Jim R.

Hacker,

Welcome to the club!

Nice looking install. Have fun with the boost. Should be even more fun with a few more psi once you add the WBO2. It is amazing how the power keeps on coming isn't it?

Jim

Cameron

Congrats! Once you have B, you never go back. B=Boost here.

hacker-pschorr

No estimations, hope to make a visit to the dyno soon. This car made 160rwhp in 2004. I do plan on upgrading the exhaust starting with the manifolds, after the dyno. This way I will have an accurate before / after number.

Other than swapping the belt driven fan for electric, everything is stock.

I will have to let Tim answer this question, I’m not sure a kit was ever in the works for the early cars from Tim. Due to my close proximity to Tim, I started bugging him about a blower for my car a few years ago. The install would have been completed a year ago had I not taken all summer to replace my head gaskets. Buying a second 928 – project / track car, didn’t help things.

Vortech FMU to add fuel pressure under boost. Other than that, the fuel system is 100% stock.

If we are able to make it, this is the car we will bring. Still working out the details.

AO

Very cool. It'll be interesting to see the numbers.

Nice artwork, Ken!

Imo000

The BOV/BPV should be hooked up to manifold vacuum (passed the throttle plate). I used the line running to the fuel pressure regulator. If the distributor advance line is like this, then you have it correctly hooked up. What typo of a BOV/BPV are you using? For the live of me I can’t see it in the pictures. I can see and did notice the braided line as soon as I saw the pictures but not the valve. Is pointing down from the boost tube?

I’m also only using a Vortech FMU, they are great, simple and do the job perfectly.

hacker-pschorr

I am a complete and total idiot. I knew the BOV should be attached to the manifold side, for some reason I was thinking the Vacuum advance line was connect to the manifold. So basically right now my BOV is not working properly. Tim was trusting that I knew what I was talking about with these cars – I told him “Use this line for the BOV, it’s receiving manifold pressure / vacuum” so that is how we hooked it up.

I’m going to move the T for the BOV down to the retard line on the distributor. Post 83-928’s do not have this post.

Nope – as Porken pointed out, the distributor advance is on the intake, non manifold side of the throttle plate. I stopped in at Page Auto to show Jim the car on the way to work, and I asked a very simple question: “Does vacuum advance go on the manifold side of the TB” He said no, showed me one of the BOSCH diagrams he has framed in his showroom, explained why and I suddenly had a moment of clarity. This will be corrected very, very soon (after work).

Rick Carter

Congratulations to you and Tim, I'm constantly amazed at the luminance of the people on this list.

heinrich

Rick ...

"Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminosity is candela per square metre (cd/m²).

Luminance is often used to characterize emission or reflection from flat, diffuse surfaces. The luminance indicates how much luminous power will be perceived by an eye looking at the surface from a particular angle of view. Luminance is thus an indicator of how bright the surface will appear. In this case, the solid angle of interest is the solid angle subtended by the eye's pupil. Luminance is used in the video industry to characterize the brightness of displays. In this industry, one candela per square metre is commonly called a "nit". A typical computer display emits between 50 and 300 nits.

Luminance is invariant in geometric optics. This means that for an ideal optical system, the luminance at the output is the same as the input luminance. For real, passive, optical systems, the output luminance is at most equal to the input. As an example, if you form a demagnified image with a lens, the luminous power is concentrated into a smaller area, meaning that the illuminance is higher at the image. The light at the image plane, however, fills a larger solid angle so the luminance comes out to be the same assuming there is no loss at the lens. The image can never be "brighter" than the source."

Definition
Luminance is defined by

L = (d²F)/dA dΩ cos Θ

where

L is the luminance (cd/m²),
F is the luminous flux or luminous power (lm),
θ is the angle between the surface normal and the specified direction,
A is the area of the source (m²), and
Ω is the solid angle (sr).

Imo000

Ok, good to know that you found the first glitch! The SC will be quieter once you take your foot off the throttle and the BOV is operating properly. Then again, I’m not sure how loud your BOV will be (some are designed to be pretty loud). From your post, I’m guessing that you are running a Blow Off Valve (BOV) and not a By-Pass Valve (BPV). The blow off valve will only open once it reached a certain pre set pressure and stays closed before that (sort of like the safety pressure valve on an air compressor). So with the incorrect vacuum the BOV probably stayed CLOSED all the time. What brand is it?

BPVs on the other hand are always open unless there is boost in the manifold. It stays open before, so if the vacuum was incorrectly connected it would stay OPEN at all times and you would notice this right away.

WesM951

Very nice Hacker.. I want to go for a ride in that thing

hacker-pschorr

I think Tim was calling it a Blow Off Valve - the unit on my car stays closed unless vacuum is applied when the throttle is closed. Reason why it's not working correctly at the moment, it's on the wrong side of the throttle. This isn't affecting performance since full boost is still reached, except now when I close the throttle at a high RPM, the throttle plate is getting hammered with boost. Right now the system is allowing boost to build up in front of the throttle plate so there is a risk of opening the throttle & getting a surge of boost.

I'm sure Tim will chime in to answer what kind of valve it is.

Bill Ball

Welcome to the club! Very nice installation.

Imo000

Yes, if it’s closed except till it sees vacuum, then it sounds like a BOV.

Don’t worry. Even if it stays closed all the time it will not open the throttle. I had two SCed (both around 6psi) cars before the 928 and none of them had a BOV or a BPV. The only draw back was that upon deceleration the extra pressure would escape at the impeller and would make a weird surging/chirping sound. It could make the belt slip a little too, over a really long period of time it could reduce the life of the SC by a little, but other than that, the BOV is not really necessary for a low boost application. It’s good to have but not essential.

Gretch

Stock Murph set up, usually mounted to the air tube after the blower....Before the MAF

hacker-pschorr

Gretch,
Tim switched to a different BOV for his kits.