CLAMSHELLS PART 3!

General General Lotus Talk
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We start work (designing and moulding) next week. The design brief is to create a look similar to the race series Elise but to retain the softop capability. A hardtop with a hinging rear window, of similar concept to the Exige will also be offered later in the year. There will also be elements of the GT1 rear lower splitters added. The panels will all be painted and laquered to original equipment levels and the mould quality will be on a par with the factory. I would appreciate any feedback on the following:agree with basic design concepts?anything to add?Timing is TBA, but a fully converted car will be available during July.Rob Gibbons

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Rob,Its just occured to me, that at this point you could think about an updated design, may incorporating some of the S2 features.I say this, because there is a fantastic early proposal sketch for the S2 that is a hybrid S1/S2. Wouldn’t mind an Exige interpretation of this!Look here http://www.absolutech.co.uk/design2.jpg CheersChris

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Chris,see what you mean! I will get ‘the boys’ to have a close look. I don’t want to loose the Exige ‘butch’ look much though. I forgot to ask in the first posting - do we want a wing? (we definitely don’t need one - the Exige wing is nearly neutral and they took all the performance figures without it!)

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Hmmm, the wing.I expect I’d want it on the closed top Exige type, but not on a soft top version.Having been through Blanchimont corner at Spa in both my Elise and the Exige, the Exige is definitely more planted. It must be down to the aerodynamics too, since I was running sports suspension and A038-R tyres. It must be doing something!CheersChris

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quote:Originally posted by Rob Gibbons:the Exige wing is nearly neutral and they took all the performance figures without it!) Can you explain this? I would have thought something that big, and at quite a steep angle would be fairly effective. I’m particulary interested in this because I guess it must add a fair bit of drag. If it doesn’t add much downforce, it would presumably be quite advantageous to remove the wing to boost the car’s top speed and high speed acceleration. What are your thoughts ?

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BrendanCan’t remember where I read it, but I’m fairly sure that Lotus officially claim 80Kgs of downforce from the rear wing at 100mph.People who have “tracked” both an Elise & an Exige say that the downforce is very noticable on fast corners & makes the Exige feel much the more stable of the two.No doubt, someone on the bbs will be able to confirm - or otherwise!

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quote:Originally posted by Rob Gibbons:we definitely don’t need one - the Exige wing is nearly neutral and they took all the performance figures without it! What do you mean by ‘neutral’?The angle at which the wing is set up? That doesn’t say a lot about the amount of downforce as the wing is indeed an aerofoil (albeit mounted updside-down) and as such generates it’s negative lift/downforce just like the wing on an aircraft.A very interesting book on the subject is Competition Car Downforce and explains a lot about wings, spoilers, splitters, diffusers, etc.The Exige wing is definitely not ‘cosmetic’ and as one of the few road-going cars out there actually provides a significant amount of downforce (this explains the relatively low top speed of an Exige as it also increases drag).Bye, Arno.

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I am told by an ex British Aerospace chap that the changes in the design of the Exige rear clamshell ie climbing wedge and semi Kam tail have more to do with the downforce than the wing, and the figure Lotus quote is 45kg. I guess the most telling point is the pedestal re-inforcement - it’s exactly the same as a standard Elise and the clamshell is 2.5mm thick at that point (hand lay-up incedentally)! Any major forces would show in paint cracks. Another interesting point - I thought the blind front 'brake cooling appertures’wwould cause significant drag, but not so. Once they fill up with air they ‘spill’ (think of it like water in a cup)and only cause mild turbulence.Rob Gibbons

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I thought, in fact almost positive, the Exige Rear Wing Mounts fitted directly to the rear of the Frame, not the Clam Shell.

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I’m with stupot re the wing supports. Also, the Elise MK2 has a similar wedge shape and chopped tail. I’d love to know for sure what the wing does. Anybody fancy running without it for a while?

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The Exige rear wing mounts to the rear clam, however it is directly above the aluminium supports which bolt to the longeron’s.

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Oh Roy,i hope the quality is not the same as the factory as that is absolutly cr*p, just have a look at the new Exige roof i have direct from the factory, full of holes and needs filling !!!Make them better !!! [image]http://www.exiges.com/ubb/NonCGI/images/icons/wink.gif[/image]

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RobPost your photo of your Exige without the wing - boy does it look weird!

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RobCan’t you just give us a piece of black plastic to cover the cr*p between the top of the windscreen pillars and the roof?Now that i would pay for!Tony

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Tone,sorry mate, I’m not quite with you (old people eh!), inside or outside. I’ve often thought there has to be a better way of holding the inside front of the hardtop on - carbon or something 'higher tech’than the current bit of fibreglass covered in crimplene. Ordered your supercharger yet??.RegardsRob

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RobI was looking at the windscreen pillar /roof join inside - neoprene duct gasket etc - only needs a bit of carbon fibre moulded to cover it x2No.I’m still getting used to the power and acceleration I’ve got now, before I start thinking about 190BHP kits and superchargers!!

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You have not read the article in CCC then! I suspect most of the Exige owners will now be looking for 260BHP! I’ll have a closer look at the joint condition you mention =- we may be able to kill two birds with one stone by re-modeling the hard top front clamp with extensions to cover the problem area.RegardsRob