JustinL

I'm trying to get some more weight out of my car, but I don't want to compromise any rigidity or structural integrity. It's for a race car, so if it doesn't do anything it can go. What is the best way of removing things like rear seat belt spare tire holder brackets? Just drill the spot welds?

SloMo228

You can buy spot weld cutters that do a fair job of, well, cutting spot welds. This way you can remove the welded-on piece without drilling a big hole through the underlying metal. You do still have to drill a small hole, though.

Anyway, if I were going to be removing brackets, that's how I'd go about it. Then you can take a grinder or flap wheel and smooth out the metal, fill the holes, and paint.

I don't know how much weight you're going to be able to remove, but if you don't mind spending the time, I suppose it is more or less free weight reduction.

JustinL

http://www.napaonline.com/Catalog/Ca...007_0380230869

Thanks, that looks way easier than what I was doing. I'm down to 2580 with me and my gear. I'm looking for another hundred pounds... but I'm almost out of places to look. Making more n/a power is almost as difficult to get to the ratio I'm looking for.

Arominus

Carbon body panels? lighter wheels? custom aluminum torque tube with the steel center shaft? You'll have a hard time pulling much more out of the shell. You can cut out the inner door skins, i wouldn't mess with the rear quarter skins (rigidity?). Li-ion battery? umm what have you done? Also how much do you weigh? can you shed a few pounds with the car?

Does your 968 engine have hotter cams in it yet?

JustinL

Millege cams are in that engine, but there is room for improvement in the AFRs. I run a Deka battery. The only steel panels are the doors, quarters, and rear panel. Rear bumper is fiberglass. Spare tire well is cut. Roof skin is fiberglass. Doors are gutted. The exhaust is pretty heavy, maybe there's an opportunity there. I was eyeing up the quarter skins where the speakers sit. Is that panel structural? Where do aluminum torque tubes come from and is there any downside?

I'm dropping down the rear wheel size from 18X10 to 17X10, but I don't think there's more than a couple pounds there. Every bit counts though.

porscharu

6061 aluminum is almost 1/3 the density of 304SS. It can be used to make an exhaust but it has several downsides (fatigue, yield strength at temp, etc.) and unless you have a fabricator friend or can make it yourself fabrication and replacement can really add up. Vibrant and others make aluminum mufflers.

Arominus

You would have to have that torque tube made, but i did see another lister post that he had one made. Hes selling a TT on the front page right now. That seems like an area where you could drop some a lot of weight. Might not be the cheapest though. 95ONE is the user that did it might be worth looking into.


https://rennlist.com/forums/924-931-...-for-sale.html

Arominus

Found the thread on it.

https://rennlist.com/forums/944-turb...rque-tube.html

V2Rocket

Alu. torque tube is only worth about 15-20 lbs, at a very significant cost.
I wouldn't cut the body - the sheet metal is pretty light. I cut off the whole front of my car in front of the front wheels and the rails, rad frame, etc really didn't weigh a whole lot.

Exh has a lot of weight to cut...do you really need the whole system
Do you really need the battery once engine is running? Got a good alternator?

odonnell

Delete the balance shafts? They're not super heavy but would be something. Plus less rotational mass.

SloMo228

Manual steering swap is worth about 15 lbs, dunno if you still have PS or not.

I'm assuming you already have race-type seats in there? I would guess you've done a lot of the more common weight-reduction mods already. Lexan windows?

The exhaust does weigh a ton. There was about a 10-15lb difference between the catless exhaust w/ a light Flowmaster muffer that came on my car and the stock exhaust. I had to swap a stock one back on because mine's a street car and the noise was irritating, but for a race car that's not such a problem. The stock muffler by itself probably weighs 20-30 pounds.

V2Rocket

Using the trusty and reliable bathroom-scale method, the NA exhaust from Y-collector to tip, all stock but with a Walker brand aftermarket CA-replacement cat, is 38lbs.

Noahs944

I cut out most interior metal panels. Not a lot of weight savings. Used a sawzall. DON'T **** WITH THE GAS TANK FILL AREA METAL. Trust me on this.

JustinL

Have a manual rack and lexan everywhere except windshield. Just one race seat. and not much else in the cabin except safety gear. I wonder if I could get a lighter muffler, I just pulled the exhaust yesterday and it did feel like a big weight on that end of the pipe. The car is pretty loud already, but not compared to some of the monsters in my run group. There's an idea, thanks guys.

SloMo228

Always good to get hard data. I guess that probably would make the muffler closer to 15 or so pounds?