Bosch BYPASS VALVE for Vortech Supercharger

[CRAZY]

I have an BMW E36 325iC from 1995 with Vortech Supercharger.
I think my By-Pass Valve is not mounted corect, because it's not working at idle... and in high rpm it's working so I louse boost with this by-pass valve? I think it's opening at high rpm when it must close... ?
Can you please tell me in what vacuum hose I must insert the T connection of the bypass valve?
I don't find one hose with the corect diameter. I must drill the intake manifold ?
I think my mecanic monted the T connector in vacuum hose for pressure regulator ! Is this right ???
Can you send me some detailed extra instructions ?

[MarvelPhx]

If he T'd off the fuel pressure regulator hose, then yes, that will work.

I'd hook a boost gauge up to a vacuum line and see if you make boost at higher RPM.

[Olepainless]

At idle the bypass valve does not need to be opened. The main purpose of the valve is to bleed off excessive pressure upon quick deceleration. When you are at boost, then quickly get off the throttle, if you had no bypass, the extra pressure could bend your throttle plate. It should not be open at all during any boost conditions, if it is opening, you can and will damage the blower. Boost on a supercharger is controlled by the pulley size not the valve as in a turbo. You can hook the vacuum hose to any good vacuum source in the engine compartment. If the valve is opening at boost, it is probably bad and needs replacement or is too small for your application. I am assuming you are running less than 10lbs so the standard bypass should be sufficient. I have owned 4 different Vortec superchargers on various cars in the past and have had bypass valves go bad on more than one occasion. Hope this helps.

[CRAZY]

Thank you all !
I think this is the correct answer, I talked with other people and they told me the same thing, at idle the bypass valve does not need to be opened, it's working normally.
I will put a boost gauge in vacuum hose to see how strong the boost is in high rpm asap. I think I need most a gauge for air/fuel mixture, maybe this will give me more answers!?

My problem started six months ago because I was having a fluctuating idle between 500-800rpm, ONLY when my car’s engine is very warm, and ONLY after I rev the engine a few time in 4-5000 rpm range. If I have lights on or I turn the steering wheel, the idle is much more fluctuating. When this is happening, my car is very slow in low rpm.
I made some recently speed tests when the engine is very warm and the times were very bad, 1 sec. more in 1/4 of a mile, than one year ago.
If I drive very softly, the idle is very stabile all the way, and the car feels much better in low rpm.

Since this problem appeared, I already changed the fuel pump, fpr, fuel filter, spark plugs, mass airflow sensor /forums/images/smiles/icon_frown.gif , O2 sensor, air filter, injectors, eprom chip, idle control valve, and nothing changed /forums/images/smiles/icon_frown.gif

Another problem is that when I open the oil sealing cover, through where the oil is changed, surprise ! absolutely nothing happened with the engine’s idle! And I know it should decrease the idle... I read somewhere that this means I have a vacuum leak !?

So, very happy that I found a little hope I’ve searched to find a vacuum leak somewhere. I disconnected the air conduct from my Supercharger, and I tried to understand something, and I thought that by-pass valve is the problem ! But it is not, the by-pass is working very well, so I don't find anything wrong and I'm very disappointed.

I use carb cleaner on the intake manifold, and on some hoses, but nothing happened. My best mechanic from the local BMW service..., also inspected all the hoses and told me I don't have any vacuum leak, because otherwise the fluctuations should have appeared all the time... I turned home very disappointed, and I tried all night in my garage to find something to prove him he's wrong...
Please, can anyone tell me what else should I verify and how ?

Best Regards

[Olepainless]

If the problem is only when the engine is hot, it would guess either an ignition or fuel problem. Seems like you have done much on the fuel side and quite a few things on the electrical side but you didnt mention changing the spark plug wires. It is very common for plug wires to go bad and they can be very tricky. They may sometimes be fine and not at other times. Start the car at night in your garage when its hot and not idling properly and turn off all the lights in the garage. Look under the hood in total darkness and see if there is any spark leaks especially around the spark plug boots. You will see some blue sparking. Also look to see if any of the wires are arcing from one wire to another. Its usually something so simple when you just cant figure things out. Superchargers add a lot of heat to the engine compartment and that can wear out some of your ignition and electrical components. My advice comes from working on other cars not necessarily BMW's so I could be off. I just got my 330i and havent modified it yet. Good luck.

[CRAZY]

OK, I will try what you tell me.
But my car is an E36 325, 24v, Vanos, from '95 and I have six ignition coil, like your 330 car /forums/images/smiles/icon_smile.gif We don't have spark plug wires... There are only some plugs, and my mecanic told me that this type of simple wires don't go bad, becouse simply don't have high tension. He tell me that only the ignition coil must be bad, and usualy the ignition coil are going bad after 7 year and after you overheat the engine many time.
Monday my mechanic promise to help me and will give me six new coil to try them, to see if this was.

Regards

[Olepainless]

Ahhh I see. I wasnt sure that the 95's had the same setup. Sorry about that. Most of my experience comes from American pushrod v-8 motors. Well hopefully one of the coils is bad and that will fix your problem. Best of luck.