For people who have eliminated their PCV valves (either catch tank or they have a '95 model) you can run fuel hose right from the PCV nipple on the UIM to the brake booster. The nipples are the same size. The vacuum location is essentially the same. This allows you to junk the hard line running across the top of the engine bay and the little 90 degree hose on the end of the UIM. Just run the new hose under the UIM by the oil filter.

However, make sure you use a barb adapter/extender (available at every hardware store) with the new hose and keep the pre-existing smaller hose on the booster, as it has an internal one-way check-valve.

Just simplification/crap removal basically.

 

It's all about keeping yer oil clean

 

Clayne you have a pic?

 

yeah wtf? I thought that pcv valve went from the uim to the side of the oil filler neck
why not just remove it?

 

He is talking about rerouting the brake booster line into the PCV nipple on front of UIM.
There is a vaccum line that goes from left side of UIM to a hard line to the brake booster. This line supplies vaccum to the brake booster.

For 1993 cars, you have a nipple on the front of UIM with a PCV valve in between to the Oil Filler Neck.
You can remove this, and route the brake booster line here.
In the end, you can remove the hard line that goes from left of UIM to the brake booster.

 

Ahh... Good explanation.

 

Great idea , I've never liked that hard line.Good to point out the one way valve in the line...However i would like to add that you must make SURE that the one way valve is in the SMALLER hose by the booster. I have had a couple of FD's come in that had it in the LONGER hose. You would have to order the correct one.( only like 7 bucks i think) Just thought id share, other wise one could blow the booster with too much pressure.

 

Yep. Just use the stock brake booster hose, remove the hard line and use a barbed coupler to connect the new line from the PCV nipple on the UIM to the existing fuel hose on the brake booster.

 

clayne lets get a pic of this

why would you want to remove the hardline on the firewall its so nice especially if polished. plus then you have to put a big ugly *** black cap on the uim where its showing...

your idea is kinda like the bov realization that someone else had on nopistons. When you remove the aws you can put your bov on the nipple on the back of the stock elbow. Fits perfect and is close to the throttle where its healthy...or you could add another stock bov there for safety. Good times when we become mazda engineers

 

Yeah, let's see some pics.
I still don't understand why we would do this.
(im kinda slo)

 

Surge, Bottle,

Go open the hood.

Look at the UIM.

Look at the large nipple on the bottom of the UIM next to the other 4 smaller nipples. Now look at the nipple on the brake booster.

 

Well guys, scratch this one..

I hooked it up this way and the brake booster effects engine vacuum too much (causes idle to jump 300 rpm when letting off the brake pedal).

Makes sense as the PCV nipple hits the entire front of the manifold where as the brake booster nipple only takes vacuum off one of the secondary runners.

Oh well!

 

I installed an oil catch tank, and did away with AWS (Power FC and GReddy elbow). All I did was cap off the PCV nipple on the extension manifold (what everyone calls the UIM). Capped off the AWS nipple. Capped off all the unused nipples for the oil blow-by route to the primary turbo. Pretty simple really, and you don't screw with brake booster vacuum For capping off stuff, I used the rubber HELP plugs with screw clamps. Much cheaper than block-off plates LOL

 

Well this was really about using the unused PCV nipple as a source for the brake booster to shorten the hose length and remove the hardline on the firewall. Nothing emissions related.

 

Guys, the short, L-shaped rubber line from the hard line on the firewall to the brake booster has a one-way valve embedded in it.

This keeps your motor from sucking out the pressure thats assisting your brakes. Without it, you could have brake problems, and a hard-to-trace fuel smell in the cockpit under boost.

Ask me how I know.

 

"Guys, the short, L-shaped rubber line from the hard line on the firewall to the brake booster has a one-way valve embedded in it.

This keeps your motor from sucking out the pressure thats assisting your brakes. Without it, you could have brake problems, and a hard-to-trace fuel smell in the cockpit under boost.

Ask me how I know."

Yea, I put that in the very first post.

This valve is not causing the problem when connecting the booster to the PCV nipple, however. It's the fact that the PCV nipple is connected to the surge area where as the brake booster nipple is only off of one runner.

 

I just read this thread and I don't understand why I want to tap vacuum for the brake booster to a different place? Why do I not like where it is now?

 

It's moot anyways. The original purposes were stated however.