Turbo Vacuum Hose Tidy Up

[John Sims]

With Beaky's inlet manifold potentially coming off I seem to recall that someone in the States did a little chart of how to rationalise your vacuum hoses when you dump the cycling valve.

Has anybody got a copy please?

 

[John Sims]

Hi Andrew,

I believe that is the original layout (as it left Porsche) and just goes to show how much extra rubish is as a result of the vapur purge system. []

There is a variation of that drawing, done by somebody on Rennlist, that is a simplification - less pipes less chance of leaks.

 

[Guest]

http://forums.rennlist.com/rennforums/showthread.php?t=246189&highlight=vacuum

 

[John Sims]

That's the one. Thanks Mike.

My only question now is why would Porsche produce the obviously more complicated plumbing if the simplified version works just as well?

 

[John Sims]

This be the modified version, to save zapping backwards and forwards.

And this being the original Porsche Plumbing version.

There is obviously some significance to the Y shaped thing that links between the Idle Stabiliser and brake booster, but I cant see what it would be.

 

[Fen]

What Y-shaped thing? If "brake booster" means servo, then surely you want to retain a connection between it and the manifold, not leave it in isolation like the bottom diagram?

 

[sawood12]

The two layouts look pretty similar apart from the gubbins between the intercooler pipe, brake booster and manifold.

Just a point of observation. For those of us with 220bhp turbo cars I seem to remeber we dont have the manifold input that is between branch 2 and 3 of the manifold. Therefore where does our brake booster get it's input from?? Maybe that funny Y-shaped thing relevant on the 220bhp cars only as the line into the brake booster is dotted so is probably only connected on the 220bhp cars. The 250bhp cars maybe get thier input direct from the manifold???

By the way how do I extract the pictures from the note? right click/save picture as doesn't seem to work.

 

[John Sims]

I think the brown dotted line is a connection on all of the cars, it is just shown brown and dotted to differentiate it.

I also think the brake booster check valve is that little blue and black valve on the line to the brake servo - the drawings don't show the servo, again for clarity.

The Y shaped thingy I was referring to is the bit of pipe (referred to in PET as a manifold IIRC) at the bottom right of the second drawing. There is also a bent T pipe that can be dispensed with in scheme 1.

 

[John Sims]

Rather embarasingly (while looking for a pictire of Beakys engine) I found this on my hard drive:-

Generaly a far better illustration of the simplified installation but I still remain concerned about the significance, and effect, of removing the Y and bent T shaped thingys. Why would they be there in the first place?

 

[John Sims]

ORIGINAL: John Sims

.........The Y shaped thingy I was referring to is the bit of pipe (referred to in PET as a manifold IIRC) .......

I lied, it is apparently a venturi pipe. So it is obviously for veturifying.

 

[Fen]

..and is therefore the "venturi delete" mod Rennlisters talk about. If you want a spare there is one in my garage - if that naswers the "do you need it" question in a roundabout way.

 

[John Sims]

ORIGINAL: Fen

..and is therefore the "venturi delete" mod Rennlisters talk about. .....

It would seem that it is. And an order has been placed with Dave Linsey for just such a beast. I could get the pipes direct from my OPC but I can't work out from PET which pipes I need.

 

[sawood12]

And what exactly is in the venturi delete kit? Is it not just a case of removing it and the T-piece and connecting up the vacuum hoses as shown in the diagrams above?

 

[Fen]

To be fair we just pulled mine out of the box of engine bits, said "what the fox's hat?" then laughed at it and plumbed the vacuum lines in without it. It's pretty much redundant when you dispose of the cycling valve. You do have a "Laust" vacuum manifold, don't you John? With that all the connections can pretty much be run direct from the manifold.

 

[John Sims]

ORIGINAL: sawood12

And what exactly is in the venturi delete kit? Is it not just a case of removing it and the T-piece and connecting up the vacuum hoses as shown in the diagrams above?

I can see where you are comming from Scott but the main point of the tidy up is to remove leaks and potential leaks. If I can get one new formed pipe that goes from A to B that has to be better than several original pipes with bits put in the middle.

Apparently, the venturi system wasn't used on later cars - so yet another Porsche "lets try this... oh it didn't work" development.

The appropriate pipes apparently look like this:-

If I could work out a convenient, and safe, way of blocking off the fuel vapour purge pipe then that lot will be comming out as well.

Fen,

I do have a "Laust". Who doesn't these days? [] If I dump the vapour purge I might end up with too many holes at this rate. []

 

[Guest]

Mine didnt have the venturi, and I've since replaced the lot with Samco hoses anyway. I've also deleted the ISV, aswell as the purge valve completely and just connected the two hoses in and out of it on the bulkhead together. I've noticed no difference. (apart from the HUGE increase in performance due to all that weight loss of course..... ) It simplifies all those hoses no end! Of course it does idle roughly when cold due to the ISV gone, but it doesn't die as badly in cold weather as I expected.