i know this is prob on here already but i do not have time im in a rush sorry guys...BUT i installed an autometer boost gauge, here is my issue....i tapped into the fuel pressure regulater air line that outmotoring tells you to tap into...reads vacuum awesome, why is it not showing boost???? please help!

 

was the line you tapped into plastic line or a soft rubber line?

 

MINI's register vaccum during idle....and you will not see any boost by revvvvvvin her either....

Boost will register when engine is under load. Take her for a spin !

 

Not true on s/c'd engines, only turbo engines don't build boost with no load.

 

https://www.northamericanmotoring.co...ight=autometer

 

if you need any help, feel free to send me a PM

 

That makes no sense what so ever, who told you that ?

 

My boost gauge :P Because s/c's are tied to the engine speed, not load, we can build boost in neutral.

 

 

Sorry, no disrespect, but mechanical engineering is not your forte', no matter what your Boost guage reads. It is not supposed to be reading any BOOST to your engine until there is a load placed upon it.......especially at idle and esp in neutral.

Boost is created at the point when the supercharger's internal impeller pushes enough air through the blower to overcome the vaccuum force naturally created by the engine's air intake, so air is being forced, rather than pulled, into the air intake.

back at ya :

 

When at idle your engine manifold vacuum is at its highest, this in turn opens your Bypass Valve, relieving the sc from building pressure, affinity or "fan laws" state that CFM varies propotionally with RPM, and the Pressure increases to the square of the rpm. when the bypass valve opens (idle) the sc has nothing to do (equal pressure on both sides); like when you put your hand over the end of your vacuum cleaner hose, the motor speeds up because it is not sucking air, the vacuum cleaner's amperage is at its lowest at this point (contrary to popular belief).

When you accelerate, your Mini's manifold vacuum drops and and the bypass closes, quickly building pressure that exceeds manifold vacuum and pushing air into the cylider versus it being sucked in. Vacuum at idle/ boost under load, somewhere in the middle, under cruising condition

 

Nice explanation. So, getting off topic just for a second, I was wondering if now maybe my bypass valve could be faulty. My car has a delay to it, but it seems more like a boost issue. I've been thinking of changing the belt out, but now am pondering the idea that maybe the bypass valve is faulty. Basically the car acts like it has an old school turbo on it displaying lag. It tries to take off fast and then all of a sudden it's like boost builds up and the car just goes. Any ideas?

 

If you look under the air horn right side as you face the engine you will see the small plastic actuating arm, cam and adjustable stop, with cold engine reach from the back and actuate the lever, it should move smooth and when released it should close where the cam just reaches the stop...(Aftermarket Detroit Tuned" bypass valve will close rapidly and rest on the stop). If your cam sits noticeably far from the stop or feels rough its probably bad...you are never getting full boost, 50% if you're lucky