Tearing into the new car, I've cascaded down the maintenance list. Car is an 86 951 with few maintenance records, with venturi, with old vacuum hoses. Replacing the belts turned into replacing AOS seals, which turned into taking the intake off, which has created an issue.

I broke the plastic outlet on the cycling valve while disconnecting it.

The simplest (but not least costly) option appears to be buying a venturi delete kit ($104) and the stock cycling valve ($122 from our host).

TexasBlake has a detailed writeup(http://http://www.texasblake.com/por...ch/vacuum.html), but that left me with questions. Q1 I'm unclear on whether he replaced only the venturis, or also removed the 3 metal hoses that run from the cycling valve towards the front of the car.

There is a great writeup on Rennlist on the Venturi delete, which suggests I could get by without the kit (https://rennlist.com/forums/944-turb...te-thread.html). But it means having to make some decisions.

Decision 1: 3 options are listed on RL, the replacement factory hose is only $10.75 from our host, that seems to make the most sense.

Decision 2: For replacing the check valve, to prevent smoking under boost. Q2: Does the venturi delete kit fix this check valve issue? I'd prefer to get a hose off a parted car, Q3: anyone selling one currently?

What the RL discussion does not answer is the combined situation of broken cycling valve and venturi delete. 5speed300 suggests that the combined problem has a solution that implies just running a single hose, subject to finding an oil-rated hose (like fuel hose?).

The alternative I've seen suggested elsewhere is to replace the cycling valve with a manual boost controller. There was a big post on it (http://forums.pelicanparts.com/porsc...ing-valve.html). The issue is that the manual boost controller does not provide the knock protection that the CV offers. I had hoped the manual boost controller would save me money, because at $65 instead of $122 for a CV, it was cheaper. However, seems I would need a better boost gauge to calibrate it to 11psi, another $60 that brings is back to par. Q4: Would I need a better boost gauge to calibrate the MBC?

My intent is to keep the car as stock as possible - I don't intend to replace the wastegate, install an EBC, or chip the car. Conclusion from the thread appears to be to buy the stock cycling valve. So, Q5: Should I just buy the stock cycling valve?

 

Buy the stock cycling valve new. Many are very brittle with age and repeated heat cycles. You probably already had a bad cycling valve when you completed breaking off the outlet. I bet it was at least cracked. You should not get a used one unless you know it to be near new.

If you decide to go with a manual boost controller, you really need to have an aftermarket boost guage and a wide band O2 meter. That adds to the expense. If you want to stay stock anyway, I suggest you do the venturi delete and cycling valve.

In trying to find the most cost effect solution to your problem, you sound a lot like me. I have learned that nothing about the 944 is cost effective. $250 is a very small expense to keep the car running. I have been investing about $0.65 for every mile I have actually driven this car over the last several years. I am hoping that I am at a relatively stable position mechanically. My point is.... at some point in your ownership, you will have to spend more than you want to keep it running. Get ready. Hopefully, it is a $250 repair this time and nothing else sneaks up on you.

Good Luck.

 

Appreciate the note. Re: stock cycling valve, LR seemed to say the same thing on the phone earlier. Stock it is!

Interesting metric. For my last 944, I was at $0.41/mile.

So that leaves Q1,Q2,Q3.
Q1 I'm unclear on whether he replaced only the venturis, or also removed the 3 metal hoses that run from the cycling valve towards the front of the car.
Q2: Does the venturi delete kit fix this check valve issue? I'd prefer to get a hose off a parted car, Q3: anyone selling one currently?

 

Good to see you already have some experience. I did the venturi delete as one of my first things. It was so long ago I don't have the details. My memory is that the hose replaces the function of the metal tubes, but I will let someone with a much more recent memory address those questions.

Michael

 

The venturi delete kit does not get rid of the 3 metal pipes. All you need to do to get rid of them is take the pipe to a hose shop and tell them you a silicone hose that matches the big one in the middle.

 

I have a great condition stock Cycling valve if you are interested.

 

Dougs951S - I'm interested, what would a reasonable shipped price be from Austin to 02134?

Black51 - Will look into it. I wouldn't really know where to look for a hose shop, other than Autozone / Advanced, which I doubt carry silicon. If I remember right, there are 3 metal hoses all parallel, but you're talking about replacing just the large diameter portion, on the understanding that the smaller diameter ones get taken care of....?

 

Oh sorry, forgot youre still running the cv. Just get all 3 in silicone. If youre not sure about where to get hose locally, you can get bulk hose from vendors likeLR. I would phone them and tell them what you need.

 

Whats the point of deleting the metal tube tree? I have venturi delete and I still have the (unused) metal pipes, and my car is far from stock.

 

Purely for looks.

 

I have a new CV to Wastegate hose I'd let you have for a good price. I think they're around $30, I'd let it go for $15 + S&H. I'm never going to use it and it's just gathering dust.

 

I am having my metal pipes yellow cad plated, not expensive. Should be done by Monday dropped off yesterday, will share results. Seems a little more sturdy and stock then silicone. Don't know what silicone costs, but had all my heat shields and miscellaneous metal bits done for 75$ Will share results.
I believe I still have my CV and would be happy to give it to you for shipping from Houston. It was recently replaced, Less then 200 miles on it. Bought the manual boost and new Lyndsey waste gate as part of my project and will no longer need it.
I followed Texas Blakes venturi delete procedure, Thanks Blake . Only issue I found was replacing one hose with motor mites ect. Just couldn't find the same parts Blake suggested at my local auto parts stores. Found that 944online sells the replacement hose in silicone making the whole thing a lot simpler. Just don't throw away your old hose as you will need to retain the crimped nipple .

 

There are several guys that have the silicone in place of the pipes. IMO, it takes away a bit of the 'rat's nest' look and is much cleaner, and would be easier to deal with when pulling things apart.

A piece of bulk silicone tube is cheap. LR sells it for $3.10/ft.

http://www.lindseyracing.com/LR/Pors...HEAT-HOSE.html

 

thanks guys, this is great info - if its purely for looks, I suspect I'll keep the metal pipes, but still delete the venturi. Consensus sounds like keep the stock cycling valve.

I started to take out the downpipe in order to get at the AOS seals last night, and first crack managed to shear the stud from the turbo to the DP! So I guess I'm taking the whole turbo out, have yet to figure out if I can drill that stud out with the turbo off the car.

 

Unlucky! those turbo studs get heat cycled like crazy, it always good to soak them in penetrating oil of choice for atleast 24 hours prior to giving em a crack. you MAY be able to drill the stud out with a right angle drill but it will be extremely tight. My vote is pull the turbo.