You don't necessarily need to go the hot V route, with relatively small turbo and one hell of a manifold planning, you should be able to fit twin turbos and keep the existing block and heads.



This would however require cams to be ground (expensive but easy enough if you can calculate a good profile) and mapping would be quite the job. It might be interesting to lock out the vanos either by mapping or mechanically (a good weld would do but require balancing afterwards).

Depending on your target output, you might need stronger valves (again, expensive but easy) and forged pistons, maybe modified to lower the compression ratio to allow for better use of the turbo. Getting crazy, stronger rods (balanced and maybe lighter), then you can go for a stronger crankshaft but that seems excessive considering you're on an auto gearbox, unless you plan on drag racing daily, you probably won't flex the crank.


It would be quite an undertaking but you could have a monster on your hands. Ideally your best friend should be a machinist with talent and equipment since all these parts could be machined "at home" with the proper tools and materials.


I've wondered about adding one or two turbos to my 4.6 but it would be too much work and I'm not sure what I would do with the extra power in such a car.

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2002 4.6is silver on black