06 gxp custom cai

**f3racer** · 03-10-2011

now this is for my 06 gp gxp. i don not know if this will work for any other ls4 vehicles. i dont see why it wont though.

items needed.
3 inch pvc - bought at lowes for 5 bucks 2 feet in length
3 inch flexible elbow- lowes 11 bucks
2 in by 15 ft heat wrap- orielly's for 20 bucks
cone filter - depends on brand and where but mine was a spectre from autozone for 25 bucks
flathead screwdriver
torx bit
rachet with 13mm,10mm, 7mm sockets
hand saw

remove front chassis brace over airbox
remove airbox and put MAF right onto the slinky looking tube

unscrew bolts holding inner fender well, headlight, and lower portion of bumper in front of drivers side front wheel
put cone filter in fender well and let lay
then measure pvc from MAF to hole into fender well approx 15 in
put rubber coupler onto pvc
then attach pvc to flex elbow
feed elbow into fender well
attach coupler to maf and tighten clamp

attach filter to elbow, tighten clamps and secure to front clip with zip ties so it doesnt wiggle around

filter is approx 14 inches above the ground at middle of filter.

wrap heat wrap from throttle body to fender well
i secured my heat wrap with safety wire

i then used some industrial strength velcro to attach the ecm to the chassis

finished product is nice. only 1 extra bend. i am hitting the track saturday and will give some input. the wrap should definately keep temps down.
if you find something that works better please post it so we all can use it.

**Bio248** · 03-10-2011

see, look at you mr. 'delete-my account'.

feel free to continue spreading your knowledge on the platform. im sure others will join in.

**f3racer** · 03-10-2011

lol thanks for talking me out of it!

**f3racer** · 03-11-2011

car felt good this morning driving to work. i was watching the DIC and noticed a small MPG increase but i wont know for sure until i get home. yesterday before i built the cai i checked my mpg's on my 81 mile round trip to and from work. at the end of the trip i averaged 19.6 mpg. this trip is 74 miles highway at 77 mph, and 7 miles of stop and go, 35 mph roads on post. today i am trying to be identical with the trip. the only difference will be the temperature. yesterdays temp never got higher than 34 degrees. today will be much warmer. i will post the results tonight.

**Koniig** · 03-11-2011

Good writeup!

May be trying this before IAGP.

**FriboRage** · 03-12-2011

'scuse me if Im being stupid here... cause I very well could be..

but isnt that slinky looking part part of the restriction we're trying to get rid of?
I was under the impression we wanted smooth walls at all costs

**blueguy** · 03-12-2011

Originally Posted by FriboRage

'scuse me if Im being stupid here... cause I very well could be..

but isnt that slinky looking part part of the restriction we're trying to get rid of?
I was under the impression we wanted smooth walls at all costs

Your not being stupid...that is the restrictive part...

A couple things I would have done differently...

4" PVC...
Get rid of the corrugated tubing that bolts to the TB...
Get a bigger filter...the 9" one...
Ditch the exhaust wrap...your intake looks like King Tut.

**f3racer** · 03-12-2011

I replaced the accordian tube, if I go with the bigger filter I get close to the ground, I don't care what it looks like I wanted cold as possibe air. 4 inch tubing might be nice but this is basically a research project. Also what good does 4 inch tubing do when the opening to the throttle body is only 3 inches.

**f3racer** · 03-12-2011

I like to responces though, it gets my mind going

**MoarkatsINmuhtrailer** · 03-14-2011

mine i just made is 4 inch pvc tubing and it reduces with a giant coupler to the throttle body. ill try and get pictures of it but its not on my car and its not even at my house haha go figure. ill have my buddytake a few pics and send em to me then ill put em up.

**starscream5000** · 03-14-2011

Originally Posted by f3racer

Also what good does 4 inch tubing do when the opening to the throttle body is only 3 inches.

This is how I always looked at it as well.

**MoarkatsINmuhtrailer** · 03-14-2011

heres my new one...

**FriboRage** · 03-14-2011

That's nice, I bet the washer gets atleast 15hp TO THE AGITATOR with that thing.

**mechguy** · 03-14-2011

Originally Posted by f3racer

Also what good does 4 inch tubing do when the opening to the throttle body is only 3 inches.

Well, not too too much of a difference for short sections. But to realize the difference, consider this exploitation:

The water tap outside of your house has the same outlet as a garden hose. Compare flow of turning the tap on without any garden hose attached. Now turn the tap on with as many garden hoses attached as you can. Pretty big difference.

**SlowNA06** · 03-14-2011

Originally Posted by f3racer

what good does 4 inch tubing do when the opening to the throttle body is only 3 inches.

The bigger the tube, the slower that same volume of air will have to move through the tube, and the slower the air, the lower the restriction will be through that tube.
Show your work

3" Diameter x 10" tube:
Volume = pi * radius^2 * height
Volume = 3.14 * 1.5^2 * 10
Volume = 3.14 * 2.25 * 10
Volume = 3.14 * 22.5
Volume = 70.65 in^3

4" Diameter x 10" tube:
Volume = pi * radius^2 * height
Volume = 3.14 * 2^2 * 10
Volume = 3.14 * 4 * 10
Volume = 3.14 * 40
Volume = 125.6 in^3

Difference: 77.78% increase in volume from 3" to 4" tube.

The longer the tube, the more air is restricted. This is something that, alone, I suspect would make a noticeable difference only with an exceptional length, such as more than three feet. It's something like a 3% increase in restriction per foot.

Bends add a considerable amount of restriction, though. A 90* bend (or two 45* bends) would be somewhere along the lines of a 17% increase in restriction in a 4 inch tube.

So a 4" x 10" tube with a 90* bend is still ~5% (or shall we say, negligibly) less restrictive than a straight 3" x 10" tube with no bends.

**MoarkatsINmuhtrailer** · 03-14-2011

Originally Posted by FriboRage

That's nice, I bet the washer gets atleast 15hp TO THE AGITATOR with that thing.

i think i had it dynoed at like 17.5 or so haha unbelievable gains over stock

**f3racer** · 03-15-2011

I understand the dynamics between 3 in tubing cfm and 4 inch. But what happens when you try to cram that 4 inches of volume into a 3 inch hole that will only allow 3 inches of volume? Still doesn't make sense to me but I'm no math wiz.

**SlowNA06** · 03-15-2011

Originally Posted by f3racer

I understand the dynamics between 3 in tubing cfm and 4 inch. But what happens when you try to cram that 4 inches of volume into a 3 inch hole that will only allow 3 inches of volume? Still doesn't make sense to me but I'm no math wiz.

Actually, the idea is to cram the entire world's worth of air into a 3" hole. This will flow better than anything else. Problem is, the world is dirty, so you need a tube with filter on the end as a "necessary evil." Anything on top of the throttlebody represents a restriction.

A 3" tube adds significant restriction on top of the 3" throttlebody. A 4" tube causes less restriction - negligibly close to running an open throttlebody.

The smaller the tube, the faster air must travel through it to create the same charge as a larger tube with slower flow. Air can only move so fast, and the filter slows it down even more. With increased need for air, eventually, on both a 3" and 4" tube, you will not be able to pull in enough air for proper combustion (such a point is rarely, if ever reached), but the 3" will see that point before the 4". Less vacuum can pull the same amount, or more air in a less-restricted setting - so it can be mixed with more fuel to create more power.

I'm short of creativity, so this is the best example I can some up with: Beer bong. The human esophagus is an inch in diameter. Now, while you can use a 1" diameter tube for your beer bong (and yes, this is cheap and easy to test amongst your friends!), you will be a vastly faster racer with a 1.5" or even 2" diameter tubing. In fact, it is fastest to use a glass, because it represents even less restriction.