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Trailblazer SS Bolt-Ons - Tricks Are For Kids
We Make An Extra 147 Rear-Wheel Horsepower With A Few Key Mods To A Trailblazer SS
Apr 1, 2009
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Trailblazer SS Bolt-Ons - Tricks Are For Kids
The 6.0L LS2 engine in the Trailblazer SS has a factory rating of 390 hp and 395 lb-ft of torque.
On the Mustang chassis dyno at Tune Time Performance, we made 309 peak horsepower at 5,500 rpm and 327 lb-ft of torque at 4,500 rpm. Note: Mustang dynos typically read lower than Dynojet chassis dynos.
Disassembly flew by as the boys at Tune Time have had their hands in a Trailblazer or two.
Once the engine cover, intake pipes, and accessories were removed, we could get down to the nitty gritty.
Sure enough, within the hour we were ready to pop off the stock cylinder heads and have the motor broken down to the short-block. Next, we popped off the balancer using a balancer puller, unbolted the timing cover, and were ready to take out the stock camshaft and replace it with the new one. The stock camshaft has a lift of 0.525-inch on both the intake and exhaust sides, and a duration of 204 degrees on the intake and 211 degrees on the exhaust.
Trick Flow's Track Max camshaft increases lift to 0.585-inch on both the intake and exhaust and the duration to 228 degrees intake and 230 degrees exhaust if we were using the stock 1.70:1 rocker arms. We didn't. We went with Comp Cams 1.75 adjustable rollers, creating a total lift of 0.602-inch on both the intake and exhaust valves. Here, Justin adds some lubrication to the cam lobes and sets the new camshaft in place.
Trick of the trade: By gently placing a thin rod the entire length of the two oil valleys, Justin prevented the lifters from falling and thus eliminated the tedious step of removing the roller lifters to install the camshaft.
Once the camshaft was installed, we could bolt the timing cover back up and concentrate on the cylinder heads. The TFS 225cc heads were delivered assembled and ready for installation, which saved us many hours of installing valves and valvesprings.
First and foremost, we had to prepare the deck. This consisted of wiping off residue left by the original assembly and making sure the mating surfaces and cylinders are free of debris and fluid.
Check out brand spanking new Trick Flow GenX 225cc cylinder heads. They are complete with 65cc combustion chambers (same compression as stock), 225cc intake runners, 80cc exhaust ports, 2.055-inch intake valves, 1.575-inch exhaust valves, and titanium retainers. At the end of the day, the most important information about a cylinder head when making power is the runner flow numbers. These are measured in cubic feet per minute (cfm) and provide the most accurate reading of how a cylinder head is going to perform. While valve sizes and cubic feet of space in the runners is good information, stick to the flow numbers as a guide.
The graph at the end of this article is comparing a stock set of LS2 cylinder heads to the Trick Flow heads (as advertised) and it is measured at every 0.100-inch up to 0.600-inch, which is where our camshaft maxes out.
Once the surface was cleaned, we laid the head gasket in place and dropped on the cylinder heads.
As per the torque specifications, we torqued down the heads to 75 lb-ft...
...using ARP cylinder head bolts.
We decided to use Comp Cams' 1.75 adjustable roller rockers. The camshaft lift was multiplied slightly higher through the valvetrain than with the stock 1.70 rockers from 0.585-inch to 0.602. Many LS applications use shaft-mount rockers, which are easier to install and need no adjustment due to the zero-lash nature of the valvetrain.
We had these Comp Cams rollers sitting around and decided this was the perfect place to put them to use. Matt Hauffe, owner of Tune Time Performance, said, "I was surprised by the Comp Cams rockers once we got the motor running. There was zero noise coming from the valvetrain and once the adjustment was set, we didn't have to worry about them."
We then installed SLP Performance 1 3/4-inch long-tube headers. The headers are mandrel bent, ceramic coated, 409 stainless. This is a great time to install these as everything is out of the way.
The passenger side header was installed from the top of the engine and the driver's side from underneath. Tune Time has found that this is the easiest way to install headers in the Trailblazers. The fit was excellent on the headers and we had no issues as we started to bolt everything back together in the engine bay.
With that, we buttoned everything back up on the topside of the motor including Tune Time's cold-air intake kit specifically for the Trailblazer SS application and a set of 46-psi Lingenfelter fuel injectors.
We then put the SUV up on the lift and gutted the exhaust. SLP took care of us from exhaust port to the ABS rear fascia panel--literally.
From the factory, all Trailblazer SS's have one exhaust pipe out the back of the truck, and due to the high demand for dual exhaust, SLP sells a complete cat-back kit.
The kit comes with a new rear fascia panel available in all TB factory colors, plus 4-inch dual polished, all the piping, muffler, stainless steel tips, and a lifetime warranty. It looks and sounds fantastic.
Like any other build, we ran across some issues along the way, but made amazing power when we were all said and done. Matt set the Trailblazer on the dyno and by the time he was done custom tuning, we were looking at 456 peak rear wheel horsepower and 419 peak rear-wheel torque, a gain of 147 hp and 92 lb-ft. We could not have been happier with the results.
We had every intention of making some hits at Atco Raceway the next day, but the transmission exploded while making a few quick hits on the street near the shop. It wasn't a surprise as the Trailblazer's nickname has long been "Transblazer" due to the stock 4L70Es they consume. Anger Management Racing is presently redoing the transmission and we are going to be installing a 3,400-stall Precision Industries Vigilante triple-disc torque converter. This combination should be good for mind-blowing 11-second quarter mile passes, while still maintaining street manners.
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