Audi S4 -> RS4 widebody conversion.

I was in an accident with the car, and almost immediately after that I started to think that what if... And then it started.

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First, I started to make a mold from the RS4 fenders and sideskirts. Luckily I had a friend whose car I could use. First, I waxed the fenders three times very carefully with the Mequiar's carnauba mold release wax. Then I applied the black gelcoat and let it dry. After the the gelcoat was dry, I started to laminate the fiberglass and resin to the fender. There are three layers of fiberglass. When that was dried, I just pulled the mold away. Luckily it came off quite easily, and I didn't had to paint the original part

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Because the fenders were in the car, I had to make the edges afterwards. It was much harder work, because I had to make every single egde one by one in original S4 fender. I made the sideskirts also, that was much easier work to do.

The mold surface was like the original paint, very good. Then I had to do it all over again, but now in the mold. The finished part was sitting very tight in the mold, but eventually it came off without breaking. Luckily it fits with the door quite nicely

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I also had to change the rear subframe because it was little twisted. I removed the old subframes from both cars, and painted the good one. It weights about 90 kg,and it was "fun" to jiggle it away from under the car. The new subframe was sand blasted, and then painted with the acid paint. After that I applied the anti-corrosion black paint. Installation was reverse of removal

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Then there was the hardest part, rear wings. Because it is part of the body, they have  to be strong. So I made these from thin sheet metal and welded together. First I had to change the rear part because it had a little damage. The outside of the wing is much easier job to do than the inside. First I installed the RS4 doors, and used those as a guide to make the wing outer line in correct place.

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All the seams are welded and then tinned. I'm going to use filler as less as possible.

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There had to be made a cuts so I could bend the metal.

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The other side is a bit more difficult to make because there is the tank flap.

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I cutted the rear wing away, and took new part from my spare part S4. That helped the work a bit, because I hadn't to use any additional metal in the gaps.

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The rear wing is now welded, and waiting for the tin. The hardest work is now done! The arc is in correct place and that is a small miracle because I only had my eyes to measure with.

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I tested new technic how to apply the tin. It is quite easy to apply it so that there is same thickness in everywhere. Well, in next project I can use it from the beginning.

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The side wings are now sanded and painted with filler primer and only one smallish error found near the tank flap. So far it looks very good!  

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Then I got new suspension set from FK,and put some grease on the threads Notice the grease color! I also have changed all the Powerflex bushes to the rear axel.

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The roof had a "little" dent, and it had to be replaced. I had a lot of stress because of that, but the replace was much easier work than modifying the rear wings. It took onlyt one hour to remove the old roof, but removing the spare roof took more time because it is laser welded.  It is a great miracle that only the center part of the roof had damage, and the new part fitted there without any extra work! Now I have sun roof also .

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The roof strip place must be 12 mm wide, and i made small wooden parts for making sure that the gap is correct widht.

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Now the new roof is installed, and the seams primed and sealing channels sealed.

Also the door handles have to be changed, because the RS4 has newer model handles. The modification seems to be easier and easier the more I do it! I use tin also here, so it wont crack and doesn't get in rust.

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I removed the side lists and welded the holes, and also removed the lover dowels. The doors are now sprayed with spray filler, and I have to sand them one last time. Also the hood is now fixed. I removed the windscreen washers from the hood.

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The body is almost sanded trough, front and rear bumber needs to be done.

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I got rear wing from Poland (, but it was quite different than in the picture. So I had to modify that also. It was very thick from the rear. I took about one centimeter off from the middle and glued it back together. Then I changed the angle how it is sitting on the rear door (little upper), and I also modified the ends.

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Then the last (almost) but not least, the rear bumper. It needed also widening, and I didn't want to buy original RS4 bumper because I don't like some things of it. The bumper was little broken, so again  I had to take mold. I also used RS4 rear wing mold for the bumper arcs. With those I could have more aggressive look, so that the wide arc goes all the way to the down, and doesn't "shrink" like in the original. This was quite a "puzzle", because it is made from many pieces. There are some phases missing because my hands were so dirty that I couldn't use the camera :) I used carbon fiber filler, it should hold parts together very good, and it is flexible.

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The bumper is still missing one part...

Now it was the carbon fiber's turn, I have been waiting a long time to get my hands on it! Firstly, I wanted to cover the FK mirrors with real carbon, I didn't want to buy the fake ones because the looks is not so good. ( the mirror support parts were also modified because othervise they are angled too up). The surface is starting to look quite good, even though it's not painted with clear coat yet. Also the side panels "screamed" for carbon, and then they should also have it!

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I had two rear bumpers, one broken and one ok one. I took a mold (I have now "couple" of molds in the garage ;) ) from the black bumper's rear skirt. Then the carbon fiber was laminated to the mold. Unluckily I didn't have enough big sized carbon, so I had to use smaller pieces. You can see the joints, but I try to fix those so that they don't show up so clearly. Other than that, the part looks very nice, and gives some detail look to the car.

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I laminated the rear skirt again  because of the bad joints. Now it looks better, but it's not perfect. Those joints are very difficult to make invisibe. The part is now clear coated, and looks quite ok.

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Because I had some carbon left, I laminated also the center of the rear wing. I did couple of mistakes when laminating, and the stripes are not straight. I have to do this again... (these are actually much more difficultier to make than fiber glass).

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I removed the carbon cover and did it all again. Now it looks how it should have been in the first place.

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Here is a video of the car, body is almost finished for the painting.

The car is goint to the paint shop.

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The car is now painted!!  And because many people wants to know the color, it is "Okkim RS blue" Notice the difference between the old and the new color. I thought that the old color was good, but now it doesn't look good any more.

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Now I have started to put the interior back inside. It is a much bigger work than I thought, there are "millions" of parts, and it takes time to clean them and figure out that where they belong to. Also because I have that spare car, the extra parts also give me a little headache because I don't know if it belongs to the car or not.

Firstly I installed the doors, and added sound absorption matt to all of them. It should kill the resonanses, and make the car little more silent. It also helps a lot with the car HI-FI. Then I removed the old sound absorption material from the rear wheel arches, and installed thicker and better material back.

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Spare engine is coming out. I put the original back after it is rebuilded.

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Now the car is 99% ready, so here are some "quick shots". Notice that the wheels are just for that I can ride the car, I'm going to change them to better ones. I will put better quality images when I have time...

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Now I got winter wheels installed, this is the first time ever I am faster than the winter! Those are RS6 replicas.

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