gtroth

Pulled my intake manifold and the new vacuum hose (944.110.235.01) doesn't have the "T" section to connect the venturi like the .00 did. What now? What does the venturi do (I read some references to a 'delete')?
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white '88 944S

KuHL 951

I think the late 88+ cars eliminated a lot of the piping including the bundle of hard pipes. I think it would help if yopu did a search on vacuum delete. There is a very good Word doc that will show you what can and cannot be eliminated. I did the venturi delete on my 86 turbo so that probably wouldn't help you much. I pretty much gutted everything and removed all the fittings and made straight runs from the OAS to the J-pipe.

joseph mitro

looks like you got it out.....good job.

i don't know what the venturi does either and would like to know.

gtroth

Yup, got it out - thanks again. Now that I realize that the whole intake comes out as one assembly, the 'S' design (with the throttle buried at the back of the engine) makes a little more sense.

KuHL - I had read that .doc file. It's for the Turbo so not all that useful. I am guessing that I remove the venturi and connect the brake booster directly to the IM where the venturi used to connect and then use the new hose to connect the ISV to the J-tube, but I want to be sure.

Does anyone know what the venturi is supposed to do? I am just wondering why Porsche thought I couldn't live without it and then changed their minds.

jonnybgood

I would like to know about this for the S cars. I purchased the replacement and it came without that same T you refer to. At some point Porsche eliminated that plastic venturi device and it would be interesting to know why. I did not install the new piece and still have the venturi in there. I also read the write up and it is for Turbos.

gtroth

This is a tougher question than I thought, I guess.

PeteL

Is there a delete for the N/A's?

gtroth

Maybe another picture will help (better than a shameless bump, heh?).

My PET5 is inconsistant for my car showing both a restricter (20) and a venturi (18). And with that little T connection missing on the new hose (16) I don't know what to do. I want my car back.

jonnybgood

Strange nobody knows about this subject.

I see you still have the factory pinch clamps on the venturi. On my car the rubber tubing had shrunk beneath the clamps and there were vacuum leaks there. I removed the pinch clamps and installed regular hose clamps. I think that helped solve the stalling on return to idle problem I was having.

KuHL 951

If the new hose doesn't have the 'tee' section what happens to the old orifice piece? Maybe this is why it was eliminated. If I remember correctly, if that piece was left out or was loose it would cause the idle speed to surge.

bader$

it probably is for crankcase ventilation. most cars have a pcv valve, some have a fixed orifice.

gtroth

Yeah, my car doesn't have the orifice. The deleted "T" goes to the venturi.
Already got my injecters back from WitchHunter (1 day turn). It's going to be hard for me to resist putting the car back together tomorrow with the original hose until we sort this out. For completeness, here's the routing from FSM:

gtroth

Ok - plugged the unused port on the venturi with a 5/8" cap and an oetiker clamp #226, reassembled everything and all is well. Idling pefectly. I had to remove the entire IM again to adjust the throttle plate a hair because of a very subtle rubbing in the throttle bore just as it closed that prevented the TPS from switching, but that's another thread.

Once again, thank you all.

Tom

gtroth

Turns out, inside that piece of tubing in the old hose there was a ~1mm orifice.

Don't know what it means, just thought it needed to be in the thread.

chrly924s

YEAH!!!! Is there a delete for NA's??!!
Do we need one?