How to install a 06 StI rear lower diffuser on a 04 up STI in 35 minutes! Possibly the same for a 02 up WRX. Parts: Rear diffuser rear lower bracket (part # 91285FE000 ) tube of sealeant 2 10mm bolts 2 12mm bolts 6 washers 2 2 1/2" long X 1/8" thick bolts 2 1" counter sinks http://wrxatl.com/forums/attachment.php?attachmentid=866&stc=1 Tools: 10mm socket 12mm socket Spark plug socket Socket wrench with small extention Phillips head screwdiver Drill with drill bits Hammer or small mallet (can be rubber) Dremel tool Sharpie marker Jack 2 jack stands http://wrxatl.com/forums/attachment.php?attachmentid=867&stc=1 From start to finish: 1. Jack up car and place it on jack stands. Giving you room to get under the car. 2. Take measurements under the car with the diffuser in place to center the fins with the center of the license plate.I held the diffuser with my knee. At the back of the diffuser (at the bumper end) there are 2 holes for the 12mm bolts, I drew a line with the arm of the socket wrench from the holes to the bottom of the bumper and put a dot on the end of the bumper with the Sharpie. 3. I removed the diffuser and grabed the lower bracket and aligned the bracket with dots on the bottom of the bumper. There is a lip were the body connects to this bracket ( It's were the body structure has seamed together) Place the bracket on this area and mark your holes for drilling in the 2 10mm socket holes. ( This area on the bracket is threaded) 4. Mount the rear bracket with the 2 10mm bolts. http://wrxatl.com/forums/attachment.php?attachmentid=868&stc=1 5. Mount the back of the diffuser with the 2 12mm bolts (only finger tight) and then mark the front 2 holes with the Sharpie. The marks should be on the rounded part of the spare tire hole. DO NOT DRILL YET!!! http://wrxatl.com/forums/attachment.php?attachmentid=869&stc=1 6. Take down the diffuser and grab the spark plug socket, and hammer.Lightly begin to tap on the bottom of the round area of the spare tire whole the object is to flatten these spots to allow the counter sinks to seat as close to flat as possible. After a few hits, the area will somewhat flatten out, you will be able to manouver the sink alittle bit once its inplace. DO NOT DRILL YET!!! 7. Repalce the diffuser and retighten the rear bolts. Hand tight. check your marks again and remark if nessacery. ( I had to remark to center the hole on one of the origanal marks) 8.Remove Spare tire.Remove the diffuser.Small prayer... Then drill a TIGHT fitting hole in the center of your marks for the counter sinks. 9. Go up top and use a washer per each counter sink, and squeeze the sink in the new hole about half the way in. Use the sealant to seal around the sink before pushing it all the way thru.Then push the sink all the way down. 10. Check the sinks to make sure they are aiming straight down.Adjust the sinks. Reinstall the diffuser and tighten the 2 10mm bolts for the last time.Use the 2 2 1/2" bolts and the remaining washers to secure the front of the diffuser to the counter sinks. 11. Useing the Dremel tool, cut down the remaining bolt stud to knub it off at the top of the counter sink. 12. Seal off the area and your done! http://wrxatl.com/forums/attachment.php?attachmentid=870&stc=1
I can't get my pictures to load up. Sorry maybe when I get my computer back and not the one I'm useing I can load up the pictures.
When I left you guys Saturday, I went to the dealership before going back the AL. Monday the wife had my ride so it was Tuesday when I finally got to mess with it. With the tube of sealent,6 washers, 2 bolts, and sinks, the total was $3.85. That $1.25 for the bolts and sinks!....I can get the pictures to send in email format, but I can't get the sizing to corperate for the thread... Anyone want to take a shot at uploading them?... Diffuser $63.08 part # 91225FE000 Rear lower brkt $17.15 part # 91285FE000 6 Washers $0.68 2 Bolts $1.25 2 Counter sinks $0.43 Tube of sealent $1.17 30 min install time = PRICELESS!!!
FINALLY! I could not get all of them to upload. Just these. Hopefully I will be able to get the rest to work later... I used this bolt system because ti's easy to do when your by your self trying to hold the end in the trunk and your underneath the car.
Does the diffuser do anything useful? Have you noticed any difference? I wouldn't mind one of those towel rack things that go over the rear window, if it reduces the amount that the wing bounces around on the highway. -- Brian
I went with the SRDEC group yesterday. I really don't think it's more than cosmedic at the speeds we were going...There is a function for it , I just didn't reach it.