Lotus Update - Combustion Conundrum

Readers with long memories will be aware that Onega is the owner of a 1969 Lotus Europa Series 2 Car, which is currently up with Banks Service Station (Europa Services) under Richard Winter.

2015 will hopefully be the year that the car returns to the road. When it went up to Banks some years ago, it was in a fairly sorry state - being original and much loved over the years, but also in less than perfect condition. Okay, in quite a poor state all-round.

The original intention was to make the repairs needed to the bodywork, renew the sub frame and to replace the engine, which was strong but thirsty with a Fiat 1.2 Diesel Turbo engine from a donor vehicle. The reasoning behind this was that it would make the car reliable (not that the original Renault engine was any trouble) and economical as well as reducing performance to a level that should be still be fun but also reasonably non life threatening.

At the time of writing, which is January 2015, I've had a good catch up chat with Richard this week and we have a joint resolution to get the project through and completed. Things have changed over the time since Onega acquired the vehicle and classic car values are on the increase which means we have to revisit the originally intended path of the diesel conversion.

The diesel engine is a transverse unit (fits across the body), whereas the original engines in the cars were longitudinal (engine at 90 degrees with the body and in line with the central shaft of the sub frame). Thus to fit the diesel engine in, a number of modifications to the frame are needed and possibly the bodywork also. These would likely need to be quite substantial changes which would inevitably detract from the originality of the car.

We are less worried about originality and purity of the vehicle, but it does seem sensible to maintain a good degree of originality if it agrees with logic; although we're committed to features like modern brakes which have improved substantially over time.

For anyone that is not familiar with them, the Lotus Europa was an early mid engine sports car (the third mid engine car design in the world after the Lamborghini Miura and the Ford GT40). Our car, UNG 135G was one of the original white UK launch cars from when these were introduced into the UK in 1969 - the Series 1 having been export only.  

So now we have to make a choice on what engine to put in the car; this is a fairly key decision as it dictates the course of the rest of the work to be done.

The main choices are:

1. Keep the original Renault engine - This would be ideal for originality and it sounded good & ran well but averaged about 20 something mpg; which was the main reason for considering the diesel option as we want to make good use of the car.

2. Go for the diesel engine as originally envisioned, with the changes to bodywork etc. that might be needed. The chances are that this would cause us to need to also swap out items like the Smith's instruments on the dash and other original features we rather like that add to the ambience and spirit of the car.

3. Consider a Vauxhall 1600 engine - This would work with the original sub frame, give performance of approx. 0-60 in 4.5 seconds and about 170Mph tops we gather, as well as 30 something MPG. The performance here is more than we need, but this could be restricted a little if needs be.

4. Think of something else - Electric, hybrid, hydrogen, a longitudinal diesel perhaps?

Choices, choices... but something important to consider.

Our criteria are:

  • Operational efficiency (MPG or equivalent)
  • Reliability - ideally this power plant will have a good long life in service.
  • Engineering compatibility with the car body (i.e. engine has to fit, made to turn the wheels and work).
  • Cost - we have to be able to afford the engine and the fitting in the first place.
  • Forthcoming changes to London ultra low emissions zone and congestion charging zone requirements and pricing.

Right now we are doing some quick research into the options. One benefit of the Europa is that it is of lightweight construction; Colin Chapman's mantra and design philosophy was to 'simplify and add lightness' and this benefits us being around 650Kg, which compares for example with the Telsa Model S at 2,108 Kg and power to weight ratios make for big performance differences (or correspondingly lower power requirements). The Tesla does have a lower drag coefficient than the Europa at 0.24 vs 0.3, but the Lotus is now 46 years old and much slippier than most modern cars still. Actually a single Tesla motor might be a nice solution if the good folks at Tesla have one to spare :-) .

We hope to have a decision as to direction within a couple of weeks in this matter and in the meantime are looking at the other elements of work needed, such as re-chroming where needed etc.

Watch this space - photos and updates will follow..