[Diy_efi] Vortec 4200 Inline 6 ECM - Twin Turbo -

[Brien Tourville]

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i dont see how
they got away with 10:1 in teh first place, but add some boost and it
doesnt sound good.  so, did they have to port heads, add thicker head
gaskets, change pistons, what?  if the latter, then where would you
find such?  or is it a standard bore that would use pistons from
another engine?  hmm... it would seem taht im getting off the subject
of this list a little, but i woudl also need to know how the ecm 
would
have to be changed to accomodate boost.
___________________________________________


"Of course, if we needed more, there's more to be had," adds a 
smiling, but equally dry Kociba. "The point was to demonstrate the 
bullet-proof nature of this engine with fairly minor modifications."

We were surprised to learn how little is changed to create this 
Bullitt Mustang-performance-equaling six, with its twin Aerodyne 
turbos and air-to-water intercooler. For example, the block, crank, 
head, head gasket, cams, and valve sizes remain virtually untouched. 
The extra breathing hardware adds but 45 lb to the engine's mass. The 
only critical mods were a switch to 8.5:1 pistons (from 10.1:1), the 
addition of piston-cooling oil squirters, shorter (by 2 mm) 
connecting rods, thicker piston pins, higher-flow oil pump and fuel 
injectors, and a freer-flowing exhaust system. As you'd expect, the 
4L60-E four-speed transmission's internals required some beefing, and 
the transfer case was swapped for the ultra-tough all-wheel-drive 
unit found in the 6.0L V-8-powered Cadillac Escalade.

Home office for the 4.2L/270-hp Vortec six is the GMT360 platform 
(Chevrolet TrailBlazer, GMC Envoy, Olds Bravada). So it was logical 
to install this experimental version in one of those platform 
variants. The Chevy was chosen primarily because of its mechanical 
relationship with the hot Chevrolet (GMT368) SSR retro pickup and the 
long-wheelbase Chevrolet TrailBlazer XL (GMT370) with the third-row 
seat, both of which will debut soon. Besides, Chevy is the most 
performance oriented of these three brands.



             Brien.
         NEW YORK
   eagle registry #501
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