InC

Hi guys. Found out that the original diverting valve consists of a plastic diaphragm and a few O rings that lasts only a year. Want to find out the symptoms when it is broken. Will there be air leak or can the car still hold the boost? Is it difficult to replace. Thanks.

WERK-I

Are you talking about the OEM 964 turbo diverter valve? Only a year? Oh-Oh!

InC

Not sure if the 930 has the same diverting valve. It seems like to me a recirculating valve that sits below the intercooler. Read some where that after market ones are much better.

jeff91C2T

I got sucked into the "internet rumor" that the diverter valve only lasts a short time. I bought a forge valve to replace mine.

I tested my potentially 15+ year old valve and it works fine. I also was not able to notice a difference between the two after installation. To test it, apply a vacuum to the small fitting (see if it holds this vacuum) and then see if air can flow through the large fittings. I believe the 91 Turbo's were the first Porsche's to get these valves. The older 930's don't have one (unless they've been upgraded to a Kokeln unit...they might have one).

WERK-I

Yep, the Kokeln's long neck IC's come with the 965 diverter valve(Blow-off valve). No problems to date after three years of service.

Stevie 77 930

Just installed the 965 version of the BOV on my '77 w/ a long neck intercooler. Had not been using one. What a difference in throttle response and much smother between shifts. The factory piece works like a charm.

nathanUK '81 930 G50

The 930's recirc. assy is huge. It does have seals that wear out.

Stevie 77 930

With a long-neck intercooler, the small bov/recirculation type is much more efficient than the older version you are referring to. I know alot of guys bad mouth the bosch part, so I've tried both the EVO and the bosch. The bosch seems better on my car.

diabolos88

who sells the parts needed to upgrade the stock 930's setup to the later C2 BOV?

nathanUK '81 930 G50

Stephen does.

PorschePhD

What they use to build and what they do now are two different things. The units coming from Porsche are junk. I have worked on many brand new cars that have less than 2K on the clock and have FOD on the turbos due to DV failure. The rubber goes through the turbo. Also, on Bene't original car the DV did go bad. So they do and you are lucky. My car came in with a bad valve.

Stevie 77 930

Stephen,

Are suggesting I should avoid the bosch DV all together? It's not as if the EVO unit didn't work, just seemed that the bosch unit provided a bit smoother run during shifts. If the word is that the bosch units have the tendency to self-destruct, than it would be piece of mind that i would be more interested in.

lebrunseven

anyone know where i can purchase a stock diverter valve for a 1987 930? or if not, which is the best aftermarket valve that required minimal modifications?

Mark Houghton

Wow....talk about resurrecting an old thread!!
The stock "diverter valve" is not the simple blow-off type valve that you would find on the later C2's. Rather, we're stuck with a "secondary intake manifold" that encompasses the boost recirculation valve assembly. This whole magnesium intake assembly sits on top of your intake manifold, above and attached to the throttle body. If the previous owner to your car deleted that manifold/valve assembly and installed an aftermarket BOV (and a long neck intercooler as necessary for this modification) then you have several options. Otherwise, the manifolds often come up for auction/sale from folks that have done the upgrade to a later style BOV.