S2000 GT

[Urban Sports]

havoc said:

I'm no Schumacher either, but I CAN tell. The car, following fitment back in November, felt like it had more mechanical grip and a smoother progression at break-away. Same thing happened last winter.

That combination CAN'T be achieved through any incidental geometry change, therefore I can only attribute it to less body flex under load.

I'd consider reading up on the conversion of coupes to roadsters (e.g. Astons, 3-series, 911...), and the additional body strengthening that is required to restore at least some of the lost stiffness when the roof is cut-off. If THAT is widely accepted (and I can't see a car company wasting money doing it for no reason...), then why are you questioning the opposite effect?!?



Oh...and I'd read up on car design to go with your Physics if I were you...the only current mass-production car I'm aware of with both a chassis and a monocoque is the LR3 Discovery. Virtually all modern cars DO NOT HAVE A SEPARATE CHASSIS!


PistonHeads - Closed-mindedness Matters!

Oh dear somebody has challenged Havoc's point of view

[MrFlibbles]

Urban Sports said:

havoc said:

I'm no Schumacher either, but I CAN tell. The car, following fitment back in November, felt like it had more mechanical grip and a smoother progression at break-away. Same thing happened last winter.

That combination CAN'T be achieved through any incidental geometry change, therefore I can only attribute it to less body flex under load.

I'd consider reading up on the conversion of coupes to roadsters (e.g. Astons, 3-series, 911...), and the additional body strengthening that is required to restore at least some of the lost stiffness when the roof is cut-off. If THAT is widely accepted (and I can't see a car company wasting money doing it for no reason...), then why are you questioning the opposite effect?!?



Oh...and I'd read up on car design to go with your Physics if I were you...the only current mass-production car I'm aware of with both a chassis and a monocoque is the LR3 Discovery. Virtually all modern cars DO NOT HAVE A SEPARATE CHASSIS!


PistonHeads - Closed-mindedness Matters!

Oh dear somebody has challenged Havoc's point of view

Now Im no engineer but wouldnt there be some flex around the hard top mounting points, thus negating any handling benefit?

[havoc]

MrFlibbles said:

Now Im no engineer but wouldnt there be some flex around the hard top mounting points, thus negating any handling benefit?

If there was, wouldn't it rattle?
More detail - hardtop mounting points (x4) are essentially metal-to-metal, and clamped/locked in place - I'll bet they're as solid as any bolted section in the chassis.

Second point - would you expect any flex around the rear-half of the hard-top where it presses into the body? (Yes, there's a rubber seal, but that's compressed for water-proofing...doubt you'll get much 'give' there) Ditto along the top of the window-frame.


I'm not saying that fitting a fibreglass hardtop will give the car the same rigidity as a coupe - fibreglass itself will naturally flex marginally more under load than steel/aluminium will. But I believe it does make a difference, both from a theoretical and an empirical standpoint.


Oh...US - if you've nothing useful to add, don't bother, eh?!?

[Urban Sports]

havoc said:

MrFlibbles said:

Now Im no engineer but wouldnt there be some flex around the hard top mounting points, thus negating any handling benefit?

If there was, wouldn't it rattle?
More detail - hardtop mounting points (x4) are essentially metal-to-metal, and clamped/locked in place - I'll bet they're as solid as any bolted section in the chassis.

Second point - would you expect any flex around the rear-half of the hard-top where it presses into the body? (Yes, there's a rubber seal, but that's compressed for water-proofing...doubt you'll get much 'give' there) Ditto along the top of the window-frame.


I'm not saying that fitting a fibreglass hardtop will give the car the same rigidity as a coupe - fibreglass itself will naturally flex marginally more under load than steel/aluminium will. But I believe it does make a difference, both from a theoretical and an empirical standpoint.


Oh...US - if you've nothing useful to add, don't bother, eh?!?

I'll say nothing and just read you spouting off useless crap then

[MrFlibbles]

havoc said:

MrFlibbles said:

Now Im no engineer but wouldnt there be some flex around the hard top mounting points, thus negating any handling benefit?

If there was, wouldn't it rattle?
More detail - hardtop mounting points (x4) are essentially metal-to-metal, and clamped/locked in place - I'll bet they're as solid as any bolted section in the chassis.

Not nesscessarily - there's flex with the suspension mounting points and various other chassis components when under load - hence the need for strut braces etc. They don't rattle but the flex is still there.

[normalbloke]

"More detail - hardtop mounting points (x4) are essentially metal-to-metal, and clamped/locked in place - I'll bet they're as solid as any bolted section in the chassis."

I strongly disagree.Our experience of our S2K with hardtop, indicates that it does move around on the car.If a bolted section did this on the car I'd be atraight out there with the spanners...

[JM-S2K]

havoc said:

I'm no Schumacher either, but I CAN tell. The car, following fitment back in November, felt like it had more mechanical grip and a smoother progression at break-away. Same thing happened last winter.

That combination CAN'T be achieved through any incidental geometry change, therefore I can only attribute it to less body flex under load.

I'd consider reading up on the conversion of coupes to roadsters (e.g. Astons, 3-series, 911...), and the additional body strengthening that is required to restore at least some of the lost stiffness when the roof is cut-off. If THAT is widely accepted (and I can't see a car company wasting money doing it for no reason...), then why are you questioning the opposite effect?!?



Oh...and I'd read up on car design to go with your Physics if I were you...the only current mass-production car I'm aware of with both a chassis and a monocoque is the LR3 Discovery. Virtually all modern cars DO NOT HAVE A SEPARATE CHASSIS!


PistonHeads - Closed-mindedness Matters!

Firstly I cant see how you've come to the conclusion that what you're car feels like when you have the hardtop on can only be attributed to "less body flex under load" but never mind.... with all the explanation of why that cant be the case you'll never change your mind. But I'm gonna add my 2 pence anyway without using pointless smilies!

Now you are a little confused aren't you. You've completely missunderstood a point I made earlier, I'll try and explain it a little better for you.
I quite understand why car manufacturers have to provide extra strengthening when converting a coupe to a convertable as they have lost a load of structural integrity and strength in the process. But this extra strengthening adds extra weight (in most cases) and it is widely accepted that the convertable version of (originally) a coupe model doesn't handle as well due to the extra weight and less structural integrity.
The S2K (as I know you know) was designed as a convertable so it already has this "extra" strengthening built in. So a hardtop made of a flimsy (in comparison to the rest of the chassis/monocoque) material will not add any structural integrity or strength. Hence I can not see how it will ever improve the handling but simply add weight.

Adding cross braces or other suspension componants are another (completely different) matter and come into their own as to how they can improve handling.

At no point did I mention that a chassis and monocoque were different things. I simply used chassis in the first place as it is the commonly used term to describe the monocoque. Oh and Monocoque means Single or One Shell so again how can something bolted onto it become part of it?

[Urban Sports]

JM-S2K said:

havoc said:

I'm no Schumacher either, but I CAN tell. The car, following fitment back in November, felt like it had more mechanical grip and a smoother progression at break-away. Same thing happened last winter.

That combination CAN'T be achieved through any incidental geometry change, therefore I can only attribute it to less body flex under load.

I'd consider reading up on the conversion of coupes to roadsters (e.g. Astons, 3-series, 911...), and the additional body strengthening that is required to restore at least some of the lost stiffness when the roof is cut-off. If THAT is widely accepted (and I can't see a car company wasting money doing it for no reason...), then why are you questioning the opposite effect?!?



Oh...and I'd read up on car design to go with your Physics if I were you...the only current mass-production car I'm aware of with both a chassis and a monocoque is the LR3 Discovery. Virtually all modern cars DO NOT HAVE A SEPARATE CHASSIS!


PistonHeads - Closed-mindedness Matters!

Firstly I cant see how you've come to the conclusion that what you're car feels like when you have the hardtop on can only be attributed to "less body flex under load" but never mind.... with all the explanation of why that cant be the case you'll never change your mind. But I'm gonna add my 2 pence anyway without using pointless smilies!

Now you are a little confused aren't you. You've completely missunderstood a point I made earlier, I'll try and explain it a little better for you.
I quite understand why car manufacturers have to provide extra strengthening when converting a coupe to a convertable as they have lost a load of structural integrity and strength in the process. But this extra strengthening adds extra weight (in most cases) and it is widely accepted that the convertable version of (originally) a coupe model doesn't handle as well due to the extra weight and less structural integrity.
The S2K (as I know you know) was designed as a convertable so it already has this "extra" strengthening built in. So a hardtop made of a flimsy (in comparison to the rest of the chassis/monocoque) material will not add any structural integrity or strength. Hence I can not see how it will ever improve the handling but simply add weight.

Adding cross braces or other suspension componants are another (completely different) matter and come into their own as to how they can improve handling.

At no point did I mention that a chassis and monocoque were different things. I simply used chassis in the first place as it is the commonly used term to describe the monocoque. Oh and Monocoque means Single or One Shell so again how can something bolted onto it become part of it?

I agree, that's absolutely drivel that Havoc is spouting, laughable in fact how the hell can a hardtop add to the structural integrity of the car?

Maybe Havoc has some sixth sense that us mere mortals do not posses. In fact my car has much more structural rigidity with the hood up.

[havoc]

JM,

Fair response.

However I've got to disagree with one point of your statement - you say that a car not designed as a convertible loses integrity when the top is chopped, so needs extra bracing, but then say that a purpose-designed convertible (WITH the extra bracing already) can't be made stiffer by the addition of a hard-top.

Now...not 100% the same (close though), but what about the Cayman and Z4 Coupe - both designed FROM roadsters, but both known to have more structural rigidity than the soft-top, and both considered to handle better as a result. And the only extra metal there is the C-pillars and the roof. Which, permanency and metal-vs-fibreglass aside, is pretty similar to putting a hardtop on a Box/Z4/S2000.

So I think you're missing a key step in the logic there...



As to your first point - how I arrived at my conclusion. Well, the only change I made (twice) was the addition of the hard-top. And the immediate consequence (twice) was greater predictability to the handling and a feeling of more outright grip. Now the grip could have been down to a slight change to the rear camber following the hardtop fitment. But doing that would have reduced the progression on the limit, not improved it. Whereas the other mods I've made (cross-braces) which have increased structural rigidity have also improved progression.
So I've drawn the most logical conclusion from that information. If you don't want to believe me, go right ahead - I COULD be wrong. But I can't think of another logical reason for the combination of effects following just the one single change...and I've put a lot of effort into researching chassis/handling dynamics so I can get the most out of my cars.


Normalbloke - I'm surprised - haven't heard a squeak or rattle from mine since I padded-out the clasp-pins that fit at the top of the A-pillars. But I've only had the one S2000. Maybe some hardtops fit better than others?!?

[havoc]

MrFlibbles said:

havoc said:

MrFlibbles said:

Now Im no engineer but wouldnt there be some flex around the hard top mounting points, thus negating any handling benefit?

If there was, wouldn't it rattle?
More detail - hardtop mounting points (x4) are essentially metal-to-metal, and clamped/locked in place - I'll bet they're as solid as any bolted section in the chassis.

Not nesscessarily - there's flex with the suspension mounting points and various other chassis components when under load - hence the need for strut braces etc. They don't rattle but the flex is still there.

Just a quick one...you're saying there's flex elsewhere in the structure - but by that measure there's flex EVERYWHERE in the structure (even an Elise/Aston), but only under severe loads. I'm saying there no OBVIOUS flex around the hard-top hardpoints.

[MrFlibbles]

havoc said:

MrFlibbles said:

havoc said:

MrFlibbles said:

Now Im no engineer but wouldnt there be some flex around the hard top mounting points, thus negating any handling benefit?

If there was, wouldn't it rattle?
More detail - hardtop mounting points (x4) are essentially metal-to-metal, and clamped/locked in place - I'll bet they're as solid as any bolted section in the chassis.

Not nesscessarily - there's flex with the suspension mounting points and various other chassis components when under load - hence the need for strut braces etc. They don't rattle but the flex is still there.

Just a quick one...you're saying there's flex elsewhere in the structure - but by that measure there's flex EVERYWHERE in the structure (even an Elise/Aston), but only under severe loads. I'm saying there no OBVIOUS flex around the hard-top hardpoints.

Meh, I'm no engineer

I stand by my orginal statement that hard tops are for woofters

[Russ H]

Lotus dont recomend you remove the 'hardtop' on the Exige, not 100% sure its
to do with ridgidity??

Anyway IMO the Honda hard top looks shite, especialy the part at the bottom
that meets the body of the car. Dont get it at all.

Russ.

[MrFlibbles]

Russ H said:

Lotus dont recomend you remove the 'hardtop' on the Exige, not 100% sure its
to do with ridgidity??

Anyway IMO the Honda hard top looks shite, especialy the part at the bottom
that meets the body of the car. Dont get it at all.

Russ.

I reckon it looks alright

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[havoc]

MrFlibbles said:

I stand by my orginal statement that hard tops are for woofters

Did I ever say what an attractive man you are Russ?!?




Personally I think the S looks best roof-down. 2nd best with the hardtop. Worst soft-top up.

...which is probably why when the hardtop comes off the roof is only ever up when the car's parked (OK, OK...or when it's raining...)!

[RedCabbage]

IME hard tops do appear to increase overall rigidity, the four point location set up certainly reduces scuttle shake.

:tossessnowballintohell:

[bracken78]

Ignoring the hard top issue, I’ve had the S2000 for about Mmmm 4 days and 200 miles and so far, love it. Wanted one ever since they came out but was never (Insurance wise) in a position to buy. But now, with insurance under £800 I have a 2005 S2000.

I’m very happy.

[MiloD]

enjoy it - take it easy on these slippery roads!

[havoc]

Get yourself over to s2ki.co.uk - lots of good advice there.

...and unless the tyres are going to need replacing in the next couple of k, get the alignment checked (and the suspension adjustment bolts too, while the car's still in warranty!)...proper alignment can make a very big difference to the handling, and the S has adjustable castor, camber and toe, so lots to play with!!!

[bracken78]

havoc said:

Get yourself over to s2ki.co.uk - lots of good advice there.

...and unless the tyres are going to need replacing in the next couple of k, get the alignment checked (and the suspension adjustment bolts too, while the car's still in warranty!)...proper alignment can make a very big difference to the handling, and the S has adjustable castor, camber and toe, so lots to play with!!!

Hi Havoc,

I've be joining s2Ki.co.uk tonight.

Do you know any good places to get the alignmnet checked, or is there a list on s2Ki? It has just had new back tyres, but the fronts only have about 3K left in them.

[RedCabbage]

bracken78 said:

havoc said:

Get yourself over to s2ki.co.uk - lots of good advice there.

...and unless the tyres are going to need replacing in the next couple of k, get the alignment checked (and the suspension adjustment bolts too, while the car's still in warranty!)...proper alignment can make a very big difference to the handling, and the S has adjustable castor, camber and toe, so lots to play with!!!

Hi Havoc,

I've be joining s2Ki.co.uk tonight.

Do you know any good places to get the alignmnet checked, or is there a list on s2Ki? It has just had new back tyres, but the fronts only have about 3K left in them.

Google 'Centre Gravity' he's the guy they all trust.