Quadzilla Stealth 2 Tuner #S2TUNER-S

List Price: $449.00
XDP Price: Discontinued

01-05 GM 6.6L Duramax (LB7 & LLY)
Mfg. Number: S2TUNER-S
XDP Part Number: QZS2TUNER-S

XDP $5 Pricebeat Guarantee

     Effective 1/23/2013, Quadzilla Performance Technologies has gone out of business. All units will be sold without manufacturer support and or warranty. Units purchased through XDP will be covered by our 30 day satisfaction guarantee. XDP will no longer offer extended warranties on Quadzilla Performance Products.

    The Quadzilla Stealth Tuner is the ultimate handheld programmer for the Duramax. While being extremely well-known for being the most powerful handheld tuner ever produced, it also offers many other features that are important to you.


    • LB7 and LLY Tuners in a single unit with 1 price!
    • Base Tuners offer an industry leading 6 performance tunes up to 135hp!
    • Race versiontuner for LB7 has an amazing 10 performance tunes up to 215hp!
    • Read and Erase Diagnostic Codes
    • Correct Speedometer for different tire sizes*
    • Removes Top Speed Limiter*
    • Raises the rev limiter up to 4400rpms!
    • Allows for Transmission Retraining
    • Fastest loading tuner on the market
    • Simple in cab installation
    • Increases fuel economy


    Precision Tuning

    At the heart of the Stealth Tuner is many long hours of precision tuning combined with thousands of miles of real world testing. We combine the use of fuel injection pulse width and injection timing to create the ultimate horsepower and torque curves. The precision tuned timing maps are one of the reasons our tuner has the lowest exhaust temperatures on the market. Perhaps the best part of the Stealth Tuner is the mileage gain that you will see. We all know that a more efficient engine will gain fuel economy and we know exactly where the stock parameters are lacking. Depending on your driving style, you can expect to see a 1-4 mpg increase!




    The Quadzilla Stealth Tuner is packed full of power and features for your 2001-2005 Duramax. Among these features are power increases up to 215hp and 415ft lbs of torque on the 2001-2004 models and up to 110hp and 225 ft lbs of torque on the 2004.5-2005 models. Also included in this awesome tuner are the ability to modify your speedometer to compensate for larger tires*, remove your top speed limiter*, retrain your transmission, and read and erase engine and transmission fault codes. All tuners also have the ability to use these user-defined categories without installing an engine tune.




    Combine all of this with the best reliability, and you can't go wrong. We offer a 1 yr warranty in the tuner and a LIFETIME warranty on the software! No one else will match this. Quadzilla also offers free updates and revision to the original owner FOREVER.


    Additional Information

    Install Sheet

Customer Reviews - Include your order number for a chance to win a $100 GiftCard

(19 Ratings, 9 Reviews) Average Rating:
Very pleased
Ian (Virginia Beach) 9/1/2012 7:43 PM
You can't beat this tuner for the price. I average a little over 20 mpg at 75 mph (you're not going to get 30 mpg at 75 so don't believe the review that says so). I run the 70hp tune and the power is very noticeable. The 135 tune doesn't seem any faster than the 70 hp tune, but I think I have a fuel delivery problem and I'm not getting enough fuel for the tune. I would highly recommend this tuner until you can save up enough money for efi live.
Very Satisfied
Ryan (Vancouver BC) 1/21/2012 11:45 AM
I recieved the chip, two minutes later I was out in the truck installing it. Ten minutes after that I was black smoking hybrids? Enough said, This chip put an instand smile on my face just pulling out of the drive way at 2000rpm. Im running it on 90hp tune as I still have stock trans. I would highly recomend this chip, it's great bang for your buck. This is the only mod on my truck this far and the difference was huge!!
lots of power little smoke
Steve (indiana) 9/7/2010 11:06 PM
tuner gives you alot of power great drivability and gives you fuel milage but i was disapointed in the smoke department. if anyone know's how to make an lb7 smoke using this programer the help would be highly appreciated
Quadzilla Stealth 2
Mark (Ohio) 4/15/2010 6:08 PM
Well, it does add power. No change in mpg over stock. Anyone reporting different needs to actually calculate the mpg, not read the DIC which becomes terribly inaccurate with any tuner. Now the bad news. Any setting but economy has poor drivability at low throttle positions, such as driving in city traffic, 35mph zones etc. The tunes seem to throw all the fuel and timing in at 1600ish rpm, then the motor jumps up to 2100rpm, then the trans shifts to the next gear, and the rpm drops to ~1400ish rpm. Next, the tach hits 1600 and off it goes again. Driving slow like this in town is a pain, constant jerking. Really crude. If all you do is drive on country roads or highways, it's fine. You'll get more power.
21 MPG AVG...33 at 80 MPH
Jeremy (Sacramento) 12/10/2009 10:19 PM
Nice tuner. With the 135hp tune, I get 30 MPG at 75 MPH & 33 at 80 MPH (Flat road). I went from an average of 14 MPG to 21 MPG. WELL WORTH THE MONEY!! Have had the tranny go into limp mode when flooring it doing 75. If I drive it like I would without the tuner, it gets excellent gas milage. I also have an after market air filter only and 4" Magna Flow turbo back exhaust, no cat.

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