Ron Adair

Just for grins I built a spreadsheet to figure how much weight I'd have to pull from my car to get to 300 "effective" horsepower.

Curb weight divided by horsepower yields the power to weight ratio and so yields the horsepower effectively added (I think). Each incremental weight loss requires less subsequent weight loss to gain additional effective horsepower.

I'd like to pull an additional 60 lbs or so to get to the effective number up to 300.

An alternative is to spend $10K or so for the 3.8 upgrade , but weight loss is so much cheaper.

Any ideas? What have you guys done?

Bull

You can save a LOT of weight (I don't have an exact number) by replacing the stock power seats with lightweight seats, replacing the rear seats and panels with RS carpeting, and replacing the front door panels with RS panels. Then replace the stock mufflers and cats with pipes and Fabspeed Supercup exhaust, and strip the trunk down to the bare essentials, getting rid of the cover.

Now that I have looked at your spread sheet, I see you have done some of the above. Did you weigh your car to begin with, or have you weighed it now? Porsche published weights are "interesting, if true" for any particular car. One weight doesn't fit all examples of a model, with all of the option combos possible, of course. Most Club Racers in the Stock classes have to add lead weights to make the minimum weights, even after installing roll cages, etc. Not that it will make a huge difference, but if you are going to the effort to make such a spread sheet, you probably want to start with accurate numbers.

My C2S, when it was factory original, weighed almost 80lbs less than the published weight.....with a full tank of gas.

Ron Adair

Bob W. -

I did not weigh the car when it was stock but, now that you point it out, I bet mine weighed less than the published weight as it was a lightly optioned car when new. Where does one go to have their car weighed. I'd like to know the real number.

I can definately notice a difference in acceleration from the ~125 lb weight reduction thus far. Handling seems improved as well.

Ron

chris walrod

An old rule of thumb the drag racers use(d) is 100lb reduction is worth a tenth of a second in the 1/4 mile..

Aero improvements (drag reduction) is more complicated as its a speed-squared law, but super interesting nonetheless..

Don Plumley

I'm in violent agreement - adding lightness is the best performance improvement you can make to a car. Less mass to brake, turn and accellerate. It also helps if you can remove mass with excess polar movement (ends of the car), and why club racers adding weight get to place low in the middle.

I'm stripping mine fairly aggressively. Important stuff like AC stays, but unimportant stuff like the sunroof goes. The interior sound deadening and panels are heavy. Here's a partial guess/SWAG at some of my net losses (I'm not building a precise weight spreadsheet, because in the end only the net number matters):

RS Carpet Kit, Al floor panels, RS Door Panels - Interior Sound deadening, rear stuff, carpets, etc = Net -65#
Sparco Seats - stock power seats = Net -70#
Momo Mod 07 - two airbags = Net -9#
Cat bypass, engine tray, sound pad and Wevo motor mounts = Net -30#
Sunroof = Net -30#
RS Washer Bottle, excess fluid = Net -20#
Foglights = Net -5#
Battery = Net -20#
RS heater bypass - blower stuff = Net -10#
Trunk: Spare tire, carpet, tools, etc. = Net -36#

So the thumbnail total is about 295#. But, this is offset by a half-cage, fire supression, heavier suspension bits. The proof will be when I c/b the car and find out what the final net weight will be.

If you pick up the hood without the hood struts, you'll be floored at how heavy that piece of sheet metal is. So long-term, a little bit of fiberglass here and there, lighter wheels, etc. and you can see how a Cup car weighs about 2,500#

Hopefully, I can get in the 2800# range, or about 100 more than a factory RS.

FlyYellow

Loosing weight is a noticeable improvement in the car's capabilities that are not just limited to increased acceleration. You also get the added benefit of faster braking and better cornering. Some may argue about weight biases that may be introduced so you should take note on where you are removing the weight (front vs. back and how high in the car).

I have kept a detailed spreadsheet of my car. if anyone wants it let me know...

cheers,
boris

Bull

Around my area, just about every Porsche independent maintenance/performance shop has a set of scales, which are used for chassis set-up and corner balancing. They can, of course, give you the total weight of your car also. I would bet you will find them at the shops out your way.

Ron Adair

Hey Don -

Tradeoffs for a low mileage "polisher":

gotta stay:

door panels (my wife likes to ride in the car)
sunroof (no die grinders within 50 feet of my car)
tools & spare tire (might get a flat while wine tasting in Santa Ynez)

gonna go:

washer bottle, 20 lbs
trunk carpet, 5 lbs

Thanks,

Ron

Bull

I think you are very close with your numbers for the items above. Given the actual weights that these cars start at stock, you should get to the 2800# range easily with the above list.

Ron Adair

Boris -

Spreadsheet please. I just sent you an email.

Thanks.

Ron

Monique

For example, an RS I know well is 1229 kgs = 2703lbs. You are still overweight

Rob 97 993c2

how does the RS get to be so light? what else does it have/not have (besides light weight glass)

Ron Adair

Here's an updated spreadsheet.

Looks like I've got it to ~295 effective hp.

Brave Heart

letting a 10 year kid or a jockey drive the car could help

Ron Adair

Brave Heart -

As does driving on empty...

Ron