B6 A4: Fabricating Ultrasport Rear Rebar

[toaster]

Ok, so i finally got my hands on a brand new USP rear (upper and lower), and i have been calling around to find a place to get it on my car.

in the past, i have always said that it can be installed without purchasing the roughly $1200 worth of euro-spec rebar mounting hardware. what i am finding out however, as i speak to different body shops, is that there is a nearly unanimous opinion that such fabrication would result in a car that has severly compromised structural integrity. this could become problematic obviously, in the event of a rear end collision.

i initially thought that it was possible, thru fabrication of the non-euro spec rebar hardware, to create a rebar with equal or very close to the same structural soundness of the actual euro-spec parts themselves. I have not found many body shops who agree that this is possible, and most are strongly advising against it.

somethng else i found out that i find interesting is that some shops refuse to do such modification on the basis that, insurance companies sometimes go after body shops that do. If god forbid you are in a crash and you sustain damages greater than normal, and the inspector comes to look at the car and sees the modification, they might seek to have the body shop owner pay some of the damages on the claim that they willingly create the "less safe" fabricated parts.

i don't want to spend $1200 for these parts, but i bought my audi because i feel it is the safest car on the road. i am not stupid enough to compromise the safety of my car just so the rear bumper can look nicer.

i am going to find a way to get this thing on my car, but i want to make sure it's done right.

maybe someone knows where i can at least find these parts cheaper, or maybe someone is switching their usp our for something else that requires a stock rebar?

anyway, important info i thought i would share with the many who i know may be considering this scenario.

[Raus]

When you have the rebar off you will see that upon an impact this part is not there to absorb any force. Its only job is to hold the rebar on the car, upon impact the rebar breaks free of these mounts and is forced against the body of the car where the whole structure absorbs impact. It acts no differently regardless of where the mounting holes are.
But you are modifying a safety feature, and it's completely understandable why nobody would want to be liable. Basically, you have to do this:

[toaster]

It's BaAaAaAck!!!!!!!!!

I spoke with Raus and my bodyshop guy thoroughly and now feel confident that this modification will maintain the safety of the car in a rear impact collision. I have stated before that you are "shortening the pistons" which causes them to absorb less shock in a crash. This is incorrect. After looking into this further, I realized, what is actually being done, involves the REBAR MOUNTS. Shifting the rebar mounts a bit, and drilling some new holes that allow you to anchor the rebar 1" receded into the body.

CONSIDER THIS: Think of the US spec Rebar as a desk drawer, extended out fully. In contrast, the Euro spec rebar is the same drawer, pushed in a little bit. To acheive this result, you are not cutting the desk drawer itself, but merely shifting back the placement of where the drawer "catches" the tracks (drilling new holes in the rebar mounts 1" further back from the original holes). And now it all makes sense. Picture 6 shows this specifically.

Shock absorption will not be hindered at all, and no structural weakening is taking place.

Back from the crash, compliments of Raus and reincarnated by me, here's $850 in your pocket...

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
You do not need a USP rebar and mounts totaling $850 to mount the bumper.
There is a small modification necessary to the regular rebar to fit the USP on:

Here's the car with the regular bumper off and the rebar exposed:



Some observations between the two:



Now the fun begins:
By undoing the nut on the aluminum rebar mount, you can turn it to adjust the position of the rebar.



At its furthest position, I was able to move it just over 1/2". That means the rebar now would sit 1/2" closer to the body...this is close but not close enough. We need it to be even more closer.




Another observation, the bottom screw needs a new bracket to hold it in place. The USP bumper is not as tall (doesn't hang as low) as the regular bumper. A simple metal bracket bent into an "L" and screwed into the rebar takes care of that.



To get the rebar 1" or so closer to the body, we need to simply drill 2 new holes on the aluminum rebar mounts that are 1" apart from the original holes.

The mounting bolts pass through these holes from inside the trunk and bolt to the chassis of the car. Measure carefully. The mounting holes are 86mm apart. Use a punch to mark the spot. I started with an 1/8" bit and worked my way up to 3/8". I used a hand drill and had more control this way. It took me 10 mins for each mount, but very easy to drill through. Having a bench drill would speed things along and ensure accuracy. I had no problems, the bolts pass through the new holes perfectly, everything line up. Measure twice, drill once.



Put the mounts back onto the rebar and adjust their positions, put the nut back on to secure it in place. Slide the rebar back in the car and pass the bolts through the new holes and tighten.
And you're done. The USP bumper now fits like a glove on to the car:

[toaster]

Finished Product: