Harley#356’s How-To’s
IAC Restrictor Plate (aka Beer Can Mod) & Oil Separator Bracket
Purpose behind the Mod:
When you rev your truck up, it usually takes a few moments for the RPM's to drop all the way down. They usually hang high then slowly come back down. The "Beer Can Mod" restricts the IAC valve openings, letting the RPM's drop down quicker when you rev the truck. This doesn't add/hurt performance or mileage, its just simply a mod free mod for sound and to get rid of the annoying hangup on RPM's when revving the motor up. Also, rather than having a restrictor plate under the IAC and a oil separator bracket on top of the IAC, I combined both into one on this mod.
Need:
-Beer Can (soda can will work but thats no fun lol) or thin aluminum plate
-Black RTV Sealant
Tools Needed:
-8 mm Socket & Ratchet
-Marker
-Tin Snips
-Hammer (for optional Oil Separator Bracket Provision)
-Vice (for optional Oil Separator Bracket Provision)
-Drill & Bits
-File
Parts:
Either kick back a beer/soda, or find some thin aluminum plate. I used some 1/16th" aluminum engraving plate. Thin enough its easy to work with, thick enough its sturdy for the oil separator bracket.
Install:
-Use the old IAC gasket to make a template on the new aluminum. Either just the shape of the IAC for the restrictor plate, or extend it out for a provision for an oil separator bracket as seen in Photo # 1.
-Cut the plate out with tin snips
-If you're doing the oil separator bracket provision, put the plate in a vice, and use a hammer to slowly work a 90* bend in the metal as seen in Photo # 2. I used a urethane headed hammer to keep the metal from getting dinged up.
-Mark & Drill your holes, use the IAC valve for sizing on the bolt holes, then for the restrictor holes, I'd say make them between 1/4" and 3/8" in diameter. The smaller they are the quicker the idle will drop back down, but if you go too small you could have idle/stalling issues when getting out of the throttle quick. 3/8" is a good balance point as seen in Photo # 3.
-File edges down with a file or dremel (obviously not needed if you're just doing the beer can version) as seen in Photo #4.
-Sand with 80, 100, 220, 400, 600, 800, 1000, 2000 then hit with Never Dull if you want to polish the bracket as seen in Photo # 5 & 6.
-Reinstall with separator plate sandwiched between IAC and plenum as seen in Photo #7 & 8. Can reuse the factory gasket on one side then use RTV on the other. Its not needed since it shouldn't leak air anywhere, but it never hurts to be safe. Mount up your oil separator if you made a mount for the bracket.
-Fire the truck up, rev it up and check for idle/stalling issues. They shouldn't be there with a 3/8" hole, but if they are just open the hole up a bit and it should solve it!
PHOTO # 1: Old Oil Separator Bracket, Restrictor Plate, & Template for new all-in-one restrictor/bracket:
PHOTO # 2: 90* Bend for Separator Bracket Provision:
PHOTO # 3: Holes Drilled:
PHOTO # 4: Edges Filed:
PHOTO # 5: Polished:
PHOTO # 6: Polished:
PHOTO # 7: Installed:
PHOTO # 8: Overall Shot:
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Originally Posted by Krix330cic(NJ)
