Boxster and Cayman weights are different

Some time ago there was a mention they had identical weights, which seemed incredible. The Technical Specifications page on Porsche's site now states:
Cayman S manual - 2888; PDK - 2954 (hadn't seen any weights stated until the past few days)
Boxster S manual -2910; PDK - 2976 (these were always stated as such)
The base Cayman on site specs are incomplete, to say the least.

Motors, multi-layers, pulleys, cables, hoops, roll bars, etc and it only weighs what 25 lb more?

I suppose this goes to show you that this chassis is in fact designed to be a convertible -- and stiff -- and all that stuff carries over to the cayman, which then gets a top and becomes even stiffer. Nice.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

The Boxster is quite light weight, at least it used to be. My 02 Boxster weighs in at 2778 lbs.

By way of comparison my 08 Cayman S weighed in at 2976 lbs. That metal roof, rear glass, hatch back really tack on the pounds.

(FWIW, my 996 weighs in at 3487 lbs.)

All cars are manuals. All cars equipped with A/C.

The Boxster was designed from the outset to be a roadster and as such it has a very stiff body structure. I drove several convertibles (rental cars) before I test rode in and drove a Boxster and the difference was night and day. While the convertibles were very rubbery the Boxster exhibited none of that behavior.

The Boxster roof and its raising/lowering mechanism looks to be heavy but looks can be deceiving, as it is quite light compared to the metal roof of the Cayman and that big rear window and hatch back.

I wonder if those car weights have been transposed?

Without doing a meta analysis of several sources, I find the numbers acceptable. Convertibles are generally heavier than a permanent roof version of the same platform. Yes, the Boxster was designed from the ground up to be a convertible, and that doesn't contradict its having added structural material built in. For the Cayman, perhaps Porsche took a page out of Tony Chapman's book and "added lightness." For a given amount of stiffness, a fixed roof requires less material than would be needed to achieve the same stiffness in a convertible. Whatever the glass/hatch etc. adds is more than compensated for by the lesser amount of stiffening material required in less effective locations. As far as the numbers themselves, the Porsche site probably uses a DIN specification of some sort, whether there's a full gas tank, etc. (I recall the 912 shop manual calling for a full tank and certain weights being put on the floor when doing a suspension alignment.) Other publications, if using independent measuring methods, could come up with different numbers, even with identically equipped examples of the same car.



Edited 1 time(s). Last edit at 12/30/2012 10:59AM by Laz. (view changes)

and does not add much rigidity, as I said in my previous post the Boxster design was roadster from the start. The body/chassis design stiffness was accomlished both structurally and metalurgically.

While the addition of a roof on the Cayman does make the chassis stiffer and reduces the need for stiffening the stiff structure components are not easily done away with or replaced with something cheaper.

Different forge/press molds would be needed to if for instance alum. was substituted for high strength steel. The form/shape of the part would need to be changed because a shape/form that works for steel does not work well for alum. Also, because these parts are an integral part of the car they are welded to other parts to make a unified chassis. Obviously an alum. structure member is not going to weld very well to its neighboring steel structure members.

An exception? Body panels for one. Now it could be that some Cayman body panels are alum. I can't be sure but I seem to recall the front trunk of my 08 Cayman S was alum. and the newer models could have alum front trunk, doors, rear hatch.

But so could the Boxster. I mean a lighter car which delivers better fuel economy and lower CO2 emissions is always preferred.

Porsche would not leave any gains in these areas on the table if they could avoid it. Also, it cuts stocking/tooling costs to make these panels/body parts from one material for both models.

I believe the weights I quoted are for a car wet -- that is with proper levels of all vital fluids but without gasoline -- but sans a driver. While some sources tout ballast is necessary to obtain the best alignment results -- I've had my cars aligned both ways and I can't tell the difference -- I've never coma across any vehicle weights that included this ballast weight.

Regardless the weights just don't seem right to me do not seem logical though I do admit logical is often *not* the best criterion to use to judge the correctness of numbers.

Grant

gee-lenahan-at-gee-mail-dot-com

[www.porsche.com]
I first noticed the mpg figures are wrong.

... my 2004 base, working from memory and the owner's manual is about 2850. S was more. Tips are more.

from the MY03 owner's manual:

empty weight 2811-3086 (5-speed, 2.7)

empty weight 2910-3153 (5-speed, 3.2-S)

Which, in today's world of 4000 lb camaros and 3500 lb Golf GTIs is quite light.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

this:
[image.motortrend.com]