S13 coupe: Fiberglass/CF trunk vs. OEM trunk

[TurboSE]

I have stripped and shaved weight almost everywhere possible on my car (exceptions this far: OEM dash). I have rewired the car to save weight on wire, replaced the gas tank with a fuel cell, removed the sound deadener etc...my question is:

Is the weight of the OEM metal trunk a bad thing? It sits behind the rear axle, so it's extra weight on the rear tires.

Is the extra traction worth the extra weight?

RB26DET, street/drag car.

[TheRealSy90]

Lighter weight = faster car.

[Ca_Silvia]

Im guessing but,

stock = 20 lbs

cf = 10lbs

The cost being

stock = free

cf = 500-600

Is it worth it?

[TurboSE]

true...

no traction = tire spin

[TurboSE]

Im guessing but,

stock = 20 lbs

cf = 10lbs

The cost being

stock = free

cf = 500-600

Is it worth it?


Stock = free
CF = $650ish
Fiberglass = $325ish

I was leaning towards fiberglass because I'm gonna paint it anyway (I'm so not JDM-tyte yo), and I haven't skipped an expense yet...no reason to do it here.

[ILoveJDM]

and I haven't skipped an expense yet...no reason to do it here.

you plan on getting fiberglass doors too then?
if you werent, you should think about it
for about the same price as a trunk, you could save much more weight doing the doors

[kirtster]

the trunk of my 240 is so light i have a 89 coupe like jeez dont waste your money i would say.. unless you have money. oh and anyone now of a place to get the fiberglass i have a dent in my trunk.

[TurboSE]

you plan on getting fiberglass doors too then?
if you werent, you should think about it
for about the same price as a trunk, you could save much more weight doing the doors


that is still up for debate in my mind, I have a cage, but I'm not sure I want to do doors..plus I'm skeptical of how well they'll hold up with regular glass (stress cracks from the weight etc)...but it's an option at present.

[TurboSE]

the trunk of my 240 is so light i have a 89 coupe like jeez dont waste your money i would say.. unless you have money. oh and anyone now of a place to get the fiberglass i have a dent in my trunk.

Fiberglass saves 10+ lbs, I rewired the car to save that much. There's a place in Md that makes the trunks...i forget the name off hand.

[mrmooseman]

if you want to shave weight just cut the webing out of the trunk support guys have been doing it on drag cars since the 60's...plus if you have the suspension in the car correct you wouldn't really need to worry about the 10 pound loss over the traction your car should be throwing all its weight to the rear at launch... plus you have so many other things you can lighten on the car (ie: cf doors, cf fenders, cf hood, replace the front bumper support with a piece of angle iron, using aftermarket control arms they are lighter then stock so a suspension upgrade saves wieght) also mostlikely you have moved the battery to the rear of the car if so make sure its on the passenger side for proper wieght balance... these should head you in the right direction...its just some stuff i did on my 10.4 pony

[TurboSE]

if you want to shave weight just cut the webing out of the trunk support guys have been doing it on drag cars since the 60's...plus if you have the suspension in the car correct you wouldn't really need to worry about the 10 pound loss over the traction your car should be throwing all its weight to the rear at launch... plus you have so many other things you can lighten on the car (ie: cf doors, cf fenders, cf hood, replace the front bumper support with a piece of angle iron, using aftermarket control arms they are lighter then stock so a suspension upgrade saves wieght) also mostlikely you have moved the battery to the rear of the car if so make sure its on the passenger side for proper wieght balance... these should head you in the right direction...its just some stuff i did on my 10.4 pony

I thought about drilling holes in the webbing to retain some rigidity and shave some weight.

Everything else in that list is pretty much done or planned (haven't replaced the bumper supports yet because I'm not sure how it'll affect the fit of my front bumper) and I haven't set up the suspension yet.

Any other places I can save a few pounds I may have missed?

[MavericStephenc]

go on a diet. honestly the best thing you can do IMO. you'll drop weight, ladies dig it, and you'll pull 10's. Plus all that money you save from not eating out all the time can be used for a sweet carbon setup. :) ( not saying you're fat, I don't even know you.)

pull a/c including all the under dash BS , p/s (including all its bull), s13 front subframe is a tiny bit smaller iirc, so mabye it would be a couple pounds lighter? mabye not?, lexan windows, also the jdm s13 front end is supposed to be lighter, so that with a carbon hood and fenders could be nice. carbon roof?

[!Zar!]

A fiberglass trunk is fine.

Since 80% of the carbon fiber products on the market are just fiberglass with a layer of CF on top yet sold for 2~3x as much (wtf?!)

[lazysk8er2]

yea i think the heaviest thing on the car is the glass...also i didnt see but did u get the z32 uprights?

[Corbic]

A fiberglass trunk is fine.

Since 80% of the carbon fiber products on the market are just fiberglass with a layer of CF on top yet sold for 2~3x as much (wtf?!)

And in many cases heavier then the OEM parts they replace (not necessarily on a 240sx though).

[R33E8]

I would get the fiberglass version unless you are sure it's full carbon fiber.. Most "carbon fiber" products available are fiberglass with a single pretty much pointless layer of carbon fiber on top..

[TurboSE]

go on a diet. honestly the best thing you can do IMO. you'll drop weight, ladies dig it, and you'll pull 10's. Plus all that money you save from not eating out all the time can be used for a sweet carbon setup. :) ( not saying you're fat, I don't even know you.)

pull a/c including all the under dash BS , p/s (including all its bull), s13 front subframe is a tiny bit smaller iirc, so mabye it would be a couple pounds lighter? mabye not?, lexan windows, also the jdm s13 front end is supposed to be lighter, so that with a carbon hood and fenders could be nice. carbon roof?

5'11'', 155lbs dressed.

it is an s13, but I never heard it was lighter. Silvia front end in the works with fg fenders. carbon roof is a little much....I'm looking for lexan windows that'll work with OEM doors...

[TurboSE]

yea i think the heaviest thing on the car is the glass...also i didnt see but did u get the z32 uprights?

I haven't installed any rear suspension parts yet, but Z32 uprights are on the list...thanks for reminding me though...still haven't found a set...

[!Zar!]

If this really is a, 'race car' I would replace all windows with lexan. As well as put a cage in it and gut the doors.

[mrmooseman]

well you don't need ragidaty in a trunk lid just cut the webbing in the center out leve the outer rib. if you have the strut brace or roll cage its about all the strength you need.

and yes its wise to replace all the windows but the front one, lexan cant take a hit as well as stock, so just incase i wouldn't replace it.

oh and have you swaped out the belt driven fan for electric ones it frees up 10 hp and like 3-4 tq you can get the fans and fan controler from any auto part store.

[TurboSE]

If this really is a, 'race car' I would replace all windows with lexan. As well as put a cage in it and gut the doors.

RB26DET, street/drag car.

It is caged.

[TurboSE]

well you don't need ragidaty in a trunk lid just cut the webbing in the center out leve the outer rib. if you have the strut brace or roll cage its about all the strength you need.

and yes its wise to replace all the windows but the front one, lexan cant take a hit as well as stock, so just incase i wouldn't replace it.

oh and have you swaped out the belt driven fan for electric ones it frees up 10 hp and like 3-4 tq you can get the fans and fan controler from any auto part store.

I've been having trouble finding lexan replacements, so it's looks like fabbing my own is the best route.

E-fans are pretty much the only way to go on an RB due to spacial restrictions.

[GripTerror]

well you get what you pay for if you wana go extreme voila pay up or get companies to make em cheaper.

Also frp usually would be lighter than the fake carbon stuff as the fake carbon stuff is basically frp layered with one layer of carbon and painted with clear.

Unless.. they used thinner frp and a layer of carbon.. however true all carbon is hard to come by and probably expensive until again someone starts making the shit cheaper.

[ILoveJDM]

that is still up for debate in my mind, I have a cage, but I'm not sure I want to do doors..plus I'm skeptical of how well they'll hold up with regular glass (stress cracks from the weight etc.

I've been having trouble finding lexan replacements, so it's looks like fabbing my own is the best route.
.

im confused.

[lazysk8er2]

i have a set of uprights for sale if u need them pm me they are just collecting dust

[NMs14.5kouki]

i also have a set of z32 uprights that need to go. pm me if ya want them...

you can also take a hole saw to unnecessary chunks of metal on the inside of the car/ doors if your gonna use the stock ones, also taking out the inside door brace will save some weight..

[TurboSE]

im confused.

I've read that the weight of the door glass has caused CF/fiberglass doors to develop stress cracks. So, I'm still undecided if I want fiberglass doors, if I get them, I want to find lexan windows instead of glass.

I've been looking for replacements for the side windows and the rear windshield, but haven't found any....so fabbing my own may be the best route.

[C-unit]

I wouldn't do frp or CF door if I were you. Just gut the skeleton/frame out of the door and have a aluminum door card and you already save alot of weight. I can't justify spending 10-20hrs on fitting and painting a pair of frp doors. You can save as much with gutted door with acrylic windows. Beside painted frp looks horrible compare to metal panels.

[!Zar!]

I don't see why FRP/CF would look any worse than metal as long as the surface is prepped for paint.

[mrmooseman]

I don't see why FRP/CF would look any worse than metal as long as the surface is prepped for paint.

agreed frp cf and metal just have to be prepped differently for them to have the same high gloss look

[C-unit]

FRP/CF will warp under heat cycle, no matter how good you prep it, it will not be as flat as metal panels.

[ZilviaKid]

I wouldn't do frp or CF door if I were you. Just gut the skeleton/frame out of the door and have a aluminum door card and you already save alot of weight. I can't justify spending 10-20hrs on fitting and painting a pair of frp doors. You can save as much with gutted door with acrylic windows. Beside painted frp looks horrible compare to metal panels.
rock no

cf will always be lighter then whatever it is they use in those mammoth ass doors.

[Taniguchi_Is_#1]

I don't see why FRP/CF would look any worse than metal as long as the surface is prepped for paint.

werd. and as far as weight reduction, if you're hardcore about it, every ounce counts. we don't primer our FSAE car because it adds too much weight to the car. :bite:

frp hood, doors, and trunk + lexan windows should take off a pretty large chunk of weight, which i think is worth the cost of purchase. just remember to get side bars for your cage if you do decide to go for composite doors.... that could be a messy side impact crash, lol.

[huffandpuff00]

how heavy is your car right now with what you have done to lighten it?

[kuppler8]

i woudnth think twice, about the bumper supports it should have been one of the first things you took care of, the rears is like 30-40 pounds i just took mine out the other day, not sure about front, my car never had one.

[Renelovesnike]

id stick to stock trunk! ie its free/same color and surprisingly a friend of mine got a carbon fiber trunk on his s14 and weighed a lil more than his stock trunk.

so hes still running the stock trunk and carbon is collecting dust...

[TurboSE]

agreed frp cf and metal just have to be prepped differently for them to have the same high gloss look


going with a matte finish, any easier to make it match?

[TurboSE]

werd. and as far as weight reduction, if you're hardcore about it, every ounce counts. we don't primer our FSAE car because it adds too much weight to the car. :bite:

frp hood, doors, and trunk + lexan windows should take off a pretty large chunk of weight, which i think is worth the cost of purchase. just remember to get side bars for your cage if you do decide to go for composite doors.... that could be a messy side impact crash, lol.


I have the Autopower 6pt with an extra set of door bars welded above the originals.

[TurboSE]

how heavy is your car right now with what you have done to lighten it?


Haven't scaled it yet.

[TurboSE]

i woudnth think twice, about the bumper supports it should have been one of the first things you took care of, the rears is like 30-40 pounds i just took mine out the other day, not sure about front, my car never had one.

removed mine, haven't fabbed new ones....any ideas or pics of your set-up?