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Discussion Starter #1
I have a 2002 Trailblazer that I'm just starting to mod. I am looking at getting a performance chip, but I've read some things saying that the PCM will eventually reprogram itself. Is this the case for a 2002 TB? Or is that only for newer models?

Additionally, what stage/brand of chip should I get? I want a stage two but cant find a 180 degree Thermostat. And which brand chips are best?

- 4Wep
 

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2003 chevy trailblazer_lt_ext
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A PCM tune won't get wiped out unless someone, like the dealer, re-flashes it.

Chips are a waste of money, IMO.
 

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2002 gmc envoy_slt
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A true tune will yield better performance that one of the add-on modules. I presume you're comparing it to the Jet-Chip, which is pretty much the only 'chip' (if you call it that) for the I6. I owned a Stage-I Jet-Chip prior to my Wester's tune and there is no comparison. The Jet-Chip daughter card simply goes between the PCM and the connector to help boost timing and fake some of the operating parameters. Yes it makes a difference, but no where near as much as a tune will and the tune isn't any more money and in some cases cheaper than the Jet-Chip module.

You will most likely not find a 180 degree stat for the I6/4.2. These engines actually need to run warmer than that and a 180 stat WILL result in the CEL lighting and setting a code. If you install one, you'll end up consuming more gas, possibly clogging the converter and not gaining any real hp in the process. - The 4.2 likes to run a wee bit hotter than that and doesn't ping like the 5.3/6.0 does at the higher temps.
 

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Discussion Starter #4
Thanks

Thanks, I appreciate the help and I'm glad I didn't waste money on a chip then. As far as getting it tuned does anyone know of a place near Savannah, GA where I could get a tune done?

- 4Wep
 

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Thanks, I appreciate the help and I'm glad I didn't waste money on a chip then. As far as getting it tuned does anyone know of a place near Savannah, GA where I could get a tune done?

- 4Wep
Go to pcmforless.com, order a tune, have it shipped to your door. Either buy another PCM outright (keep your stock one), core exchange (they send you a loaner, you send yours in, get it back, send loaner back), or send yours in. Check out their subforum under the Vendors, all the info you need is in there!
 

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2003 chevy trailblazer_ls
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The guys above are right on the money. Get a tune -- get a loaner PCM -- and when your tuned version returns, swap it in and be happy.

The small extra cost to borrow a PCM is worth it in the long run, as it is cheaper than trying to take your truck to a dealer for a CASE relearn (crank/cam sensor) which typically costs over $50 and sometimes over $100.

Don't drop the temp via T-stat on the Trailblazer. That mod works with old school vehicles -- not so well on our highly controlled versions.

Otherwise, there isn't really too much you can do to up the horsepower on the I-6. It is already pretty well hot-rodded from the factory. Double overhead roller cams, huge exhaust system, variable cam timing, capable of 7000 RPM, and making close to 300 horsepower from about 242 cubic inches. That's a hot-rodded motor by any definition. A cold air intake system (I prefer True Flow!) and pure synthetic oil will give you a bit of extra power -- not too much, but some. A lot of guys think it is worth the money and effort -- others don't. It is that close to being a wash, power wise.
 

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2007 chevy trailblazer_ls
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PCM

I just had my PCM tuned by PCMforless and I am very impressed!!! Power seems to come on stronger now, the shifts are more firm and precise and I averaged an extra 1.5-2MPG for the last 3 fill ups since installing the PCM. It only took a 4 day turn around from the day I shipped it to the day I recieved it. Great company and great results!!!
 

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2004 gmc envoy_slt
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So my question, I am sure being very simple answer to...

With the tune say level 2..will this allow *not that I am looking to burn up the tires* but to spin more free off the line? The way it is now is nice cause I won't burn through tires, but I also like the idea of being able to say floor it and have some spin at times so he doesn't seem gutless.. with the stock setup it feels like a 4 banger in there until the rpm's get up...
 

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I'm not sure if I understand your question. Level 2 would be the shift firmness of the transmission. It won't make your truck spin off the line but it does provide a harder shift. As for your truck feeling like a 4 Banger. I think the tune from PCM4fess would fix that. My truck has a lot more get and go and is a lot more responsive. I don't you would be disappointed.
 

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There really isn't much that we can do to get that "peel out" effect off-the-line with an I-6 Trailblazer. They just don't develop that sort of torque in that rpm range, and without major modifications such as a stall converter, they probably will not ever blaze the tires at will. Too much vehicle weight for the power.

You'll either need a manual transmission, where you can let out the clutch very quickly at high rpms, or get an SS, which has gobs of torque off the line. A manual transmission swap would be a fun project, but it would probably get costly, as the PCM, etc., would all need modification, and once you got all that done, you'd find out that our rear axle couldn't handle the load.

Get the tune, add a CAI like True Flow, do a resonator delete, make sure that your throttle body is clean, install new factory standard plugs (AC Delco irridium) and make sure the thermostat is running at 192 (about 210 on the dash gauge) and you're making about as much power as it is possible to make with the I-6 without MAJOR modifications.

Remember, this little engine is already hot-rodded from the factory. It is about 242 cubic inches, and puts out about 275 torque/275 horsepower at the flywheel. It has double-overhead roller cams w/variable cam timing, a huge free-flowing exhaust system, a relatively large throttle body, and adequate injectors and spark capability. All those things are the typical things added to an engine to hot rod it. They're already in place from the factory! Doing the mods above will bump that already potent package close to 300/300. That is a potent little engine any way you slice it!
 
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