elektrik_juggernaut

Can those with the Procharger please post their mods, gas octanes, and FMU settings? Thanks in advance.

SirMikel1

iTrader: (1)

Mods are on my sig, 94 octane and i'll have to check on the FMU settings for you tomorrow

GaryK

Borla catback exhaust and procharger are the only mods.

FMU slides set per manual, scale adjustment set somewhere around 12 (I'll have to check this....it did not work correctly using ATI's recommended setting). I used a test rig to supply increments of air pressure to the fmu and check which band it was operating in.

This will change some on Friday....dyno time!

jesseenglish

Gary,

What RPM does your first light kick on at? I got some plugs today and started it up. I almost messed up my pants when I heard that procharger. Anyways, I revved it up to 3000 rpm and no lights went on. Turned off the engine and pulled off the manifold pressure hose and blew into it. I blew hard enough to get it to light up the 3rd light so I know the FMU is working properly. Either I have a leak and it's not pressurizing the manifold or my FMU is set incorrectly.

What did you use for a regulated pressure source? Also, at what point does the bypass valve close? When I started it up and it's idling it stays open so the way I see it is there is no way for the manifold to pressurize.

Theoretically, I don't see how it could ever pressurize, now that I think about it. The bypass valve is open when there is a vacuum. Even if I rev it I don't see how it could go into boost because the boost is being vented before it makes it to the manifold where it can close the bypass valve.

Maybe, I'm a moron not understanding this, but I need an extra brain on this one. Someone please help!!!

GaryK

I don't know what rpm the lights for each band come on at. I just roughed in the scale adjustment so that the last light came on at about 5.5 psi. I wasn't trying to do anything more than get it to a point where I could drive it to the dyno.

I rigged up a manifold with several connections using parts from work. Connected to this manifold were:
- a calibrated pressure gauge
- supply line with valve to shop air
- vent line with valve
- a small reservoir to increase the volume of air so I could control the pressure more easily
- a connection to the fmu

Most of the fittings and valves I used are used in refrigeration circuits in our engineering lab. I just fed some pressure in from the shop air line, and used the vent line to bleed off pressure to the point I desired.

I believe it depends a lot on the load on the motor. As far as I know, my bypass valve stays open no matter what the rpms are if there is no load on the motor. I don't know exactly when the bypass should close, but based on my experience playing with the bypass valve, it should be closed as soon as the manifold pressure goes to 0 psig (gauge pressure).


Where do you have the scale adjustment set? Mine was set somewhere around 12 or 13 when I received it. I asked ATI to verify the starting point for this setting and I got two answers. One said to set it at 7, the other said to set it at 5.5. Setting it that low did not seem correct when I tested it, because the fmu would go to the last band as soon as it saw pressure. I ended up with mine set somewhere around the 12 or 13 that it was set to originally. This doesn't make sense, because based on the manual for the fmu the setting really should be about 5.5 on the scale setting. I'll verify what my setting is and post it in a bit.

GaryK

ok, I checked my scale setting and it is at 13.


Also, back to the bypass valve operation...to get the bypass valve closed, the blower has to be spinning fast enough to make some amount of boost. While you're driving, there is a load on the motor so you can hold the throttle in an open position for some time period without just riding the rev limiter. This is when the bypass will close.

Think about what happens with no load on the motor though. You can't hold the motor at some rpm with no load on it without the throttle being hardly open at all. This means the bypass valve will be seeing vacuum since it is seeing the pressure conditions after the throttle body. If you slam the throttle to the floor, it might see positive pressure for an instant, but as soon as you let off the throttle it will be back to vacuum.

jesseenglish

I just want to make sure I'm understanding what you're saying. You're saying that because the throttle isn't open, the SC isn't able to create positive boost within the manifold, right? So, if I don't have a load on the engine, I won't be on boost and the bypass valve won't close.

I guess the thing I was mainly having a hard time understanding, was the fact that the SC would have to push more air than the bypass valve could physically vent for it to create boost within the manifold.

My FMU scale setting is around 13, which is what it came from ATI with. Since I don't any access to a calibrated pressure gauge, I guess I'm SOL. I'm going to put the car back together tomorrow, so I can take it down to the tuner shop. My damn Wideband O2 is still going to take 2 more weeks so I'll have to rely on their equipment to get it done.

BTW, I don't think I have any belt squeal, but I can't hear anything over the purring of my SC

Thanks for all your help Gary, I'm not as dumb as I seem, honest.