avader906

Hi Gary. Im Swiss, not British.

What is that ?

I dont think anyone needs to convince you. I dont for sure. You install 997 Cup steering moving the weight forward - it ends around 4lbs lighter overall.

Dont confuse downforce with weight... Replacing body panels with fiberglass or carbon/kevlar will reduce weight overall.

997 hydrolic engine mounts are (if my memory correct) >5lbs each. Replacing with semi or solid will save both weight (4lbs each) and improve the feel of the car at the limit.

You can purchase them.....

Taste and colors. You can buy a Cup car or convert the street car to track, or anything in the middle - but this is not poor's man hobby.

allegretto

avader,

I think gary was speaking of the the "British" vehicle mindset, not you in particular, in reference to his MG experience

Installing CUP steering? Bring $$$$$$$

I'm certain Gary knows the diff between weight and drag. But downforce effectively adds weight when in motion sufficiently to cause aero effects. That's kinds how it works, but you know that too

Changing motor mounts and re-doing suspension? OK, bring more $$$$$$ for a few kg. You're making a lithium battery look cheap now. No poor man's hobby to be sure!

Intentionally avoided gary's quite accurate suggestion of driving lessons since some take it as an insult and will ignore it anyway. A good driver can take a stock 993 C2, spot you a few seconds and still kick your butt with you in a GT-3 (any flavor) unless you can drive well

YMMV...

GentlemanRacer

Another 3 year old thread resurrected. We have to get a name for that.

avader906

sorry this is incorrect even if assumed as gross over-simplification. Drag, downforce and weight are distinct and separate forces from each other. Timely reminder to revisit Racing 101....

http://racingarticles.com/article_racing-3.html

Fin Fever

Weight = inertia it resists a change in velocity it impedes acceleration braking and cornering

downforce has nothing to do with inertia. Out is like a big vacuum sucking you down to the surface.

Drag just slows you down due to "wind resistance" it is only a factor at speed

Aero kit adds some weight and some downforce. I am not sure if it actually adds drag, but I think it does.

ralt12

Looking at your avatar--just awesome. What thread were we on?

Mike in CA

Oops.....

alexb76

Funny thread, as always!

Basically, it is AN EXPENSIVE proposition... best bet is to start with a lighter out of the box car, like 996 GT3, then you can gut it from there, and have more flexibility playing with suspension settings, etc...

sandwedge

Sport buckets: - 60 lbs
Champion wheels: - 30 lbs
Tubi exhaust: -30 lbs

Total: 120 lbs

allegretto

Ummm, No you and avader need some basic physics. Wt is NOT inertia. Wt is mg on earth with the vector pointed to the center of the Earth. Downforce is virtually equivalent to weight at the Earth's surface in that it is the Force vector directed downward of the drag the aero parts produce. If wt = inertia then inertia would not be a factor is space where "weight" does not exist in any real sense, but of course inertia does exist in space. So it's time to rethink that idea. Inertia is an inherent property of Mass, not weight.

avader... you may be confusing yourself on this issue. Downforce is called "downforce" because it is Force directed Down (towards the tarmac). No, it's not quite the equivalent of weight since it is a dynamic force but it can nonetheless be measured in units of pounds or kilograms and thus is by definition a weight equivalent in a dynamic situation. Perhaps that the author threw in Cf causes you to interpret it differently, but that is not what's at stake here.

Force is a product of mass and acceleration in a directed vector and is the product of Net Acceleration and Net Mass, Up Force, Down Force, Left Force Right Force, Back Force, Front Force nothing more or less. Not much more to say...

Now that would be Physics 101. I really don't mind disagreement. Sometimes these issues can confuse. But I don't know you, nor you, me. Please try to be a little less snide in your remarks, correct or otherwise... thank you.

boolala

Downforce will increase "weight" without affecting inertia...However....the rolling resistance is proportional to the normal force which must exatly balance weight. Thus the power needed to accelerate an object will increase as downforce increases.

Avader needs an object lesson in basic physics.

simsgw

Sorry. Your location being London misled me. It's devilish hard to recognize accents on a forum.
Well, the 'still' is just as Alegretto said: I've owned a lot of British cars. The 'current' referred to your own suggestions, so it could read "the current Swiss approach" if you prefer, although I've never owned a Swiss car so I'd have said it some other way if I'd known. It's really unfair to blame the British or even the rest of the Swiss nation, so this time I'll limit it to your post: I would characterize your suggestions as "buying a pig to end up with a boar-bristle hairbrush." The OP just wanted to lighten his daily driver for track days, not change it to something else entirely.
Your English certainly seems better than my German or French or Italian, so this is not a criticism, just an explanation: we would use the word 'replace' in that context. In any language, it sounds like a bloody expensive way to save four pounds.Others have responded to this quite well, especially with the suggestion that you be less snide. But to clarify, you are changing your suggestion. What I objected to is adding aerodynamic bits to the car when the OP asked for ways to reduce weight. Aero bits always add weight. And if they generate downforce, they also add drag of course, but that wasn't my point. Yes, you certainly can replace body panels with ones made of exotic materials. I mentioned that in my own post, but that has nothing to do with aero directly unless you just mean he should take off the OEM aero components and replace them with lighter units made of carbon-fiber.
Ah, you're right then. The washer fluid weighs only 12 lb, so replacing the engine mounts would be a clear gain of four (4) pounds. And for some at least, it would improve the feel at the limit. In a daily driver. Where he might occasionally like to carry along a significant other without misleading her about his intentions with a Magic Fingers seat. (American expression: refers to vibrators attached to beds in cheap hotels.)
Yes, he could. Just as he could purchase a GT3. Which is why I said:
My objection to this approach, which I is what I meant by a 'disconnect', is that these changes you suggest epitomize the term Mods as opposed to simple changes. The OP asked a very straightforward question:
"Warranty issues" doesn't begin to describe the effects of all these changes as you've explained them. It would be like flatbedding the car into the service department with numbers on the door, a rollcage, and clear signs of the car having been inverted, and asking for warranty work on "that paint blemish on the trunk lid when the light is just right. Here, bend down and look." I grant you, the post turned out to be three years old, so the car may be out of warranty by now, but your suggestions are still very much the "track-style weight mods" the OP wanted to avoid.

This hobby is expensive compared to collecting stamps but it doesn't have to be stupid. Buying a daily driver equipped for the road with nice luxuries, and rebuilding it as a track car when you still want it as a daily driver comes pretty close to stupid. You can drive a track car on the road (though it might fail various government tests after the changes you suggested), but actually using it as a daily driver with those changes would come very close to masochism. Which is a different hobby discussed in other forums.

Gary

Fin Fever

Agreed, you are 100%correct. but for the purpose of the discussion being had here, weight can be equated to inertia. my point is that although weight pushes the car down, it also retards acceleration and braking and cornering. downforce also pushes the car down, but it does not interfere with those other things you are trying to accomplish.

boolala

Rumors that MB is contemplating production of a carbon fiber bodied E class which sheds 700# in weight compared to the steel and aluminum currently in use. That would result in incredible performance improvements (not to mention considerable reductions in fuel consumption and emissions) if this could be made economically feasible through technological advancements. http://editorial.autos.msn.com/blogs...cid=autos_2185

boolala

Of course the purpose of "downforce" is not to result in a net increase in effective weight but, rather to counterbalance the upforce generated by the car at speed. If done properly the tires will remain in contact with the pavement and thus accelerate faster. If downforce is excessive all it does is add effective weight to the car and increase rolling resistance of the tires. I would imagine that it's effectiveness 1) is a function of speed and 2) is a max/min problem to optimize the amount of downforce.