Chevy 454 Big-Block: Turbo or No?
Q I have an '89 Chevrolet K-2500 with a '91 454ci V-8 and overdrive automatic transmission. I was wondering what your feelings are about adding a dual turbocharger setup versus a single turbo. The motor is completely stock and has no add-ons. If I do plan on putting on one of the turbo setups, I am definitely adding bigger injectors to the truck. I would like your input on what I have to do to make this work on my truck; I am planning on using the STS Universal systems.
A While STS makes some great systems, they are primarily designed for use on street-driven vehicles. Because it's an "under-vehicle system," there is a heck of a lot of plumbing involved. Plus, they do not make a specific kit for your truck, and as you mentioned, you plan to use their universal system. This means you're going to have to fabricate all the exhaust tubing from the engine back to the turbo(s) and then back up to the engine, snaking past the transfer case and front driveshaft. There is also the issue of maintaining proper clearances for off-road travel.
Because dirt is one of the real enemies of a turbocharger, you would need some way to mount the air intake within a protected area of the bed. I really would recommend not going with such a kit and to investigate some other kit designed specifically for your truck.
As to one or two turbochargers? You're getting pretty serious with two turbos, meaning you're planning on making lots and lots of horsepower. If this is the case, you're going to have to make many more modifications other than just adding bigger injectors to your truck. Engine-wise, it will require at least stronger connecting rods and forged pistons of the proper dome shape and compression, along with an updated ignition system.
I think that the TH700R4 in your truck is a great transmission, but unless you have a very expensive rebuild done by a company that specializes in such, it won't live very long behind the added power.
Oh, and as to going to bigger injectors, that may be difficult, as your truck uses a throttle-body injection system. The real problem is not just adding larger injectors, but getting enough airflow to handle the turbo's demands. Holley offers some help in this area. You would also need to upgrade the fuel delivery system with bigger-diameter fuel lines and a larger-capacity fuel pump.
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