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100 bhp per Litre

Project TBI-2-TII

24 April 2007

The Blueprint for Building, a 4-Cylinder, 100 bhp/litre, Chrysler Minivan

Presumably you are reading these pages to learn what's involved in converting a stock Mopar four-cylinder TBI minivan van to one that would make ' ol  Carroll Shelby proud. Follow the navigation buttons in the top (overview) and left (details) margins to learn more. Hopefully these pages will inspire/assist others contemplating similar projects. Unlike some more popular cars, you won't find a pre-packaged conversation for your minivan, but by following these steps you too, can rock 'n roll.

This conversion project was performed in stages or steps over several months.  Many of the steps overlapped, and some delays were encountered waiting on parts. In some ways, it's a project that will never end!

Project Boost, (TBI-2-TII)  -- A Twelve-Step Plan for curing the Minivan Blues

1) Replacement of suspension/handling components (brakes, sway bars, shocks/struts, wheels, and tires).

2) Perform basic maintenance on in-place components to bring vehicle to full spec on the components which will not be changed out till later stages.

3) Remove  the original TBI engine and the A-523 transaxle.

4) Remove the original TBI electronics, wiring, & mechanicals (i.e. ECU's, wiring, radiator, etc...).

5) Mating and prep of the Turbo II engine and A-568 transaxle.

6) Fabrication and installation of front-mounted intercooler, oil cooler, radiator and A/C.

7) Modification and fabrication of under-hood wiring harness.

8) Installation of the Turbo II engine and A-568 transaxle.

9) Installation of electrical, mechanical, and vacuum components (i.e. Turbo I, fuel management system, and misc. electronics).

10) Careful tuning of converted vehicle to proper OEM turbo performance specifications (i.e., stock) to ensure that the conversion has been successful and properly performed.

11) Final verification that the conversion objectives are met.  Time for lotsa SPG's (Smiles Per Gallon).

12) Enhanced performance tuning (after initial break-in period).

As with any project, it is best to have well-defined objectives prior to starting. For this turbo conversion project, the following are goals we defined for the project:

Full replacement of the OE Mopar 2.5L TBI  engine to a blue-printed 2.5L "Turbo-II" intercooled engine (block, heads, manifolds).

Full replacement of the OE ECM (SBEC) TBI electronic system with the (SBEC) Turbo I, SMPI electronic system.

Modifications needed to operate reliably at 16-to-18  PSI maximum boost levels (cooling, thermal insulation, vacuum lines).

Addition of auxiliary instruments to monitor air/fuel ratio, boost, EGT, and intercooler functions.

Replacement of the stock exhaust system with 3-inch (mandrel bend) high-flow exhaust & catalytic converter system.

Replacement of  OE Throttle Body Injector with multiple fuel injectors, adjustable fuel pressure regulator, and high pressure fuel pump.

Replacement of the OE New Process A-523 (5-speed) transaxle with the stronger Getrag/New Process A-568 (5-speed) transaxle.

Other, (highly recommended) non-Project Boost related upgrades (you may want to consider doing these items before increasing engine output levels):

Replacement of stock wheels and tires.

Modifications to vehicle lighting systems.

Replacement of major suspension components, including shocks/struts, anti-sway bars, and engine mounts.

Replacement of  brake components including pads.