Jeep Enthusiast Forums banner
81 - 100 of 137 Posts

· Registered
Joined
·
2,109 Posts
hoping I hadn't overlooked this, but has anyone considered or established the CFM requirements for the engine's intake when building snorkels?
well the factory airbox hole is what,,a 1 1/2 at its biggest where it comes outta the airbox..

heres the thread to my new completed airbox for those intrested..it turned out fairly nice but better the next time..i might start selling them..just the snorkel tho not the airbox..

homebrew snorkel..
http://www.jeepforum.com/forum/showthread.php?t=810246
 

· Registered
Joined
·
452 Posts
well the factory airbox hole is what,,a 1 1/2 at its biggest where it comes outta the airbox..

heres the thread to my new completed airbox for those intrested..it turned out fairly nice but better the next time..i might start selling them..just the snorkel tho not the airbox..

homebrew snorkel..
http://www.jeepforum.com/forum/showthread.php?t=810246
The obvious limitations are with the ports and valves, I'll have to get into that when I'm not drnkng at a pool hall... but my concern is that over distance, both diameter and surface area will affect the volume of the column of air entering the throttle body. The requirements of the engine are at least the displacement times the max rpm's. So a 2.5 x 5k is in excess of 440 cfm (cubic feet per minute).

my question was if anyone has actually established a minimum.... I'm guessing 600+ cfm to be safe, and then allow the exhaust to be the limiting factor on the other side of combustion.
 

· Registered
Joined
·
452 Posts
Ok, so 441.4 CFM would be the minimum requirement per the 4-cyl engine at 5,000 rpm... I think. When it comes to physics I'm pretty sure that the actions of a column of gas are about as complex as it gets. So add enough margin of error as well as room for a port job and exhaust upgrade or modification I'd say 600 to 700 CFM is an adequate base for calculation of intake requirements...

the calculations for a column of air passing through your snokel however... I'm not sure how to derive them at this time.

I'll do a bit more research on the manor and see what comes up. The idea is to establish a safe (from debris and moisture) intake that is not restrictive. Of course, filters, bends, diameters, surfaces are all factors.... and most of this is a bit over my head so i'll have to learn as I go.

My goal is to create an intake solution that is not the limiting factor, thus allowing room for modification/improvement further down the line.
 

· Registered
Joined
·
2,109 Posts
The obvious limitations are with the ports and valves, I'll have to get into that when I'm not drnkng at a pool hall... but my concern is that over distance, both diameter and surface area will affect the volume of the column of air entering the throttle body. The requirements of the engine are at least the displacement times the max rpm's. So a 2.5 x 5k is in excess of 440 cfm (cubic feet per minute).

my question was if anyone has actually established a minimum.... I'm guessing 600+ cfm to be safe, and then allow the exhaust to be the limiting factor on the other side of combustion.
while your right..ive just been looking at all the arb and volant and other homemade snorkels and figured what ive come up with will work fine..well,i hope so..i think its still better than any stock airflow for sure as the air is kinda forced down the snorkel while driveing..haha
right now its just a new extra cooling device when im driveing,till it gets hooked up under the hood..
 

· Registered
Joined
·
452 Posts
oh, i'm sure a safe bet is to mimic the aftermarket snorkels in proportion, and I don't have a problem with your snorkel (looks bad a**), i just want to make sure if I do anything to my intake that i'm not limiting my power.
 

· Registered
Joined
·
2,103 Posts
I think your 441.4 CFM figure is a little much.
acording to the cfm formula found here,
http://www.classicinlines.com/CFMcalc.asp
the 2.5L engine only draws in about 221.9 cfm @ 5000rpm.

you have to remember that because these are 4 stroke engines, they require 2 revolutions to draw in their full displacement volume.
 

· Registered
Joined
·
2,109 Posts
ok guys,,ive just been driveing in a down pour of rain for almost 3 hrs and all i can say is the new snorkel and air box are definitly better than stock..im saying this because when all the cool rain air hits the throttle body when i floor it ,it is superior to the stock air box as i can feel quite a bit more power ans smoothness..when its hot and normal i didnt feel no diffrence,but in the rain..wow,its like a race jeep,haha..
in a minute im gonna take the filter out to see if any water gets in there at all..
im sure that it isnt as i made a 1/2-5/8 lip inside the top where the pipe meets the tubeing and i cant see it going up hill..but the fast flow of air when cruiseing may get in a little..i will see soon.
as for the aftermarket snorkels they almost have to get more water in them than the one i made..if i need to explain this further just ask and i will get into more detail to make ya understand what i did after seeing and looking at what arb snorkel does to get the water out..if it even works..id like to know who has a aftermarket snorkel and if after a rain storm is there snorkel tube perfectly dry?
 

· Registered
Joined
·
2,103 Posts
I'm in the process of putting one of these together. I'm using 3" round tube, and will be plugging the stock inlet on the air box, and coming into the side of it with the new tube.

anyway, I was wandering about the top of the snorkel(I really like the way that johnny9 finished his).
I was wandering, would you get more of a "ram" effect if you face the opening down(to try to catch the air that is being forced up the windshield)? or is having the opening facing forward, like all the other snorkels, still the best bet?
 

· Registered
Joined
·
362 Posts
well the factory airbox hole is what,,a 1 1/2 at its biggest where it comes outta the airbox..

heres the thread to my new completed airbox for those intrested..it turned out fairly nice but better the next time..i might start selling them..just the snorkel tho not the airbox..

homebrew snorkel..
http://www.jeepforum.com/forum/showthread.php?t=810246
if you start selling these let me know I defiantly would be interested.:2thumbsup:
 

· Registered
Joined
·
2,109 Posts
if you start selling these let me know I defiantly would be interested.:2thumbsup:
i would like to make some of them for you guys but im no big fancy compant,just me.i love to fab up stuff when ive got time and lately ive got a lot of it..
i can build the snorkel as you see it on my jeep exactly the same and you have to notch your own hood(i used wiss snips easly)and where the snorkel enters the hood it will stop..and people that want them will have to build there own airbox set up and plumb it..i can build it and get it powder coated satin black for 425 bucks,shipping included..i dont want to do the airbox because of the diffrent set ups there is and stuff thats got to be moved for diffrent jeeps..the material is all 1/8 inch thick aircraft aluminum exstrusion.
let me know and i will build them as i get a honest word(computer handshake,haha) of wanting one and then i can pm or e-mail the pics of it when finished..then ship it when its payed for
 

· Registered
Joined
·
613 Posts
i'm making a snorkel like the orignal one! it looks crazyyy good! i've been looking for a really nice one, and hell, i ofund it! thanks dudeee! :cheers2:
 

· Registered
Joined
·
2,218 Posts
ok guys,,ive just been driveing in a down pour of rain for almost 3 hrs and all i can say is the new snorkel and air box are definitly better than stock..im saying this because when all the cool rain air hits the throttle body when i floor it ,it is superior to the stock air box as i can feel quite a bit more power ans smoothness..when its hot and normal i didnt feel no diffrence,but in the rain..wow,its like a race jeep,haha..
in a minute im gonna take the filter out to see if any water gets in there at all..
im sure that it isnt as i made a 1/2-5/8 lip inside the top where the pipe meets the tubeing and i cant see it going up hill..but the fast flow of air when cruiseing may get in a little..i will see soon.
as for the aftermarket snorkels they almost have to get more water in them than the one i made..if i need to explain this further just ask and i will get into more detail to make ya understand what i did after seeing and looking at what arb snorkel does to get the water out..if it even works..id like to know who has a aftermarket snorkel and if after a rain storm is there snorkel tube perfectly dry?
The one I made to copy his design gets a little wet but nothing major. This is the first time my air filter has been clean for more than a month since I got my Jeep. Almost makes me want to drop some coin on a K&N now that it would be protected.:thumbsup:
 

· Registered
Joined
·
2,109 Posts
i like k&n for years and years,but the stock air filter flows real good when its getting more air than it needs also..i will try a k&n sometime this year for the heck of it..i drug my snorkel thru so much crap and trees yesterday that its all scratched up and looking abused,haha...
even if you got some mist of water in the snorkel it would just give it more grunt in my opinion..long as its hitting the filter first to break down the molocules...
there used to be water injection back in the day...
 

· Registered
Joined
·
782 Posts
Discussion Starter · #94 ·
Just to let everyone know I have pulled mine apart twice after driving in the rain and due to the ARB top design I have found no water at all in the system. Also the way the flex tubing is placed the water would collect there first. Then if you collected that much water to actually bypass that area you would have to fill the volume of the airbox to the level of the exit tube to the TB. I'm guessing but I think you would have to take in about 4 gallons of water, not going to happen...
 

· Registered
Joined
·
2,109 Posts
Just to let everyone know I have pulled mine apart twice after driving in the rain and due to the ARB top design I have found no water at all in the system. Also the way the flex tubing is placed the water would collect there first. Then if you collected that much water to actually bypass that area you would have to fill the volume of the airbox to the level of the exit tube to the TB. I'm guessing but I think you would have to take in about 4 gallons of water, not going to happen...
i agree..as with my homemade one,id have to take in a few gallons for it to reach my filter, as water seeks its own level..
 

· Registered
Joined
·
2,103 Posts
I finally got mine done to the point that it is functional(I still need to pull it back off and paint it).
I've only driven in the rain one time, but there was verry minimal water that made it to the air box(probably only a few drops worth of moisture). and as already mentioned, I think you'd have to almost fill the air box to cause a problem.
another advantage that I noticed was how clean the filter is staying. I was on some really dusty trails this weekned, that would normally left me with a verry dirty filter, and when I got back home, the filter was still spotless.

 

· Registered
Joined
·
2,109 Posts
nothing wrong with that muddy...the top turned out nice,kinda looks more like the arb top..very cool..will look great when it gets some paint,john
 

· Registered
Joined
·
2,103 Posts
making that top was a little tricky, it's all one piece of sheet metal. I cut it out, bent it into shape, and then only had two seams to weld. here's a pic of the cardboard template I made, and another pic looking down on the top(notice that I changed the origional design a bit). oh, and the aluminum screen is just temporary untill I can pick up some expanded steel and weld it in.

 

· Registered
Joined
·
4,184 Posts
81 - 100 of 137 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top