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I am new to the great site here. Thanks in advance. I have a 2008 1500 4x4 5.3L silverado on order from the factory. I want to keep my mods to a minimum at first, but one thing I do want to do is exhaust mods. Thoughts I have are SI/DO CAT BACK sys, and possibly an aftermarket CAT. Looks and sound are on my mind but more inportant is not to lose any performance (low end I have heard). I am concerned with California emissions and warranty issues. Any feedback is appreciated. Thanks. very much.
 

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I was told from the chevy dealer that a cat-back system and air intake system will not void anything. I just put on a magnaflow with turndown and ordered a K&N kit. Magnaflow is a straight-through design and pretty high quality. Plus it sounds good whether on a I6 jeep or a v8 truck. It all depends on how loud you want it. I don't think that muffler has anything to do with emissions does it? Your cats control that.
 

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honestly dont go for the aftermarket cats, they make little or no difference (not to mention they tend to burn out) . 1-2 hp (with ceramic) Unless you get the very expensive ones, and then you might see a 2-5 hp gain. For two cats, each at @700 bucks not worth it. If your HP hungry, cut them off, but i have to warn you in advance its a nasty noise. The engine coughs and backfires, and drones quite loud with a horrible raspy note. I actually dynoed mine w/ & w/o cats w/o cats lowered low/mid range tq, but higher hp (12) and vice versa with cats. so keep em on.

As far as engines go, quite similar to algebra class. WHatever you do to one side you gotta do to the other. Get shorty headers, dump the stock y under passenger seat and replace the whole way back with 2/12 duals with a h pipe (for exhaust note) h pipe has never really done much for performance, but it always makes the note sounding better by syncing the pulses. purrs rather than glubs. Pick a muffler/s of choice, and use a little inginuity and welding skill to throw up your own full exhaust for 1/3 less than wht ud pay for the whole thing
$149.00 headers summit racing
$20-200 mufflers
$60-100 tubing
 

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I'm gonna just throw in my .02. I just put on a new magnaflow muffler on my 07 4.8 and love the sound. It's not to loud and at crusing speeds to don't hear it at all. Anyways as far as shorty's go they do give you a whole lot for the 400 bucks they cost for a good set. Gibson, JBA etc. The one's for 150 from summit don't fit the newer trucks anyways. Plus they have a low heat paint on them that burns away a week later leaving rusty looking headers. Long tubes are the way to go but there's nothing really available yet for our trucks. I emailed pacesetter, who has the best prices on long tubes and they said a set are in the works. If your looking to not lose low end I'd suggest magnaflow because for the money they are a great product. If you don't mind spending more, Borla and Corsa are great as well.
 

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be sure when you are done you get a programmer because if the computer does not know what changes you made you will not get max hp out intake and/ or exhaust. I have an airaid intake and most likely end up with corsa exhuast for the sole fact that i leave too early in the morning and do not want to wake anyone up at 5am
 

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Another thing I learned from the Grand Prix community is that when you do a mod like exhaust or intake or whatever that you reset the pcm(undo neg. battery terminal) for an hour or so. It forces the pcm to reset, recalibrate(learns) itself somewhat to the new mods. ..Note, it's still not like reprogramming, but still helps.
 

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I'm gonna just throw in my .02. I just put on a new magnaflow muffler on my 07 4.8 and love the sound. It's not to loud and at crusing speeds to don't hear it at all. Anyways as far as shorty's go they do give you a whole lot for the 400 bucks they cost for a good set. Gibson, JBA etc. The one's for 150 from summit don't fit the newer trucks anyways. Plus they have a low heat paint on them that burns away a week later leaving rusty looking headers. Long tubes are the way to go but there's nothing really available yet for our trucks. I emailed pacesetter, who has the best prices on long tubes and they said a set are in the works. If your looking to not lose low end I'd suggest magnaflow because for the money they are a great product. If you don't mind spending more, Borla and Corsa are great as well.

those ****y shorty summit headers are made by pacesetter as well i bought them cause there cheap, and yea the paint comes off in 25 minutes! but than again who in the hell is gunna complain about paint coming off for 150 bucks compared to the same thing for 550 bucks because of a ceramic coating.
 

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whynot just get it all from the factory, yeah it might be a little more but it is MADE for the truck and is factory installed so if something happens they are responsible not to mention that you pay for it with the truck not after and directly out of pocket which could easily be another grand depending on what you get from the aftermarket.
 

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whynot just get it all from the factory, yeah it might be a little more but it is MADE for the truck and is factory installed so if something happens they are responsible not to mention that you pay for it with the truck not after and directly out of pocket which could easily be another grand depending on what you get from the aftermarket.
in reality, that is the best solution, but i am just offering a cheaper way us people on a budget, or for anyone who is doing it for the experience of building your own. always more gratifying!
 

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Does the GMPP parts CAI and Cat Back exhaust give the same level of performance os say a flow master cat back and a Volant CIA? I am getting a 2008 Crew Cab LTZ on Tuesday:) Ifeel like I am waiting for Christmas.
 

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I'm not sure about level of performance-wise, but cost-wise the GMPP stuff seems to be a tad bit high. When I just recently got my 08 Silverado 1LT w/ the 5.3, I had the dealer do a soft tonneau cover, drop in bedliner, and Flowmaster SI/DO exhaust w/ polished stainless tips as part of the deal. Cost me about $900 for everything, installed and the truck sounds awesome. Looking online at the GMPP exhaust, it seems to run around $800 and that doesn't include install or even the tips. I can't believe that a $800 cat-back doesn't include tips... that's ridiculous!! :shocked: And the GMPP air intake is about $400 when you can get AirAid, K&N, AEM, or AFE intakes for $300 or less online. Plus the dealer will probably want $75 to install something that takes 15-30 mins to do in your driveway with a basic ratchet set and a rudimentary knowledge of the english language (or at least the ability to comprehend pictures).


Chris
 

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honestly dont go for the aftermarket cats...
Oh, yeah... did we mention, it's also illegal (fed) to swap out a functioning cat on a newer truck. If you ever get a hard a$$ tech inspection, a shiny new cat could open the door to a healthy fine.

Here's what the Feds FAQs say:
[SIZE=-2]UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF AIR AND RADIATION
WHAT YOU SHOULD KNOW ABOUT USING, INSTALLING, OR BUYING AFTERMARKET CATALYTIC CONVERTERS

When can I install an aftermarket converter?
Generally, there are only 3 situations when you can install an aftermarket converter.
They are:
(1)if the converter is missing from the vehicle when brought in for exhaust system repair; or
(2)if a State or local inspection program has determined the existing converter has been lead poisoned, damaged, or otherwise needs replacement; or
(3)if the vehicle is more than 5 years old or has more than 50,000 miles*
(8 years/80,000 miles for 1995 and newer vehicles) and a legitimate need for replacement has been established and appropriately documented (e.g., a plugged converter or unrepairable exhaust leaks).
Any other converter replacement must be with a 'certified' or new original equipment (OE) or equivalent converter. Aftermarket converters subject to the enforcement policy requirements cannot be used for replacement if:
(1)the existing converter is present and functioning properly; or
(2)the replacement is under recall or warranty; or
(3)the vehicle is returning from overseas use.

*Vehicles with less age or mileage may be entitled to free repairs by the vehicle manufacturer under the emissions warranty if the original converter was defective.
[/SIZE]
 
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