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fenders weight

Old 10-17-08, 09:58 AM
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fenders weight

Does anyone have any idea how much the stock FC fenders weigh? Im considering going to fiberglass EP fenders, but as I don' t necessarily need the extra width at this moment weight savings would be the first priority.

For that matter has anyone already calculated stock vs. Fiberglass?
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Old 10-17-08, 10:09 AM
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There is almost no difference in weight. I would say you're looking at a couple pounds at the most on each corner.

The rears we make will save you another couple pounds because they aren't as thick as the front ones. The fronts need to have an extra layer of glass so they hold their shape when attached with dzus fasteners. The rears usually get bonded onto the car on the front edge, top, and rear edge so they get a lot of strength from that.

So, not worth the trouble to save weight. A lexan windshield will save you a lot more for a lot less.
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Old 10-17-08, 11:06 AM
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Thanks John!

After installing your fiberglass hatch (which made a HUGE difference BTW), I've just torn out the front windshield this week and bought some lexan sheeting, so Im on the way to getting that done. The problem is that I calculated that installed I should only drop about 10 lbs with the lexan windshield.

If the fenders won't yield much improvement I'm running out of ideas as to how to drop the weight any further. Any suggestions?

I was going to grind out the door crash bars, and try to shave off as much as possible in the doors, as well as removing the bumper bars (possibly fabbing some aluminum tubes to go in place or something like that), and perhaps move up to a fuel cell. Aside from that and maybe some light grinding here and there, and a lightening hole here and there I don't know what more I could do. Have I reached the limit?

What is the lightest an FC with a cage could get?
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Old 10-17-08, 11:15 AM
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Here are a few pics from us at Sebring last weekend....The "X" is the instructor classification with them, not novice..so no flaming






Last edited by designfreak; 10-17-08 at 11:18 AM.
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Old 10-17-08, 11:52 AM
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Going through the same issues with an Miata right now. Did you have the car striped/dipped before you started the build? I had my car sand blasted to remove all the undercoating and sound deadening. We have spend hours grinding and drilling holes, as we are trying to get the car into the 1,900 lb range.

You would be surprised at the weight you can save by removing all of the stock fasteners and spot welded bolts etc. Most of that type of weight removal needs to be done during the build.

What sanctioning body are you running in? I can not see a class designation on the side of the car. What are your class rules, looks like the stock dash is in place.
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Old 10-17-08, 01:49 PM
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Can't tell what is going on with the hood and driver side headlamp cover? Also, where is the air going that goes through the driver side FTP and turn signal area? I have my passenger side open for an air box but driver side is blocked off. Maybe you got an idea I can borrow from...

Also, what kind of wing is that and can you really tell a difference with it on? Not flaming, just curious as I have thought of one but didn't think it would do anything to my lap times.

BTW, great car you got.
Attached Thumbnails fenders weight-smallimg_b14337.jpg  
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Old 10-17-08, 03:34 PM
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I've seen people remove the fiberglass front bumper reinforcement then place 3-4 openings in the bumper to allow for added cooling and marginal weight savings. Using optimal bolt lengths wherever you can will add up believe it or not. Replace long stock ones with ones that offer just a 1/4 inch exta for instance the steering rack bolts, they're twice as long as they need to be I found. An aluminum or fiberglass hood helps as well. Aside from the usual (removing sound deadening material, impact beams and hollowing out doors, etc.) there isn't much weight savings to be found in an FC. I think 2250-2400 wet without driver is a reasonable range.

Last edited by RacerJason; 10-17-08 at 03:37 PM.
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Old 10-17-08, 03:40 PM
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You should be able to get the car down to close to 2000lbs.

Door bars are 12lbs each
Brake booster is 11 lbs if you go to a dual master set up.
My fiberglass hood is about 15-16lbs and includes the headlight area covers so you can remove all that stuff. I forget what the headlight stuff weighs.
Alternator 11lbs

I had my car down to 2109 with me in it(I'm about 190), dry, before I added ballast.
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Old 10-17-08, 05:18 PM
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My car was 2305 with a half a tank of fuel and my heavy r-compounds. With the light wheels and slicks I drop around 45 lbs, so say it weighs 2260. My doors are gutted, lexan hatch, fiberglass fenders and some extra lightening holes drilled in the C pillars (totally not worth it). I got my a$$ kicked by the drill and it might have dropped like 3 lbs or so. The hole saw would catch and the drill would punch me in the face or just twist up my wrists. My car has an extra 100 lbs of turbo/intercooler/piping over what an E-prod car would carry so you should be able to get into the 2160 wet range with no driver without working too hard. I caustic bathed my car when I had it stripped down to remove all the seam sealer / undercoating, etc.

-Trent
www.rxracing.com
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Old 10-17-08, 08:43 PM
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Do you NEED the extra airflow from the FTP lenses being removed? If not, cover them up, they're adding drag. How heavy are your wheels? Look into getting lighter ones. AWR 2 piece brake rotors can drop 10lbs. Run a smaller, lighter battery. Remove your headlights and all associated wiring, motors, etc. Remove your hood hinges and latch, go with hood pins. Remove the under bracing from the hood. Strip any unused wires from the wiring harness. Run aluminum bodied shocks and as short a spring as you can manage. Get a lighter seat. Have a good look behind the dash and remove any weight you can (heater, etc). Remove the dash and replace it with a simple instrument panel. Don't run a rear swaybar. Run a tubular speedway style front swaybar. Lighten your rear trailing arms (I've seen pictures of ones full of holes with the swaybar endlink mount removed).

Basically remove anything and everything that you don't absolutely need either for the rules or for getting around the track.

One thing to consider that most people could benefit from anyways: loose weight yourself!
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Old 10-18-08, 11:48 AM
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Thanks guys for the suggestions and the numbers. To answer a few questions we originally built my car per SCCA IT-s rules. We quickly got bored of running it like that, and started slowly improving. Right now both my father and I are HPDE instructors with NASA, as well as Chin motorsports in south Florida, so were get free track time with them, and are only using the car as a trackday car now. At this point Im just concerned with making what I want out of the car, and then possibly seeing where it will fit into the rules, and possibly going back to racing it down the line. In either case It sure is rewarding enough to chase down some vettes with our 163hp engine.

I left the stock dash in place just to keep the car a little more put together, but Ive fabbed a new mounting method not including the heavy steel support structure. The only thing that remains is the plastic dash itself, which isn't TOO heavy...but might go in the future.

The passenger side FTP and turnsignal opening is ducted to a cold air box, while Im running a second smaller B&M oil cooler in the driver side. The headlights have been totally removed, and the covers are just very thin aluminum plates bolted into permanent place. I made a flap outlet on the drivers side headlight cover to try to pull air out from behind the cooler. Ill try to post more pics of all this later. The fog light openings are routed to the brake ducts.

The wing is a cheap ebay aluminum erebuni, and it weighs less than the stock FC wing. The mounts are just custom fabbed. This last weekend was the first time out with it, and I noticed a big improvement with it. To take full advantage of it however I think I will need to balance the front of the car out with a big diffuser and some canards. When I went out with it originally in the middle position the car was understeering quite hard...lowering the angle to the lowest of the 3 I had calculated brought it back to neutral. I never even tried out the highest angle, but in either case the rear seems much more planted and stable in high speed corners...noticed a big difference for example in turn one at sebring, while still allowing for some oversteer in low speed corners.

The hood I have is a stock vert aluminum one with ventilation cut out of it, however I think I will spend some time lightening out the underside of it further. Weighing it out, it seems that I wouldnt really get any improvement from goin fiberglass (considering my headlight covers weigh nothing as well).

I obviously stripped it down as much as possible and got rid of all the insulation etc..during the build, but looking back really should have done a bath to it, and spent some more time with bolts/ minutia...perhaps soon.

Jason, what are the impact beams you are referring to? are they the crash bars on the doors?

Do you guys have any idea how much the bumper bars weigh in at? would they be worth it considering the decreased crash protection?

The wheels I have a re Rota's and they are 13lbs for a 15x7. Could drop a little more on them I agree, but not too much.

Do the AWR rotors work with the stock calipers? perhaps that would be an interesting option. Do you have any pictures you could post of the lightening of the rear trailing arms? Those things are tanks, and could deffinatelly lose some weight before becoming weakened.

Thanks once again for all of the feedback!
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Old 10-19-08, 04:42 PM
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Originally Posted by designfreak View Post
Do the AWR rotors work with the stock calipers?
Yes. I have AWR on the front, had them for 3 race weekends now. So far, so good. I plan on picking up the rears over the winter. Rears bolt right up, the fronts require the hub to be machined ever so slightly (need to reduce diameter). Other than that, they are direct bolt up to stock calipers. Front saves 6lbs and rear 4lbs total, per AWR, but I never weighed and checked.
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Old 10-20-08, 02:23 PM
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I know there's pictures out there somewhere, maybe zilvia.net or some other silvia/240SX forum, although I believe it's been linked to on this forum. What I remember of it is that they took a hole saw to the ring that the driveshaft goes through, along the top side, big holes that almost go the full width of the piece. I don't remember if they did anything to the arm forward of that.
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Old 10-20-08, 02:41 PM
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Originally Posted by designfreak View Post
Do you have any pictures you could post of the lightening of the rear trailing arms? !

I remember now where this was...

http://www.ziptied.com/forums/index....2422#msg132422
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Old 10-20-08, 04:21 PM
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Originally Posted by SCCAITS View Post
Some people in that thread have NSFW avatars, FYI. Interesting modifications though, I wonder how much weight came off the trailing arms. Those SOBs are HEAVY.
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Old 10-20-08, 08:03 PM
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One thing to keep in mind is that all those holes will weaken the arms somewhat, possibly increasing the likelyhood that you'll bend one in an off track excursion, sould that ever happen, or it could cause increased deflection under normal track use, messing with your dynamic alignment, or it could cause the metal to fatigue.

It's probably fine since it came from AWR and it would seem that they know what they're doing, but still, caution is in order and don't get too greedy with the hole saw.
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Old 10-20-08, 08:32 PM
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I've always wanted to make my own out of Aluminum.. I can picture them now... *drools* Maybe one day.
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Old 10-20-08, 09:33 PM
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Wait, what's this about a fiberglass hatch? Where would one procure such a thing?
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Old 10-20-08, 09:50 PM
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PM me, I make them. It looks like designfreak was too excited to put his on he didn't even get to paint it!
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Old 10-21-08, 12:23 AM
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lol...no I masked and painted it, but in all honesty I really didn't need to. The color was pretty dead on with your gelcoat color
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Old 10-21-08, 08:02 AM
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Originally Posted by Black91n/a View Post
One thing to keep in mind is that all those holes will weaken the arms somewhat....

It's probably fine since it came from AWR and it would seem that they know what they're doing, but still, caution is in order and don't get too greedy with the hole saw.

AWR only sold the parts, they didn't drill all those holes in the control arms. I'd question the structural integrity now of all that material removal, which was done by the user.
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Old 10-21-08, 01:03 PM
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mehh.. he's a drifter.. perhaps (likely) doesn't know any better..
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Old 10-21-08, 08:48 PM
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Right, I was going off memory and I (incorrectly) remembered that he'd bought it as is. I don't think I've ever heard of a trailing arm braking, so there's probably some safe weight to remove there.
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Old 10-24-08, 11:59 PM
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Originally Posted by designfreak View Post
Here are a few pics from us at Sebring last weekend....The "X" is the instructor classification with them, not novice..so no flaming





Dude your a freak!....I live in sebring and you dont know how many times i show up to the ITS class race. I even meet a guy named patrick in the E/P class that has his 7 down to 2300 LBS!. I actually know a place to weigh your car like 10 mins from the panoz office. whats your lap time?
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