Ultimate Seven Product
Discussion
Again, I do agree with you there: to spend all that money on what was effectively a completely new design, [i]but which looks just like a slightly more bloated and clumsier version of the old one, was daft.
If you're going to invest in an all-new chassis (which is a good idea, I think, given the compromises now inherent in the old one), you should at least make it look sufficiently different to the old one to appeal to a new target audience.
That's one of the reasons that I'd personally favour a mid-engined interpretation of the 'Seven' ethos. Something like a modern 23, or the very well-received (but poorly marketed, as ever with Jeremy's designs) Sylva J15.
If you're going to invest in an all-new chassis (which is a good idea, I think, given the compromises now inherent in the old one), you should at least make it look sufficiently different to the old one to appeal to a new target audience.
That's one of the reasons that I'd personally favour a mid-engined interpretation of the 'Seven' ethos. Something like a modern 23, or the very well-received (but poorly marketed, as ever with Jeremy's designs) Sylva J15.
Don't really have a fundamental problem with mid-engines - owned and enjoyed a Europa S2 (yes I am rather geriatric) an Elise and currently have a Cayman - but nothing (other than perhaps a Radical) grabs me by the short and curlies and says "drive me" like a Caterham 7. And it seems - all things being equal - that a mid engined car is 6" wider than a front engined equivalant for easily explained packaging reasons - so I'd favour FERWD for British roads.
bcr5784 said:
And it seems - all things being equal - that a mid engined car is 6" wider than a front engined equivalant for easily explained packaging reasons
What easily explained packaging reasons?There are plenty of mid-engined cars that are not excessively wide. Pertinent to a 'mid-engined Seven', I'd offer the Sylva J15 as an example:
But if you want something really tiny, there's the original GTM Coupe (Mini subframes, hence the same track as an original Mini... actually 6" narrower track than a Caterham):
And a bit of useless knowledge: the Fiat X1/9 actually has an identical front track to the Caterham.
I suppose this is where I should mention (in thee unlikely event of anybody not knowing this already ) that the genesis of the late lamented Clan Crusader was effectively as a Seven replacement. Rear engine, swoopy styling and Imp power- loved mine , but a very different experience to a Seven. You stayed dry and weren't deafened for a start.........
Equus said:
What easily explained packaging reasons?
There are plenty of mid-engined cars that are not excessively wide. Pertinent to a 'mid-engined Seven', I'd offer the Sylva J15 as an example:
But if you want something really tiny, there's the original GTM Coupe (Mini subframes, hence the same track as an original Mini... actually 6" narrower track than a Caterham):
And a bit of useless knowledge: the Fiat X1/9 actually has an identical front track to the Caterham.
Packaging. On a mid engined car you have to push the driver forward between the wheelarches to keep the wheelbase in check. You then have some difficult choices. There are plenty of mid-engined cars that are not excessively wide. Pertinent to a 'mid-engined Seven', I'd offer the Sylva J15 as an example:
But if you want something really tiny, there's the original GTM Coupe (Mini subframes, hence the same track as an original Mini... actually 6" narrower track than a Caterham):
And a bit of useless knowledge: the Fiat X1/9 actually has an identical front track to the Caterham.
1) Do you make the car wider so you can avoid an offset driving position and still retain a decent steering lock?
2) If you have a large central tunnel (Esprit/Cayman/Europa) you can't offset the driving position much so you make the car wider AND probably restrict the steering lock (Esprit, Europa)
or 3) make the car wider and keep a decent lock but bugger up Ackermann so you get a lot of tyre scrub (Cayman). The Esprit manages to to be humongously wide, have a dreadful turning circle and lots of tyre scrub - quite an achievement.
At the rear too the gearbox tends to get in the way of suspension components and tends to mean the rear track is quite wide (look at a Zenos)
I must admit I haven't driven (or sat in) most of the kit cars shown - but I'd be very surprised if they didn't suffer from some or all of the problems (the X1/9 certainly does) compared with equivalent front engined cars (with similar width wheels). eg the Elan S1 is 4ft 8" wide a Europa S1 5ft 4 with similar chassis construction. The Elise is probably the narrowest modern series production mid-engined car at 5ft 8" - which is definitely wider than I prefer and a Cayman is 5ft 10" and feels vast on the sort of country roads where the 7 would excel.
bcr5784 said:
Packaging. On a mid engined car you have to push the driver forward between the wheelarches to keep the wheelbase in check.
:cough: Bellhousing :cough:Having recently designed a 'Seven'-style front engined roadster (prototype under assembly at the moment), I can tell you that intrusion of the gearbox and bellhousing cause much more of an obstruction on a front-mid engined design than the wheel arches on a rear mid-engine one. Especially when your client insists on the option of using a Mazda 6-speed, which is a big lump, aft of the bellhousing, but that's another story.
I'm 6'0" tall and not lightly built. I struggle with the pedal box on a Seven, with my size 10 feet, but I've owned an X1/9 and was quite happy in it, and have driven a GTM without any issues.
Equus said:
:cough: Bellhousing :cough:
Having recently designed a 'Seven'-style front engined roadster (prototype under assembly at the moment), I can tell you that intrusion of the gearbox, bellhousing and, in front of that, exhaust manifolds cause much more of an obstruction on a front-mid engined design than the wheel arches on a rear mid-engine one. Especially when your client insists on the option of using a Mazda 6-speed, which is a big lump, aft of the bellhousing, but that's another story.
I'm 6'0" tall and not lightly built. I struggle with the pedal box on a Seven, with my size 10 feet, but I've owned an X1/9 and was quite happy in it, and have driven a GTM without any issues.
We are not really comparing like with like here. Cars with full width bodies have more packaging options than 7-style ones .Having recently designed a 'Seven'-style front engined roadster (prototype under assembly at the moment), I can tell you that intrusion of the gearbox, bellhousing and, in front of that, exhaust manifolds cause much more of an obstruction on a front-mid engined design than the wheel arches on a rear mid-engine one. Especially when your client insists on the option of using a Mazda 6-speed, which is a big lump, aft of the bellhousing, but that's another story.
I'm 6'0" tall and not lightly built. I struggle with the pedal box on a Seven, with my size 10 feet, but I've owned an X1/9 and was quite happy in it, and have driven a GTM without any issues.
That said, I agree about the pedal box on a 7 - but it's no worse than a Europa S1 which is much wider - and there is plenty of scope to make it wider on the 7 without making the car wider with modest changes to the chassis design. Just making the whole thing wider a la SV isn't the way to go. Although we haven't touched on it before the 7 packaging is bad and could be much improved - the Elan (S1) is no wider (with the same size tyres - narrower than current 7s) and much better packaged. Any 7-style car (ie one without a "full width" body) is going to suffer in that regard. But any "Aero" 7 would surely have a full width body with a lot of scope for a decent pedal box without going any wider.
Re X1/9 it is 6" wider than an Elan of the same vintage and it's driving position was widely critised - but I can see that the width of the 7 pedal box will be an (as I say, fundamentally unnecessary) issue for many.
bcr5784 said:
We are not really comparing like with like here. Cars with full width bodies have more packaging options than 7-style ones .
Close enough for you, or are the colours not right for a like-for-like comparison?
The first one (Sylva R1ot) is actually 3" narrower than a Caterham, and the 'packaging' is pretty much identical to the Sylva J15, pictured on my previous post, as they are essentially derivatives of the same chassis design.
king great big engine and bellhousing in the middle of the two footwells. 
I also said that in order to shorten the wheelbase you (normally) push the driver BETWEEN the front wheels in a mid engined car. In this case they have chosen/had no option but to go for a longer wheelbase and put the driver behind the front wheels. Even vaguely mainstream mid engined car designers generally don't take that route and as I have explained (ad nauseam) the result is that in the vast majority of cases mid engined cars are significantly wider than their front engined counterparts.
bcr5784 said:
I also said that in order to shorten the wheelbase you (normally) push the driver BETWEEN the front wheels in a mid engined car.
So in other words, you are saying: 'this will not work if you choose the wrong design solution, as I tell you to!'?
All designs are based on a whole host of conflicting requirements and compromises. I have demonstrated that it isperfectly possible and straightforward to deliver a mid-engined layout that is just as compact as the Seven's front-engined equivalent, if those are your particular criteria.
bcr5784 said:
In this case they have chosen/had no option but to go for a longer wheelbase and put the driver behind the front wheels.
No they haven't: the Sylva's wheelbase is 2,260mm (89"). The Caterham Seven's wheelbase is 2,225mm (87.6")... near as damn it identical, though I'm sure we'll now face several posts quibbling over the extra 35mm (1.4"), as if it couldn't easily be absorbed by other tweaks to the design, if necessary.To suggest that they had 'no option but to go for a longer wheelbase' transcends absurdity: the R1ot is one of the smallest modern cars out there (as I said, narrower than the Caterham, by 3").
For what it's worth, the Lotus 23 places the driver's feet between the front wheels, yet still manages to be 2" narrower than the Caterham, too.
You're clearly determined to put up whatever spurious and lunatic argument possible to justify that the Caterham Seven cannot be bettered: that its antique chassis construction with its woeful torsional stiffness remains superior to anything we could achieve today, that (contrary to the evidence offered by every modern race car) de Dion remains the ultimate suspension solution, and now that its dimensional packaging cannot be matched by other configurations when quite demonstrably it can.
What have we got next? That the aerodynamics are unmatched, because no other car slows down as fast when you lift your foot off the gas?
As far as I am aware, there is quite a lot less room in a R1ot than in a De Dion S3, so that partly explains its small exterior dimensions.
My suspicion is that modern mid engined designs are substantially wider than a Seven for two basic reasons:
1. Wider track and wheels/tyres is an easy way to make a car go around corners faster
2. Transverse mid engine designs using FWD components have most of their mass over the rear axle, and in a very light design this is exaggerated. This weight distribution and low polar moment will tend to cause an abrupt change to oversteer at the limit, and a wider rear track and tyres are often used to mitigate this handling trait.
My suspicion is that modern mid engined designs are substantially wider than a Seven for two basic reasons:
1. Wider track and wheels/tyres is an easy way to make a car go around corners faster
2. Transverse mid engine designs using FWD components have most of their mass over the rear axle, and in a very light design this is exaggerated. This weight distribution and low polar moment will tend to cause an abrupt change to oversteer at the limit, and a wider rear track and tyres are often used to mitigate this handling trait.
The big difference between the R1ot and the Caterham is less shoulder room, due to no tunnel, if you have a passenger. They've widened the seat area a bit (though not the pedal box) on the J15, I think.
There's the other, rather more pragmatic issue of retaining donor track dimensions for things like driveshafts and steering racks, too, of course.
Weight distribution is becoming less of a problem with modern, all-alloy lightweight engine installations like the Ford Sigma and ironically, with very lightweight engines (bike mid-engine installations, in particular), rear mid-engined cars can sometimes end up with problems due to being more nose-heavy than front mid-engined ones once you add the driver... ask the 750MC Bikesports guys!
But, yes (much to bcr5784's chagrin, I suspect), the modern trend (on both front and rear engined cars, including Caterhams) is for wider track simply for the better grip it offers.
There's the other, rather more pragmatic issue of retaining donor track dimensions for things like driveshafts and steering racks, too, of course.
Weight distribution is becoming less of a problem with modern, all-alloy lightweight engine installations like the Ford Sigma and ironically, with very lightweight engines (bike mid-engine installations, in particular), rear mid-engined cars can sometimes end up with problems due to being more nose-heavy than front mid-engined ones once you add the driver... ask the 750MC Bikesports guys!
But, yes (much to bcr5784's chagrin, I suspect), the modern trend (on both front and rear engined cars, including Caterhams) is for wider track simply for the better grip it offers.
Equus said:
No they haven't: the Sylva's wheelbase is 2,260mm (89"). The Caterham Seven's wheelbase is 2,225mm (87.6")... near as damn it identical, though I'm sure we'll now face several posts quibbling over the extra 35mm (1.4"), as if it couldn't easily be absorbed by other tweaks to the design, if necessary.
To suggest that they had 'no option but to go for a longer wheelbase' transcends absurdity: the R1ot is one of the smallest modern cars out there (as I said, narrower than the Caterham, by 3").
For what it's worth, the Lotus 23 places the driver's feet between the front wheels, yet still manages to be 2" narrower than the Caterham, too.
You're clearly determined to put up whatever spurious and lunatic argument possible to justify that the Caterham Seven cannot be bettered: that its antique chassis construction with its woeful torsional stiffness remains superior to anything we could achieve today, that (contrary to the evidence offered by every modern race car) de Dion remains the ultimate suspension solution, and now that its dimensional packaging cannot be matched by other configurations when quite demonstrably it can.
What have we got next? That the aerodynamics are unmatched, because no other car slows down as fast when you lift your foot off the gas?
I think you are being deliberately argumentative. I said "chose/had no option but" to go for a longer wheelbase. The Sylva has a VERY compact (transverse bike) engine and so it might be a reasonable to make that decision. Re the 23 - lock, tyre size vs CURRENT Caterham - and as I say 7 -style vs full width is ignored ? I have said there are a number of (potentially conflicting) compromises that have to be made and as you have implied there are compromises that a race car can make but are unacceptable on a road car.To suggest that they had 'no option but to go for a longer wheelbase' transcends absurdity: the R1ot is one of the smallest modern cars out there (as I said, narrower than the Caterham, by 3").
For what it's worth, the Lotus 23 places the driver's feet between the front wheels, yet still manages to be 2" narrower than the Caterham, too.
You're clearly determined to put up whatever spurious and lunatic argument possible to justify that the Caterham Seven cannot be bettered: that its antique chassis construction with its woeful torsional stiffness remains superior to anything we could achieve today, that (contrary to the evidence offered by every modern race car) de Dion remains the ultimate suspension solution, and now that its dimensional packaging cannot be matched by other configurations when quite demonstrably it can.
What have we got next? That the aerodynamics are unmatched, because no other car slows down as fast when you lift your foot off the gas?
And suggesting that I am suggesting the Caterham 7 cannot be bettered? For God's sake I suggest you read what I wrote!!! There is no point is arguing with someone who is arguing against points I haven't made or views I don't hold. I simply do not think that the route to a 7 replacement lies quite in the direction you do. Endof
bcr5784 said:
I think you are being deliberately argumentative.
Pot... kettle...blackBut at least try to get your facts correct: you keep coming out with these statements, then hair-splitting ad infinitum when simple, straightforward evidence is presented that they're nonsense!
Your original assertion was that "And it seem - all things being equal - that a mid engined car is 6" wider than a front engined equivalent for easily explained packaging reasons".
Which is plainly and simply wrong... so we've gone from 'all things being equal' via 'you're not comparing like with like by using full-bodied cars' to 'if you follow my specific, illogical design strategy, then it doesn't work'.
Almost as comical as your 'if you do that, it'll be competing with other cars', when the current design is on one of the most crowded sectors of the kit car indistry that it's possible to imagine!
bcr5784 said:
The Sylva has a VERY compact (transverse bike) engine
No it doesn't. The J15 was designed for the Ford Sigma engine, and has also been fitted with several other engines, including Zetec, Duratec, Rover K-series and Honda Vtec. The R1ot was designed for the Yamaha R1 bike engine, but has also been fitted with a variety of 4-cylinder car engines, including Sigma, Zetec and Ecoboost. But the point is moot: bike engines when fitted in a rear-mid installation actually take up more space (particularly lengthways) than a car engine, due to the need for a separate chain-driven diff.
Can we start again - you seem to be getting hot under the collar? I think (know) the aero of the 7 is crap. I know the packaging of the 7 is crap (though it does lead to low weight). I disagree that radical changes of suspension or even chassis design are going to yield significant gains (we will disagree - so what?) and I'm unconvinced that a mid engined solution will be better for a road car (we will disagree - so what). Can we just agree on that?
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