Both of these 86 turbos felt really felt really strong when the boost came on but they would cut out in the upper RPM ranges in 3rd and 4th. After some investigation I discovered both had broken cycling valve ports. These things take a beating because of where they are positioned. Sonnen Porsche sells them new for only $75 plus shipping! I've got a new one on the way - had only one good spare. I was able to swap out the first one with the intake still in place. The part number is 951.606.117.00.

 

Good public service announcement!

 

Why have a cycling valve if you do not race in stock class?

 

Please explain, I like removing unnecessary parts.

and thanks for the heads up Josh!

 

Just unplug the wires. and leave the ports on the CV unconnected. All you are doing is bypassing it and using an MBC or EBC instead.


While your doing that you can also do a venturi delete (that is the metal pipes under the intake manifold. Several ways of this this....

 

Yes first upgrade for any 951

 

I just replaced mine last week, both nipples were busted off. Found it when I smoked the intake system, just after replacing the brittle cracked WG hose. If it wern't for smoking it, I would have never known I had so many leaks! Amazing how well it can run with so many small leaks.

I replaced mine with the intake still on as well. Removed banjo and booster hose on the intake for extra room. If the small hoses need to be done between the valve and the pipes, it's a pita to do. Long needle nose pliers and lots of patience is going to be needed!

 

Unless it's model year 1988 or later.

 

Correct. Lots of folks don't realize that they don't have one on their 86-87 cars.

 

Ah yes, that's right. For as many projects as I've completed on my car, I have not changed or updated the P.O.'s engine mods. Only engine maintenance. Someday I may go with a dual port wastegate and MBC but for many reasons, I haven't to date.

Venturi delete I have completed.

Ried / Ehall, you have me confused. Car's an '89, cycling valve or not?

 

MJ they all have cycling valves.

Reno and Josh, is there a reason why you would disconnect the wiring?
I have had mine bypassed for years and have never unplugged the wiring.

 

Yes Cycling valve. They all have/had cycling valves. Also, yes, your 89 has a venture tube, unless the P.O. deleted it. Just do a search here or on google, and you'll find all the info you need on the Venturi delete mod.

 

Also, if your car runs well, and you aren't planning on any major new mods. it's just fine to leave it alone. Venturi delete is a non essential item. Cycling valve gets bypassed if you run a manual or electronic boost controller. Hope that helps clear this up for you.

 

It does, thanks ehall. I went through and replaced all the vac, coolant, power steering, oil, brake and fuel lines, including the venture delete when I first bought the car but that was over ten years ago. I must have had a brain fart the other night when I post the question, couldn't remember the CV. My car is still in winter storage but I pulled the cover and peeked under the hood the other day and it all came back to me. Also has me anxious to drive it again this season. Thanks for the clarification.