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

[dh at busb.com]

They would probably add 20 horsepower if the inlet to the bottom turbo
weren't ingesting hot air from the top tubo's exhaust headers.
dh


----- Original Message ----- 
From: "Brien Tourville" <hh7x at verizon.net>
To: "jb" <jonnbell at gmail.com>
Cc: <diy_efi at diy-efi.org>
Sent: Friday, August 19, 2005 8:00 PM
Subject: [Diy_efi] Vortec 4200 Inline 6 ECM - Twin Turbo -


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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
> eagle kammback registry
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