Project TBI-2-TII
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100 bhp per Litre

Turbo II Overview
Long Block

24 April 2007

Project  TBI-2-TII  involves taking a base model 1993 Plymouth Voyager Minivan from 100 bhp to 250 bhp. And doing it with reliable, "easy-to-install and maintain," readily available "off-the-shelf" technology. 

The project starts with a 1993 Plymouth Voyager, base-model ("short" wheelbase - 112 in.) minivan. The factory originally fitted the 100 bhp, 2.5L, 4-cylinder, "Naturally Asphyxiated" Throttle Body Injection (TBI) with an A-523 5-speed transmission. The original TBI engine threw a counter-balancer chain, resulting in block and crank damage, which made the decision to swap engines easy.

To achieve 100 bhp per litre (250 bhp) a Forward Motion-built, 2.5L Stage III, with Turbo II-spec internals engine is installed, with front-mounted intercooler, 1990-91 Sequential Multi-port Injection, and an A-568 (New Process built, with Getrag internals) heavy-duty five-speed transmission.

To cope with the increased power, the chassis (exhaust system, brakes, suspension, wheels and tires) is also upgraded. The idea is to create a daily driver with an improved balance of performance, handling, practicality, fun, and reliability, wrapped in a stealthy package. The eco-friendly R-134a A/C is retained, as are the driver's side air bag. Emissions and daily driveability are actually improved. Towing capacity is increased from 1500 pounds to 3500+ pounds. The Quaiffe ATB limited-slip differential provides vastly improved traction and security, especially on wet or snow-covered roads.

View the TBI-2-TII Project Photo Gallery

View the results of my baseline DynoJet pulls

Why would anyone undertake a Turbo minivan project?

Let's face it, the minivan gets no respect. It just ain't cool to be seen in one. Especially, a 4-cylinder model. The factory offered the Gen-2's from 1991 to 1995, but the 2.5L/5-speed drivetrain was only offered from 1992 -1994, and only on base model (swb) vans.  To the best of my knowledge no one has ever done this with a 2nd Generation (1991 - 1995) Chrysler Minivan, including the factory. Since the van came from the factory with the A-523 five-speed manual transmission, it seemed a good candidate for conversion such a conversion. We liked our van (it's our second, four-cylinder, T-115). But we knew it's weaknesses and decided it was high time to stop being the butt of "Click and Clack"  jokes.

All Rights Reserved © 2003 - Lee K. Shuster

Project goals: Double  the original horsepower and torque on regular (87 AKI) unleaded fuel without anti-detonation timing reduction losses using upgraded internal Turbo II components. (view the project results: dynojet graph)

Typically this vehicle operates at 5000 feet above sea level with frequent trips to 9000 feet.  The van will also see light (Class II) towing duty, so good low-to-mid range torque is required.

For comparison the 2002 Honda Odyssey with its 240-horsepower, 3.5-liter, VTEC™ V-6 engine weighs in at a portly 4350 pounds. Our project van (at 3450 pounds) will have no problem dispatching this hi-tech competitor, with technology Chrysler engineers perfected almost twenty years ago! Suddenly, our stealthy minivan instantly gains 250 hp of "hidden" street-wise respect.

Is a 2.2/2.5 TBI-2-TII project right for you?

Well, if you have the time (I spent the better part of nine months) and have a lot of patience, I'd say go for it. Some will condemn such a conversion project as sheer lunacy, others will applaud your ingenuity. You'll need to learn about the specifics of your particular vehicle, which the internet and various e-mail groups make a little bit easier. For a good background site on TBI-2-Turbo conversion details, I recommend Derek's Garage. Don't take short cuts, I replaced virtually everything but the gas tank and radiator.

Also,  what I'm sharing in this web pertains specifically to my 1993 Gen-2  AS-body, so as they say, "your mileage WILL vary." Click on the menu bars in the left margin to learn more about the subsystem upgrades employed within each area of  Project TBI-to-TII.

And yes, as of Summer 2006, my van's IS FOR SALE .. see "The End."

 -- >>  Continue to Turbo II (Engine) Overview  -- >>

Shown below are cross-sections comparing the original 2.2L NA and 2.2 Turbo I.

All Rights Reserved © 2003 - Lee K. Shuster