Long neck adaptor for BOV conversion?

[b930]

Hi
Looking for any pointers on where to get me an adaptor for my andial shortneck to convert to a later BOV. My stock BOV is leaking and I want to keep my andial short neck cooler.
Thanks

[mark houghton]

If you're speaking of removing the entire stock boost recirculation manifold and BOV assembly - and looking for an adapter to bridge the gap between the short neck and the intake manifold throttle body - there aint one.

Usually for this conversion a person gets a long neck intercooler and removes the entire boost manifold assembly, which requires the following hose to connect an aftermarket BOV to:


I would suggest you fix your current leak (I presume you are using the stock boost recirculation setup, and have leaking end gaskets is all). Then, if you wanted, you could pull off the vacuum line to it so it no longer functions and install an aftermarket BOV to a hose coming off the intercooler (provided you have a port available on the IC for a hose connection).

Or, you can go extremely radical and do what I did if you don't mind some Frankenstein engineering BOV update with short neck IC

[cole930]

b930:

Do a search here, there is a man known as the "Madman of the
Pacific Northwest" who posted doing this. Lots of pics and a good write up.

His name is Mark Houghton search using his name or BOV conversion

Cole

[cole930]

See !!!!! He's magic, he apeared as I'm posting his name !!!!

Cole

[TT Gasman]

Do tell

[mark houghton]

The PNW Mad Man here....just call me Mr. Unconventional. Been Jones'in today, really want to go for a spin since winter snow just doesn't seem to want to come this year. Instead, we have freezing fog all over the place (damn near fell on my ass going down the drive to get the newspapar this morning) and had to do the 4x4 thing last night coming home from my birthday dinner with my 84 year old ma, it was that slick. Still Jones'in, mostly due to lack of nicotine since I've decided to quit after 40 years of cancer stick sucking fun. Wearing the patch...I wonder if a guy could roll one of those patches in a ZigZag paper and smoke it?

Way the hell off topic again. B930, lots of options out there and some really nice professionally done conversions that our members can share.

[JFairman]

[QUOTE=mark houghton;6439672]
I would suggest you fix your current leak (I presume you are using the stock boost recirculation setup, and have leaking end gaskets is all). Then, if you wanted, you could pull off the vacuum line to it so it no longer functions and install an aftermarket BOV to a hose coming off the intercooler (provided you have a port available on the IC for a hose connection).
QUOTE]

If you just remove the vacuum line from the stock recirculation blow off valve there is a possibility boost pressure could push the piston down it's cylinder far enough to make a huge boost leak back into the turbo intake. I dont' know if the spring behind the piston is strong enough to hold the piston from opening far enough for that to happen under boost. Depends alot on how much boost you're running.

That won't happen as long as the blow off valves vacuum line is attached because boost pressure replaces vacuum behind the BOV piston and helps hold it TDC in it's cylinder so it doesn't get pushed down to the opening in it's cylinder wall by boost pressure.
If you keep the old blow off manifold in place take out the spring behind the piston and put a piece of PVC pipe or even a broom handle cut to length that holds the blow off piston at TDC in the shut position so boost can't push down it open.

Then you'll need the 964 turbo intake hose Mark mentioned Pelican Parts - Product Information: OEM-93011038200
That hose is not stocked and is special order from Pelican so maybe it's OK to mention you can get an OEM one for alot less elsewhere. It's part number is in the link.

The Garretson/Andial shortneck intercooler doesn't have a 1" ~ 25mm hose connection for a C2 blow off valve but it does have an extra unused hose fitting above the aux air valve hose fitting on the right side. It's too small though so it would be much better to have a 1" OD piece of aluminum pipe welded onto the back end tank of the intercooler for a C2 type blow off valve hose connection.

Connect the C2 blow off valve's vacuum line to the top left vacuum line fitting on the throttle body. Thats the same place the stock deceleration valve's vacuum line is connected.

[b930]

Thanks. I'll tear into the stock recirc valve and see what gives. Suspect just seals. Before I do so, how does the stock steel plunger that gets drawn in and out inside the valve by intake signal actually seal off the recirc passage to the inlet?? is there a window in the side adjacent to the piston or does one of the end seals perform this (I mean, does the recirc air go around the end of the piston covers to the inlet). From the outside it hard to tell. Just wondering if changing the end seals will remedy internal leaking back to the inlet under boost, and in wondering this, I am unclear as to how the piston actually seals off between the inlet / pressure side.

Guess I'll find out when I get in there.
Cheers

[mark houghton]

Originally Posted by b930

... how does the stock steel plunger that gets drawn in and out inside the valve by intake signal actually seal off the recirc passage to the inlet?? is there a window in the side adjacent to the piston
Cheers

Yep, you guessed right. Fairly close machined tolerances, letting very little air get past. There really isn't much to go wrong with these piston valves; a spring and a piston, and two end caps with seals....that's it. Unless it's seriously gummed up and the piston is stuck or the spring is broken, what else could go wrong?

In your comments....why do you feel yours is "leaking"?

[b930]

thanks, mine has erratic boost onset and varying boost levels hence I am suspecting the bov. It used to make the clonking noise on sharp transitions of manifold vacuum to no vacuum (stabbing the throttle) but now it does not.

[jimtweet]

Porsche: 911 Turbo 930 Silicone Hose

[JFairman]

Originally Posted by b930

how does the stock steel plunger that gets drawn in and out inside the valve by intake signal actually seal off the recirc passage to the inlet?? Guess I'll find out when I get in there.
Cheers

There is a hole and duct in the cylinder wall that is uncovered as the piston is pulled down by manifold vacuum. Boost pressure is let out and recirculated to the intake hoses there when closing the throttle after accelerating like during an upshift.
It's an old design and slower acting than C2 type valves.

[b930]

So the end seals only repair leaks out of the body but the is no positive sealing of the recirculation path under boost, I get it.

[willtel]

diverter valve (blow-off valve, re-circ. assembly)....AGAIN! - Rennlist Discussion Forums