Bob Corb Posted July 5, 2002 Share Posted July 5, 2002 How many G does a well driven Caterham pull when cornering on a track and how does it compare with a good road car (M3/Skyline), track day special (Radical), touring car or supercar (Ferrari F50?). I've heard that the old BMW M3 could hold a constant 1G and that formula 1 cars can get up to 4.5 but I dont know where other cars would stand. I dont suppose anyone with data logging could produce a plot of time vs lateral G?? BC Link to comment Share on other sites More sharing options...
rgrigsby Posted July 5, 2002 Share Posted July 5, 2002 Bob, Take a look here. That's a plot from a datalogger in my car at Outlon Park about 3 weeks ago. There's other graphs etc here if you're interested. The maximum peak lateral reading was 1.46, since then I've done a few other circuits and haven't seen much beyond 1.3 although I think my tyres are at the end of the their life!! This is all done on ACB10's. I'm about to switch to slicks so it should be interesting to see the difference. As a complete aside, there were a couple of Radical ProSports at Oulton Park at the same time I was there, I thought I was going fairly quickly until they caught up. Trying to follow them through a few corners showed just how much more "grip" they have, the Radical wesbite says they can pull 2g through corners apparently... that could explain why!! Cheers Rob G www.SpeedySeven.com Edited by - rgrigsby on 5 Jul 2002 09:55:31 Link to comment Share on other sites More sharing options...
V7 SLR Posted July 5, 2002 Share Posted July 5, 2002 You have to be careful with logging. The AC-22 I have can be set up to compensate for the car "dipping" on acceleration from standstill. Although it can measure lateral G as well I'm not sure the dip-compensation works in that direction. The angle that a car leans from side to side will be greater than the angle that it dips fore/aft which could lead to some slightly exaggerated cornering G claims. Thant said, I have also seen approaching 1.4G, and the car doesn't lean over that far, so I'm confident that it can generate comfortably greater cornering G than the BMW. ISTR the old Countach could corner at 1.2G according to a magazine or two at the time. I would have thought that a lightweight Se7en on sticky tyres should be able to exceed that but to go much further on any car is going to require downforce. Might be a fun experiment to mount a sheet of plastic on the roll bar, angled to provide some downforce. Not very "millenium" scientific but probably consistent with the kind of knowledge that was floating about regarding aerodynamics when the Se7en was first designed. teeth.gif Worcs L7 club joint AO Membership No.id=red> 4379id=blue> Link to comment Share on other sites More sharing options...
Peter Carmichael Posted July 5, 2002 Share Posted July 5, 2002 Here we go with light cars cornering faster than heavy cars again. Mostly it is down to tyres. ACB10s get somewhere into the 1.4 bracket. Slicks aren't much better. Peterid=teal> 253 BHP K-seriesteeth.gif, gearbox and diff on the waythumbsup.gifid=red> Link to comment Share on other sites More sharing options...
V7 SLR Posted July 5, 2002 Share Posted July 5, 2002 Slicks not much better? Really? So is their advantage mostly in braking then? Worcs L7 club joint AO Membership No.id=red> 4379id=blue> Link to comment Share on other sites More sharing options...
Bob Corb Posted July 5, 2002 Author Share Posted July 5, 2002 Thanks Chaps That was exactly what I was looking for. I'll have to post the same thread on various tin top owners web sites and see what they can do!! BC Link to comment Share on other sites More sharing options...
Peter Carmichael Posted July 5, 2002 Share Posted July 5, 2002 smile.gif Link to comment Share on other sites More sharing options...
Graham Perry Posted July 5, 2002 Share Posted July 5, 2002 I bet you could pull more than 1.4 in the two High grip corners on the sprint cirtuit at Mira. It felt like more than 1g on 1a tyres Link to comment Share on other sites More sharing options...
Peter Carmichael Posted July 5, 2002 Share Posted July 5, 2002 ...mostly down to tyres and road surface. And I've seen 1.8G too on the banking at the Karrussel. With the angle of lean, this would equate to significantly greater force which was certainly what it felt like - at the end of two tiring days I was struggling to hold onto the steering wheel. Peterid=teal> 253 BHP K-seriesteeth.gif, gearbox and diff on the waythumbsup.gifid=red> Link to comment Share on other sites More sharing options...
Ian Kellar Posted July 5, 2002 Share Posted July 5, 2002 Originally posted by Peter Carmichael Here we go with light cars cornering faster than heavy cars again Fancy elaborating a bit? I think I have my head round it, but I'd be sure than make an arse of myself. Cheers. Link to comment Share on other sites More sharing options...
rgrigsby Posted July 5, 2002 Share Posted July 5, 2002 1.8G around the Karrussel!! on 032r's earlier this year I saw around 1.4-1.5G, I guess you were on ACB10's. I know what you mean about tiring though, I only did 6/7 laps and that was already enough to notice the effort involved. Rob G www.SpeedySeven.com Edited by - rgrigsby on 5 Jul 2002 12:41:56 Link to comment Share on other sites More sharing options...
Flying kiwi Posted July 6, 2002 Share Posted July 6, 2002 What you up to Bob? Will you be going to Silverstone on the evening of the 16th, Weather permitting i will be there along with the seven. [Not doing the track event though as too late booking]. Kiwi. Link to comment Share on other sites More sharing options...
Bob Corb Posted July 7, 2002 Author Share Posted July 7, 2002 Kiwi I'm designing a novel oil handling system to allow Beagle to perform inverted low flying in the seven, he drives it fast enough to get airbourn... I'd like to go along to Silverstone for a bit but I'll have Tom (my 2 year old) with me so I doubt they'll let us in. Its club night in Blakesley that night so I'll probably see you there at least. Bob Link to comment Share on other sites More sharing options...
Morls Posted July 8, 2002 Share Posted July 8, 2002 The weight thing is: The masses cancel each other out, so, all other things being equal, a seven's low mass will not help it generate better cornering force. The car's mass acts to generate a force pulling the car out of the corner but also to generate the force pushing the tyres into the ground. If you reduce the mass both these are reduced... Unless... You get wings... then you have a virtual mass acting downwards, but not sideways. Without these the tyre/surface friction is the limiting factor in generating g. Mark (Personally, I prefer cheese smile.gif) Edited by - Mark Jackson on 9 Jul 2002 00:02:12 Link to comment Share on other sites More sharing options...
Mike Bees Posted July 9, 2002 Share Posted July 9, 2002 >> The masses cancel each other out, so, all other things being equal << Ah but they don't and they're not... Mike Link to comment Share on other sites More sharing options...
kjp Posted July 9, 2002 Share Posted July 9, 2002 ahh Mark I guess you could extend the Newtonian friction argument to say tyre width is unimportant or suspension geometry!! Unfortunatley tyres didn't read Newton Ken P KenP Link to comment Share on other sites More sharing options...
kjp Posted July 9, 2002 Share Posted July 9, 2002 ahh Mark I guess you could extend the Newtonian friction argument to say tyre width is unimportant or suspension geometry!! Unfortunatley tyres didn't read Newton Ken P KenP Link to comment Share on other sites More sharing options...
Peter Carmichael Posted July 9, 2002 Share Posted July 9, 2002 How much ground clearance does a Seven have? How low is the centre of gravity? How many Caterham owners fit sticky tyres that only last a few thousand road miles? There you go. The three secrets of Caterhams going round corners quickly. Caterham's design priorities let them compromise ground clearance by design . You cannot modify a production saloon to do the same thing unless you get fancy with suspension pickup points. After that it is just a matter of tyre choice and set up. ... but please note ... There is nothing inherent in low mass that makes a car corner quickly, because the forces scale linearly with the mass. If you have a heavier car you need bigger tyres and a fatter wallet. Peterid=teal> 253 BHP K-seriesteeth.gif, gearbox and diff waiting to go inthumbsup.gifid=red> Link to comment Share on other sites More sharing options...
Morls Posted July 9, 2002 Share Posted July 9, 2002 Mike, Ok... I admit it, all the other things aren't equal. But I have to make some assumptions smile.gif Ken, Ah.. yes... the tyre width / pressure / area thing, that old chestnut. um.. Nice weather todayquestion.gif Ok, I don't understand that one completelyblush.gif but I think it might be something to do with the fact that (unlike ice & sledges) roads aren't smooth and tyres can deform... maybe... But suspension... IMHO the limit is where a car slides (Understeer, oversteer or drift), or falls over (Suzuki Jeep wink.gif ). Good suspension means the tyre is always firmly on the ground, preferably right across the area, so the tyre can make the most of it's grippiness (techncal term). A 7s low CoG means it won't fall over... so the tyre friction (Ok and maybe width), and suspension quality determine the limit. Mark (Personally, I prefer cheese smile.gif) Link to comment Share on other sites More sharing options...
Alias Posted July 11, 2002 Share Posted July 11, 2002 One of these days they will make a Caterham so light that it will float in the air - this will have extreme difficulty going round corners teeth.gif Link to comment Share on other sites More sharing options...
Mike Bees Posted July 12, 2002 Share Posted July 12, 2002 Ah, but if it's that light then it'll change direction very easily... wink.gif Mike Link to comment Share on other sites More sharing options...
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