Hood vents the engine compartment temps tend to stay much lower at slower speeds. add to this. With the placement of the opening of the stock air box to the rad support. It tends to pull cooler air in anyway.
If your looking for REAL extra low RPM power. I say get a 4.7 or regear or both.
For you go faster, things may differ.

The best intake mod for SLOW SPEED offing is HOOD VENTS.
With Hood vents the engine compartment temps tend to stay much lower at slower speeds. add to this. With the placement of the opening of the stock air box to the rad support. It tends to pull cooler air in anyway.
If your looking for REAL extra low speed power. I say get a 4.7 or regear or both.
For you go fasters, things may differ.

i have a snorkel its whole made from 3 inch pvc some silicone a little straping and a k&n air filter total on all parts about 120$ and 3 hours. hardest part was cutting the hole in the side of the truck with a sawzal because i was too cheap to buy a whole saw..:doh:






works good too!

video of this puddle
http://www.youtube.com/watch?v=KxBxcxoMf64

Nice Job and Great Video!

Except for the type of trees, it looks a lot like down here. LOL