rusnak

nolift, I was hit hard enough to throw my 911 20 feet into the intersection....with all 4 wheels on my 911 locked fully under braking. I was stationary at a red light and the Toyota Celica that hit me had a TOTALLED FRONT END.

You sound like someone who never even had to use the "tumors". "Oh I was tapped on the bumper". Excuse me? Try that again. If you get a really heavy hit in the rear, those rubber bumperettese are much better than nothing. I was rear ended twice. Once on the freeway. The rear bumperettes do a nice job, and they absorb a lot of energy, as do the bumper shocks. You must change the rear shocks after each large impact because they will explode oil. Ask me how I know.

nolift911

Sounds like your rear tumors were the least of your worries in that instance...if you are replacing bumper shock oil...you are making my point. Your bumper/shocks are what absorb energy.

Ed Hughes

The point rusnak is making is that bumps also absorbed energy. The reason we don't lose more lives in racing is now we know about energy absorption. Sure, the bumpers may not have saved his life, but they may have contributed ENOUGH to avoid a catastrophic bending of the 911.

The only true benefit of a change here, in my book (.02), is aesthetics, and the look improves-no doubt. I'd not worry too much about the weight.

nolift911

I'd be worried about 15+ lbs hanging off the way back of my car...rub strips, hardware, US oil filled shocks - put's you closer to 20lbs in the wrong place.

To each their own - it's an easy cheap mod, saves weight, increases performance all around and looks better.

Ed Hughes

I'm well focused on weight. I took 50+ lbs off with the old Carrera tail, condenser and A/C going bye bye. Much higher located than the bumps. With no rollbar, I'm sub-2550 with stock bumpers. Tons of easy places to find weight.

theiceman

nolift sounds like your mind is made up ... go for it .....

BTW guys I go rear ended by an econoline van last year. i was actually at a red .. it went green and my car wouldn't go into first gear immediately ... due ti a stnchro issue likely .. the guy coming up behind me didn't notice i hadn't pulled away and basically rolled his monistir econoline van into my 911 .. just a tap really but enough to push my small car right into the intersection. I got out and noticed my parachute had a punch in it from the bolts hokding his license plate on.
The next day i worked in some 101 into the rubber and a day later in the heat the signs of impact were totally . gone .

But go ahead .. you have your mind made up take em off .....

nolift911

They have been off for 11 years...so I did "go for it"

Let's see some more pics of modified bumpers in this thread.

ked

The aesthetics of the rubber overriders are so bad to me (enamored of the long-nose body style) that I rationalized the added excuse of weight reduction to remove them - they ARE heavy & at the extreme of polar moment. I did so in such a way to easily re-install them at some distant future date if my heirs so desire. I don't have to worry about parallel parking on crowded city streets very often. As you can see, I am not a fan of bumpers on old sports cars (seems only Italian ones & a few English ever executed them really well, though monster US chrome bumpers & "Dagmars" made a uniquely American statement of industrial style).

Phil Ehlen

While I did not realize that this topic was a veritable Pandora's Box, I choose to take all of the passion and energy as positive .

So - a few more pics:

Pic 1 - Just a pic of the rear with the bumper removed. I am super tempted to do something with the muffler at this point. For another thread, modifying the stock muffler is neck and neck with picking up the Fabspeed muffler.



Pic 2 - All of the screws holding the valence resisted all efforts to remove them naturally, so I turned to the drill press. Actually, in this picture I am drilling out the remainder of the screw from the bumper.



Pic 3 - The results of my new palm sander as my old one had apparently retired over the past 5 or 6 years. I think this face of the bumper will be the most difficult to get sanded since the other sides are more or less flat.



Pic 4 - My small scale test using the Alumiprep 33 and Alodine 1201 to prep aluminum for painting

rusnak

Nice shop, Phil.

Just go into it with eyes open. You are removing a key component of a (well) proven safety system. The rationale of,either aesthetics or weight savings are pointless when it comes to safety.

Ed Hughes

Screw Fabspeed.....go headers and a Flowmaster twin out!

ked

the 5mph bumper mandate was pushed through Congress by the insurance industry & safety lobbies in the early '70s.
while some in industry made noise about them being "safety bumpers", it was a misnomer. everyone (industry, Congress, DoT/NHTSA, even the NSC) knew that that argument was part of the ins ind PR effort to bring low-speed accident claim-costs under control - all based upon cost/benefit models of damage & repair costs in very low speed accidents. they (ins ind) demanded it as a quid-pro-quo to support the costly fed regs that the safety lobby (the NSC & the "Nader movement") wanted. {this also split the insurance industry interests from the auto industry, who naturally were against any mandates of any kind. ins ind was not happy that repair costs would rise with the intro of mandated safety technology. they wanted stronger bumpers to save them $, thus "buying" their support for the legislation}
subsequently (taking many iterations modeling & sim), bumper systems have become part of an integrated chassis safety solution. be aware that around '82 the spec was decreased to 2 1/2 mph - I seem to recall Porsche left theirs at 5mph, but not certain.

anyway, that's the way it looked to me when I studied the matter in some detail in the '70s, in DC.

nkgosselin

GothingNC, glad to know I am not the only one who uses the bumpers for a 'beer table'.

nolift911

Where is the "well proven" evidence of this "safety system" ... I would really like to see...I keep hearing these are part of a "system" ? It's a bumper attached to a chassis...also in terms of the 911 and safety, unless I am unaware the 911 shell had remained unchanged from the 60's, 70's, 80's - automobile safety had come a long way. Not sure Porsche adopted much if any other than 5mph tumors.

If I am wrong please correct. I guess the funny part about people touting a part of the 911 as a "safety feature" and should not be removed - on the very chassis that has not changed in 30-40 years? Crumple zones?

Just don't take those tumors off - now your 911 is unsafe.... Show me the proven facts of this safety system please...

Ed Hughes

jeez, give it a rest. We've said it is a personal decision, and that there are aesthetic benefits. But, there MAY be drawbacks. That's all. To say they don't serve much, if any, purpose, is ludicrous. Any reslilient material is going to offer SOME shock protection. What that means depends on the situation.

I think we're just offering balanced observation for when people consider mods.