Boss diffuser/GT500 splitter instal guide.

Nuar

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I got tired of this one long/tall box propped up against my closet so I went out to the car and tore into the body.
The instal is fairly straight forward, but a guide would have been helpful to prepare me for the job. I looked around everywhere but I couldn't find an in depth guide. Late model did one, but its fairly vague (though it did the trick for me for the most part).
Sooooo If anyone is in the market for a nice new Boss splitter or the 2013 GT500 rear diffuser (same process), then I decided to put a little guide together for you guys.

First step for me was to go inside the trunk and take off the panel directly behind the taillights.
There are two screw type clips in the corners of the trunk behind the tail lights and two push pins lower down around the trunk latch on either side.
Then there is just one connector for the trunk light.
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After that panel was removed, I disconnected all the connectors that were behind it. Two for the tail lights and one for the license plate lights. Go ahead and push the rubber grommets through out of the trunk.

Next step is to remove the tail lights. Those are held in place by three 11mm nuts. They come off quickly and without putting up any fight, take them off along with the wire and the grommet you pushed through earlier.

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Once that is done, you're done in the trunk.
Next step is on either side of the car, in the wheel well.

Behind the rear tires there are 3 screws holding the mudflap/bumper onto the car. Remove all three on both sides of the car.

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Then there are two push pins under the car, right behind the mudflaps, along the edge of the bumper. Pull out the center first, then the rest of the push pin will come right out.

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Finally, under the car there are 4 more clips to be removed.
Two push pins, similar to the ones you just removed.

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One on each side of the bumper, and then there are two white pain the the friggin ass clips that hold the center of the bumper to the underbody.
I couldn't get them out easily and I used a panel removal tool (fork like tool) and pried them out of their holes, completely destroying them lol.

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After all that is removed you can pull the bumper away from the body of the car. Start around the mud flaps, pull the sides of the bumper towards you and away from the car, they will un-clip really easily.
Once you have the sides, you can pull the whole bumper off, starting on one side and working your way to the other.
I couldn't take any pics here since I didn't have a helper around :p

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Once the bumper is off, lay it out on a soft blanket and get hackin' :rockon:
This part is actually VERY easy. There are lines to follow under the bumper.
Just grab your favorite cutting device (I used a dremel) and start cutting.

I sliced off the lip around the edge to make it easier and follow the line thats on the bumper. Don't be affraid to cut away small chunks a little at a time.
Take your time here and you will be fine.

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Once you're done chopping away at your shiny new bumper, go ahead and remove the long black plastic trim piece you can see in the last pic there.

After all that is done, there are two oval slots to cut out right around each exhaust tip cutout. I forgot to take a pic so, here is one courtesy of late model restoration :p

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I used a thin router bit for my dremel. Be careful here, that thing gets a little wild when it bites into the plastic and it cuts very fast. So slow and steady moves here guys.

Once all that is done, slap a little grinding bit into the dremel, clean up all the edges on the cuts.
Now would be a good time to gently wipe down the whole bumper as its going to be covered in plastic shavings.
Grab your splitter, clip it into your bumper. use all the half circular clips on the back and you're ready to slap it back on the car!

The bumper goes on very easily and since you just took it off, you know what to do here. A helper comes in handy to line it up before pressing it into place.
Re attach the push pins under the sides of the bumper, put the screws back into the mudflaps, put in the two black push clips in under the bumper and reattach the two white pain in the ass clips back onto the car (my kit came with only one.... so if you can salvage one of the clips that were on your car, do it. I will have to go buy one more now)
One last step is to put the c clips onto the edge holes on the edges of the bumper right by the tip and put in the two screws that came with the kit.

Thats it, you're done! :beer:

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Hope the guide helps someone out there. I tried to take pics along the way, but I got carried away along the way and spaced it on few steps.

As I mentioned, this will be the same process for the gt500 diffuser.
 
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LSX_Terminator

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Great write up! I got my GT500 valance coming in tomorrow and it kills me to cut my new shiney bumper. lol I was wonder what tools everyone was using to do this. I have seen ppl use the dremels and I've seen the body saws. How bad was the dremel to use?
 
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Cribby

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Nice write up! That would paint me to cut into the bumper but what has to be done is what has to be done! Did you say you were doing the front lip as well?

- James
 

Nuar

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Thats all I used. Its not bad at all, but wear some eye protection. Hot plastic flies everywhere.

Its hard to reach the line on the back of the bumper with that large cut off wheel in the pic i just posted, so i sliced the lip off and through out the process i cut small sections off instead of trying to do it all in one piece. You will see what i mean once you start cutting.
Your gt500 splitter might have more of those oval slots to cut, but those are no big deal once you do one.
 

Nuar

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It really isn't.
The worst part is getting the courage to hack up a perfectly good bumper.
 

dirtyd88

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You're making me want to spend money on the Boss rear....stop it. :lol1:

I'll just have to plastidip mine for the time being.
 

Nuar

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No problem, good luck.
Personally I would make sure to get all the required hardware. Its less frustrating that way.
 

BV600

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I got mine off Ebay for $100
Looks way better than stock imo
Also if your someone with exhaust tips that stick out a little further than usual this will help, the center in the boss diffuser sticks out, See pic
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Mikegee1028

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do you see the imperfections of the cuts from the dremel up close? or does the splitter cover up these imperfections.
 

clean92lx

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Looks good OP! So being my car is a 13' GT/CS, I shouldn't have to do any cutting or drilling to instal the GT500 diffuser right?
 

dirtyd88

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I got mine off Ebay for $100
Looks way better than stock imo
Also if your someone with exhaust tips that stick out a little further than usual this will help, the center in the boss diffuser sticks out, See pic
20131010_182538_zps9eaecc5c.jpg



20131010_182520_zps0331a24b.jpg
Shoot, $100? Send me the link, and I'll pay you in beers to help me install when you are in DFW! :D
 

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