Grand National with a Turbo 4.3 L Ecotec V6

Grand National with a turbocharged 4.3 L Ecotec V6

Jeff and Dan Jost from Jost Boosted Performance enjoy building hot rods with a lot of power as a hobby. So when the factory turbocharged 3.8 L V6 (LC2) in their Buick Grand National suffered a catastrophic failure, there was nothing holding them back from rebuilding the car the way they wanted.

Jost Boosted Performance Grand National

The team started by removing the factory frame. After close inspection they discovered stress cracks and opted to replace it with another factory frame. All the joints on the “new” frame were ground and re-welded. They also replaced the rusty body mounts and reinforced it with round tubing.

Grand National factory frame

modified Grand National factory frame

reinforced Grand National frame

reinforced Grand National frame

The restored frame received a full RideTech coilover suspension package including their StrongARM tubular control arms in front while the rear uses a set of Metcos billet control arms. Stopping was improved thanks to Corvette C6 Z06 six-piston brakes in front and four-piston brakes in back.

RideTech coilover suspension kit

reinforced Grand National frame with RideTech coilover suspension

reinforced Grand National frame with RideTech coilover suspension

reinforced Grand National frame with Detroit Truetrac LSD with Moser 30 Spline axles

reinforced Grand National frame with Detroit Truetrac LSD with Moser 30 Spline axles

When it came to replacing the factory V6, the team originally chose a Buick SIII 3800 V6 built by Intense Racing. The engine featured Diamond forged and ceramic coated pistons, ZZP 4340 forged rods, and a BorgWarner EFR-9180 twin-scroll turbocharger.

turbocharged Buick 3800 V6

turbocharged Buick 3800 V6

turbocharged Buick 3800 V6 in Grand National engine bay

They mated the 3800 V6 to a 4L80E four-speed automatic with a Circle D custom torque converter and Detriot Truetrac LSD with Moser 30 Spline axles.

GM 4L80E four-speed automatic

GM 4L80E four-speed automatic with Circle D torque converter

reinforced Grand National frame with Detroit Truetrac LSD

reinforced Grand National frame with Detroit Truetrac LSD with Moser 30 Spline axles

Unfortunately after completing the project, the 3800 V6 suffered a broken main cap and failed main bearing. The team chose to replace it with a more modern and lighter motor. They opted for a 4.3 L LV3 V6 (Gen 5 Ecotec3) from a 2016 Chevy Silverado.

4.3 L Ecotec V6 from a 2016 Silverado

4.3 L Ecotec V6 from a 2016 Silverado

4.3 L Ecotec V6 head

The Ecotec V6 was converted from direct injection to port injection. They also shortened a Moroso LT1 V8 oil pan and Holley LT1 V8 Hi-Ram intake to work with the V6. Eventually the EFR-9180 turbocharger from the previous engine will find its way onto the V6.

modified Holley LT1 V8 hi-rise intake for 4.3 L Ecotec V6

modified Holley LT1 V8 hi-rise intake for 4.3 L Ecotec V6

4.3 L Ecotec V6 with a modified LT1 V8 oil pan

4.3 L Ecotec V6 with a modified Holley LT1 V8 hi-rise intake and oil pan in a Grand National engine bay

4.3 L Ecotec V6 with a modified Holley LT1 V8 hi-rise intake and oil pan in a Grand National engine bay

4.3 L Ecotec V6 with a modified Holley LT1 V8 hi-rise intake and oil pan

The Ecotec V6 will be controlled via a custom wiring harness and plug-and-play ECU designed and built by Jost Boosted Performance. The ECU uses a MS3-Pro processor module and offers features like coil-on-plug ignition, flex fuel, boost control, 2-step launch control, and wireless tuning.

Jost Boosted Performance custom ECU with a MS3-Pro processor

Jost Boosted Performance custom ECU with a MS3-Pro processor

Source: Jost Boosted Performance FB page

3 Comments

  1. JimmyinTEXAS

    WOW! The builders mentioned finding cracks in the frame and that seems to be a common experience. The G.M. engineers did not allow for the twist applied to the frame from the high horsepower boosted V-6. It looks like they expended much energy remedying that problem. Looks like the rest of the chassis will handle anything that engine will toss at it. What a ride!!

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