Cayman vs boxster

[cardigankid]

The only way is to drive both yourself. I was astounded by the ability of the Cayman S, which, though less meaty than the 911, was to my mind perfection on wheels. I haven't driven a 3.4 Boxster S though.

Is it not the torque which is making the difference between the Cayman and the 911, rather than the power?

[heebeegeetee]

shoestring7 said:

Road & Track (Sept 2005) said: "Compared with the Boxster, the big difference of course is that the Cayman is a closed car......Porsche engineers have retained the Boxster’s strong floorpan without modification with the result that the close car is only 11lb lighter that the comparable Boxster.

On the other hand the Caymans S's torsional stiffness is 2.5 times higher that the Boxster S (which ranks as one of the structurally stiffest contemporary open cars) and only 5% lover that the 997 series Carrera. The beam stiffness is also doubled compared with the roadster’s."

Porsche must hve slipped this information into the Cayman press packs. I've seen it reference in a number of press articles, but the actual figures are not, as far as I can tell, published.

SS7

wow. Makes you wonder where they'll end up, when every new car is twice as stiff as the previous.

[S1MMA]

heebeegeetee said:

shoestring7 said:

Road & Track (Sept 2005) said: "Compared with the Boxster, the big difference of course is that the Cayman is a closed car......Porsche engineers have retained the Boxster’s strong floorpan without modification with the result that the close car is only 11lb lighter that the comparable Boxster.

On the other hand the Caymans S's torsional stiffness is 2.5 times higher that the Boxster S (which ranks as one of the structurally stiffest contemporary open cars) and only 5% lover that the 997 series Carrera. The beam stiffness is also doubled compared with the roadster’s."

Porsche must hve slipped this information into the Cayman press packs. I've seen it reference in a number of press articles, but the actual figures are not, as far as I can tell, published.

SS7

wow. Makes you wonder where they'll end up, when every new car is twice as stiff as the previous.

They'll probably end up with a stiffy.

Boom boom tish.

[noumenon]

shoestring7 said:

heebeegeetee said:

shoestring7 said:

Correct, although the Cayman has >2x tortional stiffness of the Boxster,

Are you sure, is that right? Given than manufacturers have been making cars stiffer and stiffer from day 1, i'm surprised to learn that they are still able to make such leaps and bounds with road cars using conventional materials. Given that we are talking road cars here, with road suspension and tyres, i really would think that there comes a point where increased rigidity of the structure is not going to make much difference anymore. Is the roof of the Cayman stressed? if not, it won't be adding any major difference to the rigidity of the structure. (Porsche being Porsche though, i would imagine that it is indeed a stressed skin).

Had the Cayman come out first, and Porsche had lopped the roof off to make the Boxster, then the cayman might be twice as rigid as the Boxster, but as that's not the case i'm surprised to hear that there's such a difference. Or, as the Boxster is getting a bit old now, had the body shell been substantially re-engineered to make the Cayman, i could understand the difference, but again, i don't think that is the case.

Road & Track (Sept 2005) said: "Compared with the Boxster, the big difference of course is that the Cayman is a closed car......Porsche engineers have retained the Boxster’s strong floorpan without modification with the result that the close car is only 11lb lighter that the comparable Boxster.

On the other hand the Caymans S's torsional stiffness is 2.5 times higher that the Boxster S (which ranks as one of the structurally stiffest contemporary open cars) and only 5% lover that the 997 series Carrera. The beam stiffness is also doubled compared with the roadster’s."

Porsche must hve slipped this information into the Cayman press packs. I've seen it reference in a number of press articles, but the actual figures are not, as far as I can tell, published.

SS7

A bit google suggests stiffnesses of (in NM/deg):
early MX5 4,800
Elise s1 10,000
Z4 14,500
BMW e46 coupe/saloon 13,500 - 16,000
Boxster 16,000
Ferrari 360 23,000
Z4 Coupe 28,000
Cayman 31,500

We know cars are getting stiffer. I wouldn't say stiffer is automatically better. There are some brilliant cars out there with poor torsional stiffness (by today's standards) - mx5, 205gti, elise. Even the e46 comes in less stiff than a Boxster and I never heard any complaints about them.

Cornering loads are small compared to this. Consider that a boxster weighs about 1300kgs, say 1600 fully loaded (and to make the calcs easier). It can corner at about 1g, creating a centripetal force of about 1600N. The rigidity is 16,000 NM/deg. Assuming the cornering load is shared between the two outer wheels alone and pessimistically assuming the chassis is 45 degrees to the load (unlikely unless you're russ swift). That equates to 400/16000 = 0.025 degrees of flex. If a cayman flexes half that, do you really think you'll notice that extra 0.0125 degrees? (Feel free to correct me if my engineering maths is wrong, it's been a while!).

Porsche want you to feel slightly better about the Cayman so you'll pay a premium to buy them. If it didn't have some mythical handling advantage, you'd just buy the cheaper boxster. IMHO it's 99% marketing hype, 1% real world.

My advice is to try them both and buy the one you like.

Edited by noumenon on Monday 18th August 17:29

[Andrew D]

heebeegeetee said:

Had the Cayman come out first, and Porsche had lopped the roof off to make the Boxster, then the cayman might be twice as rigid as the Boxster, but as that's not the case i'm surprised to hear that there's such a difference. Or, as the Boxster is getting a bit old now, had the body shell been substantially re-engineered to make the Cayman, i could understand the difference, but again, i don't think that is the case.

[EngineerMode]Ah, you see it's all about the second moment of area (kinda)[/EngineerMode]

[Adam B]

noumenon said:

Porsche want you to feel slightly better about the Cayman so you'll pay a premium to buy them. If it didn't have some mythical handling advantage, you'd just buy the cheaper boxster. IMHO it's 99% marketing hype, 1% real world.

My advise is to try them both and buy the one you like.

should be the default cut and paste response to the "Cayman v Boxster" or "are Caymans too expensive?" threads

[Dr S]

Geneve said:

IMO, £ for £, the Boxster 'S' is one of the best cars Porsche has ever made.

2nded

[4sure]

turded

[jackwood]

noumenon said:

shoestring7 said:

heebeegeetee said:

shoestring7 said:

Correct, although the Cayman has >2x tortional stiffness of the Boxster,

Are you sure, is that right? Given than manufacturers have been making cars stiffer and stiffer from day 1, i'm surprised to learn that they are still able to make such leaps and bounds with road cars using conventional materials. Given that we are talking road cars here, with road suspension and tyres, i really would think that there comes a point where increased rigidity of the structure is not going to make much difference anymore. Is the roof of the Cayman stressed? if not, it won't be adding any major difference to the rigidity of the structure. (Porsche being Porsche though, i would imagine that it is indeed a stressed skin).

Had the Cayman come out first, and Porsche had lopped the roof off to make the Boxster, then the cayman might be twice as rigid as the Boxster, but as that's not the case i'm surprised to hear that there's such a difference. Or, as the Boxster is getting a bit old now, had the body shell been substantially re-engineered to make the Cayman, i could understand the difference, but again, i don't think that is the case.

Road & Track (Sept 2005) said: "Compared with the Boxster, the big difference of course is that the Cayman is a closed car......Porsche engineers have retained the Boxster’s strong floorpan without modification with the result that the close car is only 11lb lighter that the comparable Boxster.

On the other hand the Caymans S's torsional stiffness is 2.5 times higher that the Boxster S (which ranks as one of the structurally stiffest contemporary open cars) and only 5% lover that the 997 series Carrera. The beam stiffness is also doubled compared with the roadster’s."

Porsche must hve slipped this information into the Cayman press packs. I've seen it reference in a number of press articles, but the actual figures are not, as far as I can tell, published.

SS7

A bit google suggests stiffnesses of (in NM/deg):
early MX5 4,800
Elise s1 10,000
Z4 14,500
BMW e46 coupe/saloon 13,500 - 16,000
Boxster 16,000
Ferrari 360 23,000
Z4 Coupe 28,000
Cayman 31,500

We know cars are getting stiffer. I wouldn't say stiffer is automatically better. There are some brilliant cars out there with poor torsional stiffness (by today's standards) - mx5, 205gti, elise. Even the e46 comes in less stiff than a Boxster and I never heard any complaints about them.

Cornering loads are small compared to this. Consider that a boxster weighs about 1300kgs, say 1600 fully loaded (and to make the calcs easier). It can corner at about 1g, creating a centripetal force of about 1600N. The rigidity is 16,000 NM/deg. Assuming the cornering load is shared between the two outer wheels alone and pessimistically assuming the chassis is 45 degrees to the load (unlikely unless you're russ swift). That equates to 400/16000 = 0.025 degrees of flex. If a cayman flexes half that, do you really think you'll notice that extra 0.0125 degrees? (Feel free to correct me if my engineering maths is wrong, it's been a while!).

Porsche want you to feel slightly better about the Cayman so you'll pay a premium to buy them. If it didn't have some mythical handling advantage, you'd just buy the cheaper boxster. IMHO it's 99% marketing hype, 1% real world.

My advice is to try them both and buy the one you like.

Edited by noumenon on Monday 18th August 17:29

Obviously that is all assuming a steady state condition. And correct, in those circumstances nobody would be able to tell the difference and nobody would care.

Would the benefit of the increase in structural integrity be in the ability to more closely control damping be when you are already at the optimum cornering attitude and then throw in a sharp ridge or dip?

Isn’t that more the point and benefit of increased structural and torsional rigidity?

[jackal]

Geneve said:

jackal said:

i drove a boxster recently.. it was all silky and light and sort of sanitised..
all the controls made it feel like any old VAG car tbh

sure, engine sounded quite nice (bugger all torque though) and body control/ride was exemplary but it was all a bit mainstream and non-special. Could just as well have been in a seat leon with a slightly more interesting engine note imo. I'd say go for the Cayman.

Which model was that - a 2.5 or 2.7?

It certainly doesn't describe the 3.2/3.4'S'.

I often drive a 987'S' back to back with a 2.7RS and a 997GT3, and I've never been disappointed.

IMO, £ for £, the Boxster 'S' is one of the best cars Porsche has ever made. Of course it's now 10 years old, and so familiar that I suppose most people take it for granted.

it was 8 month old 987
but not the S, just the standard car

[heebeegeetee]

Andrew D said:

heebeegeetee said:

Had the Cayman come out first, and Porsche had lopped the roof off to make the Boxster, then the cayman might be twice as rigid as the Boxster, but as that's not the case i'm surprised to hear that there's such a difference. Or, as the Boxster is getting a bit old now, had the body shell been substantially re-engineered to make the Cayman, i could understand the difference, but again, i don't think that is the case.

[EngineerMode]Ah, you see it's all about the second moment of area (kinda)[/EngineerMode]

I see.

So a Cayman Targa could be on the cards, then?

[edinandrew]

I guess it depends what you want. Are you really a good enough driver to notice the extra rigidity? Unless you're gonna track it a lot then I doubt you are going to really notice it much on the road, unless you're Tiff Needell or something. Always seems like a silly comparison - I got a 987S because it is definitely the best pound for pound Porsche you can but and gives me the flexibility of open top motoring and it really isn't that noisy with the roof up at speed. I would never buy a 911 in cab form as they truly are meant to be coupes, that's why they were built as one, just like the Cayman. If you want a convertible buy a Boxster, if you want to spend more money on what is 97% the same car, buy a Cayman - sorry, but it's true.

[shoestring7]

edinandrew said:

I guess it depends what you want.

Quite.

If you want a cab, buy a Boxster, if you want a coupe, buy a Cayman (think of it as Boxster with the £4k permanent hard-top option if you will).

BTW If you think Porsche developed the 997 coupe and then said "Hey! If we cut the top off we can make a cabriolet" you are mistaken. Both were developed at the same time. And I've driven a 997 cab and the lack of body rigidity is very evident - and I'm no great wheelman.


SS7

[Photogirl]

I'm afraid I'm rather late finding this thread, but I'll comment anyway. As to structural rigidity, what has already been said is quite correct, it's doubtful you'd notice any difference.

Anyway, why not have the best of both worlds? Here's my Boxster Coupe:




I can simply remove the hatchback and top when I want to go back to a convertible (this bolts on and off in the normal manner). I love both the Boxster and the Cayman, so this satisfies my fickle nature. There aren't many of these around, it's not cheap, but it is unique and rather beautiful.

[heebeegeetee]

Photogirl said:

I'm afraid I'm rather late finding this thread, but I'll comment anyway. As to structural rigidity, what has already been said is quite correct, it's doubtful you'd notice any difference.

Anyway, why not have the best of both worlds? Here's my Boxster Coupe:




I can simply remove the hatchback and top when I want to go back to a convertible (this bolts on and off in the normal manner). I love both the Boxster and the Cayman, so this satisfies my fickle nature. There aren't many of these around, it's not cheap, but it is unique and rather beautiful.

Blimey. Its a hatchback?

[Photogirl]

Yes, a hatchback. I had to get the parts made in Cape Town and flown over though. Well worth it. It's so nice to have the extra visibility, too. It's given the car a very classic look, sleek and perfectly proportioned.

[heebeegeetee]

Photogirl said:

Yes, a hatchback. I had to get the parts made in Cape Town and flown over though. Well worth it. It's so nice to have the extra visibility, too. It's given the car a very classic look, sleek and perfectly proportioned.

I'm impressed. I think we need more pics.

[Photogirl]

Here are the parts being unpacked:

[Orangecurry]

Photogirl said:

Yes, a hatchback. I had to get the parts made in Cape Town and flown over though. Well worth it. It's so nice to have the extra visibility, too. It's given the car a very classic look, sleek and perfectly proportioned.

I think some photos taken at the car park at the top of Chantry Lane are in order.

[4sure]

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