Super Charged 2005 Chevy Z71

A Mild Example of Obsessive Compulsion


The Only Signs Of Customization are a Joe Gibbs Spoiler, Corsa Exhaust Tips, and GMC Door Guards



The Engine Bay




Specifications and Modifications

·       Options - Fully Loaded LT, Z71 4X4, Leather, Bose Premium, Satellite Radio, Tow Package Metallic Storm Gray, 3.42:1 Locking Differential.   

·        Engine – We began with The Stock Aluminum Blocked RPO Code - "L33" 5.3 Liter V8 GM factory rated at 310 hp/335 ft·lbf of torque the crank. We dyno tested mine in stock form before any modifications were made near the 5000 mile mark and verified a 267HP at the wheels.

      The L33 was only used in 2005-2007 extended cab 4x4 Sierras and Silverado's. Less then 5000 trucks in 05 had the L33.

      One of the biggest differences between an LM7 and L33 besides the aluminum block are the cylinder heads. The LM7 uses the same heads as the 4.8 (LR4) where as the L33 uses 799's which are identical casting to the 243s found on the Ls2 and Ls6 in the corvettes, which have heavier valve springs and hollow exhaust valves not found on the 799 heads.

      Another major difference is the pistons. The LM7 uses dished piston and the L33 uses the same flat top pistons found in the LR4 which gives it a bump from 9.5:1 to a 10.0:1.

      A cam only used in the L33 which has slightly more lift and duration then the LM7's.


·       Engine Modifications

MagnaCharger Radix Supercharger 112 intercooler model a roots type Eton Supercharger kit complete with larger injectors and higher capacity fuel pump replacement. Installed July of 2005 @ 5K miles. Current Pulley is a 3.4" providing  7 PSI of Boost.  HPTuners Tuned. Gates belt tensioner, 90mm steel idler pulleys. Under hood photo and Dyno history listed in order of "Stock Engine with No Supercharger", "Supercharger" with Magnuson supplied Superchips  tune with 3.5 inch pulley, and final tune and 3.4" pulley HERE.

The Magnuson supplied belt tensioner, and 80mm idler pulleys were replaced with Gates p/n 38042 90mm idlers, and Gates p/n 38131 Belt Tensioner for the best in a tensioner and more pulley wrap to prevent rapid deceleration slippage when the blower doesn't want to slow down as fast as the belt. Picture.

Stock Photo Polished Radix


·      Tuning - I own and use HPTuners software as a novice, mecanicman is the mentor of this tune that includes MAF and VE tables, strict WOT plug reading and more via his care and guidance.

·      Intercooler Heat Exchanger - The Magnuson supplied Radix heat exchanger was upgraded to a larger triple pass unit by . Comparison & Install pictures HERE.

      This heat exchanger, other than running a noticeably cooler really shows a marked improvement in much faster recovery times over the Radix Magnuson supplied heat exchanger.

      Another improvement to the system was insulating the coolant lines and moving the pump and reservoir out of the engine bay heat to the grill area.


Showing the Insulated Coolant Lines and the 90 mm Blower Belt Idler Pulleys


The Mercado Heat Exchanger and Reservoir Re-location

The Pump is Behind the Bumper Air Slots


·         Exhaust – Corsa Performance Touring Edition Cat back system for great performance with in-cab comfort. Loud on the outside only when romped, always nice inside. With GM's improved exhaust  manifolds this system really complements the performance package of the truck without  demanding an aftermarket exhaust header system.


·    Transmission  - A  4L60e Build Level 4.5 Installed 8/15/15.  Level 4.5 Build List.

The original factory 4L60e lasted 40k before losing a 1st gear thrust bearing. I tried running a Sonnax Performance Pack

and GM parts conversion to a 4L65e with aftermarket frictions. Although I liked the performance, there was a stubborn

harsh light throttle 1-2 slide-bump that took lots of time in the shop to solve.

The transmission built locally kept blowing snap rings out of the input drum.


I decided to seek out a professional performance builder 


Of the three most mentioned services in performance circles I chose Transbuilderguy. What began as a tough

choice Robert Godfrey made it easy.


The transmission after months of pounding is doing great. His after the sale & installation follow up's are prompt and thorough. Also a great is his Facebook Customers Page, a great way to interface, share, learn and keep in touch.    



        ·    Torque Converter - The stock converter was replaced it with a  Circle-D GM 300mm HP 4L60 LS in a Stock Stall. I like

              to crawl in the North GA mountain back roads and a high stall is not suited to this application. I do not do standing launches

              racing. The stock converter failed @68k miles. 



       ·       Gears – Locking 3.42's are a perfect match for the added low end torque providing spunk off the line and pure 

             joy on the highway where she really breaths well.


·         Brakes - Front brakes use R1Concepts Premium Series Rotors and Raybestos Police Formula (Tahoe P/N) Pads. The rear system uses Raybestos Advanced Technology drums with GM OE shoes. Brake lines are the Russell Performance braided stainless steel 3-line kit providing a faster and firmer pedal feel. Brake fluid is Valvoline's Synthetic DOT 3 & 4 and is changed regularly using Speed  Bleeders.

      The above braking modifications just add to the already  great braking that came on the truck. In 2005 GM went to drum brakes on the rear of their 1500 trucks.

Read Here About GM's Conversion to Rear Drums On The 2005 Silverado's

      Most are confused how going from disc to drums on the rear was an improvement. All I can say is this truck stops really great as shipped. The upgraded components added contributed greatly to ending pad material transfer to the rotors (some mistake for rotor warping). You can really feel the rear brakes doing their job in a precise proportionate manner. I managed to get 65k miles out of the rears before servicing them (See Pics This Link).


      Since going to the R1Concepts Premium rotors and the Raybestos police pads the distance has decreased noticeably, and brake fade is hard to make happen. The Police pad formula was engineered for pursuit conditions and it shows.


·         Tires – The Michelin LTX M/S2 P265/70R17. These replaced the LTX M/S after more than 66k miles on 7/20/13. The M/S were speed rated @ S=112 mph. The M/S2's are T=118 mph. The compound changes can really be felt in the wet. Great Tires.

      Tire test by FOURWHEELER Magazine reports on the M/S2 improvements over the M/S version.

·       Instrumentation Cluster includes a 140 mph Police Instrument Cluster including a transmission temperature  gauge and PLX Wideband  Air/Fuel Ratio & Boost/Vacuum Gauges.

·         Suspension - Bilstein HD Shocks all around. Airlift Company's Ride Level Control rear air bags filled by Viair's 450c air compressor with in cab gauge and controls. The compressor is a 100% duty cycle  150 PSI unit. For keeping the ride level when loaded and a very fast tire fill setup.

      I can level when loaded and have a ride that does not sag or sway with properly aimed headlights. I have repaired many a tire for stranded motorists and myself.    

Back lighted In Cab Ride Control Panel with lighted  3-Position Toggle Switch, On/Off/Momentary and a Bleeder valve button


An Air Bag & Three Way Valve to the Bags, Tire Fill Outlet, or to Isolate the Pump

The Tire Fill Hose Port and Manual Bag Fill Valve

The Tire Fill Setup. This and a Plug Kit Has Saved My Bacon More Than Once

The VIAIR 450C Air Compressor Mounted Under The Cab


 ·       Tire Pressure Monitoring System - By Orange Electronic Model P409.

I Have Used the Orange Electronic P409 in three Vehicles Over the Years. A Great Unit.

The Next Time You Get New Tires, Consider This System

·         Radar/Laser Detection - Lidatek Laser LE-30 Jammer providing excellent and reliable warning while  scrambling police laser probes for 5 seconds while I heat up the breaks. The Escort 9500ix Radar Laser detector with GPS aided false alert prevention is a really great radar detector.

·         Bed Cover – ACI-AGRI-COVER Inc's Access limited edition Tonneau cover. After trying several other brands  this is simply the best cover system and material out there. It still looks and works great after 8 years of use.

·       Head Lights - High beams are modified for optimum brightness with –'s Head Light Booster Wiring Harness powering Philips HIR1 (9011) and HIR2 (9012) Halogen Infrared Reflective bulbs. Factory fog 35watt lamps are replaced with 65watt 9005 lamps. 

      Reverse lamps - are the 3156 CREE 5W Reverse LED's from A significant  upgrade from the 50Watt halogens found on the market.

This truck is really fun to drive. With a modest 7psi of supercharger boost she is somewhat of a wolf in sheep's clothing. It looks, feels and handles like any stock truck running smooth and quiet not consuming any more fuel than a normally configured engine ....... until we mash it. The supercharger screws are bypassed under normal loads only coming into play on demand. The exhaust flows really well but is very quiet in the cab at all times. When we need to pass or harass she demonstrates a very noticeable amount of added power and noise getting the job done nicely as the blower whine turns heads.


·         Dual Battery Power – Along with the Current add-ons I am adding auxiliary driving lights soon. GM provides an auxiliary battery option by adding parts  TRAY, AUX BATTERY 15246518 / The Clamp 356668 / And the Bolt 11509853.

 The Batteries are Sears DieHard Platinum's Group 34/78, a re-branded Odyssey PC1500DT .  Same battery, different color and price.

Batteries are connected in parallel and manually isolated using a Bear DC 225 Amp  100% Continuous Duty Cycle Contactor. The controls are via a dash 3-Way Toggle Switch with LED Lighted lever tip - Position 1 Green Light = Ignition On Main & Auxiliary Batteries Connected, Position 2 No Light = Ignition On or Off Main Battery Only, Position 3 = Red Light = Main & Auxiliary Connected with Ignition On or Off.

Auxiliary positive cable joins the main battery positive cable at the starter. The Aux battery ground cable connects the block. All cables are 2GA.

A Hella Time On Delay Relay is in the position 1 circuit and allows the Main battery to start the engine alone and run for 2 minutes before connecting the Auxiliary battery.

Ignition On signal is provided from a wiring outlet in the factory harness for factory installed Aux battery. This female plug comes on all trucks regardless the option and is factory fused. Its location is kind of hidden behind the HVAC Dryer on the firewall

The Contactor Mounted on the Side of the Aux Battery Tray

The Aux Battery RPO requires a fender support removal. I fabricated a replacement.



The power and build configuration of this truck is balanced to provide nice amount of performance increase without sacrificing reliability. With nearly 400 horsepower at the wheels in the heat of the summer she is not the average running pickup.

Updated 3/4/2017 @ 80+ Miles