There were many folks within GM Powertrain that severely got their feathers ruffled when they found out that Dave McLellan and Corvette Engineering decided to go out of house to develop the LT5 engine.
However, at the time, GM owned a majority share in Lotus and many GM Powertrain engineers spent just as much time at Lotus working with Lotus engineers as Lotus engineers spent at the Warren Tech Center in Michigan.
In my opinion and based upon what I have read and heard, I believe the ZR-1 (not just the concept of a ZR-1 convertible), met an untimely death for the following reasons:
- GM Powertrain exerted enough pressure on higher-ups at GM to influence a decision to kill the car.
- Extremely poor marketing. Other than a couple magazine ads when the ZR-1 first debuted in 1990, GM COMPLETELY dropped the ball in marketing the car. GM isn't the only one guilty of this though. Another example is the Chrysler Crossfire. As soon as that car came out, Chrysler never bothered to market the car, hence the reason why sales were low, Chrysler stopped production, and dealers are selling what's left at nearly half the original MSRP. Same situation with the ZR-1.
- The ZR-1's signature rear bumper appeared on the 1991 Corvette and the 1991 base model's front clip and body-colored side molding appeared on the ZR-1. When someone spends nearly $30,000 more for an exclusive car; above and beyond the base model - they want to be seen and noted. They don't want their $65,000 car to look like one that costs $35,000.
- The debut of the LT1 in 1992. The one thing the LT5 did, was light a fire under GM Powertrain's ass. The LT1 engine was the direct result of that fire and GM Powertrain's answer to the LT5 engine.
The LT1 engine produced 300 hp. 75hp less than than the 1st gen LT5 of 1992, but the LT1 Corvette was lighter than the ZR-1. That's the reason why the performance between the two wasn't that much different. in 1993, the second generation LT5 engine debuted and horsepower was bumped up to 405hp. However, the problem with that is that the weight of the ZR-1 gradually crept up as well.
That's why performance wise, there isn't much difference between 1st gen. and 2nd gen ZR-1s and not much performance difference between the LT1 and the ZR-1.
With the debut of the LT1 engine, GM Powertrain drove the final nail into the ZR-1's coffin. Here is an engine that cost a hell of a lot less to manufacture and had a lot less moving parts.
In my opinion I don't think that at the time the C5 had anything to do with the demise of the LT5/ZR-1 project. The last LT5 engines were built in November of 1993. The decision to kill the car was probably decided in late 1992, early 1993. It would be another 4 to 5 years before the C5 would see the light of day, and according to James Schefter's "All Corvettes are Red" book, the C5 concept almost met an untimely death in 1992.
I am willing to bet that some of the financial problems that weighed heavily on the C5 concept also had some sort of influence on the decision to kill the ZR-1.
As a little aside, one of the comments that I've heard several times over the years, and heard last weekend at Carlisle - the LT5 engine is NOT a "boat motor". :eyerole
GM went to Mercury Marine (Mercruiser) to build the LT5 engine because they had experience building all aluminum engines at low volume. Remember that historically, GM does not build cars. They build "units". And units = numbers. GM had experience at building units and engines in the hundreds of thousands. The LT5 engine program was the first low volume engine program that was conceived at GM. It also helped that at the time, GM owned a commanding share in Mercury Marine, hence during the LT5 years, GM, for all intents and purposes, owned both Lotus AND Mercury Marine.
That's my take on the demise of the LT5/ZR-1 program.
Jane Ann
