924Board.org

jjadczak · Joined: 03 Jan 2003 Posts: 346 Location: Accokeek, MD

In light of the SCCA's recent rules modification that would allow a 2200 pound 924 run in F Production class, where could we shave off 400 pounds on our race car? If you understand the SCCA ITA rules, we must run stock fenders, doors, hood, windshield, rear hatch, can't gut out the doors (unless your installing NASCAR door bars), and basically fiberglass body panels are prohibited. Our car weighs in at 2600 with a half a tank of fuel and and driver in the car (228 pounds). I know we could basically run fiberglass body panals and lexan windshield & hatch but what else. How much weight does the dash weigh? the stock 924, 944 mirrors weigh? How much weight would you probably save by removing the undercoating material under the car? how much weight could be saved by removing the gas tank and replacing with a fuel cell. WHere else guys and gals could we lose weight on the car? If we balanced and blueprinted the engine and lightened parts in the motor would we save 60-80 pounds? I know John Brown has been experimenting with this but has anyone else looked into this?

Jeremy

Lizard · Posted: Thu Oct 09, 2003 2:15 am Post subject:

strip everything off and have it acid dipped that will take off probably a good 60-80lb, short of the other things you have mentioned,
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jjadczak · Joined: 03 Jan 2003 Posts: 346 Location: Accokeek, MD

Acid dipping is illegal and expensive. I wanted to do that though......

OR_Sunset · Joined: 04 Jan 2003 Posts: 312 Location: Veneta, OR

Okay... here we go again. I don't think you are going to lose 400 lbs without being able to use composite body panels. You might get close though. I assume you already took out the rear seats, passenger seat, the sound/heat insulation from the floorboards and stripped off the hood insulation.

Don't use metallic paint

Have the entire underbody, chassis and engine bay steam cleaned. Remove a ton of weight in dirt and road debris, small animals, etc.

Gun drill brake rotors (if legal)

Use lighter rims (if legal)

Remove the dash and everything behind it all the way to the firewall (including leftover nuts, bolts, washers, etc). Take a piece of thin aluminum sheet metal and use it to mount your gauges. Use only the gauges you need, or that are required for the race. Most can be replace with lighterweight units.

If you can't strip the doors down, at least empty them out. This includes window winder mechanisms, locking mechanisms, etc.

Cut out the metal in the trunk and replace with a fiberglass panel. Lighter, and easy access to the gas tank and tranny top.

Shave the underside of the rocker panels. There is at least half an inch of metal lip there that can come off.

Strip of the undercoating of the car and respray with a lightweight, waterproofing agent.

Use an aftermarket composite seat instead of stock (if it is legal to do so)

Have a sunroof? Either strip the trim off of it, or (if it is legal) replace it with a fiberglass panel. Heck, the original sunroof is fiberglass anyway, but really thick and heavy.

Remove the antenna and power antenna mechanism if you have one. Remove any other wiring related to this component also.

Use a 1/4 inch drill to drill the frame in "safe" places (areas not directly stressed by the drivetrain or suspension). Sure, your car will have the structural integrity of swiss cheese in those places, but it will be lighter.

Look for every single bolt or screw which has a flat washer on it. (You will find close to 100 of these without dismantling the entire car.) Buy the appropriate size washers in magnesium or alloy instead of steel. You will spend hours and hours, and lose another pound maybe. If you really go the extra mile, cut off the excess bolt or screw end that just hangs out the other side of the nut.

Probably quite a bit of savings there. Probably not 400 lbs. Good luck.

J1NX3D · Joined: 06 Feb 2003 Posts: 1333 Location: New Zealand

wing mirrors are suprisingly heavy, especially if theyre electric!
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'86 944

AndyFranklin · Joined: 07 Oct 2003 Posts: 184 Location: Novelty OH

Sunroof hole has to be filled by similar material to the surrounding roof - ie, sheetmetal instead of fiberglass.

Don't forget that you can rip out the alternator and air pump, which also reduces the number of pulleys. That air pump/AC compressor bracket must be 15 pounds by itself! And the wiper assembly. And the pop-up headlights.

And we get to remove the bumpers.

Gastank to fuel cell is probably a weight gain, but required.

Has anyone figured out how to make a fiberglas door? Or the means to replace that molded rear window with lexan?

Gutting the doors will yield some, but requires side bars. Which you probably should have anyway.

There seem to be many useless brackets after unecessary items have been removed from the engine. I presume these can be ground off.

Aluminum driveshafts are legal.

Fiberglas fenders are easier to repair than metal. Use a fiberglas hood with 4 pins and remove the hinges.

I think 2200 is very possible.

Mikri184 · Joined: 12 Sep 2003 Posts: 746 Location: Ferndale, WA

Don't forget to ditch the headlight motor and gut the buckets of the lights theres almost 15- 20 pounds right there. Also use later 944 door their lighter, and if you swap all the mechs it will work. Just get rid of everything you don't need. then start scarificing. Funny how much little stuff can add up.
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jjadczak · Joined: 03 Jan 2003 Posts: 346 Location: Accokeek, MD

Thanks to all so far for their suggestions. We've done a lot already but I am really curious about the undercoating. I was told that aircraft grade paint remover works really well on that stuff. It's like napalm jelly and you scrape it off. It's just a lot of work.

I really like the idea of replacing the bolts. That's pretty smart. I saw the boys at www.gunnarracing.com doing that with the 904's and 935's.

I am curious about cutting the metal out of the rear of the car. Wouldn't that hurt the structural integrity of the car? I'm more concerned about that in a high speed crash.

Can we run the car without an alternator (i'm still a rookie at this, no flames)?

I'm also looking at replacing the windows with plexiglass but that's one of the last things because it's $$$$$ except for the side windows you can got to Lowe's and get plexiglass there and cut to form.

GT Racing has all the fiberglass panels to make a proper 924 track car. that too is $$$$$$$.

What about lightening part in the engine? How much weight could that potential save?

The car's interior is completely gutted, per the rules. All the sound deadening has been painstakenly removed and sunroof innards have been gutted. The dash would be the next thing to go and is the last item from the original interior to go.

Who makes lightweight 15X7 5 bolt wheels besides BBS?

Joes924Racer · Posted: Fri Oct 10, 2003 7:53 pm Post subject:

It gets cold inside the interiot when light weight seats are installed and the int
is stripped so invest in a cool leather jacket like I did.
I would like a fuel cell back there after cutting it out the top
and a fire ext. system
I just removed all the heat/sound mat there on top of the rear hatch area
so I can paint it
need to mount a battery hold down back there somewhere.
the dash doesnt way to much you could keep it and fix it up
like I did, needs a aftermarket [better] more cfm output
heater for rainy drives also.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

ryoji · Joined: 10 Oct 2003 Posts: 168 Location: NNJ

gt-racing seems charging $10~$15 per lb save.

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R.I.P.:a 924 ITA race car

OR_Sunset · Joined: 04 Jan 2003 Posts: 312 Location: Veneta, OR

Joe... I noticed just the opposite. With all the insulation gone, the car now has radiant heat! The center pillar heats up just like a radiator and the inside of the car can actually get warm. This is prefered to the blower heater, at least by me.

How much a modern luxury car with radiant floor heat cost?... probably too WAY much.

wdb · Joined: 02 Nov 2002 Posts: 2024

I was just reading on http://www.flat-6.net/view.php?model=924&sel=924+Carrera+GT&tab=info that the 924 carrera gts wieght in at 945kg or 2220 lbs . I think that was the best the porsche engineers could do with full factory support . for you guys to get the 924 down to 2200 lbs is gunna be tough . since getting that much wieght off is gonna be dam near impossible , maybe you could tell the sanctioning body you would prefer to trade in wieght reductions for other mods instead . I dont know what you would like as opposed to what your allowed ,but anything useful would be better than not being to take advantage of the new wieght rules .

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

Hi Jeremy.

Just like SCCA to give you a new lower weight; but then make it impossible to get there, heh!?

Well, you already know what we have done to get the car (without driver) down to 2200. I think the next 50 is easy, the 150 after that real real hard. And remember, we are on the little wheels and that weight was Hoosier tires.

See you in November.

John

jesse wall · Joined: 09 Nov 2002 Posts: 284 Location: blanch nc

didn't the d production cars weigh 1950 empty ?
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jesse wall 'new driver' , 87 924s

MoonBoy · Joined: 31 May 2003 Posts: 6 Location: Boston, MA

the 924D weighed 2138lbs.