LS4 V8-Powered! A 1981 DeLorean DMC-12 5-Speed

This is a 1981 DeLorean DMC-12 that benefits from an engine swap – the original 130 bhp V6 has been replaced with a 303 bhp LS4 V8 sending power back through a UN1 5-speed transaxle to the rear wheels.

Perhaps the key disappointment of the DeLorean DMC-12 was the lack of power, though the car looked fantastic thanks to the Giorgetto Giugiaro designed body, the performance just wasn’t there, with a 0-60 mph time of 10.5 seconds and a top speed of just 117 mph (188 km/h). An LS-swap solves this problem, and gives the car the performance it should have had right off the factory floor.

Fast Facts – An LS-Swapped DeLorean DMC-12

• The 1981 DeLorean DMC-12 in this article has undergone a significant engine upgrade, replacing its original 130 bhp 2.85 liter V6 with a 303 bhp LS4 V8. This swap addresses the DeLorean’s primary weakness: lack of power. The LS4, originally designed for transverse mounting in front-wheel-drive GM vehicles, is compact and lightweight, making it ideal for the DeLorean’s engine bay. This modification dramatically improves the car’s performance, giving it the power to match its iconic Giugiaro-designed body.
• The LS4 V8 engine is a unique member of the LS family, developed for high-performance front-wheel-drive cars. It features an aluminum block and heads, a shortened design, and originally included a Displacement on Demand system for improved fuel efficiency. This system often caused reliability issues, leading many owners to remove it. The engine in this DeLorean has had it removed and it’s been further modified with series of performance upgrades.
• The DeLorean DMC-12 was initially intended to have a Wankel rotary engine, but ended up with an underpowered V6 due to engine development issues. This led to disappointing performance, with a 0-60 mph time of 10.5 seconds and a top speed of just 117 mph. The V8 swap solves these shortcomings, giving the car the performance it should have had from the factory.
• While the engine swap significantly improves the DeLorean’s performance, the car still requires some attention. It has 53,000 miles on the odometer, with 7,000 added under current ownership. Issues needing address include rust in the front frame extension and fuel tank closing plate, a non-functional passenger window, cosmetic refinishing needs, and a broken driver’s door lock.

The Unusual GM LS4 V8

The LS4 V8 was one of the more unusual members of the LS family, it was developed to be fitted transversely to the engine bay of various high-performance front-wheel drive cars in the early 2000s, including the Pontiac Grand Prix GXP, Chevrolet Impala SS, Chevrolet Monte Carlo SS, and the Buick LaCrosse Super. This transverse configuration meant the engine had to be made shorter, which also means it’s ideal for engine swaps into compact engine bays.

This LS4 has been significantly modified from new, it now has a Lunati Voodoo camshaft, a Holley Terminator X fuel-injection system, stainless steel headers, Borla mufflers, and the Displacement On Demand system was removed with a Texas Speed & Performance kit.

The fact that the LS4 was developed to be installed up front over the front wheels meant that General Motors engineers had to make it as light as possible. As a result it was given an alloy block and heads, and as noted above it was shortened to fit, helping further reduce the weight.

Reducing the length of the engine required a few changes, these included shortening the crankshaft at the accessory drive end, the use of a single serpentine belt to save space, and a remotely-mounted water pump. The LS4 was also given revised oil pan baffles to ensure that oil starvation doesn’t occur during high-G cornering maneuvers.

Depending on the version, the LS4 was capable of up to 303 bhp and 323 lb ft of torque from its displacement of 5,327cc or 325 cubic inches with a 10:1 compression ratio. The LS4 is no longer in production, however it’s generally not too hard to find them for sale secondhand for engine swaps.

One unusual feature of the LS4 was the Displacement on Demand (DOD) system, later known as Active Fuel Management (AFM). This essentially allowed the ECU to deactivate four cylinders when under light load to reduce fuel consumption, resulting in the engine operating as a V4 with four additional pistons along for the ride.

Displacement on Demand included a solenoid based lifter manifold, spring-loaded lifters, and a unique camshaft. Unfortunately the system wasn’t entirely reliable, and many owners suffered issues with it. As a result of this, there are kits you can buy online to completely remove Displacement on Demand and run your engine as the good lord intended – with all eight cylinders working all of the time.

The LS4-V8 Swapped DeLorean DMC-12 Shown Here

A lot of people don’t know that the DeLorean DMC-12 was originally supposed to be powered by a lightweight, centrally-mounted Wankel rotary engine built by Comotor, a joint venture between NSU and Citroën.

For a time the DeLorean seemed to many to be the car of the future, the company had grand planned for a number of follow up models as well as a turbocharged version of the DMC-12. Image courtesy of the DeLorean Motor Company.

The Comotor project would ultimately fail, resulting in DeLorean management scrambling to find a new engine that would fit, they finally settled on the 2.85 liter V6 PRV engine which had been developed jointly by Peugeot, Renault, and Volvo for passenger car use (hence the “PRV” name).

This V6 produced just 130 bhp and 153 lb ft of torque, not enough for a sports car that weighed in at 1,233 kgs (2,718 lbs) at the curb. DeLorean did have plans for a turbocharged version of the DMC-12, if reliable it would have certainly solved the power and torque issues, but sadly the company collapsed before the turbo version could enter production.

A number of aftermarket turbo kits have been developed for DeLoreans in the years since, and many owners have gone even further by swapping in a new engine to solve the power issues once and for all.

The 1981 DMC-12 you see here now benefits from one such engine swap. Due to the compact nature of the LS4, and its lower weight when compared to the iron-block LS engines, it has become the recommended choice for V8-swapping a DeLorean. There are even kits you can buy online to make the process relatively straightforward.

The LS4 that’s been fitted to this car has been given a series of performance upgrades, including a Lunati Voodoo camshaft, a Holley Terminator X fuel-injection system, stainless steel headers, Borla mufflers, and the Displacement On Demand system was removed with a Texas Speed & Performance kit.

The original speedometer has been replaced with a Speedhut GPS unit, and a Holley EFI module is mounted ahead of the shifter. The car keeps the original seats, steering wheel, and shifter which is plumbed into the Renault UN1 5-speed transaxle which has been fitted with a high-performance input shaft coupler.

The interior of the car remains largely original, save for the addition of a Speedhut GPS unit, and a Holley EFI module is mounted ahead of the shifter.

The car is now showing 53,000 miles, 7,000 of which have been added under current ownership. The car does need a few remedial issues addressed, there is some rust in the front frame extension and fuel tank closing plate, the passenger window does not currently roll down, the engine cover and lower valances will need refinishing, and the driver’s door lock tumbler is non-functional.

If you’d like to read more about this unusual DeLorean or place a bid you can visit the listing on Bring a Trailer here. It’s being offered for sale out of Jackson, Tennessee with a clean Carfax report and a Tennessee title.

Images courtesy of Bring a Trailer