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2007 chevy trailblazer_ls
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Discussion Starter · #1 ·
well ive got the pcm4less tune, exhaust and all the other bolt ons, is there anything else to do to the i6 to make a huge power and speed difference? Like can you put a programmer lets say superchips or something along with the pcm4less tune? Or could you replace the throttle body with a larger MM sized one? Any ideas are appreciated, let me know everyones input!
 

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2005 gmc envoy_sle_xuv
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The throttle body on their is pretty optimized as it is, i think i remember someone saying swapping it will actually make you lose power. But a PCM4less tune is a custom tune done by them, they have different stages of tunes but i would stick with the pcm4less one. Other than that you won't get a super amount of power from this engine unless you spray or go FI
 

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2003 chevy trailblazer_ls
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I agree with the guys above. Unless you have DEEP pockets (or Mama's Mastercard) you are not going to get major power gains from the 4.2. The factory just about optimized everything.

Best way to add power that I can see is an add-on turbo kit. The kit alone will run you between $1500-$2500 and once it is all in place, you'll still need to convert to an 06 or newer MAF setup and build a custom PCM to run it. Doable, but you'll probably have $3000 + in it, and for that, you can trade up for an SS.

There are reasons why doing a turbo on the I-6 might be worth while, though. Fuel economy is one. Insurance rates is another. I'm looking at the whole deal myself.

I like this:

http://www.ststurbo.com/

It mounts under the rear of the vehicle, where the stock resonator would sit. It has an oil pump setup to return oil to the block, and uses engine oil pressure for the turbo oiling. The length of the intake line acts as an intercooler, adding some power that makes up for the losses via the distance away from the heat source at the manifold. Probably not the biggest/most powerful turbo setup under the sun, but doable if you could sort out the PCM/fuel issues that come with the added air flow.

I can see a realistic-drivable 450+ hp out of a setup like this.
 

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2005 chevy trailblazer_ls
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I like this:

http://www.ststurbo.com/

It mounts under the rear of the vehicle, where the stock resonator would sit. It has an oil pump setup to return oil to the block, and uses engine oil pressure for the turbo oiling. The length of the intake line acts as an intercooler, adding some power that makes up for the losses via the distance away from the heat source at the manifold. Probably not the biggest/most powerful turbo setup under the sun, but doable if you could sort out the PCM/fuel issues that come with the added air flow.

I can see a realistic-drivable 450+ hp out of a setup like this.
I saw that setup on Trucks or Muscle Care or Two Guys Garage one of them. It really stuck in my head because where it mounted. Can't remember the gains but they where pretty good. Obviously or they would have done an episode on it.
 

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well ive got the pcm4less tune, exhaust and all the other bolt ons, is there anything else to do to the i6 to make a huge power and speed difference? Like can you put a programmer lets say superchips or something along with the pcm4less tune? Or could you replace the throttle body with a larger MM sized one? Any ideas are appreciated, let me know everyones input!

Since your starting with an '07 - the next step would be to dive into the engine. A good head port job on the exhaust side will allow the engine flow. The '06 up head is already better then the 02-05 but its still restrictive on the exhaust port just under the bowl. Best bet is to buy another late model head and send to a good cylinder head shop that has a flow bench. Get them to re-work the exhaust port and do a good 3 angle valve job. Once done swap the head. The intake port is 98% good to go - just need a bit of casting flash removed.

rough cost - 300 for the core head then $800 to $1000 for the head work.

$80 for a head gasket

If your not comfortable with the head swap best to farm it out. Put an ad up - bet there are lots of un-employed GM mechanics looking for some side work....

On the other hand of you know what a degree wheel is - dive in.

Bet there is 50+ HP in just the head work with a fuel tune. Based on the head flow data from my own head if the engine was built e.g. strong internals with proper cams the power would peak at 480HP(190 HP over stock) mind you this is at 9100 RPM - not practical for a street engine but 6500 rpm the power increase is there. The stock internals are supposed to be good to 7200 so 6500 is safe - I've spun my stock '05 to 6400 no problems.

I'm going to find out "very" soon what head and cams are worth power wise.
 

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2007 chevy trailblazer_ls
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Discussion Starter · #10 ·
sounds good, my girlfriends cousins owns a mechanics shop, and told me that cat on my exhaust is choking me out bad, he referred me to buy a magnaflow high flow cat for the truck to see a huge power gain with a simple part
 

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Cams huh efi? Custom ground? If you can, Id love to see dyno numbers and possible cam specs if it turns out well. Im be so down for a cam.
 

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2007 chevy trailblazer_ss_1ss
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im with everyone as stated before... just trade up to an SS instead of wasting all your money in "minor" bolt on items...On a bone stock SS with just a tune and CAI it takes the SS from mid 14's at the track to low to mid 13's.. thats not to mention you could put on e-fans, headers, UD pulley's etc.. the possibilities are just endless on the LS2 motor...and almost every bolt on upgrade shows significant changes in numbers...my stock SS is rated at 395hp at the crank and im putting 325hp to the rear wheels... (i have a 2WD)...

just my thoughts... good luck on your upgrades tho.. sounds like tyou have a lot done already..:thumbsup:
 

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2003 chevy trailblazer_ls
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Turbo is likely the best option, and based on what I can see, one of the likely scenarios that GM had in mind when they engineered and built this engine platform.

The 4.2 is a natural for turbo charging. Only real drawbacks are the restrictive fuel/air management via stock PCM below the 06 model year and cost of parts.
 

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you want power?? add in a yank tc
Eh that actually kills low end power but lowers your E.T.s too because you can powerbrake to 3000+ rpms vs 2200ish. And Ive talked to a lot of SS guys that have lost 1-2mpg doing a TC but pick up big 1/4 mi gains. Not sure Id really recommend this unless you dont care about mileage and just want speed.
 

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Eh that actually kills low end power but lowers your E.T.s too because you can powerbrake to 3000+ rpms vs 2200ish. And Ive talked to a lot of SS guys that have lost 1-2mpg doing a TC but pick up big 1/4 mi gains. Not sure Id really recommend this unless you dont care about mileage and just want speed.
I didnt lose any gas mileage. its still the same probally due to the 4.10 and removing the 4x4.

it didnt kill my low end power. with the proper tune up can help increase performance. (I learned this by accident)
 

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No torque converter can "add" power. It can multiply gear ratio in a certain rpm range, but the power is produced by the engine, not the torque converter.

What a loose converted does is allow the engine to spin up to a higher rpm before sending that power into the transmission. With slight pressure on the brakes, the converted will "stall" at a certain speed before the power supplied to the axle overcomes the braking force (or you cook the internals in the transmission, whichever comes first).

When a converter has its vanes modified to stall at a higher rpm, the launch rpm will be higher into the power band, which gives a quicker and harsher launch, much like revving up the engine and dumping the clutch on a manual-shift vehicle. You get more "bang" for your buck with a high stall converter, but sometimes that "bang" is just that -- parts breakage or tickets from excessive acceleration.

This is typically for track use only. On the street, unless one is street racing, there really is no need or use for a high-stall converter. What good does it do to induce slippage in the drivetrain on purpose? That is what a high stall converter does.

If one's only goal is to be able to smoke the tires, go out and buy an old Camaro with a manual shift and have at it. The ENTIRE object of any racing venue is to absolutely avoid spinning the tires, and if you are doing it for street cred, well... It's your life and your wallet.
 
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