Lotus SID

Car of the Day #83: Lotus SID

Lotus SID
• via Lotus, Vehicle Dynamics International

This is not a Lotus Esprit. It’s a mutant.

Lotus was pretty much the only big-time British sports car manufacturer, until McLaren came onto the scene and (for a time) made Lotus look like McLaren 1.0.

Now, both coexist, with Lotus still left to fulfill the promise of a category it never really mastered: the mid-engine supercar.

In production, that is.

In prototype form, the Lotus SID — "Structures, Isolation and Dynamics" — was one of the most advanced prototype cars made in the ’90s. The original Autocar review of the car by David Vivian has a number of eye-opening passages, but this one is my favourite: 

“…it's on the fast and bumpy roads of Norfolk…that the true, bludgeoning significance of its technology hits home. It's possible to forget about the rough engine, recalcitrant gearchange, cramped driving position and tatty, research-car cabin. What shines through like a halogen beacon is the sublime effortlessness of it all.”

• via Lotus, Vehicle Dynamics International
• via Lotus, Vehicle Dynamics International
Rear backbone chassis detail, including the engine, brakes, and rear suspension • via Lotus, Vehicle Dynamics International

What did Lotus engineers manage to pack under its largely Esprit-like bodywork? 

  • Turbocharged V6 engine and 5-speed gearbox from the MG Metro 6R4 Group B car
  • Fully-removable bodywork with a full composite monocoque underneath
  • Steel subframes for suspension components (double wishbone) but with electro-hydraulic actuators instead of springs and shocks
  • Rear suspension actuator that gave the car active rear steering
  • Active front steering
  • Active engine mounts
  • Active braking
  • …and four-wheel drive

You thought the Nissan MID4, Ford RS200, Lancia Delta S4 Stradale, and Panther Solo were some of the only mid-engined, all-wheel-drive cars from that era? (Damn things grew on trees if you know where to look.)

Magazine scan of SID • source unknown via Vehicle Dynamics International

In period, Lotus itself may have believed that the next Esprit would have entered production using much of the tech found in the SID — here's a car that was capable of leaning into corners, like a motorcycle! Finally, the Citroën Xantia Activa would have had some competition in slalom tests…

“On the lumpy and patched back straight at 90mph, a tough ride test for a luxury saloon, SID obliterated the contours at the expense of neither harshness not float. And on the straight at 60 mph, a violent right-left-right flick to simulate an emergency lane change gave a g-force range of plus 1g to minus 1g, all within about half a second. Same streaming wet surface, but still the same ferocious turn-in, grip and neutrality.” — Bob Murray, Autocar September 1992

I haven’t gotten into specific technical details, because the two sources here, Vehicle Dynamics International and Lotus Esprit World, both have considerably more detail than I can add into a newsletter. 

VDI includes an older article written by a member of the Lotus test team, and makes for highly technical reading — with some anecdotes included that give us an indication of how different SID would have been from other supercars of the era:

“The cockpit was very cramped due to a very wide transmission tunnel. Fortunately I got on well with my driving partner George Howard-Chappell – or “dangerous George” as he was affectionately known. With the hydraulic pump whining and Metro VR6 rally engine howling away behind us, the first impressive feature was the solid structural feel of the car compared with a normal Esprit or any car for that matter – no shake, or body rattles.” - John Miles, Vehicle Dynamics International

Where is the car now? As of 2012, SID reportedly sat outside, behind a Lotus facility, decaying. With any luck, it hasn’t been crushed and a competent YouTuber can snatch it up and ensure SID rides again…


Thank you to my supporting members: Ben B., Brad B., Chris G., Daniel G., Damian S., Daniel P., Drew M., Ingrid P., Karl D., Luis O., Michael J., Michael L., Michelle S., Mike B., Mike L., Mike M., Richard W., Sam L., Wiley H.