Cross-Fire Quandary Yet Again
I have an '82 Corvette with Cross-Fire injection. I have the Hypertech chip, K&N air filter, and I recently installed side-mount Hooker headers. The performance is still lacking. I'm thinking about converting the Cross-Fire injection to a TPI system. What kind of performance can I expect from this modification? What would I have to change and what kind of costs are involved for a job like this?
Dennis Brown
Like all throttle-body-based EFI systems, the Cross-Fire incorporates a low-pressure fuel pump. Direct port systems like a Tuned Port incorporate high pressure (typically 42 to 45 psi). Consequently, a conversion from throttle body to direct port requires installation of a high-pressure fuel pump.
The next item of concern is the ECM. Since the '82 ECM is relatively primitive, it would be best to replace it with a later model from a '90-'91 C4. However, this requires removing the engine harness and having it reworked by a company like Howell Engine Development, (810) 765-5100.
Theoretically, it's possible to control a Tuned Port system with the stock ECM and a few adapter harnesses. However, it's going to take a bit of work to develop a proper calibration for the TPI system. And in the end, you'll be left with an antiquated ECM.
Once the fuel pump and ECM issues are addressed, the rest of the conversion is fairly simple, requiring some fabrication work to connect an air filter and throttle linkage. As for costs, the biggest question is what you'll have to pay for the TPI system and replacement ECM. Check with a used parts supplier like C&S Corvettes in Sarasota, Florida.
LS1 Swap
I have an '84 Corvette with 138,000 miles. I want to know what it would take to put an '03 LS6 engine in it, besides money. My car has a 4+3 transmission. What harness or other components would I need (such as mass-air or speed density ECM and fuel pump for the tank)? Should I use a different clutch?
Mel Watson
Reno, NV
You've answered your own question. Find yourself a Corvette or street-rod specialist who's used to doing engine swaps, bring him an engine and a bucket of money, and you'll be driving a really fast '84. Swapping any LS-series engine into a pre-'97 Corvette is a major task, and covering it in detail is beyond the scope of this column.
Briefly, the fuel system has to be converted to high-pressure and the LS6 PCM (or an aftermarket controller such as a DFI Gen 7 from ACCEL) will have to be married to the original ECM so both engine and vehicle controls are retained. Custom headers will be required and an intake system will have to be fabricated, so a mass air sensor can be plumbed in (assuming you're going to use a stock PCM). You'll also have to adapt the transmission, fabricate motor mounts, and handle a variety of other details.
Thousands of LS1/LS6 engines have been installed in a variety of vehicles, so completing an installation is obviously not an insurmountable task. However, it's not a swap for someone who isn't an experienced wrench turner and fabricator.