I found some info on the original engine, the V6 PRV : the 1975 first version, which was in the Delorean, was indeed not very powerful and was criticized because of its uneven ignition timing and its vibrations at certain speeds, since it was a 90° V6 like some Buick engines and not the usual 60° V6. Actually originally the company planned to build V8 engines, so with a 90° angle between banks, but these were later scrapped in favor of a smaller and more fuel-efficient V6 after the 74 oil crisis .The ignition and vibrations issues were solved around 84, 85 by a new crankshaft with offset split crankpins.
More than 900,000 PRV were manufactured until 1997.
The turbo versions were actually powerful, the maximum power in a street car was 408hp in the bi-turbo Venturi 400 GT, not so bad.
According to wikipedia
- carbed 2.7L PRV : 131 hp
- injection 2.7L PRV : 142 hp
- injection 2.8L PRV, new crankshaft : 160 hp
- turbo 2.5L PRV : 180-205 hp
- injection 3.0L PRV : 170 hp
- turbo 3.0L PRV (Alpine A610) : 250-280 hp
- bi-turbo 3.0L PRV (Venturi 400) : 408 hp