Angus Posted October 4, 2007 Share Posted October 4, 2007 If you were in the fortunate position of speccing up a new car for self-build from Caterham, what would be on your wish-list to have done to the chassis at Arch (or the new supplier, Cage), before it was fully assembled ? It would have to be an original (S3 ?) chassis, rather than a wide-body. The list I have so far is: Thicker cockpit floor fixed with steel rivets Black powder-coated cockpit, engine bay and boot area Removeable spare wheel carrier - this to be done so nothing is visible from rear of car, eg posts or holes. Fixing to be entirely underneath. What would you do ? Angus Denny (ex-Surrey AO and ex-Seven owner who's been away far too long but now seen the light) Link to comment Share on other sites More sharing options...
MartinWoodham Posted October 4, 2007 Share Posted October 4, 2007 The cockpit floors are fixed with steel rivets anyway, IIRC, since they hang from the chassis tubes and therefore the rivets are taking the weight. Powder coat the interior and engine bay is a good idea IMHO, and one that I wish I'd had done. I'm allergic to excess weight (unless its pie-induced) so a can of tyre-weld rather than a spare wheel carrier! Have a think about a lowered floor on either side - gives more head clearance to the roll bar/ cage, although if you're planning on running the car very low you'll hit the deck every now and then with the seat bolts. If you might want a brake bias lever it's probably best to get this plumbed in while the chassis is being fitted out with brake lines - a stage on from chassis-related stuff I know.. Its fun doing the choosing isn't it! Martin Aero'd supersported ex-Roadsports B...anyone got a cheap LSD/ 6 speed box? Link to comment Share on other sites More sharing options...
Mick Day Posted October 4, 2007 Share Posted October 4, 2007 *wavey*Hi Angus, welcome back to the fold. When your 1st car was built (& certainly my 1994 car) the floor would have been fixed with alloy rivets. It's well worth asking for a thicker floor fixed with steel rivets. I don't think CC are too keen on having the engine bay interior powder coated as some customers have complained about the side skins getting a little wrinkly. The black absorbes heat rather than reflecting it. I had both the above done when I rebuilt my car & haven't noticed any wrinkles. One additional advantage of the powder coating is that it puts an additional layer between the steel of the chassis & the aluminium. It's also easier to keep clean. Mick Link to comment Share on other sites More sharing options...
silver-7 Posted October 4, 2007 Share Posted October 4, 2007 If you have big engine plans ....... id think about / enquire about some chassis strengthening around the diff area regards Alex Link to comment Share on other sites More sharing options...
F355GTS Posted October 4, 2007 Share Posted October 4, 2007 lowererd floor depending on your height? Mark Link to comment Share on other sites More sharing options...
Angus Posted October 4, 2007 Author Share Posted October 4, 2007 ....Strengthening round the diff area..... Now there's a thought I am going Duratec, as in the new R400 spec. Does that need diff strengthening ? Anyone with any experience ? Is there a 'standard' way to strengthen the diff mounts, or is the strengthening custom every time ? Link to comment Share on other sites More sharing options...
Angus Posted October 4, 2007 Author Share Posted October 4, 2007 Hi Mick, good point about black absorbing heat, and heat is supposed to be a problem with the duratech. What about other colours for the powder coating - grey / silver perhaps ? Can you even get it in a colour other than black ? Link to comment Share on other sites More sharing options...
Angus Posted October 4, 2007 Author Share Posted October 4, 2007 Another point about the current chassis - it doesnt have the engine bay diagonals - at all. The sales guy explained that the chassis was '10% stiffer' and could take all the current engine range without modification. Quite how removing the diagonals makes it stiffer wasnt explained. Are there any structural engineers on here ? Whats the view - could it be that the diagonals has so little effect on stiffness that removing them doesnt prevent a 10% improvement ? Angus Denny (ex-Surrey AO and ex-Seven owner who's been away far too long but now seen the light) Link to comment Share on other sites More sharing options...
Julian Thompson Posted October 4, 2007 Share Posted October 4, 2007 To be honest the thicker floor is still a bit of a bodge. Go for some proper welded in seat supports on the chassis instead and dispose of the silly U channels underneath. Then you can do thinner carbon floors instead... The "new" chassis I think probably means the later type with the proper centre tunnel frame rather than just the ally skinned tunnel. Removing the engine bay diagonals will obviously reduce the stiffness. Can't hurt to put some strategic bracing in there to suit your specific engine install. I think CC removed it to make a very "universal" engine bay. Adding a cage stiffens the car up *a lot* - and adds no/little weight compared to the FIA bar as the guage of tube is so much thinner. I am also doing some diagonals across the footwells I think. I suppose it's just a question of how much to add before the extra bracing adds more weight than the stiffness does good....I will add that my car is to run on solid Nylotron wishbone and pivot bushings all round rather than the rubber ones so I think that the chassis stiffness will be more noticable I guess than if you were going to run the standard CC bushes. Link to comment Share on other sites More sharing options...
BAZZA Posted October 5, 2007 Share Posted October 5, 2007 Angus, Arch don't make the chassis it's made by steel fabrications and a R400 is different I believe to a sigma chassis.Interior of cockpit is powder coated but not boot or sideskins in engine bay. Link to comment Share on other sites More sharing options...
Paul Formston Posted October 5, 2007 Share Posted October 5, 2007 Hi Lads I would like the new CSR back end on a standard chassis 😬 Regards Paul Link to comment Share on other sites More sharing options...
Powderpuff Posted October 5, 2007 Share Posted October 5, 2007 Someone will no doubt correct me if I'm wrong...but I think that the tubing of a Steel Fab chassis is heavier guage (stiffer but heavier) than an Arch chassis hence an increase in stiffness. How much modification to a standard chassis will Caterham do now? Do you simply have to have one of their off the shelf production line models...or will they weld a bit in here and there for you to taylor it to your requirements? Link to comment Share on other sites More sharing options...
Rob Walker Posted October 5, 2007 Share Posted October 5, 2007 The race chassis are still made by Arch so that all the race cars use the same chassis old or new. I doubt that steel fab will mess about with different mods as all the production is largely automated and adding bits here and there would be difficult to programme in. Steel fab produce only one universal S3 type chassis which can accomadate all engine varieties and be either LHD or RHD. I do not think that there is any problem with the diff mounts, this problem was with early chassis that had the deformable transmission tunnel and the hand brake under the dash. Chassis from late 96 onwards the tube in the tunnel run through the car and are triangulated / braced and directly support the diff mounts. Rob Edited by - Rob Walker on 5 Oct 2007 08:49:33 Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted October 5, 2007 Share Posted October 5, 2007 Hi Angus! Welcome back. I had towing eyes fitted all round. Makes it a doddle to strap the car down on a trailer. Edited by - Alex Wong on 5 Oct 2007 09:53:18 Link to comment Share on other sites More sharing options...
I.Mupferit Posted October 5, 2007 Share Posted October 5, 2007 Caterham did do a 'Duratec Spec' chassis which included strengthening gussets around the diff mounting tubes which were not present on the standard chassis at that time when I specced mine (3 years ago). It may well be a standard fitment now since CC actually fit the Duratec in the S3 chassis themselves but worth checking. If it is a Steel Fab chassis, they are allegedly stiffer due to the use of mig welded joints and a better grade of steel utilised in the chassis. I know some owners of the new R400 have complained about heat soak into the cockpit but I don't believe the Duratec runs especially hot and I do wonder if this reported phenomenon is due to other influences. Certainly on the CSR it appears to be due to lack of airflow through the engine bay and transmission tunnel but I haven't seen an R400 chassis to compare so can't comment. Two things I do know though:- 1) My own SV with a 235 bhp 2.3 Duratec suffers none of the oft quoted heat soak problems. Now some of this may be due to the extra space in the engine bay allowing the air to flow more freely and I did line the external side of the footwells with heat resistant mat during the build, just in case. 2) Mike Edge built a Duratec R400 just over 3 years ago using the older K series chassis and he has reported none of the heat soak problems either. So maybe there is a clue in there. If anything, my 2.3 runs too cool most of the time. Brent 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Edited by - Brent Chiswick on 5 Oct 2007 10:16:19 Link to comment Share on other sites More sharing options...
Sheds Moderator Posted October 5, 2007 Share Posted October 5, 2007 Tyre carrier is useful for a small case if you want to go touring - ask the other Angus (and Tessa!) Link to comment Share on other sites More sharing options...
Angus Posted October 5, 2007 Author Share Posted October 5, 2007 Good stuff so far guys - keep it coming ! On the R400 heat issue: I was told that early cars ran hot because of the radiator installation. A shroud was fitted that filled the space between the rad and nose that had the effect of channeling all the airflow coming into the nose thorough the rad. The engine ran super-cool, but there was now no air flow past the engine, exhaust header, footwells etc. Result - hot feet. This shroud has been removed, and the heat problem allegedly much improved. Interestingly the demo / mule R400 I saw at Caterham did have some (tatty) heat shield applied to the outside of the drivers footwell, so perhaps there are still some lingering heat problems. Link to comment Share on other sites More sharing options...
Angus Posted October 5, 2007 Author Share Posted October 5, 2007 Alex - hi, hope you are keeping well. Ref the towing eyes - that sounds a good idea. From memory are there not two fitted as standard - diagonally opposite ? So I assume you just had two more fitted on the other two corners ? Elegant. Rgds Angus Link to comment Share on other sites More sharing options...
Angus Posted October 5, 2007 Author Share Posted October 5, 2007 Powder Puff Your theory about thicker guage tubing would explain the extra stiffness - I have also heard that the TIG welding (as opposed to brazing) helps as well, although the downside is its more difficult to repair. Anybody got any weight figures for the different versions of bare spaceframe chassis ? The question about how much modification Caterham will tolerate is an interesting one - yet to be fully tested, although the sales guy seemed amenable. We shall see ! Link to comment Share on other sites More sharing options...
I.Mupferit Posted October 5, 2007 Share Posted October 5, 2007 The heat shielding I used is a self adhesive backed, foil faced material approx 4mm thick and available from Demon Tweeks which looks very neat especially if you can finish the corners with aluminium foil tape. I can supply you some foil tape if you need it. I believe it is a good idea to insulate the footwells externally during the build as it is very easy to do at that stage and can pay dividends in vey hot weather. I've used mine in ambient temperatures of high 30's and heat soak just wasn't a problem for us. Brent 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Link to comment Share on other sites More sharing options...
I.Mupferit Posted October 5, 2007 Share Posted October 5, 2007 I know when the present management took over, the general feeling was that they were trying to move away from bespoke one offs but I understand they may have moved from that position now. Mig welded joints and better quality steel is what is responsible for the added stiffness in the chassis I believe. Brent 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted October 5, 2007 Share Posted October 5, 2007 Ref the towing eyes - that sounds a good idea. From memory are there not two fitted as standard - diagonally opposite ? So I assume you just had two more fitted on the other two corners ? Yup - that's exactly what I asked for. Link to comment Share on other sites More sharing options...
Powderpuff Posted October 5, 2007 Share Posted October 5, 2007 better quality steel I wouldn't say thicker is better Wonder if the spec of the steel changed? Link to comment Share on other sites More sharing options...
I.Mupferit Posted October 5, 2007 Share Posted October 5, 2007 Yes, it has changed - allegedly. Brent 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Link to comment Share on other sites More sharing options...
RiF Posted October 5, 2007 Share Posted October 5, 2007 But the welding looks crap!!!! Robots?? Someone needs a new programme for them I too have a Duratec and had all the panels powder coated on the inside. No problems but it depends on how it is panelled. I have seen new cars with woobles down the side, before an engine has even turned a key!!!! CC stopped powder coating the insides of engine bays as they found sometimes it will make the woobles worse. RiF Driving one of the first Duratec 7, and building CA07BON for Henrietta 😬 😬 😬.for pictures of 7 and carbon andCA07BON Link to comment Share on other sites More sharing options...
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