Track car weights
Discussion
clubsport said:
Lets not forget sunroof is additional weight in the wrong place on a performance car.
True, but a manual sunroof wouldn't add much weight and while it's high up and not doing the centre of gravity much good it is in the middle of the car so doesn't affect the polar moments of inertia. I'm not sure a 911 needs another 30kg over the rear as with aircon.
Trackdays are different to raceing IMHO in that you're there for the whole day rather than just have to worry about a 20 minute session for a race. I find a full trackday pretty tiring. Nowadays I try and limit my track milage to about 150 miles per day otherwise my concentration goes off. If it's possible to make life a bit easier so you don't get so tired then perhaps a little extra weight can be considered a performance enhancing item. Aircon and power steering may well fall into this catagory.
tony.t said:
steve rance said:
Yep.. Aparently you have to have a sunroof if you buy a 997RS in the States!
What a shame, I can almost hear the tears from the Porsche engineers and sense the friction between them and the marketting boys
Steve
My C2 has a sunroof and when open on hot days it makes a significant difference to cabin temps. I'll bet it doesnt weigh 30kg though.
Doesn't aircon use engine hp to work? I'll guess they use about 10hp to run.
Edited by tony.t on Thursday 7th September 11:10
Hi Tony. No problem with a C2 having a sun roof. Great car, brilliant all rounder. It's not only the weight of a sunroof, its the marginal torsional strength that you loose when you cut a hole in a load bearing structure. A Stiffly sprung, paired down, hard edged road racer really shouldn't have one unless the body isn't load bearing; ie the car has a separate monocoque.
steve rance said:
Hi Tony. No problem with a C2 having a sun roof. Great car, brilliant all rounder. It's not only the weight of a sunroof, its the marginal torsional strength that you loose when you cut a hole in a load bearing structure. A Stiffly sprung, paired down, hard edged road racer really shouldn't have one unless the body isn't load bearing; ie the car has a separate monocoque.
I accept that. When I enquired about replacing the sunroof with a CF roof skin ALA M3CSL I was informed it would be a non starter because the roof was structural. My sunroof is due for deletion but it's how to replace it: properly with a new roof skin or cheaply with a fiberglass panel.
I suspect that for the 997GT3RS ( and my C2) the marginal loss of ridgidity of a sunroof is more an ideological problem than a physical one.
tony.t said:
steve rance said:
Hi Tony. No problem with a C2 having a sun roof. Great car, brilliant all rounder. It's not only the weight of a sunroof, its the marginal torsional strength that you loose when you cut a hole in a load bearing structure. A Stiffly sprung, paired down, hard edged road racer really shouldn't have one unless the body isn't load bearing; ie the car has a separate monocoque.
I accept that. When I enquired about replacing the sunroof with a CF roof skin ALA M3CSL I was informed it would be a non starter because the roof was structural. My sunroof is due for deletion but it's how to replace it: properly with a new roof skin or cheaply with a fiberglass panel.
I suspect that for the 997GT3RS ( and my C2) the marginal loss of ridgidity of a sunroof is more an ideological problem than a physical one.
I agree. I think Porsche make a statement with the RS it represents a pinacle of performance driving, a no compromise road/track car. I agree that the marginal difference in performance is negligable but I don't think that a sunroof fits in with that phylosophy.
Steve R
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