OK, so the S4 UIM I recently picked up is apparently JDM, no big deal. Finished doing the emissions removal and everything seems to be running great. Except... I now have no idea where the brake booster feed is located!
I've done some searching and have seen pictures showing it by the BAC location on the UIM, but my UIM apparently doesn't have that nipple. I've also seen pictures showing JDM brake booster feed lines coming from the LIM. That wouldn't work with my USDM LIM.

All the brake booster needs is a vacuum source to work right? Having removed everything emission related couldn't I just hook it in to any of the various vacuum feeds on the UIM? Or is there some vague concept I'm not getting?

 

any vacuum source after the throttle body will work, but it needs a bit of flow, so you need a 6mm nipple instead of the 4mm that everything else uses. you can drill and tap and add one somewhere if you like.

 

thanks

 

The break booster line gets hooked up at the back of the UIM off the rear runner (if I remember correctly) and I believe it was secured with a banjo bolt (There isn't a nipple, just a threaded hole). My FC (jdm swap) is under a cover otherwise I'd go take some pics.

Edit: I'm not 100% sure on this info, its been 4 months since my heads been under the hood. Just going off memory.

 

JDM cars use the LIM for their brake booster setup, USDM uses the UIM. this is becaue of the position of the brake booster being different (right hand drive/left hand drive)

you will have to drill and tap, like stated above. Does the USDM LIM have a thick section where it would be machined on a JDM lower?(rear secondary runner just below the UIM flange) if so just add your brass fitting there..and use a longer brake booster hose.

 

Good point, it is on the LIM on a JDM engine. My bad, should have caught myself.

 

It's on the back of the JDM LIM. I have an s5 T2 JDM LIM. What I did was tap the rear runner for I believe 3/8 NPT (works easily) and then installed a 90 degree brass barbed fitting to attach the brake booster hose. Then I took off the last part of the OEM hardline on the firewall so it would be a straight shot.

 

my jdm s5 t2 lim has a hole in the same position as shown above, except mine already had the banjo bolt with the tube thingy so I just got a longer piece of hose and whalla.

man what a nice setup in that pic!