My turbo setup is complete but something is definately not right.

The first problem I am having is that my fuel pressure is not going up as it builds boost.

The second problem is when I rev the car, and let off, there is no blow off, and you can hear the compressor surge.

I have not driven the car yet because I do not want to risk anything. I am using the SFMU with the silver spring, 2.72 disc, accel 310cc injectors. Also, when I take the vac line off the sfmu, the pressure doesnt change, it always reads about 22psi. What is the correct way to adjust the sfmu for the first startup? I have the vacuum line ran straight to the intake manifold, with the restrictor in line. I also have the bov vacuum line running straight to the intake manifold.

The car runs and idles well, but these are major problems.
Please help me out!

Originally posted by fresh95The first problem I am having is that my fuel pressure is not going up as it builds boost.

How do you know? Where is your fuel pressure gauge mounted?

Originally posted by fresh95The second problem is when I rev the car, and let off, there is no blow off, and you can hear the compressor surge.

That's not a problem, that's normal; well the no blow-off while revving thing is normal...

Originally posted by VelocitaPaola The fuel pressure shouldn't change while under vacuum; that represents your idle fuel pressure. Ideally you should be able to remove the vacuum line, and the fuel pressure should hold steady.

Not necessarily true, There is the static pressure and the idle pressure. When you remove the vac source from the SFMU you should notice a difference in the fuel pressure.

Turn on the key and prime the pump, you have static pressure. Start the car and the pressure should drop to your idle presure because the vaccum should act against the diiaphram of the regulator. go for a drive or put the car on a dyno and you should see the pressure increase with boost. Just a question but do you have vaccum sources hooked up to your FPR and BOV? This would explain alot.

Yeah, all vac lines are hooked up to the intake manifold, except the wastegate, which is hooked up to the compressor housing.

So, your saying the blow off valve will only work when I'm driving, and not if I'm just reving the car?

Originally posted by fresh95
So, your saying the blow off valve will only work when I'm driving, and not if I'm just reving the car?

If there's no load on the engine, the car won't build boost when you rev the engine, therefore the BOV won't open.

Ok, so if I prime the pump, then I should adjust my static fuel pressure to like 30 psi? And when I start the car it should drop to around 20 psi or so? I checked the vacuum and it was right at about 18 hg. That's good right. Also, on the SFMU, what do the vacuum and boost set screws do. I know one of them limits max fuel pressure, but neither of them did any thing (that I could notice) at idle. I plan on getting the bleed valve too. Where can I get this. I looked on Vortech's site and I couldn't find one.

Never mind...

...

Originally posted by VelocitaPaola

Originally posted by djtrickee Not necessarily, There is the static pressure and the idle pressure. When you remove the vac source from the SFMU you should notice a difference in the fuel pressure.

Must be thinking of my 1:1...

What kind of 1:1 are you running? I have an Aeromotive A1000, my static is set to 47psi, I idle at about 38psi and boost is 47psi+amount of boost.

I am deleting my previous posts... I'm completely backwards today, and apparently unable to comprehend text: I'll try again tomorrow. :shrug

Ok, so I'm kinda confused.

How come when I rev the engine (from engine bay) I can see the turbo spool, and hear it, but it's not building boost?

Also, if it doesn't build boost unless I'm driving it, that would explain why my fuel pressure isn't rising, right?

I have my fuel pressure guage mounted under my hood and I can't really monitor it while I'm driving, so that's why I'm so cautious. I just want to make sure that everything is stable before I wreck something. Thanks for all the info so far!

The engine has to have a load on it to create boost. I remember reading a lengthy discussion about this on DSMtuners. Personally if I free rev I will get a tiny bit of boost, 3-4 psi, just enough for a chirp.

because when you free rev there is very little load on the motor, therefore there is little airflow, and very low velocity in the exhaust manifold. You need flow and velocity to make the turbo spool enough to create actual boost. it's always gonna spin when the motor is running, just not fast enough to really make some pressure. a lil boost is possible with a smaller sized turbo, but any more than 5 lbs is gonna be hard without some sort of ignition control.

A word for the wise, free revving an engine is very bad for the engine.