l26 UIM swap on a l36...

**The Gut** · 02-04-2015

Originally Posted by BillBoost37

I'm confused. That new thread tells you the same thing and reasoning as the one I linked. The reasoning is so that you don't meter the air...but you put it through the throttle plate where it won't cause idle issues.

lol that was from another member, damn near same name as me though. The Guz vs The Gut. But just to make sure I'm following, heres my understanding.
-crankcase needs vaccuum for gases, so drilling out the throttle body and attaching a fitting that will let you run a line to a breather cap on the valve cover will supply fresh air.
-the vent for excess pressure is the PCV valve on the top of the plenum on the passenger side.
-putting a breather valve on the stovepipe on the top of the L26 manifold gives the crank gases a way to vent (???bypassing the PCV valve????) but does not supply fresh air to the crankcase.

now assuming i got that straight, heres my questions
-where is the crankcase gettting air from now that it needs to vent through the breather? do i need to plug something when i install the vacuum line?
-everyone keeps referring to a "metered air supply" in those threads you gentlemen have posted for me. Not sure, but I've gotten the impression that that applies more to L67 then L36?
-when i tap out the plug and put in the fitting, should i also put a fitting on the rear valve cover so i can run fresh air lines to both sides? or maybe grab another front valve cover out of the junkyard so i can screw on another breather assembly same as the front? or is just air to the front valve cover sufficient?

thanks again guys, sorry to make you break it down barney-style for me.

**GT in Kennesaw** · 02-25-2015

The link referenced by The Guz is from a follow up post where I corrected a mistake in routing the vacuum for the PCV. I was following a post on a Bonneville forum that I will not link. I ended up following BillBoost37's method, which is why he mentioned it was the same. It was exactly the same. You do not need to use breathers anywhere. The drilling and tapping on the underside of the throttle body is to re-route the vacuum. Necessary because the L26 UIM does not include a passage for it. That's the pipe sticking out the top of the manifold. Here's the link to my swap with step by step photos of the entire process. http://www.grandprixforums.net/threa...lloy-questions Again, I was getting help from BillBoost37 when I did it. I also got a great piece of advise from Bio248, "I don't see a point in switching." He was kind enough to not say "I told you so" when I finally finished. It is a lot of work for no gain. But you'll probably do it anyway. I did. Good luck.