C6Performance Journal

• Torque Convertors: How they Work– What size is right for you? depends on the application DO YOUR OWN RESEARCH, start in the Automatic Transmission Forum we have here, its there for a reason . General rule is 3200-3600 for daily drive, 4k+ for alot of track use.

• Manual Transmissions: How they Work– When looking to upgrade think of current and future mods. 01-02 cars come with the ls6 clutch and hydraulics which is a good setup for basic bolt on and daily driving.

  – You’ll find the Spec 3 to be one of the most popular clutch setups here. Ram also makes a nice setup. Again, Do your OWN research n he Manua Transmission forum concerning chatter, clutch break in, hydraulics, ect. 98-00 cars will want to upgrade to the 01+ hydraulics when installing a new clutch.

RPO Production Codes (LS1)

AG1 – Power Adjuster, Driver Front Seat, Multi-Directional

AK5 – Inflatable Restraint System, Driver and Passenger Seat

AQ9 – Front Bucket Seat, Driver and Passenger Recline

AR9 – Front Bucket Seat, Driver and Passenger Recline, European Style

AU0 – Remote Entry Lock Control

AU3 – Side Door Electric Lock Control

AX4 – Restraint Conversion Seat, Manual European

A26 – Window Glazing, European

A31 – Window, Power Operated, All Doors

A90 – Lock Control, Right Component Lid, Remote Control Electronic Release

BAG – Parts Package Export

BBS – Knob Shifter Hurst

B35 – Covering Rear Floor Mats

B9W – Wiring Provisions, DRL Override

CC1 – Roof Hatch Removable Panels, Glass

C49 – Rear Window Defogger, Electric

C60 – HVAC System AC Manual Controls, Front

DD9 – Mirror, Breakaway, O/S LH & RH Remote Control Electric Color

DE4 – Sunshade, Removable Hatch Roof

DG7 – Mirror, O/S LH & RH Remote Control Electric Color

DL5 – Decal, Roadside Service Information

DS1 – Sales, Diplomatic

D21 – Sunshade, Windshield

D35 – Mirror, O/S LH Remote Control, RH Manual Control, Color

ETA – Harness, I/P Wiring #1

FE2 – Suspension System, Ride and Handling

FE4 – Suspension System, Special Ride and Handling

FE9 – Certification, Federal Emission

FLT – Fleet Processing Option

F41 – Suspension System, Front and Rear Firm Ride and Handling

GU2 – Axle Ratio 2.73, Rear

GU4 – Axle Ratio 3.08, Rear

GU5 – Axle Ratio 3.23, Rear

GU6 – Axle Ratio 3.42, Rear

G80 – Axle Positraction, Limited Slip

JAF – Brake Provisions, European

J65 – Brake System, Power, Front and Rear Disc

K05 – Heater, Engine Block

K29 – Module Powertrain Control

K34 – Cruise Control, Automatic, Electronic

K43 – Generator, 102 Amp

K68 – Generator, 105 Amp

LS1 – Engine, Gas V8 5.7L SFI Aluminum

L36 – Engine, Gas V6 3.8L MFI HO

MAE – Marketing Area Europe

MM5 – Merchandised Transmission, Manual 5 Speed

MM6 – Transmission, Manual 6 Speed O/D

MN6 – Merchandised Transmission, Manual 6 Speed

MX0 – Merchandised Transmission, Automatic O/D

M30 – Transmission, Auto 4 Speed Electronic

M49 – Transmission, Manual 5 Speed O/D

NA3 – Emission System, Japan

NC1 – Emission System, California

NF7 – Emission System, Federal

NK3 – Steering Wheel, Sport, Soft Rim, Simulated Leather

NM2 – Emission System Export, Leaded Fuel

NP5 – Steering Wheel, Leather Wrapped

NP7 – Steering Column, EEC Approved

NT3 – Emission System, EEC 00

NW9 – Traction Control, Electronic

N36 – Steering Wheel, 4 Spoke Sport

N60 – Wheel, Aluminum, Painted

N66 – Wheel, Styled Aluminum

N73 – Wheel, Custom Sport Var4 17″

N92 – Cover, Wheel, Bolt-on

N96 – Wheel, 16 X 8 Cast Aluminum

N98 – Wheel, 16 X 8 Cast Aluminum Chrome

PA6 – Wheel, Styled Painted

PW7 – Wheel, 16 X 8 Aluminum Styled

P05 – Wheel, Chrome

QB3 – Wheel, 16 X 7.5 Steel

QCB – Tire, All P235/55R16-96T BW AL2

QEA – Tire, All P215/60R16-94T BW AL2

QFK – Tire, All P275/40R17-93W BW HW4

QFZ – Tire, All P245/50R16 BWAL3

QF6 – Wheel 17 X 9, Aluminum

QII – Tire, All P215/60R16-94H BW AL3

QLC – Tire, All P245/50R16/N BL HW4

TR7 – Headlamps, Control Leveling System, Automatic

T2H – Ornamentation Exterior, Export Unique Requirements

T2J – Ornamentation Interior, Export Unique Requirements

T37 – Lamp, Fog, Deluxe

T39 – Lamp, Turn Signal, Auxiliary

T43 – Spoiler, Rear

T65 – Lamp System, Daytime Running, Export

T72 – Headlamps, LH, Rule of the Road

T78 – Headlamp Control, Delete

T79 – Lamp, Fog Rear

T82 – Headlamp Control, Automatic ON-OFF

T84 – Headlamps, RH Rule of the Road

T85 – Headlamps, LH Rule of the Road

T89 – Lamp, Tail & Stop, Export

T90 – Lamp, Signaling and Marker, Export

T96 – Lamp, Fog

UA6 – Theft Deterrent System

UB3 – Cluster, Instrument, Oil Cool Temp Volts Trip Odom Tach

UC2 – Speedometer, Instrument, Kilo & Miles, Positive Bias

UD4 – Alarm, Vehicle Speed, 120 K/H

UK1 – Frequencies, Japanese

UK2 – Lever, Directional Signal, Includes Multi-Functions

UK3 – Control, Steering Wheel, Accessory

UL0 – Radio, AM/FM Stereo Seek/Scan Auto Rev Music Search Cass Auto-Tone Clock ETR

UL2 – Frequencies, European

UL8 – Frequencies, Saudi Arabian

UM6 – Radio, AM/FM Stereo Seek/Scan Auto Rev Cass Clock ETR

UN0 – Radio, AM/FM Stereo Seek/Scan Compact Disc Auto Tone Clock ETR

UQ0 – Speaker System, 4 Dual Front Door Mounted, Dual STD RGE, Qtr/Shelf

UW3 – Radio, AM/FM Stereo Seek/Scan, Auto Rev Music Search Cass Data System Clock ETR

UZ7 – Speaker System 8, Quad Front Door Mounted, Dual Sail Panel, Dual Rear Hatch Amplifier

U12 – Speedometer, Dual Scale with Kilometer Odometer

U19 – Speedometer, Instrument, Kilo & Miles, Kilo Odometer

U59 – Speaker System 8, Dual Front Door Mounted, Quad Sail Panel, Amplifier

U73 – Antenna, Fixed Radio

U75 – Antenna, Power Radio

VA5 – Language Label, English

VD1 – Provision Options, Europe

VE1 – Provision Options, Japan

VE2 – Protector Source Applied

VG1 – Protector, Underhood Compound, Clear

VG4 – Protector, Undervehicle Compound, Black

VG9 – Protector Wax, Exterior Body

VH5 – Plate Vehicle Identification

VI6 – Fleet Incentive, American Standard

VJ1 – License Plate Rear Mounting Package, Japanese

VK3 – License Plate, Front Mounting Package

VL4 – License Plate, Front Mounting Package, EEC

VL5 – License Plate, Rear Mounting Package, Export

VL6 – License Plate, Front Mounting Package, Japanese

VP6 – Noise Control

VR6 – Hook, Tie-Down, Shipping

VR7 – Hook, Tow, Second, Rear

V12 – Cooling System, Power Steering Fluid

V76 – Hook, Tow

WS6 – Performance Package Special

WX7 – Wiring Provisions

W53 – Entertainment System Option C

W54 – Entertainment System Option D

W55 – Entertainment System Option E

W66 – Merchandised Package, Formula

W68 – Sales Package, Firebird Ground Effects

X10 – Entertainment System, Option L

X20 – Entertainment System, Option M

Y3F – Sales Package, Sport, Appearance Upfitter

Y4A – Exhaust Cat Back

Y4B – Provisions Level II Ultra Performance Suspension

Y4C – Lubricant Engine Oil & Performance

Y4D – Axle Torque Sensing Differential

Y4E – Cooling System Engine Oil

Y4F – Provisions Hurst Shifter

Y4G – Provisions Chrome Wheels

Y4H – Ornamentation Dash Plaque & Key Fobs

Y4J – Covering Floor Front Mats

Y4K – Protector Car Cover

Y4L – Provisions Spoiler

Y81 – Merchandised Package, Firebird

Y82 – Merchandised Package, Firebird, Trans Am

Y84 – Merchandised Package, Firebird Trans Am, GTA

Y87 – Merchandised Package, Performance Enhancement

1R3 – Vehicle Identification Label 1

1R4 – Vehicle Identification Label 2

by Hib Halverson
Electronic Version, copyright 1996, 1997 by Shark Communications

Adapted from material published on the Vettenet and ZR1 net mail lists in August 1996 and from a printed version in the August, 1996 issue of Corvette Fever magazine

Before the 1997 Corvette was even in dealers, it had been reported for a year or more that the all-new platform, known to insiders as “C5,” would be the first General Motors Corporation product to use a new family of medium-displacement V8 engines. Though the car did not debut on the show circuit until January 6, 1997 and in dealers on March 6. 1997, way back on June 11, 1996 in Los Angeles, GM confirmed the engine rumor with a preliminary to the C5 launch: a press show spotlighting its engine.

My first reaction back then was that what’s known as “RPO LS1, 5.7L SFI V8,” is an outstanding design, engineering and manufacturing exercise destined to be yet another landmark in the history of America’s Sports Car. My second reaction? A snicker at the show biz that clouded the engine’s debut.

It is not unusual to introduce a new Corvette engine before its car. In 1988, media got a comprehensive technical seminar on the LT5 nine months before it was shown the ZR1. Of course, this is now; and that was then.

A major deficiency of this June 11 show and Chevrolet’s other LS1 publicity efforts around the country in the summer of 1996 was that 1) they failed to adequately address the most striking feature of LS1: its pushrod valve gear and 2) they came wrapped in a spoof of medical TV shows. The Corvette community contains many potential C5 customers who were not served well by this program because its information value was degraded by its need to entertain.

The quality and timeliness of the in-depth, LS1, technical information reaching the Chevrolet enthusiast was further blunted by only average coverage to date from Corvette media and Chevrolet’s decision to let Hot Rod magazine break the LS1 story ahead of all other publications. The stories that finally made it into print in the Corvette media were either too brief, poorly researched or lacked depth because their editors felt preempted by Chevrolet’s leaking the story.

These shortcomings of these processes are why you have The Idaho Unofficial Corvette and Corvette Surfing WWW sites. Like a beacon of reality, we’re going to cut through the smoke to the hard-core, gearhead story behind this stunning, new engine.

The LS1 press kit said, “Based on a timeless design by former Chevrolet Chief Engineer Ed Cole, the ‘Gen III’ 5.7-liter V8 marks a bright new chapter in the highly respected lineage that GM small blocks have established in more than 40 years.”

I think Chevrolet understated its case.

LS1 is brilliant.

Rather than just a chapter in engine history; it’s more like a whole new book!

What it is not is: “based on” Ed Cole’s legendary Small-Block. LS1’s greatness comes from being a clean-sheet-of-paper design. The only major feature it has in common with the Small-Block is a bore center-to-center measurement of 4.40 inches and we believe that exists for marketing reasons rather than an engineering case.

When and Why

By 1991, writing was already on the wall. While tens of millions of Small-Blocks had been produced in 36 years, the basic architecture would be a liability if customer demands for world-class performance, increasingly stringent exhaust emissions regulation and higher fuel economy standards were going to be met. While Chevrolet and the General Motors Powertrain Division (GMPD) knew the Gen II (LT1/4 and L99, introduced for 1992) and Gen I-E (light-truck, Vortec series engines, introduced for 1996) upgrades would stretch the Small-Block’s life; it was clear that further improvement was needed, if those demands were going to be addressed in the late-’90s and early-’00s.

That winter, deep inside GMPD, study began of a third iteration of the Small-Block V8. Expectedly, someone coined the name “Gen III” and it stuck. The project had SAE net power and torque goals of 1 horsepower and 1 pound/foot of torque per cubic inch displacement. There was a weight reduction goal of about 60 lb. When asked about durability, reliability, drivability and pleasability objectives; GMPD said only that intent in those areas was “best in class.” While that phrase was maybe a bit ambiguous, because Corvette has few direct competitors and none with big V8s, my road test of a C5 pilot car (VIN 00063) in March of 1997 showed the new engine exceeds expectations for drivability and meets them for pleasability. I suspect that time will show the engine’s reliability/durability equaling and possibly exceeding that of the Gen II Small-Block.

The first major challenge may have been more philosophical than technical. John Juriga, LS1 Project Manager, talked about the initial design period, “Trying to decide what was the right engine technology for the application was probably the biggest hurdle we faced.”

This was really not one decision, but a series of them that carried throughout the early phases of the program.

In February of 1993, a stunning decision, arising from this GMPD “soul searching,” was to discontinue Gen III as a Small-Block and do it as a totally new, medium-displacement, V8. The change was made after it became obvious that a Small-Block could not meet the program’s goals; however, don’t think that Gen III work to-date had been for nothing. Significant technology developed for the still-born, Small-Block Gen III went into the 1996 LT4. Roller rocker arms, more aggressive camshaft, hollow-stemmed valves, intake and exhaust port enhancements, rolled-fillet crankshaft and “powdered-metal” rods, all early Gen III ideas, were pulled ahead for the last Small-Block in a Corvette.

Initially, it was thought that the first of the all-new Gen IIIs might show up in a low-volume, 1996 truck application, but as engineers better understood the time necessary to take it from paper to production and make it best-in-class; it was decided that the engine would debut for 1997 in Corvette trim. A similar, but slightly less powerful LS1 goes into the Camaro in 1998 and the all-new, ‘99 or ’00 C/K trucks will get the iron block/aluminum head version. Perhaps other places a Gen III might appear are a “Monte Carlo SS” (front-drive, smaller displacement, aluminum), maybe a high-performance compact truck (iron block/alum. head) and in trucks over of 8600 lbs. GVW and higher (iron block/iron head).

We suspect that the first, very early prototypes of the all-new, Gen III ran on the dynos at GM Powertrain sometime in the early spring of 1993. In-vehicle testing began at the GM Milford Proving Ground in the first week in May of 1993 with the “Chevrolet Engineering and Research Vehicle IV-A” (CERV4a) powered by a prototype, of 5.0 liters and having an iron block and aluminum heads. Eight months later a second car, the CERV4b fitted with a 5.7L iron block/aluminum head Gen III, was added to the test program.

The Gen III passed the “Concept Direction” “gate” in the development process in September of ’93. To do this, it had to have demonstrated the capability to meet the requirements set for the project. Then came Concept Approval. That happened in May of 1994 when the LS1 was within 10% of all development targets.

The C5 “alpha” build, which produced the first prototype cars that were reasonably close to how the 1997 Corvette would look, began in June of 1994. By late-summer, the alpha phase was in high-gear and most all used iron block/aluminum head Gen IIIs at first, with a few all-aluminum units showing up late that year.

The next C5 iteration, the “beta,” began to appear at the end of June 1995. Betas were very representative of what production C5s would be and were the last cars built in Michigan at GM prototype assembly line. Betas used mostly, aluminum LS1s. By fall-’95, the beta build was complete, but the number of cars in testing, believed to have been about two dozen, sometimes exceeded the supply of reliable, all-aluminum engines. Betas not used in development where vehicle mass approximating production intent was necessary, sometimes got iron block/aluminum head engines.

By late 1995 or early 1996, the aluminum block shortage was less of a problem and the LS1 progressed to the point that final development in prototype C5s was underway. That continued into the April of 1996 when the engine was released for production.

An interesting aspect of the engine program was the “Cormaro”. In the first six months of 1995, twenty C5 structure/chassis/powertrain combinations were fitted with modified ’95 Camaro bodyshells. These cars were used well into 1996 for powertrain development and were a perfect way to put street miles on the LS1 without drawing attention…at least until ace spyshooter, Jim Dunne, published a picture of a Cormaro in AutoWeek magazine and identified the car as a Gen III V8 “test mule.”

There was also an unknown number of C4s that were fitted with Gen III engines. These cars were used to develop cold-start ability and the traction control system software.