Lotus Seven Replica's: So many choices...
Discussion
Well ok as I mentioned in a previous post Im a total NOOB when it comes to these cars.
Initially I thought only Caterham and Westfield made these, however after looking through the classifieds, there are many.
Would someone be able to jot down a little bit about them, or even put them from good to bad ?
Im looking to spend around 10K on a car (excluding insurance ect), with a great bike engine.
Thus Im not looking at cats/westies (probably out of my range).
Anyway, so it would REALLY help me and maybe anyone else in a similar position to narrow our choice.
Initially I thought only Caterham and Westfield made these, however after looking through the classifieds, there are many.
Would someone be able to jot down a little bit about them, or even put them from good to bad ?
Im looking to spend around 10K on a car (excluding insurance ect), with a great bike engine.
Thus Im not looking at cats/westies (probably out of my range).
Anyway, so it would REALLY help me and maybe anyone else in a similar position to narrow our choice.
It's an often asked question and you will get a different answer from everyone 
With your budget you have a wide choice of all the tier two manufacturers. And it depends on whether you're building or buying ready built. I have an MK Indy currently and it's great but knowing what I know now, I'm going to have a good look at MNR next time round. If I was a smaller chap I'd have a look at the Fury too. HTH.
With your budget you have a wide choice of all the tier two manufacturers. And it depends on whether you're building or buying ready built. I have an MK Indy currently and it's great but knowing what I know now, I'm going to have a good look at MNR next time round. If I was a smaller chap I'd have a look at the Fury too. HTH.I'm really quite bothered about most of the Locost-derived chassis, I'm building one at the moment (hare-brained scheme to finish a part-built project and flog for profit - not that it'll work out that way) and it's sadly lacking in terms of rigidity and in fact basic safety. In fact there are some chassis diagonals that are plain missing, which ought to be unforgiveable but hasn't stopped a few fabricators with a gleam in their eye knocking out faarsunds of 'em.
OK it's a chassis built to original ("book", that's the very optimistic and fairly useless Ron Champion book) dimensions but then so are most of the usual suspects, or derivations of the theme.
Frankly I wouldn't even consider getting in my completed Locost for a serious blast on the road, and I'd only be marginally less skittery about it on the track where it's a lot harder to hit really solid stuff. Consequence of an impact doesn't bear thinking about, and there's no way the unmodified chassis will be anything like stiff, therefore there's no way the handling will be predictable.
The best chassis I've seen along the lines of a Seven but derived from the Locost principles is the MNR which has been taken back to a fairly blank sheet of paper and redone by someone who's aware of the main tenets of chassis design.
I believe the Sylva (Striker) chassis is pretty decent but they're a bit different from a Seven clone so are a bit Marmite in their appearance. Still probably the fastest per pound though.
I'd just recommend a very careful look at any chassis on your shortlist, it's the hardest bit to change and most likely if it's not designed very well the rest of the kit, although mebbe fitting together perfectly well, won't have been well designed either. Someone who can't produce a chassis with structural integrity won't have developed a suspension geometry either, and if those two aspects aren't right you'll never have confidence, or fun, in the car.
OK it's a chassis built to original ("book", that's the very optimistic and fairly useless Ron Champion book) dimensions but then so are most of the usual suspects, or derivations of the theme.
Frankly I wouldn't even consider getting in my completed Locost for a serious blast on the road, and I'd only be marginally less skittery about it on the track where it's a lot harder to hit really solid stuff. Consequence of an impact doesn't bear thinking about, and there's no way the unmodified chassis will be anything like stiff, therefore there's no way the handling will be predictable.
The best chassis I've seen along the lines of a Seven but derived from the Locost principles is the MNR which has been taken back to a fairly blank sheet of paper and redone by someone who's aware of the main tenets of chassis design.
I believe the Sylva (Striker) chassis is pretty decent but they're a bit different from a Seven clone so are a bit Marmite in their appearance. Still probably the fastest per pound though.
I'd just recommend a very careful look at any chassis on your shortlist, it's the hardest bit to change and most likely if it's not designed very well the rest of the kit, although mebbe fitting together perfectly well, won't have been well designed either. Someone who can't produce a chassis with structural integrity won't have developed a suspension geometry either, and if those two aspects aren't right you'll never have confidence, or fun, in the car.
I can't see how the ridgity of the 7 chassis can make the car safer unless the geometry was wrong or simply dangerous to start with. A 7 chasis doesn't have any crush zones really so I consider my car an alternative to the bike in respect of crash safety.
I've got an MK Indy and I think the quality is way in excess of the price. I'm using an R1 engine which is about 150bhp.... The MK's with an R1 engine can be got for less than £10k easy, mines quite high spec and even mine falls in that price range.
I've got an MK Indy and I think the quality is way in excess of the price. I'm using an R1 engine which is about 150bhp.... The MK's with an R1 engine can be got for less than £10k easy, mines quite high spec and even mine falls in that price range.
I would agree with FNG that the Locost chassis is an abortion; I'd have serious reservations about it.
Jon Ison said:
...check out MK's latest offering, 100% computer/cad chassis and suspension with all new chassis and suspension
A word of caution... Computer Aided Design is only as good as the guy who is using it. In theory, there is no reason whatsoever that a competent designer/engineer cannot produce an equally good design 'longhand' - it will just take him longer. Furthermore, to produce a good 'manual' design requires understanding of the mathematics and geometry behind it, whereas CAD can do some of the work for you, so that a person with a very incomplete understanding can produce a design which appears to be competent.
I use CAD on a daily basis professionally, though I still use manual drafting techniques for initial sketch work, because it's faster and more fluid. Most of the actual CAD work in my office is done for me by (relatively) low paid, low skilled Technicians, known in the trade as 'CAD Monkeys'. As with Shakespeare, if you give an infinite number of them an infinite number of AutoCAD workstations, one of them might eventually manage to produce something worthwhile unaided.
'100% CAD designed chassis and suspension' is meaningless marketing hype.
I haven't seen the new MK chassis in the metal, yet, so I'm not in a position to comment, but the front suspension bay shown on their website does not initially impress me much. The upper wishbones appear to be mounted in the middle of an unbraced tube and the pushrods feed from the middle of the wishbones (where they will impart significant bending loads) to rockers that appear to be similarly badly mounted. Even the bottom wishbone mounts are offset inwards from the chassis node points. In other words, it appears to fall over immediately on a number of very basic principles of good practice for spaceframe design.
They also appear to be concentrating on camber control under bump. If you look at the photo on their website showing the deflected suspension, it would appear that the design might suffer from positive camber on the outside wheel under roll (cornering), which is very bad indeed. Suspension design is always a compromise, but there is a very good argument that camber control under bump is the least of your problems... I'd be more bothered about geometric roll centre location and camber control under skewed roll.
I'd want to see the chassis in full, see it's performance on the track (in the 750MC championship) and see the tested figures for torsional stiffness before I was convinced.
Back on topic... the Sylva chassis is very good indeed, though not perfect. There have been chassis breakages under race conditions, but then these are an occupational hazard if you try to make a chassis light enough to be genuinely competitive!
With the possible exception of the Caterham, the Sylva (and RAW/Fisher derivatives) probably offers the best overall compromise of any chassis on the market, as is demonstrated by its massive dominance in the 750 Club race series, but there are several other very good cars (DAX and Westield, amongst others).
I'd be incline to avoid any of the LoCost derived designs, though, and don't touch anything by Robin Hood (academic, as you won't find any BEC Robin Hoods on the market).
Edited by Sam_68 on Friday 22 December 11:16
andygtt said:
I can't see how the ridgity of the 7 chassis can make the car safer unless the geometry was wrong or simply dangerous to start with.
It's true that chassis stiffness is a false idol, worshipped to excess by those who don't see the bigger picture. Seven's tend to be quite stiffly sprung (and, again, people who don't quite understand what they are trying to acheive tend to use springs and dampers that are far too stiff for road use), so a reasonably stiff chassis is required to prevent the chassis itself acting as an undamped spring in series with the road springs. Stiffness is only required in moderation, though... it's easy to get obsessed with it at the cost of everything else.
Sam_68 said:
andygtt said:
I can't see how the ridgity of the 7 chassis can make the car safer unless the geometry was wrong or simply dangerous to start with.
It's true that chassis stiffness is a false idol, worshipped to excess by those who don't see the bigger picture. Seven's tend to be quite stiffly sprung (and, again, people who don't quite understand what they are trying to acheive tend to use springs and dampers that are far too stiff for road use), so a reasonably stiff chassis is required to prevent the chassis itself acting as an undamped spring in series with the road springs. Stiffness is only required in moderation, though... it's easy to get obsessed with it at the cost of everything else.
Sorry if my post read that if a chassis is fairly flexible, it's unsafe. Not what I meant.
My Locost chassis is unbraced in enough areas that I wouldn't want to have a shunt in it in any direction. Insufficient engine bay triangulation, loads of offset members missing their node points, critical joints around the front suspension that are designed for easy manufacture not strength. Go in backwards and you'd die in my car. The rear impact protection is non-existent. I know there's not a lot of space to do much, but the whole rear end is supported by the rollcage and two unbraced 1" square tubes. More like nothing's been done, rather than as much as possible. Side impact, fair enough, you're in bother regardless of design.
Was trying to say that if the principles of chassis design aren't closely followed and a lot of thought put into all aspects of the design, likelihood is there will be an unforseen failure mode that may not affect your health in an off, but then again easily could.
Agree 100% with Sam's reservations about use of CAD. Great tool, but as with all computers rubbish in equals rubbish out - but with a false impression of adequacy / competence handed to the operator for his trouble.
Lastly, controlling camber movement in bump is the first thing you look at in developing a suspension system but it's a false dawn. Matching the rates of camber change and rollcentre movement front to rear, based on tyre stiffness and proportion of vehicle weight at each end, is more like what you're aiming to deliver. Minimal or effectively zero rollcentre movement is the laudable aim (I developed one solution that even compensated for tyre deflection, although that was the theoretical deflection so I never used it) but it's not as important as making sure the front and rear rollcentres behave in the same way at the same time.
And yes just about every Locost I've seen has tried to tune out the deficiencies of a poorly or not-at-all developed suspension system by increasing spring stiffness - hiding poor camber and rollcentre control by restricting suspension movement as much as possible.
I take nothing away from MK who have at least developed antiroll bars to contribute some level of adjustment and the ability to run softer springs to aid traction and braking performance. Most don't / haven't even got that far, and you have to wonder how many truly knowledgeable designers are out there developing kits into competent performers, and how many are made by guys who can weld a chassis together and commission a slightly different set of body panels...
Ok let me just put what I mean in perspective. I had a Bike engined MK Indy (possibly Jon Above) catch me in my 500bhp Ultima at Donnington about 4 years ago. Now I was being conservative in the corners which is probably why it caught me as I was miles faster on the straight BUT I was having fun and hardly hanging about which is fast in an Ultima (only 3 cars ever caught me on track in that car).
Having made the chasis for my GTT I know the 7 type cars chasis are hardly stiff or well braced, but its all about the application. The heavier the car the more stiffer the chasis needs to be as not only does it have the extra loads but it will have stiffer springs and roll bars etc which will all work to twist the chasis.
But with a Bike engined 7 type if its a well put together car it will be lightweight with soft springs and probably no roll bars and therefore most locost chasis should be OK for road and trackday use...
One bit of advice on buying though is that I'd add in £500 to the budget to get the car you purshase properly set up.
Having made the chasis for my GTT I know the 7 type cars chasis are hardly stiff or well braced, but its all about the application. The heavier the car the more stiffer the chasis needs to be as not only does it have the extra loads but it will have stiffer springs and roll bars etc which will all work to twist the chasis.
But with a Bike engined 7 type if its a well put together car it will be lightweight with soft springs and probably no roll bars and therefore most locost chasis should be OK for road and trackday use...
One bit of advice on buying though is that I'd add in £500 to the budget to get the car you purshase properly set up.
andygtt said:
But with a Bike engined 7 type if its a well put together car it will be lightweight with soft springs and probably no roll bars and therefore most locost chasis should be OK for road and trackday use...
Andy I agree with you, with the exception of the above simply because I don't believe the Locost chassis is a robust solution. It relies too much on material strength instead of structural integrity when if it was designed in strict accordance with spaceframe design princples, it would be a far more elegant solution for little cost or weight penalty, and you would be able to feel the difference.
I just think that "a well put together car" [with respect to manufacturing not build quality] and "locost chassis" are mutually exclusive terms. Which is not to say you can't enjoy them, drive them quickly, maybe even have a crash in one without personal damage. But there's stronger, lighter, safer and stiffer Seven-style chassis available which owe little or nothing to the Locost's legacy, and my recommendation to the OP is to get one of those.
andygtt said:
One bit of advice on buying though is that I'd add in £500 to the budget to get the car you purchase properly set up.
Very good advice. A fella local to me has a Dax which he's not driving at the moment due to it being dangerous to even drive in a straight line. He's got rampant bumpsteer, unequal front camber and castor, and massively over-stiff springs
Car's trying to throw him off the road at any given bump. He's mechanically adept but unsure about chassis setup, and that holds true for a lot of builders I'm sure - can't be expected to know it all. A setup by a 'proper' motorsport prep company is money well spent, I know they'd do a much better job than I could!
andygtt said:
So shall we put a list of the 7 types we do recomend....
At the top of the list for me is the Dax rush, more expensive than an MK Indy or MNR etc but might be in the £10k price range and definatelly worth it.
At the top of the list for me is the Dax rush, more expensive than an MK Indy or MNR etc but might be in the £10k price range and definatelly worth it.
totally agree, and defo achievable for under 10gs...
budget wise my friends just put together a stuart taylor... seems very nice also
andygtt said:
So shall we put a list of the 7 types we do recommend....
OK. Sounds like a good idea.
1 Top of the list for me would be the Sylva, 'cos it's by far the best value for money, has a great race record and outhandles the other Sevens that I'm properly familar with.
2 Caterham; great if you can afford them. Limited availability with bike engines, though.
3 Dax; well designed and manufactured, but quite pricey and a bit big and bulky for a 'Seven' type.
4 Westfield are pretty good with brilliant factory support and plenty of set-up information available. Suspension geometry isn't ideal, though and they are a bit on the bulky side now that they've standardised on the wide body.
5 Tiger. Well made but overweight and dynamically not top-rank.
.
.
.
.
.
997 LocOst and close derivatives. Good, cheap fun, but flawed suspension and chassis design
998 All the malformed, ugly one-hit-wonders that appear once at Stoneleigh then disappear without trace!
999 Robin Hood; Galvanised steel shed.
999 LocUst; plywood shed.
I'd probably go Dax then MNR too.
Much as the Sylva Striker Mk2 is cheaper and has a great rep for racing, it's a bit oddball to look at and I think is live axle only - fine on track, not so fine on roads. If going for a Sylva I'd prolly go for a Fury (same thing, enclosed body) anyway and do away with the crap aero of a Seven.
Reckon the Dax is the best looking Seven, period, and is very well made by one of the very best manufacturers. Whether you'd get one with a top end engine for £10k I'm not sure - if they support R1 / ZX12 engine fitments, then maybe?
If looking for more power and / or shiny bits I'd have the MNR instead. Not as good a looker, but built by someone who knows his stuff and you have more scope to tart it up, or datalog it, or add lightness / engine tuning / dry sump / trick tyres etc.
Much as the Sylva Striker Mk2 is cheaper and has a great rep for racing, it's a bit oddball to look at and I think is live axle only - fine on track, not so fine on roads. If going for a Sylva I'd prolly go for a Fury (same thing, enclosed body) anyway and do away with the crap aero of a Seven.
Reckon the Dax is the best looking Seven, period, and is very well made by one of the very best manufacturers. Whether you'd get one with a top end engine for £10k I'm not sure - if they support R1 / ZX12 engine fitments, then maybe?
If looking for more power and / or shiny bits I'd have the MNR instead. Not as good a looker, but built by someone who knows his stuff and you have more scope to tart it up, or datalog it, or add lightness / engine tuning / dry sump / trick tyres etc.
FNG said:
Much as the Sylva Striker Mk2 is cheaper and has a great rep for racing, it's a bit oddball to look at and I think is live axle only - fine on track, not so fine on roads.
For the record, the Striker is available with independent rear. Also (with it's derivatives, the Stuart Taylor Phoenix and Fisher Fury) the only Seven type available with a streamlined bodyshell.
Beauty is in the eye of the beholder, though, so I think we'd better leave that to individual choice and stick to engineering/quality recommendations?
I do really like the looks of the MNR, I must admit, but I don't know how far the chassis has developed from its 'Locost' origins.
Edited by Sam_68 on Friday 22 December 15:07
Sam_68 said:
For the record, the Striker is available with independent rear. Also (with it's derivatives, the Stuart Taylor Phoenix and Fisher Fury) the only Seven type available with a streamlined bodyshell.
Stand corrected on the axle - thanks.
Sam_68 said:
Beauty is in the eye of the beholder, though, so I think we'd better leave that to individual choice and stick to engineering/quality recommendations?
Disagree on this one, I believe the content of that whole post was clearly my personal opinion. Also don't think you can separate opinions on aesthetics from those on design, mechanicals, structure etc. It's just one more criteria to consider and feedback on all of them are useful to those making a choice judgement, or else none of them can be.
I know I've been fairly scathing about the average Locost chassis and stand by that, but it remains my opinion, to be considered or rejected by the reader as they see fit. I don't think a general comment about the look of a car is out of place if someone is looking for a range of feedback on possible candidates.
Sam_68 said:
I do really like the looks of the MNR, I must admit, but I don't know how far the chassis has developed from its 'Locost' origins.
Some pics here
[url]http://rogb.locostsites.co.uk/galleri[/url]
You can still see the Locost lineage: although I haven't checked all aspects of the chassis yet, it does seem that at least some of the most cringeworthy faux pas on the book chassis have been addressed.
edited for poor formatting
Edited by FNG on Friday 22 December 15:36
FNG said:
Sam_68 said:
Beauty is in the eye of the beholder, though, so I think we'd better leave that to individual choice and stick to engineering/quality recommendations?
Disagree on this one, I believe the content of that whole post was clearly my personal opinion.
Ok, but at least try to separate aesthetics and engineering quality?
Some Locusts and Lowcosts look really quite authentic, but I still wouldn't dream of buying one.
Personally, I can't live with the Dax...the square headlights and caricature 'gumball' rear tyres and wide arches don't do it for me; Seven types should look light and nimble, and the DAX looks a bit wide and bulky, IMO. On the other hand, I quite like the Sylva/Raw Striker (because it doesn't look derivative, looks light and simple, and form follows function) and think that the enclosed-body Phoenix is one of the prettiest 'Seven' derivatives available (quite apart from the aerodynamic advantages) - which is one of the reasons I own one, of course.
...but if you like the looks of the Dax, Tiger, or whatever, that's not a problem!
Apart from aerodynamics (which are appalling on all true 'Seven' types!) appearance has no effect on performance or handling, so if we are 'recommending' models to prospective purchasers, there's no harm in allowing them to make up their own mind on looks?
Edited by Sam_68 on Friday 22 December 15:49
Actually I agree.
With this bit at least
I think my take on the Sylva Striker is that I don't really see it as a seven clone, although the parentage is visible. It's down to the OP whether he wants a Seven lookalike or something along similar lines though, and if not a Caterham then the Stuart Taylor is probably the closest in looks (to my squinty eyes at least). If looks don't matter, IRS Striker gets my vote.
Will not second-guess the OP again :slapwrist:
Re Dax, I must have some deep-rooted fascination for wide rear wheels. See my profile for further clarification. I'll get over it one day.
Having driven their 4.6 V8 Rush, I thought it was a lot better than the Westfield demonstrator despite the coarse powertrain. And their quality is very high. Retain reservations that a good stab at a BEC Rush can be made for £10k without looking at the finished product and wishing it could've been more comprehensively finished if only there was a little more budget.
This conversation is why I opened the thread on the Mongoose. For a £10k budget that thing should dynamically murder anything but the best Sevens (which you can't buy for £10k). You'd need to really not bother about appearance, though...
With this bit at least
Sam_68 said:
I think my take on the Sylva Striker is that I don't really see it as a seven clone, although the parentage is visible. It's down to the OP whether he wants a Seven lookalike or something along similar lines though, and if not a Caterham then the Stuart Taylor is probably the closest in looks (to my squinty eyes at least). If looks don't matter, IRS Striker gets my vote.
Will not second-guess the OP again :slapwrist:
Re Dax, I must have some deep-rooted fascination for wide rear wheels. See my profile for further clarification. I'll get over it one day.
Having driven their 4.6 V8 Rush, I thought it was a lot better than the Westfield demonstrator despite the coarse powertrain. And their quality is very high. Retain reservations that a good stab at a BEC Rush can be made for £10k without looking at the finished product and wishing it could've been more comprehensively finished if only there was a little more budget.
This conversation is why I opened the thread on the Mongoose. For a £10k budget that thing should dynamically murder anything but the best Sevens (which you can't buy for £10k). You'd need to really not bother about appearance, though...
Slightly off topic but...
Aerodynamics ref the Fury, is there any factual info or is it all "well it looks like it has less drag (than a seven) and doesn't generate lift" and so anecdotal or subjective? And yes, they win races... but is this more to do with driver/chassis/setup surely.
Back on topic...
I own a Westy (which, understandably, I think is the best car in the entire universe and not only the best car, but the best Westfield - just my unbiased and non-partisan opinion you understand), however, if I wanted a good handling, value for money, light car with a good following... I'd go for a BEC Striker.
As stated, the looks may well be an acquired taste - but from inside the cockpit, you really can see much of it...
I've had a test drive in a BEC Dax and yes, they are well designed and thought out... but heavy, yes they are. So unless you fancy a 350hp Busa motor (which you can't get for 10 anyway) maybe not.
Westys aren't bad and if you can get hold of a BEC Caterham for that budget... why not, it's lighter and apart from normal inter-marque squabling, they're not bad either.
Fury/Silva's are indeed very pretty cars...
Note: I would use the smiley thingys but can't work out how... so just bung 'em in where you feel they are appropriate.
Edited to say: Standard Megablade Westys seem to go between 8 - 10, so they are in your range... and not to be sniffed at.
Edited by tb500 on Friday 22 December 18:03
Edited by tb500 on Friday 22 December 18:03
tb500 said:
Aerodynamics ref the Fury, is there any factual info or is it all "well it looks like it has less drag (than a seven) and doesn't generate lift" and so anecdotal or subjective? And yes, they win races... but is this more to do with driver/chassis/setup surely.
Nothing measured, but have read that the Fury / Pheonix are far superior on faster tracks purely due to aero performance. Under say 60mph there'll be little adverse effect on a & so the weight penalty of the enclosed body will probably negate things if there's one short main straight. On the faster and more open tracks, no question the enclosed cars are quicker.
It's unavoidable that a smoother shape with less sharp edges and profile changes will have a better drag factor. Exposed suspension members on a Seven are a major aspect of their aero performance. Then add the significant effect of a pair of rotating wheels exposed to the airflow at the front end and you have an aerodynamic disaster in action. No getting away from it. Add lights etc for road use and that's more turbulence that there's no solution for.
Also, it'll definitely still generate lift, but less than that of a Seven due to less turbulence in the car's wake.
To truly eliminate lift you really need splitters, wings or diffusers, or all of these, to produce an amount of downforce in excess of the amount of lift the car generates!
All broad statements but have the basic principles of aero theory behind them.
tb500 said:
Note: I would use the smiley thingys but can't work out how... so just bung 'em in where you feel they are appropriate.
When you're posting your next message, click "Smilies legend" to the left of the message box to pop up a smilies decoder. Eg : censored : (without the spaces) for
and so on. But try and keep it cleaner than that Gassing Station | Kit Cars | Top of Page | What's New | My Stuff