In my bordom (and automotive A.D.D.) I planned out a turbo setup after scouring the info on this and the MB forums. Unfortunately, I do not have the money nor am I insane enough to void my 5 year bumper to bumper at this point. But for anybody who has considered it or would like to help fine tune the plan for anybody crazy enough to try it, read on...

-Custom cat-back exhaust setup that puts a Garrett turbo of appropriate size and trim (GT3571?) in place of the stock muffler. A heat sheild already exsists. Fabricate brakcets that position the turbine outlet to the rear of the car. You will see how all the other connections fall into place. To make it easy use a "3 bolt to V-band" adapter into a turbine housing with a V-band outlet. From there it's all fabricating tubing and supporting boost...

~40mm Wastegate (or go internal to make it easier)
RBracing Oil scavanger setup (best in the biz)
Coolant pump/scavanger? (for a water cooled turbo)
A large surface area/thin core air to air intercooler (or better)
Split Second FTC1 timing and MAF filter piggyback (FTC1-024 on similar MB setups)
Aeromotive Digital Fuel Management Unit to boost stock pump output
Larger injectors (SRT6 should prove large enough)

Hook up the FTC1 to react based on MAF, RPM, and Manifold Pressure (TPS might be good enough for a supercharged setup, but not for turbo). Put the big injectors in and filter the MAF voltage down to lower duty cycle to acheive acceptable A/F ratios when you're not under boost. Then tune the FTC1 to pull timing and multiply the MAF signal (resulting in higher injector duty cycle) and tune the Aeromotive DFMU to increase fuel pump voltage to supply the neccessary fuel pressure when under boost.

You're going to want some monitoring tools. Wideband A/F meter, Boost controller, laptop with a serial port and the "Split Second" software, fuel pressure gauge, etc.

It's certianly more crude that paying somebody to "tune" your OEM controller (although that will cost about the same if you even find someone to do it), but it's been done before on MB supercharger setups with great success.

^ Care to critique it?

Unforseen problems?
Additional equipment needed?
Cheaper alternatives (other than "buy an SRT6")?

Volunteers?

 

1. You forgot an Intercooler.
2. The Garrett GT3571 is limited to less than 300hp at the flywheel. Way too small, unless you're planning to twin-turbo with two GT3571s.
3. The engine produces 219hp stock. We want to run enough turbo to provide 2x the power at 1 bar boost, even if the wastegate is set to 4-8 psi. At 1 bar, the adjusted power output is 440hp at the flywheel. At 10 hp/ lb/min of airflow, the engine needs an estimated 44 lb/min airflow from the turbocharger(s).

The cheapest twin-turbos would be rebuilt junkyard water-cooled T3-60 trims. (2), Mitsubishi TD06-20G, or IHI RHF55 or RHF6.

A good single turbo would be a ball-bearing Garrett GT35R or GT37. On the cheap side would be a Holset HX35 or HY35 (depending on your tune)

4. With the stock engine compression at 10:1, you're looking at 7psi on 93 octane pump gas ( 324 flywheel hp ). If you have access to 98 octane, go up to 11psi ( 385 flyhweel hp ). Access to 110+, go up to 1 bar ( 438 flywheel hp ).

5. I read recently in a tuning mag about someone running twin-turbos on an S54B32. This engine has 11.3:1 static compression and the guy runs it at 4psi with pump gas + methanol injection. He cranks it up to 8psi with 98+ octane + methanol injection.

 

Twins would take up far too much room. I like the dual BB GT35R idea better. Don't go too big though. With the turbo at the back of the vehicle you need to be able to spool it quickly. And providing 7psi to a 3.2l motor spinning @ 6000rpm isn't THAT big a task. And any plans for more than that will surely result in the eventual destruction of everything from your input shaft to your rear CV axles.

And I mentioned a large surface area but thin core air to air intercooler. That should provide the best cooling.
I'd like to find a way to mount it UNDER the car with vents to suck up the air running past it. That would give you more room to work with that cramming it in the nose.

 

Sure beats eventual destruction of everything due to rusting

 

I think your selection of tuning electronics is a bit on the expensive side.

I would recommend this unit for timing retard and knock detection:

http://www.jandssafeguard.com/safeguard.html

and using something like the MAF Translator Pro for injector control.

A full piggyback solution would therefore be around $1000, all said and done.