Trans Am GTA Technical Specifications



DRIVETRAIN 

RPO LB9

Engine Type: Eight Cylinder, V-Design
Valve Design: Overhead Valve
Bore/Stroke: 3.74 inches x 3.48 inches
Displacment: 305 cubic inches
Compression Ratio: 9.3 : 1
Fuel Injection/Manufacturer: Multiple-Port Style, Bosch-Rochester
Fuel Requirements: 91-Octane Unleaded

 

Brake Horsepower / Torque Ratings:

1987:

205 HP @ 4400 RPM / 270 FT/LB @ 3200 RPM

1988:

190 HP @ 4000 RPM / 295 FT/LB @ 2800 RPM (MXO Transmission)
215 HP @ 4400 RPM / 285 FT/LB @ 3200 RPM (MM5 Transmission)

1989:

190 HP @ 4000 RPM / 295 FT/LB @ 2800 RPM (MXO Transmission)
225 HP @ 4400 RPM / 295 FT/LB @3200 RPM (MM5 Transmission with N10 Dual-Converter Exhaust)

1990:
215 HP @ 4400 RPM / 285 FT/LB @ 3200 RPM (MXO Transmission)
225 HP @ 4600 RPM / 300 FT/LB @ 3200 RPM (MM5 Transmission with N10 Dual Converter Exhaust)

1991:
215 HP @ 4200 RPM / 285 FT/LB @ 3200 RPM (MXO Transmission)
230 HP @ 4400 RPM / 300 FT/LB @ 3200 RPM (MM5 Transmission)

1992:
205 HP @ 4200 RPM / 285 FT/LB @ 3200 RPM (MXO Transmission)
230 HP @ 4200 RPM / 300 FT/LB @ 3200 RPM (MM5 Transmission)

Axle Ratios:

1987:
2.73 : 1, 3.23 : 1 (MXO), 3.08 : 1, 3.45 : 1 (MM5)

1988:
3.27 : 1 (MXO), 3.08 : 1, 3.27 : 1, 3.45 : 1 (MM5)

1989:
3.08 : 1, 3.23 : 1, 3.27 : 1 (MXO), 3.45 : 1 (MM5)

1990:
3.08 : 1, 3.23 : 1, 3.27 : 1 (MXO), 3.45 : 1 (MM5)

1991:
3.08 : 1, 3.23 : 1, 3.27 : 1 (MXO), 3.42 : 1 (MM5)

1992: 3.08 : 1, 3.23 : 1 (MXO), 3.42 : 1 (MM5)


 RPO B2L

Engine Type: Eight-Cylinder, V-Design
Valve Design: Overhead Valve
Bore/Stroke: 4.00 inches x 3.48 inches
Displacment: 350 cubic inches
Compression Ratio: 9.3 : 1
Fuel Injection/Manufacturer: Multiple-Port Style, Bosch-Rochester
Fuel Requirements: 91-Octane Unleaded

 

Brake Horsepower / Torque Ratings:

1987:
210 HP @ 4400 RPM / 315 FT/LB @ 3200 RPM

1988: 225 HP @ 4400 RPM / 330 FT/LB @ 3200 RPM

1989:
225 HP @ 4400 RPM / 330 FT/LB @3200 RPM
(235 HP @ 4400 RPM / 335 FT/LB @ 3200 RPM with RPO N10)

1990:
235 HP @ 4400 RPM / 340 FT/LB @ 3400 RPM

1991:
240 HP @ 4400 RPM / 340 FT/LB @ 3200 RPM

1992:
240 HP @ 4400 RPM / 340 FT/LB @ 3200 RPM

Axle Ratios:

1987:
2.77 : 1, 3.27 : 1

1988:
3.27 : 1

1989:
3.27 : 1

1990:
3.23 : 1, 3.27 : 1

1991:
3.23 : 1, 3.27 : 1

1992:
2.73 : 1, 3.23 : 1
 


 1989 RPO LC2

Engine Type: Six Cylinder, V-Design
Valve Design: Overhead Valve
Bore/Stroke: 3.80 inches x 3.40 inches
Displacment: 231 cubic inches
Compression Ratio: 8.0 : 1
Fuel Injection/Manufacturer: Sequential-Port, Bosch-Rochester
Turbocharger: Garrett/AirResearch T3
Fuel Requirements: 93- Octane Unleaded
 

Brake Horsepower / Torque Ratings:

250 HP @ 4400 RPM / 340 FT/LB @ 2800 RPM
 

Axle Ratio:

3.27 : 1



For 1991 and 1992, GM offered the SLP Engineering "Street Legal Performance" performance kits through GM dealers. These kits were offered either as a dealer-installed option or could be installed by the customer. Each kit consisted of the following: 1) SLP Hi-Flow Aluminum Siamesed Intake Runners, 2) SLP Tri-Y Stainless Tuned Exhaust Headers, 3) SLP Low-Restriction Stainless Exhaust System, and 4) Revised Engine Cal-Pac PROM (specific to application).
 


These kits were the first GM-authorized totally integrated performance upgrade packages for TPI-equipped cars which substantially improved performance without sacrificing fuel economy, drivability, and emissions legality. These kits were warranteed through GM by SLP Engineering. Engine power increased by 50 HP at 5500 RPM, long above the point where the stock LB9 and B2L stopped performing, and there were corresponding torque increase from 2800 up through 5500 RPM. Each part was also available seperately thorugh GM dealers. There was also an available SLP Cold Air Induction Package that was not part of the complete kit, but sold seperately.

The kits were offered specifically tailored to the engine the car was equipped with and other variables. The part numbers were as follows (these numbers are the ones relating to GTA models; kits were also available for other Firebird models as well):

1987-1988:

GM # 12341390 -- 305 TPI with 3.08 ratio - Single Exhaust (S.E.) -- $1,930
GM # 12340391 -- 305 TPI with 3.23 ratio - S.E. -- $1,930
GM # 12341392 -- 350 TPI with 3.27 ratio - S.E. -- $1,930

1989:

GM# 12341393 -- 305 TPI with RPO N10 -- $2,085
GM# 12341394 -- 350 TPI with RPO N10 -- $2,085

1990-1992:

GM# 12341398 -- 305 TPI with RPO N10 (91-92 RPO R6P) -- $2,085
GM# 12341399 -- 350 TPI with RPO N10 (91-92 RPO R6P) -- $2,085
 

All of the package components were also available seperately through GM dealers. The cost of the components were as follows:

Tri-Y Stainless Exhaust Headers: (1987-88) $1,050, (1989-92) $1,100
Stainless Free-Flow Exhaust System: (1987-88) $390, (1989-92) $415
Hi-Flow Siamesed Intake Runners (specific to model year application): (1987-92) $450
Cold Air Induction Package: (1987) $295, (1988-92) $270
CAL-PAC High Performance Engine PROMs (specific to model year application): (1987-92) $225


BODY / INTERIOR 

Curb Weight: 3460-3530 pounds
Weight Distribution: 57% (front) - 43% (rear)
Wheelbase: 101.6 inches
Track: 60.7 inches (front) - 61.6 inches (rear)
Overall Length: 191.6 inches
Width: 72.0 inches
Height: 49.7 inches
Rear Storage Space: 5.8 cubic feet (rear seat up) - 9.1 cubic feet (rear seat folded)
Fuel Tank: 15.5 U.S. Gallons (supposedly 18 U.S. Gallons on 1989 20th Anniversary Indianapolis Pace Car - not verified)

Vehicle Lay-out: Front engine / Rear drive
Body/Frame: Unit Steel Construction
Brake System: Four Wheel Power-Assist Disc**

** - Some models were equipped with the RPO J42 disc/drum brake system

Rotor Size:

10.5 inch (front and rear) - 1987-1988
10.5 inch (front) and 11.7 inch (rear) - 1989-1992
12.0 inch (front) and 11.7 inch (rear) - 1989 20th Anniversary Trans Am

Wheel, Type and Size: Cast aluminum alloy, 16 x 8 inch
Tires:

Goodyear Eagle VR50 Radial, size 245/50-VR16 (1987-1988)
Goodyear Eagle ZR50 Radial, size 245/50-ZR16 (1989-1992)

Steering: Recirculating ball, with power assist
Wheel Turns, lock-to-lock: 2.4
Turning Circle, Foot-in-diameter: 37.6
Suspension Components (front): modified MacPherson struts, lower A-arms, coil springs, tube shocks, and anti-roll bar
Suspension Components (rear): Live axle, with trailing arms, torque arms, and Panhard arm, coils aprings, tube shocks, and anti-roll bar