Chevrolet LT5 Impala SS Tim Allen's Way of Saying 'Get Me to the Show on Time' (PR Newswire, 11/11/96)




    Chevrolet isn't normally in the "made- to-order" custom

automobile business. But for the right opportunity, exceptions

can be made.  Several months ago television star Tim Allen

approached Chevy with a fervent desire to create the Impala SS of

his dreams. Chevrolet Specialty Vehicles Manager Jon Moss

acknowledged that Allen's vision had promise.  And, it might

serve as the perfect send-off for Chevy's renowned SS in its

final months of production. After due consideration, Moss agreed

to help Allen build this interesting variation on the SS theme.



   Allen dreamed of a ride to special events in a carriage

distinctively different from the customary stretched limousine. 

He was thinking of something very black and menacingly fast but

also supremely comfortable for two formally-attired,

chauffeur-driven luminaries.  He was imagining a custom- built,

power-packed Impala SS, exactly the kind of machine his macho

character Tim Taylor might create in his garage on Home

Improvement.



   Allen already owned and enjoyed a 1995 Impala SS.  (That car's

tune-up is another story.) What he longed for was a DOHC 32-valve

Corvette ZR1 V8 under the hood of a '96 edition.



   That transplant sounds simple, but it turned out to be a

sizable undertaking.



   The LT5 is a rather bulky powerhouse that didn't exactly drop

into the space left by the original engine.  Adapting it to an

automatic transmission was another challenge because this engine

was engineered solely for use with a manual transmission in the

Corvette ZR1.  The number of systems to be created rapidly grew

to arm's length: engine mounts, wiring, cooling, air induction,

exhaust, power steering and driveline.  The frame's front

crossmember had to be radically modified to provide the necessary

clearance for the LT5's nine- quart oil pan.  The windshield

wiper motor, ABS hardware, heater core and AC evaporator all

required some fiddling.



   Soon this project grew beyond the scope of an engine swap into

a full- blown engineering program.  Instead of using a

salvage-yard engine, a new LT5 was acquired from GM's Service

Parts Operation and extensively modified for better-than-stock

performance.  An aftermarket crankshaft raised the stroke to 3.82

inches, while the cylinders were bored to 4.00 inches and new

pistons boosted the compression ratio to 12.2:1.  Those changes

resulted in a new piston displacement of 385 cubic inches or 6.3

liters versus the standard LT5's 350 cubic inches or 5.7 liters. 

Ported intake and exhaust passages in the otherwise stock

32-valve cylinder heads improved flow characteristics.

Custom-made stainless-steel tubular headers routed exhaust to a

pair of LT1 Camaro catalytic converters.  The use of a specially

calibrated PROM module in a Corvette engine control computer

helped manage all of the LT5's original functions including

emissions controls.  During dynamometer tests, Tim Allen's highly

tuned prime ride delivered a peak 446 net horsepower at 5500 rpm

and well over 400 lb-ft of torque from 3250 to 5750 rpm.



   To transport Allen to "openings" and the like without fail,

various driveline upgrades were deemed necessary.  The Impala's

4L60-E automatic transmission was modified by Hydra-matic for

high-rpm longevity and fitted with a 2000 rpm stall speed torque

converter.  A custom four-inch aluminum driveshaft was fortified

with heavy-duty universal joints.  A new 4.10:1 ratio

limited-slip differential was specified to help provide the

desired 'off the line' acceleration.  A quicker steering-gear

ratio should aid maneuverability through crowds of paparazzi.



   Once the powertrain engineering was in hand, Allen focused on

aesthetic details to achieve just the right look for his dream

ride: Lower-profile BF Goodrich radials ride on wider Enkei alloy

wheels; vent holes drilled through the disc brake rotors and

aftermarket brake pads improve this hot Impala's stopping

performance; and a tasteful crossed-flag LT5 SS emblem on each

front fender affirms the source of the commotion under the hood. 

To acknowledge credit where it's due, Chevy's bowtie badge floats

on a blacked-out grille, while a new "Binford 6100" logo has been

attached to the decklid. (Binford is the hypothetical tool

manufacturer that sponsors Allen's Tool Time TV show on Home

Improvement.  Every hand tool, drill press and band saw featured

on the show is supposedly from that firm's 6100 product line.)



   Inside, seating accommodations were altered to maximize

comfort for four passengers.  Front-bucket side bolsters were

enlarged for additional lateral support, and fold-down trays have

been added to each front-seat backrest.



   The center console is configured for auxiliary power jacks and

the requisite cellular telephone.  Seats and door panels are

upholstered with supple leather trim and finished with wood- and

carbon-fiber-motif accents. Bose Corporation created a

one-of-a-kind entertainment system for Tim Allen's enjoyment by

using the same amplifier and speaker technology fitted to $30-

million Gulfstream V business jets.  Engineers first mapped the

car's passenger-cell acoustics and then established speaker

locations, equalization curves and the sound system's frequency

response.  In total, 10 speakers are placed in the doors, the

A-pillars, the center console and on the rear package shelf.  The

10 distinct channels of amplification and equalization provide

117 decibel listening levels with no audible distortion.  Source

material is provided by a Rockford Fosgate head unit working in

conjunction with a trunk- mounted six-disc CD changer.    Opening

night may never be the same after this black sheep rolls forth

with dual pipes and 10 speakers serenading the crowd.



    Specifications for Tim Allen's Impala LT5 SS



    Engine

    Type ...... DOHC 32-valve LT5 V8

    Bore x stroke ...... 4.00 in. x 3.82 in.

    Displacement ......... 385 cu. in. (6.3 liters)

    Compression ratio ...... 12.2:1

    Horsepower (SAE net) ....... 446 @ 5500 rpm

    Torque, lb-ft (SAE net) ....... 448 @ 4250 rpm

    Pistons ..... J-E

    Piston rings .... Speed Pro

    Connecting rods ..... Oliver

    Crankshaft ..... Doug Rippie Motorsports

    Air Cleaner and induction tube .... Wheel to Wheel



    Exhaust system

    Stainless-steel headers and pipes ..... Wheel to Wheel

    Mufflers ........ Exhaust Tech

    Resonators ..... Walker



    Driveline

    Transmission ....... modified Hydra-matic 4L60-E

    Driveshaft ...... Dyno-Tech 4.0-inch aluminum with

Dana-Spicer universal joints

    Limited-slip differential ...... Auburn Gear Company

    Final drive ratio ......... 4.10:1



    Chassis

    Power steering ratio ............ 12:1

    Wheels ........... Enkei 17 x 9.0-inch aluminum

    Tires ...... B F Goodrich 275/40ZR-17

    Front springs .... stock trimmed by 3/4 coil

    Rear springs ..... Eibach variable rate

    Brake rotors ..... cross-drilled

    Brake pads ...... Raybestos Super Stop



SOURCE  Chevrolet Motor Division