Vortec 4.3L Compression

[ztrane]

I have a 05 GMC sierra 1500 4.3L and I am about to put a kit on it but I dont know if I should just get the regular turbo kit (5-10psi) or get a few minor engine internals upgraded and get the twin turbo (15-20psi) from sts turbos (http://www.ststurbo.com/). Both come with the injectors and stuff. I just dont know of anyone boosting a 4.3 and didnt wknow what it can really hold. I know that its basically the 5.3 shaved 2 cyl. 5.3 is a tough engine so im not sure if the tt will work or not.

[rat]

The 4.3 unfortunately is not a 5.3 with 2 cyls hacked off.

The 4.3(262) is a gen 1(1955-2002 era) 5.7(350ci) with 2 clys cut off. It works also if you do the math, 350ci/8clys=volume per cyl. Volume per cyl*6=262

The 4.8/5.3/6.0 in the '99 and up full size trucks are the gen 3(ls1/ls6) version of the small block. About all that is shared is the 4.4" bore spacing. And the new motors coming out are gen 4(ls2/ls4/ls7).

Now that being said, the 4.3 is still a fairly stout motor. It has an offset ground crank, so that makes it weaker than the v8 version. It can probably take 300-400hp if the afr is kept in check, and detonation is kept at a minimum. The fuel injection system also stinks on the 4.3. The injectors are not upgradeable in the stock intake manifold. This is the biggest drawback, and requires a compleate rethinking of the intake manifold. Like the edelbrock 2114 converted to multiport. Or other bandaids like aditional injectors, or an fmu.

So, if you are keeping the stock injection then i would say keep the boost in the 5-7 psi range, and if on the high end of that scale plan on an fmu or something for more fuel.