Essaycho's 03 Trailblazer ext v8's CNG build thread

essaycho348

Original poster
Member
Mar 7, 2012
58
Bought the Truck in May of 2011

147k miles Lt v8, Loaded (everything except the rain sensing wipers, dvd and auto dimming side mirrors)

a few pictures of the truck after i got it cleaned up the week i brought it home...

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My plans are/were to turn the truck into a 4x4 Natural Gas powered, lawn trailer, pulling people hauler...


a few months later put the lift on markmc 3" lift, bilstein hd's, pulled the spare tire, moved the exhaust in front of the the rear axle on a 45 degree dump. Rebuilt the entire front end with all new parts, and put an air lift air bag kit in the rear complete with gauge and air compressor. Installed the air compressor in the cubby behind the third row in the floor. Put in tekonsha Trailer brake controller.

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and threw on some LED amber marker lights in the grille for kicks.
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I bought a cng kit used from a guy that pulled it out of his 04 3/4 ton silverado, it had two tanks and all the electronics necessary. My plan was to put both of the tanks where the spare tire went, but after mocking up just one tank underneath i soon realized a second tank was not a safe option and then decided to put in behind the third row seat.

after tons of fab work and mockups i finally had the two tanks mounted...
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the braces were a little long and those soon got chopped off and i made some skid tubes that bolted on below the tank...
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Around this time i was taking my lawn trailer down the highway to cut a few accounts and had the air bags blow on me. this made the skid tubes hover only an inch or two above the ground. soon realizing my exhaust dump produced enough heat to melt one of the bags...doing more research and ordered avalanche springs and avalanche air bags, (thanks Roadie for the tip)
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then i pulled the exhaust out and sent the dump a lot further below the rear axle than it was, sorry no before or after pics on this one.
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Also i wanted to keep using the HD shocks so i fabbed up a "shock shortener mount whatever you wanna call it" so i could keep the hd's without bottoming out.
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i bolted and welded the bottom of the mounts in so that they wouldn't spin when force was applied from the shock.
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The Tanks each weigh about 150lbs a piece plus all of the tubing and bracing made this truck pretty heavy in the rear so for something like this the tahoe/avalanche shocks were a must.
 

essaycho348

Original poster
Member
Mar 7, 2012
58
next was running all the wires and getting the hardware put in place first i decided where i would want my switch to go. This shows me how full the tanks are and where i can control if im running on natural gas or gasoline. i Decided to put it in the center console because i wanted it to be as discrete as possible. All the wiring from this got ran into the engine bay.
CNGswitch004.jpg


Then i welded a piece of angle on the rear engine bay brace to hold the two injector emulators, these shut off the fuel injectors when i switch to CNG.
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i welded a brace on the fender and custom fabbed up a mount to that which my pressure regulator then bolted to
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Then i made a custom mount to hold my filler nozzle that bolted to the side of the alternator bracket.
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Then i ran all the wiring, tapped into all the injectors and found a bunch of other key wires they wanted me to splice. i had a hard time finding the wires but just decided to buy an alldatadiy subscription and figured out what the exact wires were. Yes i know the wires look like a rats nest, im in the final stages and have a lot of cleanup work to do. i didn't wanna make the wiring all pretty until i knew i had all the right wires.

Next i had to tap into the coolant lines and run 3/8" hose to the regulator, the gas will freeze the regulator otherwise.
enginebay009.jpg

then i had to redesign the entire intake to be able to use the mixer they recomended
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the mixer works via the venturi effect which required the intake to be made smaller and then larger again. i toyed with the idea of cutting up the stock intake but then i went the route of ordering turbo tubing off ebay and some home depot pvc.
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Finished up on installing the tanks and painting the bracketry
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made a little storage area above the tank behind the third row
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Checked for leaks using the soap test and filled up with cng
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HARDTRAILZ

Moderator
Nov 18, 2011
49,665
Impressive. Wonder how long it will take to recoup the costs.

The tank underneath kills any offroad or even mall crawling abilities as well.
 

Cable810

Member
Dec 5, 2011
690
What tires are you running?? Looking Good!!
 

essaycho348

Original poster
Member
Mar 7, 2012
58
thanks everyone, its been a ton of work but im finally putting an end to the cng chapter on this truck.

in running 265/70 on 17" next set will be 285's these are a bit to bubbly for me tastes but they work.


Yea the tank below does cut down on the off roading abilities. there hasn't ever been a time where ive hit pavement yet, in the city of milwaukee or the suburbs even with my mowing trailer on the back. the only time ive touched ground is going through a heavy construction zone near my house. ya know the ones that say "road closed to through traffic" there was a steep grade downward about 4 feet down at a length of 10 feet and a sharp level off, i was going at a pretty good speed too, only then did i feel the back scrape but the cage underneath it didn't bend or anything.
 

essaycho348

Original poster
Member
Mar 7, 2012
58
Finally got around to getting pictures of my spare tire carrier too. I had to make something so i was going to throw it on the roof. i ended up getting a really good deal from discount on a matching spare rim and tire because they gave me the wrong size tire so i bought another rim from them and kept the tire. With the weight of the spare tire and rim i decided ill go the route of making a rear spare tire carrier.

I got my idea on the tire carrier from Karo's build thread on offroadtb, but i decided to go the route of using a 3500 lb hub and spindle assembly.Then i went to the Junkyard and found an old axle from a 6lug pickup to use to hold the rim and then added some of my own flare integrating a rear bumper brush guard too.



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redleg6

Member
Apr 10, 2012
686
great work and fabrication you have there (love the spare carrier) :2thumbsup:
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
essaycho348 said:
i ended up getting a really good deal from discount on a matching spare rim and tire because they gave me the wrong size tire so i bought another rim from them and kept the tire.

So your spare tire is the wrong size?


The tire carrier/brush guard came out looking really nice. Well Done.
 

essaycho348

Original poster
Member
Mar 7, 2012
58
yes my spare tire is the wrong size, its a 285. i had it on the truck for two weeks before they got me the new tire and rim...but next set of tires i have will be the size of the spare.
 

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