Exige Carbon Fiber bodywork...

General General Lotus Talk
21

As far as I understand, the attaching points are different.But what kind of prices are we talking here?Any website ?Uldis

22

Angelo,Assuming your right about the rear one being 28Kg’s, if your going to save 58Kg’s, that implies that the front one must be considerably more than 30Kg’s, otherwise the replacements must weigh nothing…And the bit about crash protection, how did you work that out?GRP is one of the best materials there is for energy absorption in an accident, way better than steel/ali/Carbon Fiber etc.Simon (S)

23

Simon, I’m not going debate the energy absorption qualities of all the different materials, because frankly, I don’t know enough about it. I was under the impression from what i have read that the car depends on its chassis to a great degree for this and that the body does not contribute significantly to its structural integrity.As for the CF components, I am talking about replacement of ALL components, not just the front and rear clams. That includes the engine lid that I mentioned before (saving 6kg) front splitter assembly, roof, doors, bonnet, undertray, EVERYTHING/. Front and rear clams alone save about 38kg total. The entire kit is being fited to another local Exige shortly. Haven’t heard any rumblngs about difficulties with fixing points yet.

24

Well,how about getting the real figures for a before and after weights then?I personally think you would have to do more than this to save that sort of mass, but I await the real figures…Simon (S)BTW, exactly how much did/will all this cost (assuming that it’s being paid for as a customer)(For example, to make the rear wing from pre-peg CF costs over �400 in CF material before you start.)[This message has been edited by SimonS (edited 01 March 2003).]

25

Simon,you are sounding increasingly sceptical. I am not trying to sell you anything and I have no vested interests here. The weight saving of 58kg refers to simple replacement of the GRP components for CF, If you were to include other weight-saving measures, such as Aluminium fuel tank, polycarbonate windows etc,there’s close to an additional 20kg to be saved.As we are all aware already, seats, exhausts, mag wheels etc can push the total weight-savings to almost 100kg in total. Think about the implications of that to the power/weight figures!The exact weight figures have been made available to me under some confidence, so I am reluctant to divulge all that info on this BBS.As I stated above, the people here at Lotus Motorsport Australia are very serious about their racing. They have made exceptional developments in all aspects of the car’s performance, including weight-saving. They have disassembled both an Exige and a Sport Elise and weighed each component individually.If you or anyone else here would like to direct your enquiries to them, try their webpage: www.lotusmotorsport.com.au They have all the info on weight differences and costs.Angelo

26

Angelol,sorry if I come accross as having a go at you personally, this was/is not my intension.Reason I am as sceptical as I am is that I have seen so many clains for this that and the other on weight, most of which is total fabrication.It is quite possible to strip out well over 100Kg’s out of an Exige, in fact, if you go mad, you can loose nearer 200Kg’s, but if you plan on keeping it as a road car, then most of this is a no-no.The real problem I have with this bit though is I just don’t belive that it’s possible to loose 58Kg’s with just changine GRP pannels out for CF.Even if you assume that CF is half the weight of GRP, that would make the std pannels weigh some 116Kg’s, and I can tell you catagorically, that’s just not reality.I have no doubt that Lotus Motorsport Australia are very serious about their racing, but what bearing has that on this?(BTW their web site says next to nothing).Simon (S)

27

ok,I think the problem lies with the assumption that CF is half of the weight of GRP. It does in fact weigh much less than half.With regards to the weights,these CF panels are in the order of 25% of the weights of the GRP. The total weight of te GRP is about 82kg as opposed to the total weight of the CF components, which is 24kg. Re: the seriousness of LMA, the bearing of that is that they have gone through with these developments in CF components and gone to the trouble of quantifying and documenting the changes in weight that you are being quoted. No one is making incredible claims that can’t be backed up. The link to the website was not intended to give a full account of their developments and products. I gave it as a reference for you or others to direct your specific enquiries via the link at the bottom of their page. OK I’ll be more specific: please direct your enquiries to:[email protected] turn to be sceptical now. How would you lose another 100kg? (I’m not taking the p*ss, but genuinely interested)Angelo

28

Angelo,Thanks for the lead, I just sent them an e-mail. I’m interested but it might bump me under the minimum weight for my class…Roy

29

Angelol,Err - CF is not 25% of the weight of GRP, it’s actually denser - ie. for the same volume it’s heavier.Only reason you can save weight with some parts is that it’s possible to use much thinner sections, however, this is not practically possible with shapes and designs that were not optimised for CF production, hence the reason I said 50% as this is tupical of the end results people get when doing this stuff.Back to your question, the basic’s are:Fuel tank - use an FT3 spec bag tank ~6Kg’sWheels - use Mag rimms ~15Kg’sRear uprights, brake calipers, disks ~16Kg’sRe-plum water system ~4 Kg’sdump air/oil cooler and replace with water exchanger ~2Kg’sDump the heater & A/C ~15Kg’sEngine, replace all internals with steel/forged stuff etc. ~11Kg’sAlternator, replace with smaller one ~2.5Kg’sDrive shafts, replace with gun-drilled items ~1.5Kg’sThis is just for starters (like 73Kg’s worth), then you get onto starting to cut holes in things, etc.I think Dean probably made the lightest one, I belive he was down to ~600Kg’s, although it was nothing close to a road car.Simon (S)

30

Roy, take the easy option…replace only enough clams/panels to ensure you stay within your required class!Simon,point taken re: the weight differences between GRP and CF. Sorry, I was referring specifically to the weight disparities between the body shell components that have been produced, not to equivalent volumes of each material. It seems like the guys here must have obviously produced thinner sections to achieve the weight savings quoted.Out of interest, which uprights and calipers are you referring to? The Motorsport items, or possibly the Eliseparts gear?Has anyone fitted the bag tank? Where is it available from and is it street-legal over there? I would have assumed this weighed next to nothing. I am surprised that it only saves 6kg over the standard item, as we saved 7kg by fitting and Aluminium one to my car. I’ve already incorporated (or thrown out) most of the other items you mention on your list,although I think I’ll give the holes a miss. I assume you are referring to the Speedline wheels? While we’re at it, has anyone got any further comments/tips for weight saving?Angelo

31

How much do YOU weigh Angelo [image]http://www.exiges.com/ubb/NonCGI/images/icons/wink.gif[/image] [image]http://www.exiges.com/ubb/NonCGI/images/icons/grin.gif[/image]

32

Angelo,If you get some hard figures out of them, then I would be interested to see exactly how much the std and CF pannels come in at.Upright wise, the Motorsport ones are no different to the steel one (for weight). I am suggesting that you change to Ali ones, either the original Elise ones or (comming soon) new billet machined ones, these will not only be lighter, but also a fair bit stronger and stiffer than the steel ones.These will come with new billet calipers and lightwight disks, total saving is looking like over 16Kg’s for an Exige/340R.Bag tank wise, I have one.They are avaliable in a couple of sizes, 58L and ~77L, the 58L one is a direct swap with the std tank, is fullt FIA FT3 approved and is OK for road use (certainly in EU).I have a hard time beliveing that an ali tank can save you 7Kg’s when the steel one only weighs 10Kg’s in the fist place, whist the bag tanks are light, they still weigh something, I can’t remeber exactly, but ~4Kg’s from memory.Wheel wise, yes currently there are only speedline avalible in Mag, not the greatest in terms of weight saving, but a safe well made wheel (unlike some!)Items I forgot to mention before:Engine mounts ~2Kg’sClutch ~3Kg’sExhaust ~2-10Kg’s (depends on which way you go)Some of these things are almost no-brainers, as they don’t compromise road performance/legality and are not hugely expensive to do.wheels for example cost ~�1,400so if you work out a cost per Kg, that’s ~�100/KgDepends on how much your prepared to spend, but once your over the �100/Kg bracket, you have to start looking hard at VFM.Simon (S)

33

Phil,already looked at this option, unfortunately am at the limits of weight-saving at 73kg, and cannot achieve any significant weight reduction without removing some limbs.Maybe some CF replacements for these will help.Simon, The figures for the Al tank we have fitted should be accurate. Even the Lotus Al tank weighs in at 3.45kg. Looks like most bases are covered except for the body panels then!I think you would be surprised at the weight differences between the GRP Exige panels, the GRP Sport Elise panels, and the CF panels. As I said before, I’d rather that anyone genuinely interested in these make the enquiry via their website. I think that they would probably make your specified 100pounds/kg.

34

Simon - where did you get your bag tank from?Cheers

35

quote:Originally posted by angelol:already looked at this option, unfortunately am at the limits of weight-saving at 73kg, and cannot achieve any significant weight reduction without removing some limbs.Maybe some CF replacements for these will help. [image]http://www.exiges.com/ubb/NonCGI/images/icons/grin.gif[/image] [image]http://www.exiges.com/ubb/NonCGI/images/icons/grin.gif[/image]

36

Long story.Current one I have came via Geary.I belive he has at least one on the shelf (a 58L one).I have the ~77L version, but unless you really need it, it requires a lot of work to fit, the wiring/brakelines/fittings etc all have to be moved, the 58L one just fit’s in without having to modifiy anything.Simon (S)PS. why did I see your car in Maidstone SC the other day? they were muttering something about gearbox?

37

Guys,forgive my ignorance, but… what is a bag tank? [image]http://www.exiges.com/ubb/NonCGI/images/icons/confused.gif[/image]Uldis

38

That are a flexable fuel cell designed not to rupture in an accident where the tank get’s deformed.They are normaly make out of kevlar composites etc. I think the FIA’s web site has the tech stuff on them (look for FT-3 spec)As for what they look like: madasafish madasafish madasafish this is the one I have.Simon (S)

39

Had a bag tank in the Mini - but they are date recorded and you cant use them after I think 5 years from manufacture, you can get them extended by one year by having the factory ( ATL or whoever ) re-certify but only one year.Of course this is only relevant in the case of race or sprints etc where they check … but I was told mine was past it sell by date and had it logbooked - so had to change.Andrew

40

A bigger tank would definatly be nice but i see they only have a life of 5 years [image]http://www.exiges.com/ubb/NonCGI/images/icons/blush.gif[/image]Is this just a racing reg or do they start to go brittle or something?