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2003 chevy trailblazer_ls
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Discussion Starter · #1 ·
I am going to detail, step-by-step, the installation of a new True Flow CAI system on my 03 TB 4.2. I'll include pictures of every step, plus a couple of short video clips of the sound my TB makes once the kit is installed.

Note that my 03 has a PCM for Less Tune: 87 octane, shift point 3, torque management eliminated (may still be 5%), and spec'd for resonator eliminate and drop in K&N air filter in a hogged out air-box. I am planning on sending the PCM out for a re-tune with the CAI system and new tires in place. I also have a .490 boost valve in the transmission (soon to be a Vette servo also), and am running 255-70-16 Cooper ATR w/3.73 gears.

Here goes:

Package as it arrived:



Open it up and this is what is inside: Two metal (powder-coated) air tubes, 2 silicon sleeves, 4 worm-drive clamps, 2 pieces of rubber tubing for vacuum connections, the air filter, instructions and stickers (ARB compliance for inspections, "don't throw away the filter" and a manufacturer's sticker)



Here is the unwitting donor vehicle. Yes, it is dirty. I drive it!



The air box is the place to start. It has 3 screws. You can use either a flat-head screwdriver with about a 1/4" wide blade or a Phillips. I've found that the flat blade works better, as the screw does not have deep grooves.

Screw 1 is sort of hidden. You may need to shine a light down the hole to find it:



Screw 2:



Screw 3:



Air box lid lifts off. You sort of have to wiggle it some, as it can hang up on some of the hoses around the front. It will come out of its hole without removing anything else, just have patience and press the hoses out of the way a bit for clearance.

Note the K&N drop in filter. It did a good job, but I was wanting to move to a CAI system to replace the entire factory setup. The K&N is for sale. Let me know. I have cleaning solution and oil for it. It has been cleaned once and has around 30K miles. Due for another cleaning!



Some of you may have noticed the hogged out air box in the prior picture. Here is a better look at it. I just took a cut-off wheel to it. Leaves a bit more room around the filter.



Here is the factory intake tube. Note the famous resonator hole that has so many people mystified. It is there JUST to help quiet the air flow. Only God and some factory engineer know just how much time was spent to figure out that design -- at the cost of usable horsepower -- to make the air intake silent so that we enthusiasts could dump it in the scrap heap for something that made our TB sound like a man's vehicle!



And next, is the air temperature sensor. This helps the PCM adjust to air temps hitting the intake manifold. It pops right out of the rubber grommet and will later be placed into the new CAI.



Traveling up the factory intake, here is the throttle body and connection.



And, here is the fuel pressure regulator vacuum line. This will later connect to the new CAI also.



And, now a word from our sponsor... I used this handy Blue Point 1/4" socket set for the two bolts that had to be removed from the factory resonator. You could use a simple 10mm wrench. Snap On has these kits available in a number of formats and they are nice tools for a reasonable price.

All tools needed for this job include: 1/4" wide flat screwdriver, 10mm wrench or socket, cleaning supplies. I also used a nut driver for the hose clamps, but you could use an 8mm socket or the flat screwdriver as well.



Let's get the rest of the factory system off. Pull the intake from the resonator by loosening the worm-drive hose clamp:



Pull screw #1 on the resonator housing:



Pull screw #2 on the resonator housing (and note, I chose to not retain the resonator housing on my install -- some guys like to cut it out and reinstall it. Your choice. I figure that it is nothing more than a heat trap for the top of the engine, so I plan on running without it. I'll save it for trade-in someday. If you run without it, you may also want to remove the clip nuts on the top of the engine and retain them with the resonator for future use.



Here is the throttle body clamp removed. Same as the other side, then the resonator box can be lifted from the engine bay.



Here is what you see once everything is removed. The silver thing at the rear of the photo is the throttle body. Inspect it and clean it if necessary. Now is the time! It comes off the intake with 4 bolts, and as long as you have the socket set out already...



Here is my throttle body before cleaning. Not too bad figuring it has 88,000 miles and hasn't been cleaned since I installed the K&N drop in. guess the K&N was doing a fair job of filtering. I'll not detail the cleaning procedure here as others have done so in other threads, but in my case it only took a couple of minutes.

 

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2003 chevy trailblazer_ls
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Discussion Starter · #2 ·
Step-By-Step True Flow CAI Install - Part 2

Speaking of the K&N, here is mine as it came out. Due for washing and re-oiling! The inside, as seen in the next shot, isn't nearly as bad looking, however. Dirt SHOULD be on the outside and not the inside.

As I mentioned above, the filter and cleaning kit is for sale...




Here is the pile of old parts removed. I recommend saving them for trade-in time!



Let's get the new intake in place. The new system replaces ALL the factory parts except the air box itself. True Flow says that the advantages of the factory air box are that it runs cooler than sucking up hot under-hood air, and that it protects the filter element. They have dyno tests to back up their beliefs, and in this instance the dyno says that they gain about 6 hp over stock with their setup.

In this shot, you can see the two fittings for vacuum duty. The larger one will connect to the top of the head (the bent tube under the factory resonator box). This draws out oil vapors from the engine blow-by and re-burns them. Note: It is this blow-by that makes the throttle body get dirty (unless you have a horrid or no air filter). Without a "wet" intake track, there is no way to clean the throttle body, which is why we must disassemble it for cleaning periodically as part of the regular tune-up procedure).

The smaller vacuum line will hook to the fuel pressure regulator, and will help to regulate -- fuel pressure (doh!) based on engine needs as signaled by engine vacuum.

On full throttle, the engine vacuum drops to zero, which will give full fuel pressure boost. At idle or part throttle, engine vacuum will run somewhere between 14-16 Hg., which will cut back on fuel pressure. Best economy is found when the engine vacuum is held as high as possible for any or all driving circumstances. Driving with an add-on vacuum gauge will really show some things about driving habits and can help you to be more efficient. Lifting the pedal just a little bit can drastically change vacuum readings, and likewise improve economy.




Here is the new intake, boots in place, and fastened to the throttle body. I chose to hide the heads of my worm drive clamps, even though it made it a tad more difficult to tighten. Just rotate them around to a spot where they are hard to see and tighten snugly. Don't over-do it, or you will either strip the clamps or cut the connector boots.

Parts fit is sort of self-explanatory, but the True Flow Company does include two pages of instructions for installation. Like the typical man, I glanced over them, then went to work. Didn't really need them, but it was good to know they were there (in case my wife asked a question... ).



The new air filter comes pre-oiled -- and note well -- you MUST use the correct oil and cleaning kit from True flow, available from their web site. Using another product, like K&N, for instance, will void their warranty and may damage the filter.

The instructions said to blot off the excess oil with a towel (Okay, I did read them... ) and I did so. I got some extra oil from the end caps, and very little from the foam itself.

A word about the True Flow foam filter. It is a full-thickness layer of foam. Between the oil and the foam, all particles will be caught and held before they reach the throttle body. Because of the design of this particular type of foam, NO dirt can go all the way through the filter.

See True Flow's website (www.trueflow.com) (http://www.trueflow.com/video_1.php) for a video demonstration.

In real life, I have found this to be the case, and I have been running True Flow filters on my off-road trucks for years. I've filled the air box with mud, but nothing made it into the intake tract. I cannot say the same for other filters.

The filter itself just presses over the intake tube. There is no clamp, and the tube will enter inside the filter by an inch or so. It fits snugly and is a snug fit in the factory air box. I recommend not doing a final tightening of the clamps until you have the entire assembly trial fit and in place, as some wiggling may be required to get everything to line up just right.



Don't forget to re-install the factory air temperature sensor in the back of the new CAI tube. True Flow sends a rubber grommet that fits into a pre-drilled hole in the back of the tube. Insert the grommet, and press in the air temperature sensor. You may need to lube the sensor just a bit to get it to slip into the grommet. Soap works well.



Time to tighten all the clamps and reinstall the factory air box cover. I also installed the supplied stickers to the top of the air box lid. In some areas of the country, the ARB exemption sticker is a necessary item to pass inspection. I'm glad to see True Flow included it in the kit.

I was not fully satisfied by the rubber tubes sent along with the kit. I found that they were too short to fit well, so I went of in search of better looking and fitting parts. This was the one thing in the kit that wasn't just right, and it wasn't a deal breaker. Vacuum hose is cheap and I was able to get the truck running for a test. I plugged the new small vacuum line onto the existing line for the FPR, and just got the larger line to fit (it was somewhat kinked).



Here is a bit of bling that I added in place of just replacing the vacuum lines. I found a 5/16" stainless covered hose kit with aluminum ends that dressed up the small tube, and also found a pre-bent 1/2" hose (had a 90 degree molded end to hold the tube close to the head) that I covered with a piece of red wire molding. I'll look for a 1/2" stainless braid kit to make it match the smaller line as time goes on, but it fits better, and works great just as it is. I also like seeing my engine, instead of just plastic covers. Makes for conversation when the hood is popped.



I also shined things up under the hood. I used a bottle of Amour-All multi-surface cleaner/shine that sprayed on (sort of like tire wet spray). I wiped stuff down and got all the plastic white again, and black stuff black again, except in areas needing paint (another job for another weekend!).

Looks a bit different than the in ital engine bay picture!



Here are two brief video clips of the sound from inside the cabin, windows up. The first, just revving it up in the driveway -- has a bit of a growl to it now (I also have a resonator delete). The second is a 10 mph roll-on, nail the throttle until the 2nd gear shift.

What I like about this system is that it is not bothersome at all at regular idle or freeway speeds, but when you get on it, it sounds more like a man's truck -- and it gets out of its own way pretty good also. MUCH improved from where I first started with a pure stock vehicle.

It FEELS like a pretty good kick in the pants after 3000 RPM compared to the stock system, but without dyno or track testing it would be impossible to know if it actually makes all that much difference. I like it just because -- and I also like the sound -- and for me, that is good enough. If I get some gains from it, so much the better. I'll post later to let the group know if I see mileage gains, and I'll also be running this on the 1/8th mile track here in Louisville in the next week or so.





Hope this install helps someone else with their own project.
 

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2007 chevy trailblazer_ls
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Gotta give it to you for the full intake. I have the K&N system which only goes up to the engine resonator box (box on top of engine doesnt get removed, only the airbox). It gave it a slight throatier sound which is plenty noticeable. I decided I wanted a full (Ive had full intakes on every other car ive owned and LOVED them) intake. So I modified it and removed the resonator box.

Needless to say, I put it back when I got home. It was just TOO loud for my tastes in the middle of the rpm range when youd get on it. It was bad if you were LIGHT with the throttle but once you opened it up, it would make the inside of the car shake and sounded like the car would come apart.
 

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Discussion Starter · #4 ·
Mine just sounds good -- and tough. Not too much buzzing or too loud. I think that the factory air box may have had something to do with that.

Sound clips that I posted are fairly close to actual in cab sounds.
 

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2003 gmc envoy_slt
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Nice write-up. That's just the way mine sounds.
 

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Nice how to... Got mine on this week, too. Quick and easy. I definitely had no improvement in my mileage this week, had my foot in it too much.

Only thing that I need to mess with is that at idle there is some kind of rattling from the air box. I don't know if it is the filter or the tube. Only happens at idle. Hasn't been bothersome enough for me to check it out yet. I may need to isolate where it is making contact with a small piece of foam, maybe weather stripping?

Great deal at amazon... I'm kind of surprised that they haven't been sucked up. $47 http://www.amazon.com/gp/product/B0009N4O7S (page says there's 2 left)

Sticker on True Flow box says for 02-04 4.2
 

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2006 chevy trailblazer_ls
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this won't fit an 06 because of the changes to the 06 intake right?
 

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looks like amazon's part thingy says it only fits 02-03, but as e-iowa-o said, the box says 02-04
 

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Discussion Starter · #12 ·
Wish I could help you newer guys, but I've never seen the differences in the intake systems on the newer versions. I'd think that a kit of this nature would be almost universal -- if the air box and the throttle body are in the same location, it should work, but I could be wrong.
 

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that intake from amazon says it wont fit my 04 ls
read the post from e-iowa-o. The box from True Flow says 02-04. I find quite often the amazon thing is wrong. I'd believe the product box and say it'd fit an 04
 

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2003 chevy trailblazer_lt_ext
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You can push your intake air temp sensor a bit more. It's not completely in the grommet the entire way
 

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Discussion Starter · #17 ·
You can push your intake air temp sensor a bit more. It's not completely in the grommet the entire way
I decided to run it there based on how far into the intake stream it ran on the stock intake. It seals and is a good compromise between getting a good reading and disrupting the air flow more than it already does.

Good eyes though. :yes:
 

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that intake from amazon says it wont fit my 04 ls
http://images.amazon.com/media/i3d/01/true flow app guide.pdf

True Flow guide says 02-06 for the 4.2 TB. Sticker on box said 02-04.

there is one review on amazon, as follows:

The price on this Air Kit was one of the better prices I could find anywhere. Shipped exactly as promised.
The only problem I had was the kit was manufactured sometime before the date of my car, and the car design had changed slightly since the kits Mfg. date making the unit somewhat uncompatable.
I was able to call the manufacturer on this problem, and they were more than happy to send me the needed modifications to make this kit usable in my car. Would have been nice if instructions by the Mfg. were more detailed.


Don't know what difficulty that guy had. No problem on my '04.
 

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I know 07+ has the MAF, so this intake wont work. I dont know on the 06's, I know 05 and lower dont have it.
 
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