Mledbetter

I just sent this message to Lindsey, but was interested to see if anyone here has an opinion on the subject.

On all my other cars, the blow-off valve has been installed in a manner similar to the first picture below. They normally vent to atmosphere...

Email I sent to Lindsey below:

Mike and Dave,

I purchased your upgraded bypass valve a couple of months ago along with a few other goodies. Looking at the valve, I'm curious as to if I have it installed correctly.

On your website, the picture shown on the bypass valve link: <a href="http://www.lindseyracing.com/944eng17.htm" target="_blank">http://www.lindseyracing.com/944eng17.htm</a>

This shows the compressed air side going in to the bottom of the valve. The side directly opposite the vacuum line nipple.

Most of the other pictures, including the one on the main 944 page: <a href="http://www.lindseyracing.com/944intro.htm" target="_blank">http://www.lindseyracing.com/944intro.htm</a>

These all show the compressed air side going in to the inlet that is 90 degrees out from the valve.

Looking at the construction of the valve, logic would say it should be installed as is shown on the bypass valve link page. So, the valve would stay closed against the positive pressure of the intercooler outlet pipe. On gear shifts, the vacuum from the nipple would pull open the valve.

Does any of this make sense or am I confusing the issue?

Thanks,
Matt

Pat Kennedy

I forget where I saw this written, but I learned that the bypass valve could be mounted either way. Some guys mount it horizontally to gain some hood clearance.

When you get that thing mounted, let us know what differences you perceive. I'm more than a little tempted to opt for one myself.

Mledbetter

[quote]Originally posted by Patrick Kennedy:
<strong>I forget where I saw this written, but I learned that the bypass valve could be mounted either way. Some guys mount it horizontally to gain some hood clearance.

When you get that thing mounted, let us know what differences you perceive. I'm more than a little tempted to opt for one myself.</strong><hr></blockquote>

Hi Patrick...

Thanks for the reply.

I've actually had it in the car for about 3 months now. I replaced the stock valve because it was starting to leak a bit. I think there is a cheaper alternative that would do the job equally as well. I think maybe its from the 930, but I can't remember for sure.

Looking at the valve, I guess it could mount either way. It's a real tight fit with the Guru map kit, so I'll either need to get some new hose or just vent it to atmosphere.

Thanks again...

-Matt

Mledbetter

Below is the response I got from Dave. I'm going to switch mine, cap the inlet on the intake, and vent it to atmosphere.

-Matt

[quote]
<strong>

Matt,

It's a long story, but position it the way you see it on the bypass valve page. Lying
down so to speak. It works both ways, but better this way.

With kind regards,

Dave </strong><hr></blockquote>

NZ951

Thank goodness for you people! I just got one, installed it upright and its a tight fit, I thought I could try it flat as in the picture which I checked after... down works for me!

A

dmoffitt

i've got my stratmosphere hyperboost installed exactly as shown / as dave describes. works great.

Ski

I've got mine "reversed" as well. One thing I have noticed is that boost response between shifts is better and when letting off the gas around town, I don't get the popping sound. If clearance is a problem for some, just loosen the intake plumbing(whatever you have)on your turbo and give it a slight twist clockwise and you should end with about 1/2" from the throttle body linkage.

Wormhole

The picture on the Lindsey site is orientated in the opposite direction then stock.
I really don’t understand how they can suggest mounting it like that. The pressure from the inlet, (in their setup the spring side), is equal to the pressure from the top vacuum line (what keeps the valve closed). So, the only thing keeping the BOV closed is the spring.

I tried mounting my stratmosphere BOV like that, just to see what the effect would be. Well, I could hear my turbo SCREAMING, and I quickly changed it back. My guess is the spring wasn’t strong enough to keep the valve closed and was leaking air out, which caused the turbo to over rev while trying to maintain boost pressure.

I think the only reason they have it installed that way is because it doesn’t clear the hood.

AC

bump.

I have mine installed reverse from the pic as well.

pedro951

i found this helpful: <a href="http://home.attbi.com/~mistertam33/dv/5.htm" target="_blank">great diverter valve face off</a>

pedro951

the one lindsey sells sooks just like the turboXS one tested here. under "results of the testing" they reccomend installing it reverse of stock.

dmoffitt

aftermarket ones can be used either way typically - the piston inside is grooved to allow this... or at least, that's how my strat. is made...

Wormhole

There is no benefit to installing it backwards. It a very simple devise and they all work the same (except for some like T.nextics which use two vacuum lines), vacuum opens the valve and boost pressure keeps it closed. By reversing the origination you now apply pressure to the spring side, and jeopardize yourself to air prematurely leaking out, which can cause rich AF conditions, and having your turbo over rev. Both of which may not be noticeable depending on how much is leaking. If you have the option and it fits, I don’t see any reason why you wouldn’t want to install it the correct way.

Mledbetter

You always have pressure on the spring side, regardless of which way it is installed. Either positive pressure from the vacuum line or positive pressure from the intake (IC outlet) pipe (actually both).

-Matt

Wormhole

Matt, pressure from the vacuum line keeps the valve closed. Pressure from the pipe outlet forces the valve open. They both apply pressure but in opposite directions.

In the original orientation from the factory, the IC pipe outlet does not put pressure on the spring.