Okay…so my last bumper was an ///M3 bumper that I hacked up to fit my car and molded a lip to it, ect. Anyway…after a year and half of abuse the lip cracked pretty badly and other flaws that bother me. Bottom line, it was time for a change. This is infact my 4th bumper change.
I liked the CSL bumper, but didn’t care for the single duct on the driver side, so i decided to modify the CSL bumper to my liking.
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1st. The Splitters were very weak looking. Holding them up to the light i could see right through them! Worried that I would crack them if i hit anything, now was as good a time as any to reinforce them:
So…i dipped into my ballistics kevlar supply (this isn’t the aesthetic stuff)
Reinforced the backside of the splitters. The ‘pointed’ frontmost section has 7 layers of kevlar which is thicker than standard issued army helmets. It’s not pretty stuff, but it works!
Next I started taking measurements for the duct so i could make an accurate mold and posistion it correctly. It’s not simply just cutting a hole out. To do it correctly, the duct is angled slightly and has a taper to it.
I found a large yogurt container had a near pefect size. Taking my depth measurements i transfered them to the yogurt container to get the proper sizing and angle.
I then took an uncut yogurt container and poured plaster in to allow it to solidify an make a good sturdy mold. I used my vacuum bagging system to force the Carbon Fiber tightly around the yogurt container. If i didn’t reinforce it, it would just colapse under the pressure. (this obviously wouldn’t make a great mold)
This pic is fresh from the vacuum bag. There are several layers ontop of the carbon fiber. This process removes a lot of excess epoxy so you have a higher CF to Epoxy ratio which gives you a stronger lighter (not that it matters much for this) part. But i had to make sure the CF was pressed firmly against the mold to get a nice smooth shape on the inside of the new duct
Once all the garbage has been removed and the yogurt container pulled from the CF this is what it looks like:
Now I cut the CF to shape using the template i made earlier out of the other yogurt container. Putting the CF duct in the appoximate place on the bumper, i used more CF to build a flange around the duct. Doing this gives a more rigid part, more as well as surface area to bond the part to the bumper.
Now to cut the hole. I put a piece of paper over the OEM duct and traced it. Flipping the paper over gave me the mirror image i needed to be able to a hole in the proper shape and location on the opposite side.
Using a high strength 2-part epoxy to bond it in place. I left the hole slightly undersized so i would have material to play with once the duct was in a permanent location:
