2G Rear bumper (crashbar) install and lightening

[Chris@Rvengeperformance]

I've switched to a 2G rear bumper support since they are very cheap to pick up and save about 20 pounds.

I don't want to ditch it completely, but it still a bit of weight, has anyone gone medieval with a hole saw on there's?

Any idea how much weight could be saved with some moderate about of drilling? 3,4,5 lbs? With some careful drilling I think 85%+ of the strength would still be there.

I realize that almost 10 lbs are in the shocks, but prefer not to solid mount the bumper.

I'm going on a bit of a weight attack and just losing weight where it is free or almost free and doesn't detract from the appearance or comfort of the car in anyway. I don't want it to be visible at all. Every oz will help, i.e. I'm going to a shark antenna to save a pound and ditch the stock antenna motor crap.

[i3igpete]

how much was wayne charging for his tubular bar? I'm sure that will be stronger than drilling holes into a box structure - recall that second moment of area is what is important for beams that are loaded transversely. When you drill into that box structure horizontally, you're removing the surface that gives the bar it's strength. (similar to how the top and bottom of an I-beam are what support the load).

[Chris@Rvengeperformance]

how much was wayne charging for his tubular bar? I'm sure that will be stronger than drilling holes into a box structure

Yeah that's the only thing I'm worried about, I may leave it alone. If it was steel you could use an arbor and bend around the edges to make them stronger, but I'm sure this cast aluminum will not stand that.

[Chris@Rvengeperformance]

how much was wayne charging for his tubular bar? I'm sure that will be stronger than drilling holes into a box structure - recall that second moment of area is what is important for beams that are loaded transversely. When you drill into that box structure horizontally, you're removing the surface that gives the bar it's strength. (similar to how the top and bottom of an I-beam are what support the load).

What about drilling vertically?

[Lithium]

I would be willing to bet if you drill enough holes to actually make it lighter that it would weaken the bar so much it would be almost usless. I wouldnt advise you to take it off either, Ive seen to many rear end accidents on local tracks turn out bad. My advice, get these or make your own for a lot cheaper..

http://www.3sx.com/store/comersus_viewItemBundle.asp?idProduct=29422

[Chris@Rvengeperformance]

Yeah you could certainly be right, that is why I asked if anyone has tried.

Please keep in mine I'm looking for backyard free weight reduction, I don't want to spend $300 this year to save 5-7 lbs.

[Lithium]

Yeah you could certainly be right, that is why I asked if anyone has tried.

Please keep in mine I'm looking for backyard free weight reduction, I don't want to spend $300 this year to save 5-7 lbs.

Do you have access to a mig welder by chance?

[Chris@Rvengeperformance]

Do you have access to a mig welder by chance?

yeah and I already built a front bumper before to clear my FMIC, for the rear though the effort to construct another one exceeds the weight loss for me anyway. That and the rear one is more critical to safety IMHO.

[Lithium]

Im trying to remember what the rear one looks like. If I remember correctly the crash bar itself doesnt really weigh that much, All the weight is in the two dampener's.

[Atrosity]

:smartie:

[Chris@Rvengeperformance]

Im trying to remember what the rear one looks like. If I remember correctly the crash bar itself doesnt really weigh that much, All the weight is in the two dampener's.

Yeah for the most part that is true, the rear is basically a straight bar. The dampers are approx 10 pounds and I would say the bar separated is about 10 pounds. I just have it all apart right now and I'm looking for ideas before I re-install the bumper cover. Going to pull the left tow hook for at least right now.

I may also move back to a stealth wing, the 99 combat wing is really heavy.

[Lithium]

Yeah for the most part that is true, the rear is basically a straight bar. The dampers are approx 10 pounds and I would say the bar separated is about 10 pounds. I just have it all apart right now and I'm looking for ideas before I re-install the bumper cover. Going to pull the left tow hook for at least right now.

I may also move back to a stealth wing, the 99 combat wing is really heavy.

Just go no wing and our cars would be almost identical lol, If you come up with any ideas of how to lighten the rear crash bar be sure to update us. I was thinking of just removing each damper and weld in a solid tube. The only bad thing I could imagine happening with that setup is the crash bar would be stonger then the frame of the car. With that now being stronger it would tear (as a verb) apart the frame with a stong enough impact.

[Austin@STM]

Yes wings are heavy in the sense of weight, but also in the downforce they create at speed which puts more weight on the car. If you were to change it up i would go no wing at all.

There is a decent amount of weight in the interior as well, if you have some down time there are tons of brackets, and supports in the center console and inside the dash that are not necessary.

Also in the engine bay there are a lot of parts that bolt to a bracket and then to the car. Most of the brackets can be removed and the parts bolted directly to the car, which does 2 things. Makes it lighter obviously, as well as cleans up the engine bay making it easier to work on.

Then if you want to get really hardcore ther are things like the sound deadening on the floors, both sides of the firewall have a thick pad on them, the backing to the carpet, ect...

Once you start really looking you will find it all, i started the same way, i even went as far as to cut out the entire back of the glovebox and then reinstalled just the skin so it looked like it was there to save 5 pounds before i just pulled the dash all together. :p

[J. Fast]

I started my weight loss program too! I think we should start a definitive thread on changes with effects on weight. Have you swapped the non structural connections with nylon nuts and bolts yet Forrest? There's about 30lbs in there too :)

[Chris@Rvengeperformance]

I really haven't done much of anything at all, going to pull the crap out for the power antenna and its wiring tomorrow.

[Chris GTO TT]

Yes wings are heavy in the sense of weight, but also in the downforce they create at speed which puts more weight on the car. If you were to change it up i would go no wing at all.

Right but that depends on your goals and plans for the car at a drag strip downforce is unnecessary. But at a road course or mountain road rear end lift becomes an enemy and even the stock AA wing combats it and makes a noticeable difference above 60mph.

[J_Parker]

One thing I've seen some people do on other cars to get rid of that dampers is replace them with some reasonably thin metal tubes or flat stock. It'll still have some give to it if the bar takes a hit, but will weigh much less than the shocks. That was the rout I was going to take when I get going on mine again in the spring. Hope it helps some. :)

J.

P.S. I took my spoiler off a while a go to clean up the paint under it a bit, and holy crap does that sucker weigh a lot! Even on the Stealth it weighs about 20 or more lbs, I'd imagine even more on the 3KGT.