XJ220 – a hidden story

The chances are you have already heard about the ‘Saturday Club’, a band of enthusiastic engineers who designed the stunning Jaguar XJ220 in their own time just because they had a burning desire to make their dream into a reality. But what happened after the concept was unveiled and why did the V12 get dropped in favour of the Metro 6R4 engine?

The original spec had the Jaguar V12 powering a 4WD system, the engine would be based on the race versions which were doing rather well in GT cars such as the 7 litre XJR9. The V12 engine also saw life as the 6 litre 450bhp motivation in the XJR15 road car. In fact Jaguar made 6 litres the standard displacement for the V12 in the last XJS and the XJ12, which soldiered on under increasingly stringent emissions regs until 1997 (X305).

The XJ220 concept had a 6.2 litre variant which had been producing a reliable 550bhp+ on test, it had been run at full power for extended periods of time and performed well under all manner of arduous test conditions. But the Friday before the 1988 NEC motorshow début the over worked engine unexpectedly seized, with no time to fix it the show car that thousands ogled at that year (including myself) had to be pushed onto the stand. Not a lot of people know that.

The car was simply stunning and orders poured in. So the next step was to put it into series production and the job was given to TWR who already had strong links with Jaguar. At this point things started changing and customers start cancelling orders, partly due to the recession and partly due to the spec change.

The original concept was declared too heavy, but at 1560kg it was still a good 200kg lighter than the lowest spec XJS and stacks up well against modern supercars. Curiously the Jaguar V12 was declared unfit for emissions, even though it was managing perfectly well in the XJR15 road car and the 546bhp Lister storm, as well as in lower state of tune in the XJ12. The 6R4 engine owned by TWR had proved a reliable and powerful lump, not only powering Metro 6R4s but also some of the Jaguar GT racer cars such as the XJR10, and was modified to get it through emissions regs and slipped in place. Extensive development of the engine was conducted on public roads in secret by grafting the whole XJ220 back end with the engine, gearbox and suspension, into a normal looking Ford Transit van (Now owned by Goodwood). I am sure this change from Jaguar V12 to TWR V6 was in no way motivated by any financial advantage to TWR for using their own engine. TWR still have the service contract for these cars, with costs totalling many thousands each time, providing a useful revenue stream to this day.

But with this engine the production car failed to meet its 220mph ambition, 217mph was achieved only by removing the wing mirrors and other tweaks.

Traditionally the problem with turbo engines is keeping the intake air cool at full load, as the turbos compress the air it gets hot and can easily exceed 100C. Hot air is less dense and reduces power. In a race a turbo engine can work well, as the intercoolers have a chance to cool down every time the car brakes for a corner, but when testing maximum speed the engine is flat out constantly and the heat just builds and builds. This is where a naturally aspirated engine has an advantage, the V12 had been run regularly in competition at power levels above 600bhp, in fact the XJR12 race car managed 750bhp from its 7.4 litres. So surely this would have been a more logical choice for a high speed super car?

Then there is the matter of the 4wd system, this was a version of the Ferguson Formula as seen on the Jensen FF. Ferguson research was another company offering engineering services to the car and motorsport industries, in a similar way to TWR. Ferguson would later be bought out by the mighty Ricardo organisation in 1994, and Ricardo would later take on a lot of Jaguar engineering work. Whether TWR saw the Ferguson involvement as a threat is unknown, but dropping the FF 4wd system meant that TWR had sole control over the whole project. In engineering terms the 4wd system has many advantages and the weight penalty is relatively small, as proved by later Lamborghinis.

What ever the real reasons for the changes, the car’s weight dropped by about 200kg which helped in cornering but did nothing for it’s main selling point – top speed. It also made it a lot cheaper to make, which must have been a consideration.

With many orders cancelled and built cars selling significantly under their list price the project lost a little of it’s shine. Many cars are still locked away with delivery mileage only, and in 2007 two unused shells were discovered in Jaguar’s Browns Lane factory when it was being cleared for demolition.

I am sure the decisions made at the time were based on sound judgement, but I cant help but wonder what would have happened if they had stayed with the original concept. Certainly a 750bhp V12 and 4wd would have giving it something in the order of 250mph capability and made it faster in a straight line than a McLaren F1. Maybe in some alternative universe they did just that, and the magnificent Jaguar matched the dreams of the Saturday Club and is the legend that it deserves to be.


About Ralph Hosier

I love exploring everything the world has to offer, the fabulous beauty and intricacies of nature, the stunning majesty and grandeur of the universe, and the fascinating range of chocolates available from the local sweety shop. I have led a charmed life, sure there has been extremes, but the highs far outweigh the lows. I get paid for arsing about in very fast cars, I get to write about them and amazingly get paid for this too. My days are usually filled by making prototype and concept cars for car companies, a dream job. I have lived many of my dreams, worked all over the world, raced cars built by my own hand (and hardly ever crashed really badly), seen things and done stuff. But nothing compares to the love of Diana and my son Peter, beyond my greatest hopes. I am a chartered engineer, a member of the Institute of the Motor Industry (IMI), and of the Institute of Engineering and Technology (IET) and I am a member of the Guild of Motoring Writers. A pleasing fact is that there are now more letters after my name than there are in it ;) R.Hosier B.Eng(Hons) C.Eng MIET MIMI MGoMW
This entry was posted in Car industry uncovered. Bookmark the permalink.

3 Responses to XJ220 – a hidden story

  1. Lawrence Jorge Rs says:

    Nice blog! I’m a fan of XJ-220, a shame it wasn’t make with the V-12!

  2. Scott Brownlee says:

    I have no personal experience of either car, but I gather the V12 engined XJR15 was very tricky to drive due to the weight of the engine, whereas the XJ220 was praised for its handling.

    Undoubtedly, the heritage of the V6 would have put off many (not me, being an ex-Austin Rover Motorsport press officer during the 6R4 era) for snobbish reasons, but I’d guess it ended up a better car.

    As for top speed, surely aero has the biggest impact on this and here the XJ220 was hindered by a desire to retain the styling of the after hours club which, presumably had never been near a wind tunnel.

    Overall, the car suffered by coming to the supercar splurge of the time a bit too late. If I’m honest I feared the Lexus LFA might suffer a similar fate being too long in gestation, but with a full order book for the car I am pleased to be proved wrong.

  3. Phil Huff says:

    An interesting background piece on the XJ-220. I’ve got a lot of opinions about TWR from experience over the years, but it’s probably best that I leave it there.

    As an aside, I was fortunate enough to get in to the original V12 concept model. I lusted after one of these even when the spec changed to V6 and RWD, but that lust only increased when I got the chance to experience the concept about five years ago.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s