1991 Trans Am Convertible - Coil per Cylinder Gen 1 Small Block

History | Engine | Transmission | Suspension | Interior | Exterior | Special Thanks

History We had been looking for a 3rd gen f-body to receive our prototype LS1 PCM controlled TPI engine. This car had been sitting in the back of a country garage after a minor front end accident in Georgia several years ago. It was rough, but being a southern car, had no rust. The car was purchased in April 2008 and given an aggressive schedule to be completed by fall 2008. The engine bay was untouched. A stock 5.0L TPI was under the hood. This would be coming out of the car to be replaced with a 5.7L engine. The TPI was the original choice, but we chose to clean up the engine compartment by using a Corvette LS1 throttle body. This allows for the removal of the throttle cable, cruise control cable, cruise control vacuum lines, and cruise control module. The Corvette Throttle Actuator Control (TAC) module integrates cruise control with the electronics. A natural choice for an intake manifold was the Ram Jet 350 because the LS1 throttle body is a direct bolt on. The interior was neglected. Mice had made their home throughout the car and the odor was unbearable. The interior had to be completely removed and replaced. The 2000-2002 Trans Am interior, in our opinion, is the best looking f-body interior put in these cars. We found a very clean interior from a 2002 Trans Am and adapted it to fit in the car. Because the Ram Jet 350 engine would be running with a true LS1 calibration, the Trans Am dash would be completely compatible with the PCM. This is an exciting build and we hope that you enjoy!

Engine The highlight of this car is the use of the LS1 PCM, using a Corvette LS1 calibration, with a fuel injected Generation 1 Small Block Chevrolet Engine. The original 5.0L TPI engine was replaced with an original 10k mile 1989 5.7L TPI engine. The 5.7L engine was stripped down to a short block and built back up using all of the components found in a Ram Jet 350 crate engine, boosting the power to 350hp/400tq. Intake Manifold A new Ram Jet 350 intake manifold was installed. In fact, the entire engine was rebuilt to the same specs of the GM Ram Jet 350 crate engine. The cable driven throttle body was replaced with a new 2002 Corvette LS1 electronic throttle body. The LS1 throttle body is a direct bolt on to the Ram Jet 350 manifold. EFI Connection's Custom 24x Crankshaft Timing Ring Due to the LS1 24 pulse crank signal, the Generation 1 Small Block Chevrolet Engine was not capable of using the LS1 PCM and operating system. Since the fall of 2006, EFI Connection has been offering "LS1-like" wiring harnesses for the 4 pulse crank signal found in the 96-99 Vortec truck engines and 01-02 Express Van engines. The 4 pulse system requires a Vortec distributor, ignition module, and single coil. It also requires the use of the 01-02 Express Van operating system and calibration in the PCM. Many 3rd gen f-body owners have already converted their TPI engines to use this Vortec system. However, now EFI Connection is the first to use a 24 pluse crank timing ring for the early engines! We put a lot of research and development into this ring to allow the use of a distributor-less, coil per cylinder, system for just about any early GM V8 engine. This timing ring installs easily on the crankshaft behind the 96-99 Vortec timing cover. Camshaft Positon Sensor The LS1 PCM requires a cam signal. The 96-99 Vortec distributor was used only for the cam signal. The cap and rotor were removed from the Vortec distributor and replaced with a sealed cap. The 96-99 Vortec distributor's function for this system is to drive the oil pump and produce a cam signal. It no longer delivers spark. Electronic Throttle Control This may be a first for the Generation 1 Small Block Chevrolet Engine! EFI Connection's custom 24x crank timing ring allows the use of the LS1 Corvette operating system and calibration in the PCM. This system uses an electronic throttle body. Conveniently cruise control is built into the system, so that means all of the vacuum controlled 3rd gen cruise control components go away entirely. Coil Per Cylinder This may be a first for the Generation 1 Small Block Chevrolet Engine! EFI Connection's custom 24x crank timing ring allows the use of the LS1/LS6/LS2 or any Generation 3 Small Block Chevrolet PCM, operating system, and calibration. These systems are all distributor-less and use one coil per cylinder. A set of polished cast aluminum valve covers were fitted with custom brackets and brand new 2002 Corvette coil packs. Due to the length from each coil to spark plug, the truck spark plug wires were used.

Transmission
The car came with a T5 manual transmission. We really didn't think this would hold up well to the Ram Jet 350, so we have a T56 from an LT1 car. The 2002 Trans Am center console is a perfect for the manual transmission. The T56 is fitted with a B&M shifter and a SPEC Stage 2+ clutch.

Suspension
The car came with the "Performance Suspension" package, but with 100,000 miles on the odometer it is ready for a few upgrades. The car will retain the original ride height and Bilstein shocks and struts installed all the way around. Polyurethane bushings will be installed throughout. To reduce body flex, Alston sub frame connectors will be welded to the underbody.

Interior There are no words to fully describe the condition of the interior of the car when we purchased it. The smell, stains, smell, mold, smell, broken pieces, and did we mention smell? Due to the smell, the entire interior will be replaced. Dash The dash was removed from a wrecked 2002 Trans Am and is ebony in color. The 4th gen air bag was removed because the 3rd gen air bag system will remain fully functional. HVAC System The 4th gen HVAC ducting will be modified to mate to the 1991 HVAC system on the firewall. The 4th gen HVAC vacuum controls will be replumbed to operate the 3rd gen HVAC system. Seats The 2002 Trans Am seats were removed from a wrecked car. These seats have full power and the air compressor for power lumbar and sides. They are a direct bolt in to the car. The seat covers will be replaced for 100% leather covers to blend with the tan interior. Carpet Brand new tan carpet will be installed to replace the original. Door Panels The 2002 Trans Am door panels will be modified to fit the 3rd gen doors. Stereo System The 4th gen Monsoon CD receiver was replaced with a Pioneer DEH-P77DH CD receiver to fit the DIN-and-1/2 opening.

Exterior A rust-free car in Pennsylvania is hard to come by. Fortunately this car spent most of its life in Georgia. Our intention is to keep the car red with a camel (tan) convertible top. The bottom of the car will get a good cleaning and a light coat of gray POR-15 to keep the floorboards from rust. Due to the Ram Jet 350 intake manifold on the engine, the hood will likely be changed due to clearance issues.

Thank You...
There are some very talented people contributing to this car's transformation.

EFI Connection extends a VERY special "thank you" to:

• Mark...for your efforts in the research and development of the crank timing ring.
• Bill...for your efforts in the research and development of the crank timing ring.
• Troy...for your help with the engine build and general work.
• Scott of "Sew it Seams"...for your help with the research and development of the prototype coil brackets.
• Craig of www.moates.net for your help with RoadRunner realtime tuning.