Manifold hoses?

Stoked 930 · Stoked 930's Garage

Hello Fellows - (84 row ) on my manifold there is the "y pipe" for lack of a better word on the drivers side. One pipe going up/one down. Both are capped - the one facing up had my decel valve plumbed to it.

Question is - the one facing down originally went / or is supposed to go to what? I have checked the workshop manual diagrams and pet diagrams and can't find it. Anyone know? Just for stored knowledge purpose .

Also - With the decal valve hooked to the top pipe when I bought the car-Should the bottom pipe have been capped? Or connected to something else ? Would this have made any difference?
Thanks again for taking the time. Much appreciated

JFairman · 02-21-2015, 09:39 PM

It's been 7 or 8 years since I removed that junk but I think the lower pipe was the oversized vacuum line that operated the prehistoric slow reacting blow off recirculation valve inside the intermediate manifold or whatever you want to call it.
Yeah you can tell I hated that heavy thing and was glad to see it go.

Replacing it with a small faster reacting C2 type recirculation blow off valve and rubber elbow hose with rubber bung for mounting it along with a long neck intercooler is a big improvement.
Or put on a blow off valve that vents metered air to atmosphere that causes a CIS rich mixture during initial upper rpm throttle lift and blast flames out the exhaust freaking out people that follow closely.

T77911S · 02-23-2015, 04:07 AM

i think i pulled that pipe out and plugged the hole with a wheel stud.

i cut off the threaded part and epoxyed it into the hole before having the manifold powder coated.

Miguel Antonett · 02-23-2015, 05:34 AM

No way to follow your description... probably an aftermarket piece... a picture would be helpful to assist you. May be I'm just slow and don't get it!

Ronnie's.930 · 02-23-2015, 08:05 AM

Quote:

Originally Posted by Miguel Antonett

No way to follow your description... probably an aftermarket piece... a picture would be helpful to assist you. May be I'm just slow and don't get it!

Miguel, the OP is refering to the aluminum, combination spout in this pic (jbrown's newly re-finished intake manifold), and Jim is correct - curved portion of the spout goes to the same sized spout on BOV cap, and the short, straight pipe (like Paul's!) goes to the vacuum limiter (decel valve).

T77911S · 02-23-2015, 08:19 AM

i figured that was the one you were talking about. i plugged. it

Ronnie's.930 · 02-23-2015, 08:25 AM

Quote:

Originally Posted by T77911S

i figured that was the one you were talking about. i plugged. it

So where do you vent the recirculation valve/BOV?

Stoked 930 · Stoked 930's Garage

Great. Thanks so much. I have the "intermediate manifold or whatever you want to call it" in a box.

Didn't occur to me that the connection is there-just assumed the angle of the downward pipe went to some formerly removed emissions crap.
JFairman-I do have the c2 type with the smaller bov (P.O> installed ) and a Garretson- Appreciate the thorough direction though.
Ronnie-thanks for posting the pic

T77911S · 02-26-2015, 03:24 AM

i have the rubber elbow with the return on top that goes form the AFM to the turbo.
i removed the decel valve and use the port off the IC that use to goto that.
i think the elbow is from the 964.
RUF does not use a valve, which i dont agree with and my car is a partial RUF conversion so i had to put one on it. i put on a synapse, but have been having problems with it.

i sometimes vent to atmosphere just to hear it.

Bucketlist · Bucketlist's Garage

Quote:

Originally Posted by T77911S

i have the rubber elbow with the return on top that goes form the AFM to the turbo.
i removed the decel valve and use the port off the IC that use to goto that.
i think the elbow is from the 964.
RUF does not use a valve, which i dont agree with and my car is a partial RUF conversion so i had to put one on it. i put on a synapse, but have been having problems with it.

i sometimes vent to atmosphere just to hear it.

Will the 964 elbow fit all of the old cis Turbo cars? I need to replace my elbow (cracking from age) and also need to add the BOV. I have heard some builders (RUF) didn't feel the bov was needed with CIS?

T77911S · 02-26-2015, 06:11 AM

i dont see why not. i have both elbows, one with the DV fitting and one without.

from what i understand the turbo can be damaged under hi boost when the throttle is closed.

maybe they know something we dont. maybe they did it to keep from losing boost between shifts. but then i dont know what it does to the turbo's "momentum" in keeping it spinning and turbo lag....if it would create anyn at hi RPM's.