I have one like Todd pictured above. I bought it at McMasterbater for maybe $20 and plumbed it into my engine bay. I didn't put it in the cockpit cause I am a weak weak man.

You can also build one with a needle valve instead of the air regulator that is commonly used. Or even a tee with a restrictor will work.

Dean,
Can you show a picture of the unit and install?
Which unit from "McMasterbater" did you order, they have a large selection. Hard to get a HAND-le on it....

Here it is if this workshttp://forums.pelicanparts.com/uploa...1194992838.jpg

Hey it worked.

The unit is just a basic air pressure regulator. I think if I did it again I would use a needle valve. Only $7 instead of $20

Re-opening this thread for more ideas and options on what others have done that works.
Anyone with more thoughts or ideas?

So I have to ask the question, what really does one hope to gain with this mod? Please don't misunderstand, I'm not trying to be a smart azz! Just wondering what the driving force behind this is for a street car? I tend to be a "set it and forget it" type of person...so once the novelty wore off for me, it's doubtful that I'd mess with it again. FWIW, I have a 46mm Tial with a .80 bar spring and full boost for me hits at 3,300 RPMs.

"The factory 935 used a dial that was adjustable in the cockpit.....but this may be too tempting."

With the twin turbo 935's they could turn up the boost for near 900hp for one shift, and then turn it back down to around 750hp or you had a good chance of melting a piston(s).
Some 935's I've seen had the regulator and knob installed where the clock goes so the driver didn't have to reach as far from the steering wheel.

some further motivation for you, Fred (since 935s came up):
http://img85.imageshack.us/img85/406...7572072xn9.jpg
http://img85.imageshack.us/img85/6284/knobcp5.png
http://img85.imageshack.us/img85/9026/knob2cm2.png
http://img85.imageshack.us/img85/213/knob3dp0.png

these last pictures show exactly what I have in my 930, mounted in the central console.
bought it this way ..(seller info .8 bar and .2 additional boost available through controller)

question, on the centrale console I discovered a very little swith with a red light under it. could this kind of system be switched on and off with a switch ?

the sensor on the tube of the IC is disconnected (I suppose it to be the boost sensor) where would the boost then be measured now ?

They also had a key to lock it at a preset boost level at the mechanic / car owners discretion. Also note the Factory Porsche boost gauge from which these and other parts were salvaged from a factory car and installed in this street 1977 930.

http://forums.pelicanparts.com/uploa...1208910997.jpg

See my post above. This one is from a period 934 / 935 Porsche turbo with the key lock out.

Bringing this one back from the dead...
 

So I ordered one of these, a Joe P MBC...the Pro-Z model :
http://www.boostcontroller.com/produ...epmbcproz1.jpg
http://www.boostcontroller.com/produ...epmbcproz2.jpg
http://boostcontroller.com/index.php?item=351&ret=http%3A%2F%2Fwww.boostcontr oller.com%2Findex.php%3Fpage%3D1%26category%3D4
I'm still running the .80 bar spring in my Tial, but for a while now, I've been noticing that the wastegate has been creeping open before the .80 mark on my aftermarket VDO boost gauge is reached. I guess a couple factors could cause this, including a possible inaccurate gauge. However, I think this MBC will help me fine tune the boost. I also think that having the signal to the wastegate diverted until it's absolutley required will help with accuracy.

I know all aout the "dial of death" stuff, but I'm planning to install it in the engine compartment, away from my greedy hands. And though my engine is setup for it, I don't plan to run more than .90 bar.

This knob is installed in a dp center console. Right above the shift knob. It's plumbed into the bottom of the wastegate.http://forums.pelicanparts.com/uploa...1211311195.jpg

So are you gonna tee into the boost line from the intercooler with the controller and then mount it where you can adjust it and leave it?
Was interested in seeing where you got the supply pressure for the controller from.
Let us know how this works.

Everyone, thanks for the ideas.

I should have it this week. I haven't seen the install directions, but I was planning to use the line that's already in place that runs from the driver side of my 965 intercooler down to the wastegate. I was planning to just install the boost controller directly within this line: intercooler to MBC, then MBC down to wastegate. And yes, planning to locate it where I can adjust it and then leave it.

subscribed...

Ok as long as we are reviving this thread. Does anyone make a 0.5 or 0.6 boost spring for a stock gate ?

hmm,
please correct me if I am wrong, but I understand this boost regulation in a different way.

You connect the waste gate vent with a T connector to the wastegate boost control line.
Between this you connect the air regulator,whatever this is...needle valve etc.
With the valve you control the wg upper/lower chamber difference.
You use a 0.6bar WG spring for example.

more playing:
With this + some more T connectors, you can add a magnetic valve,
switched from the cockpit for either 0.8 standard or 1.0 bar when needed.

another option is, brian asked for in another threat:
if you have a rpm switch or your WBO2 system maybe has
( zeitronix has this option for example), you can drop boost at a desired rpm.

maybe someone can translate this to english? :confused:

Falk

I have a similar scenario on my 930, and thought it was odd. There is a "speedaire" regulator. It is tee'd in, with one connection going to the intercooler, and 2 to the waste gate...I just don't understand how this would work?

The regulator presumably opens at a preset pressure, and allows the air into the WG control to open it. So far so good. But, how does a tee'd in connector off the intercooler to the top of the WG help? Seems to me that the pressure to the WG line on the bottom and the top of the diagphram would cancel each other out???

The car I am working on had a lot of "modifications." The WG had two springs in the original WG, and it took 20psi off an aircompressor to budge the diagphram. On top of that, it had the tee'd in regulator as listed above. I don't know what the engine internals are, but it was/is fast as heck. Dash boost guage doesn't seem to go past 0.7/0.8. But thats a bit off topic.

Can someone explain to me how tee'ing a regulator to both the top and bottom of a waste gate is beneficial? Supposedly RUF did it this way too...

Or you can use and AEM Boost Solenoid. You need a driver but by changing the duty cycle you can control your boost levels. With the right driver you can even taylor your boost by rpm and or other factors like what gear you are in.


AEM - Boost Control Solenoid Kit

http://forums.pelicanparts.com/uploa...1273330757.jpg