RacingAristo

Polyurethene and fiber glass are two main material for the bodykit. I'm considering adding a bodykit to my car and would like your opinions about these two materials.

Pro and Con.

Kajukenbo

Hey RA,

You should ask gs4will in regards to that question. He and I had a discussion about that.
I believe you definitely want the fiber glass instead of the polyurethene. Fiber glass is the better and stronger material of the two. It has higher impact strength and it can also handle higher temperature (just in case you reach to the warp speed with your new mods). If you want the actual engineering material data sheet I can email them to you.

This is why many performance cars such as the Corvetts use the fiber glass as their body panels.

RacingAristo

what if something hit my fiber glass bumper, will it shatter? Because if it is polyurethene, I could get it fixed in the bodyshop.

2SAVVY

RA,

Polyurethane (PU) is alot stonger than Fibreglass but most kits are made from Fibreglass which kinda sucks..

L-Sportline and RMM kits are the only ones I know off the top of my head that are made with PU which hurts your choices.. Any idea what kind of kit you are looking at.. Something sedate or a bit on the wild side??

LOTC

RA,I think u got it the other way around,if polyurethene shatters,u cannnot fix it,on the other hand if fiberglass shatters u can take it back to a body shop and have it repaired.Although polyurethene is stronger,u will have less of a choice in kits,cause most kits are made from fiberglass.

If its a real kit imported from Japan the fiber glass is strong enough and it should be able to wistand alot. Just ask Wei when he heard the loud clunk from my front bumper smashing into the cement on the way to 20/20 autobody leaving the gas station a while back.Fiberglass doesnt crack like most poeple say it does.

HI98GS

Dennis,
Fiberglass will end up cracking if you hit something. My friend who does a lot of body work and who did my front bumper told me it is all up to how the fiberglass is prepared. Some are gel coated and this makes it much harder. Some are layered much thicker (kinda like the vettes panels) but others are thin.

If I have the choice I would go with PU. I really smashed my front lip into a peice of wood, that is why the new TTE and reworked bumper. I did quite a few curb checks and stuff prior to that and the PU greddy lip held up flawlessly. The stock front bumper held up well even after the accident with the wood that destroyed my front lip.

The benefit of fiberglass is that if the fit isn't good, you can re work it somewhat. IF your body shop knows how to work well with fiberglass.

ricky

RacingAristo

According to Kajukenbo, fiber glass is stronger but the other say is the opposite. If fiber glass is weaker than PU, how come all the japanese bodykits are mady by fiber glass? Like Ken mentioned, if I want PU, my choice is limited by (1)RMM which I really hate (2)LSportline which I don't really like (3)do some molding like Ricky did. Since Ricky already did the TTE front lip, I don't want to be a copy cat.

I'm about "this close" <---- very very very very close to order the kit. I really concern the safety and the strength of fiber glass. I just don't want to throw the whole fiber glass bumper away or pay a high fee for the bumper repairment since I already paid A LOT for the bodykit. Ya'll know how expansive those japanese bodykit is. (And please, stop asking me what bodykit I'd get.)

If this problem can't be answered/solved, I will not purchase the bodykit.

Kajukenbo

RA,

Considering this is a kit that you are going to put on the bottom of your car with a great potential of scrapping and hitting the cements, as some have already pointed out you may want to go with polyurethene for being not as stiff and rigid as the Fiberglass.

As HI98GS has already mentioned, when the fiberglass is prepared properly, the panel can be very strong. Fiberglass is a lighter material than the Polyurethene.

Unless you know the quality of the fiberglass panels that you are getting, maybe it is safer for you to purchase the polyurethene made kit.

RacingAristo

Which means I will get none. Don't like RMM and LSportline. On the other hand, those money could spend on my other project. Pioneer NAV/DVD system for my car. Eh.... we will see.

Kajukenbo

RA,

You just saved yourself alot of money and now you can go buy the TOM's STB!

By the way, are you running in the stealth mode or what? I do not see your name anywhere at the log-on status on the top of the main page. How did you manage to reply this thread?

humm......velly velly intelesting......

I went to San Gabriel area over the weekend, and I actually scraped my stock front lip many times on those uneven roads and the damn cement blocks in the parking lot. I cannot even imagine driving with THE aftermarket front lip around.

Dai Ca GQ

This polyurethane, fiberglass issue isnt a really complicated deal.
Here are some pros and cons to each...
Fiberglass kits:
-easier to produce than PU
-Gives a better finish when painted (meaning more glossier)
-easier to work with when damaged or during installation
-fiberglass kits from japan are superior to the kits made in the US
-less impact resistant than PU kits
-only cheap thin fiberglass shatters, others will only crack

Polyeurothane (polypropelene)kits:
-will last longer than fiberglass
-same material used on OEM bumpers
-can withstand harder impacts without breaking than fiberglass
-very expensive to produce- that is why only a few companies do it
-it is very hard to paint PU bumpers
-more expensive to repair

That is all that i can think of right now. If I were to decide between the two... I would pick the fiberglass kits from japan. If you've noticed, PU kits are only lips or add-ons and not full bumper replacements. The only thing to be careful of is when buying fiberglass kits from here. Just make sure you buy from reputable shops. Hope this cleared up a little...

RacingAristo

hehe.

Before you purchase any addon front lip, be sure to check the angle of your garage's pathway. You don't want to scrap your front lip everyday when you enter/leave the garage. Or you can just park on the street. When you lower your car and add some aftermarket bodykit, you really compromise the convenience for the look.

GlobeCLK

iTrader: (5)

I think OEM bumpers are reinforced plastic. Aftermarket PU bumpers like RMM and L-Sportline are alot heavier than stock, whereas the LECS bumper (which is made with reinforced plastic) weighs the same as a stock bumper.


So to sum this up:

1) If you're gonna scrape alot (especially SGV, with TEINs) you better get PU stuff.

2) PU is very strong, but once you break it you're dead.

3) Fiberglass is weak, but it's repairable.

4) PU is HEAVY!!!

RacingAristo

Dai Ca GQ,

Appreciate your input. I will make sure the kit I want is gel coated.

I think my shop @ Yokohama is pretty reputable.

David GS400

iTrader: (1)

Hey RacingAristo:

Bottom line is if you drive where driveways, speed bumps and parking bumpers are a concern; go with PU. If you can avoid hitting or scraping these, then you can go with the FG. It depends on low you slam your car. I'm running a Sportline front (which is a replacement bumper, not a bolt-on), RMM sides and a bolt-on JDM rear. All are PU and are very strong. I've mistakenly pulled up to curbs, parking bumpers and have scraped my butt on steep driveway approaches. I can guarantee you that if I had fiberglass, those parts would have been cracked or broken.

I know if you go with fiberglas, you definitely get a wider selection. But a lot of those Japanese kits don't fit that well and require some reworking. Both PU and FG can be repaired. After I installed my bumper, some idiot at my office with a 4 x 4 sporting a trailer hitch baked into me cutting the top of my bumper. The bodyshop repaired so you can't tell. If you do go with PU, make sure the bodyshop knows how to paint them. You need specail sealers which seals the PU and are somewhat flexible.

So if you are a super-careful driver and like the looks of a FG kit, go with it. But if your car is an everyday driver, PU is a lot more durable. If you don't believe me, go to a reputable bodyshop and ask them. I try to be careful how I park and go over speed bumps, but my car is lowered so I scrape my bumper and skirts more than I want. The bottoms of my bumpers are all scraped up, but there are no cracks or visual defects that you can see; unless you crawl under the car. So it comes down to personal preferences and driving habits. Good Luck!