adrian1

I have a 1986 951 completely stock with new vacuum lines, intake gaskets, venturi delete, hoses, tune up ,etc....... I had a problem with overboosting and changed the control valve and same thing. Thinking it can only be the wastegate I purchased a used Tail 38mm with adapter plates and the famous black ****.

1. Should I connect the black **** or leave the CV? (Stock healthy engine)
2. Top port on wastegate is open and the bottom port connects to the black ****/CV?
3. If I do run the black know do I need chips to fix my AFR due to the car holding boost longer?

Suggestions and help is all appreciated, Thank you -Adrian

(Installing it tonight)

adrian1

Without a Wideband in the car; I don't want to take a chance running lean.

Crackership

what spring does the new WG have?

adrian1

Not sure, # on it is SN06081072, I don't think that will tell us.....

adrian1

In this case would it be better to just connect to the MBC ****?

Crackership

well... sure, but the WG spring will determine the minimum pressure needed to open it. It seems that most of the 951 guys use a 0.8BAR spring, which would equate to a little less than 12psi, but I have a 1BAR spring in mine, so I can't go any lower than ~14.7psi. That's going to be important information to have before you proceed... you could probably get away with 12psi on stock chips, but I doubt that you'd be ok at 14.

either way, the top port on the WG goes to the "out" side of the MBC, and the side port should T into the line from the turbo to IC hard pipe and then go to the other side. You'll need to delete the CV entirely.

Lindsey Racing has a good diagram of the routing, just make sure you're using the right one, and, as they say at the top of that page, the Tial is the reverse of the LR WG

onspeed

Cycling valve will not work with a Tial 38mm in my experience.

ramius665

I deleted my CV and just ran with the spring on my Tial 38mm. Holds boost to 1 bar all the way to redline and has never over-boosted.

Paulyy

Are you running stock chips?

adrian1

just got my vitesse chips, exhuast, and 3 bar fpr to go with it. Doing it now . Thanks

adrian1

The previous owner of this car ran it at 15 psi with these exact performance parts in an 86 951 as well.