So far so good,cold air mod

tjkj2002 · **Posted:** Thu May 17, 2007 10:07 am

Well I got board the other day and came up with a cold air mod that so far has impressed me.Since I'm running the AFE induction kit I decided to wrap the intake tube with header wrap,hey it's good for keeping heat in so it should work great for keeping heat out right?

The next thing I did will only work if you have relocated your windshield washer bottle.I purchased a APC universal expandable ducting and ran it through the hole left behind in the wheel well for the washer bottle.I secured it (via zip-tie) to the unibody just under my ARB bumber to catch cold air while driving down the road.Next I ran it up close to my cone filter(about 2" from the filter) and secured it to the AC line close by.The next 3 pics show all 3 angles of it on my KJ.

I've been driving around for 2 days with this done and have felt a noticeable increase in power going down the highway(60-80 mph),it's unreal the change it's done.It's not no 40 HP increase or nothing but you can feel it has more get up and go a highway speeds.Don't ask about mpg increase because I did not do it for milage,I did it to help give a little more get up and go for my overwieght hog.

jeepkj02 · **Posted:** Thu May 17, 2007 10:30 am

Great idea!

Looks awesome. BTW, I like how you painted those control arms and springs to match the color of your Jeep!

SavageUrge · **Posted:** Thu May 17, 2007 10:55 am

IMO I don't think the air is in the tube long enough to heat up to the point where it is going to adversely affect performance. I to, have thought about wrapping my intake, but then decided against spending the money and time for the above reason. I bought the K&N instead the AEM becasue the tube is plastic and therefore MUCH less prone to absorbing and retaining large amounts of heat, unlike the metal AEM tube. I'm running this setup and have had VERY positive results with it.

(streetKJ's photo)
It only cost $1.99 at Lowes, so it paid for itself and then some after the first tank :wink:

tjkj2002 · **Posted:** Thu May 17, 2007 11:06 am

My air tube is also plastic,it's made by AFE,the filter is AEM dry flow filter.It gits nice and hot in the summer time,just trying to keep the cold air cold that is now getting to it.Didn't cost me a thing for the header wrap,had some laying in my tool box for years now that I got from a buddy.

FastTRX · **Posted:** Thu May 17, 2007 11:48 am

I really like that idea with the hose adding more air...

The only is I don't run a cold-air intake...I have the stock box with a wix so it would do no good for me unless I fashioned it in a way so it went directly into the box...but I would have to filter the hose in the long run...

I've thought about doing an intake but I've had experience with K&N's in the past on my ATV's and I just didn't like what it did to my intake tubes. I loved the performance/flow but it was just too risky for my engines. But that was an ATV...a majority of my miles on the KJ are spent on the road so maybe I should try one....

I'm eventually guna do a gibson exhaust...I might just shell out some more dough for the intake to see what kind of gains as well as mpg I can get out of that. But awesome write up Troy...looks great. Really interesting...can't wait to try this.

csukoh78 · **Joined:** Thu Mar 08, 2007 10:34 pm **Posts:** 501

tjkj2002 wrote:

Well I got board the other day and came up with a cold air mod that so far has impressed me.Since I'm running the AFE induction kit I decided to wrap the intake tube with header wrap,hey it's good for keeping heat in so it should work great for keeping heat out right?

The next thing I did will only work if you have relocated your windshield washer bottle.I purchased a APC universal expandable ducting and ran it through the hole left behind in the wheel well for the washer bottle.I secured it (via zip-tie) to the unibody just under my ARB bumber to catch cold air while driving down the road.Next I ran it up close to my cone filter(about 2" from the filter) and secured it to the AC line close by.The next 3 pics show all 3 angles of it on my KJ.

I've been driving around for 2 days with this done and have felt a noticeable increase in power going down the highway(60-80 mph),it's unreal the change it's done.It's not no 40 HP increase or nothing but you can feel it has more get up and go a highway speeds.Don't ask about mpg increase because I did not do it for milage,I did it to help give a little more get up and go for my overwieght hog.

That is not a very good place for your intake hose. Your theory is correct (and good job on the install), but what you dont see is that the intake tube needs to be in a high pressure area, and where you have it is very low pressure. (Almost a vacuum, really) The air will hit your bumper and be canted down nearly completely missing your hose. Since there is no suction on the other end from the engine, pulling air into the hose, chances are that since there is no high pressure forcing air up that tube and around your filter, it isnt doing you a whole lot of good. The air around the intake hose may actually have a venturi effect sucking air out of the hose!

A better place to mount that would be in the grill or somewhat out in front where the air is forced into it. This will force air up the tube and down onto your filter.

If you wish to test this, go buy a portable anemometer (wind speed device) and mount it in front of the exit of your intake pipe, and ride around. Check the windspeed of the air from that hose before and after mounting in high pressure area. You will see a pretty astounding difference.

And the header tape is a really good idea that works. A lot of people dont do it because of the looks, but the practice is sound and does keep that air cool. A metal air intake is just asinine. (but on that same point, air goes into the engine so quickly that its impossible to heat it up more than a degree or two, but that is another subject)

PS expandable piping is not a good choice for air intake piping. Smoother is better, because every single one of those grooves creates "dirty" air (turbulent) that greatly slows down the incoming air charge. Try mandrel bent exhaust pipe or some other heat resistant, smooth, sturdy tubing.

SavageUrge · **Posted:** Thu May 17, 2007 2:14 pm

Quote:

PS expandable piping is not a good choice for air intake piping. Smoother is better, because every single one of those grooves creates "dirty" air (turbulent) that greatly slows down the incoming air charge. Try mandrel bent exhaust pipe or some other heat resistant, smooth, sturdy tubing.

Actually I was thinking about something to replace that with due mainly to the looks factor, however what you mention here also was a factor in that decision.. I was thinking an old radiator hose or something similar in material and rigidity would work well. It may slightly decrease the flow, but it would be a smoother flow, possibly allowing a greater density of air to the filter. I'm open to any ideas, but now that I know this method works, I'd like something that looks a little better or hidden more - no offense streetKJ! :wink:

You still get big kudos from me for the idea!

tjkj2002 · **Posted:** Thu May 17, 2007 2:27 pm

Quote:

the intake tube needs to be in a high pressure area, and where you have it is very low pressure. (Almost a vacuum, really) The air will hit your bumper and be canted down nearly completely missing your hose. Since there is no suction on the other end from the engine, pulling air into the hose, chances are that since there is no high pressure forcing air up that tube and around your filter, it isnt doing you a whole lot of good. The air around the intake hose may actually have a venturi effect sucking air out of the hose!

A better place to mount that would be in the grill or somewhat out in front where the air is forced into it. This will force air up the tube and down onto your filter.

If you wish to test this, go buy a portable anemometer (wind speed device) and mount it in front of the exit of your intake pipe, and ride around. Check the windspeed of the air from that hose before and after mounting in high pressure area. You will see a pretty astounding difference.

And the header tape is a really good idea that works. A lot of people dont do it because of the looks, but the practice is sound and does keep that air cool. A metal air intake is just asinine. (but on that same point, air goes into the engine so quickly that its impossible to heat it up more than a degree or two, but that is another subject)

PS expandable piping is not a good choice for air intake piping. Smoother is better, because every single one of those grooves creates "dirty" air (turbulent) that greatly slows down the incoming air charge. Try mandrel bent exhaust pipe or some other heat resistant, smooth, sturdy tubing.

I'm actually moving the inlet right to the bottom of the bumber lip as soon as I recharge my drill to have a place for the zip-tie,it's not that much of a low pressure spot as you think and since my KJ is nose high there's alot of airflow in that spot.And the idea for using the expandeable pipe(besides being cheap and easy) is for the "scatter" effect is creates,it fans the air coming out of the pipe in a greater area and will less likely ruin my filter in that spot.Alot major race leagues use the same theory in the race cars for different apps for years to spread air from a small port to a wide area with no ill effects.Plus the KJ and many other vehicles come the same expandeable pipe that conects the airbox to the TB.I do understand your point but why spend the money to have someone bend a pipe for me(which is getting expensive these days) when this setup works just fine.Also the hose is rubber construction so if I slam it on a rock it won't hurt it,unlike a metal tube then I'm out about $50-$75 that the metal tube cost.

GPR65 · **Posted:** Thu May 17, 2007 9:31 pm

Here is what i did a few weeks ago. In a couple of the pics you see i relocated the IAT sensor. Made a big difference.

SavageUrge · **Posted:** Thu May 17, 2007 11:48 pm

Wouldn't relocating the IAT sensor cause the computer to enrich the mixture? I'm looking for a nice balance between performance and fuel mileage, which is where I'm at now. What sort of a difference does doing this make?

GPR65 · **Posted:** Fri May 18, 2007 8:14 pm

when you trick it (resistor) it doesnt make anything better. but on the 02 and 03s the sensor is on the manifold and 04+ put it on the intake tube. so why not let it read the actual temp instead of 116 degrees or more. i improved my mileage hands down from 15.5 to 17 per tank.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

GPR65 wrote:

when you trick it (resistor) it doesnt make anything better. but on the 02 and 03s the sensor is on the manifold and 04+ put it on the intake tube. so why not let it read the actual temp instead of 116 degrees or more. i improved my mileage hands down from 15.5 to 17 per tank.

How did moving it affect your afr, and timing? I would think that tricking the computer into measuring the air as colder by using a resisitor, or relocating the IAT sensor, would lean it out a little, and advance the timing unless the computer adjusts to it over some time. IMHO, it's best to actually get colder air to it, and if that isn't enough, reprogram the computer instead of trying to trick it.

GPR65 · **Posted:** Sat May 19, 2007 3:25 pm

all i know is that its reading the correct air temp now. Its Just like the 04+s now. the intake maniflod is a bad place to take air temp. the computer gets a better more accurate reading now. when i had the resistor that made it think the air was 76 degrees i had an engine light every 150 miles and crappy gas mileage.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

It's programmed differently then the '04+ KJ's though. Also, did you do the sensor relocation and additional cold air at the same time? More cold air actually makes a surprisingly big difference by itself. The sensor relocation may only be a temporary increase since the ECU looks at the afr also and may adjust to it. I would recommend checking the afr. I've learned that from tuning my KJ. It runs much leaner at speed than it does on the dyno. I would estimate mine makes 10-15% more power from the massive amount of cold air getting to it the way it's set up now.

SavageUrge · **Posted:** Sat May 19, 2007 5:19 pm

KY Liberty wrote:

It's programmed differently then the '04+ KJ's though. Also, did you do the sensor relocation and additional cold air at the same time?

I was going to ask this as well. You really got my attention when you stated that your mileage increased by 1.5mpg. Mine increased slightly after I did the cold air mod, but so did my acceleration and throttle response. As long as those aren't affected, I'd like to see what kind of difference relocating the IAT sensor makes as long as it's reversible without adverse affects. If you could post a step by step "how to" on this one, I'd be really interested. Thanks in advance!

P.S. What is that black tubing you're using? It looks a lot better than the "Flexi-gutter" that I have currently.

GPR65 · **Posted:** Sat May 19, 2007 7:08 pm

i have had the cold air kit from k&n now for 4 years and i have been through 5 tank fulls and they are all over 17 mpg same driving and everything it is definetly significant. I couldnt even hit 16 before. its not going to change were talking over 1300 miles.

GPR65 · **Posted:** Sat May 19, 2007 7:19 pm

Btw Savage, i used the flex pipe from autozone for 15 bucks. it is great and serves its purpose.

As far as a write up:

Buy and 04 intake sensor for 25 bucks (you cant use old one)

Find a drill bit that will cut into your pipe i think its 5/8

Cut the hole as near the filter as you can. put the sensor in and either glue it in or use some aquarium sealent.

Unplug the sensor pig tail at the manifold and cut the wire about 2 inches back.

Crimp some wires long enough to go around the enging and attach the sensor pig tail. you will need to cut the existing sensor you bought cause they dont mate perfectly. cutting plastic will make this work you will see what i mean.

Doing this changed a best temperture on my scan guage from 116 to pretty much acual temperture. now i took the resistor off when i did this so i dont know if that alone made my mileage better or not. i am not going to argue about that but doing this mod on my buddys saturn raised mileage also.

SavageUrge · **Posted:** Sat May 19, 2007 8:15 pm

Sounds good, thanks for the info! I remember when I put my K&N FIPK on I noticed a slight difference, but nothing significant. The most noticeable mod I ever did was putting the flexible tubing ram-air mod in!

tjkoen01 · **Posted:** Mon Jun 04, 2007 1:11 pm

GPR65 wrote:

Btw Savage, i used the flex pipe from autozone for 15 bucks. it is great and serves its purpose.

As far as a write up:

Buy and 04 intake sensor for 25 bucks (you cant use old one)

Find a drill bit that will cut into your pipe i think its 5/8

Cut the hole as near the filter as you can. put the sensor in and either glue it in or use some aquarium sealent.

Unplug the sensor pig tail at the manifold and cut the wire about 2 inches back.

Crimp some wires long enough to go around the enging and attach the sensor pig tail. you will need to cut the existing sensor you bought cause they dont mate perfectly. cutting plastic will make this work you will see what i mean.

Doing this changed a best temperture on my scan guage from 116 to pretty much acual temperture. now i took the resistor off when i did this so i dont know if that alone made my mileage better or not. i am not going to argue about that but doing this mod on my buddys saturn raised mileage also.

I relocated the IAT sensor on my '96 GC and it made a difference as well. When it was all said and done with some other mods, I could get 25 mpg average on a 350 mile trip with the cruise set at 72.....and no, I wasn't drafting either.

The latent heat that the sensor picks up from being on top of the engine changes the reading, so moving it away from the engine is what makes the difference, the air is probably close to the same temp at both locations.....this isn't tricking or lying to the computer, just giving it accurate data. If DC thought the original spot on the intake was good, they wouldn't have moved it in '04.

Jstodda79 · **Posted:** Fri Jun 15, 2007 12:14 pm

Ill throw this out for fun... lol. A common mod for other platforms is to split the mas (mass airflow sensor) so that the car reads half of the air that is actually coming in. In some, there is a honey comb that splits the air so it crosses the sensor uniformly. Taking the honeycomb out on one side reduces restriction and air will ALWAYS travel to the area of less restriction. This usually causes the car to run a bit lean, advancing the timing and adding a few HP to the mix. The IAT move is a common mod that does practically the same thing by fooling the car into thinking the air coming in is more dense than it really is. In every air application, a smooth pipe for airflow will work SO MUCH better than accordian style. Most cars have a (resonator) near the intake to do just this.. It kees the flow of air from humming, like when you blow over the top of a bottle. This reduces sound, but also airflow. The ridges move the air around way to much and wont allow it to move quickly to where it needs to go (engine bay). Try using a combination of PVC pipe (2.5 or 3 inch) and couplers.. The PVC is better than metal as it wont heat up near as much allowing the cold air to stay as cold as possible..

A few recommendations for self made CAI:
1. Ensure its as straight and smooth as possbile
2. Like said above, make sure its in an area where air will either be sucked or forced in ( a pipe facing the side of the car is useless as the air pressure in the engine bay wont allow air to move in)
3. Keep in mind when using a cone filter, if your CAI is TOO effective youll be forcing all the wind, dust, rocks, air, and possibly rain right onto your filter.. use wiesely..
4. Have fun.. lol.. jk...

Great idea though, and obviously prooven to be effective!!!

So far so good,cold air mod

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