Wastegate controlling regulator?

[robndeb]

When I originally got this car, I ran it as is. 9 pound wastegate spring and 100 octane fuel. It ran great except for a little stutter at about 3000 rpm., no biggie. Before the next trip I replaced the 9 pound spring for a 6 pound spring, and ran 91 octane fuel. Another thing I changed was the vacuum hose from the wastegate to the fuel pressure regulator. It was too large and was falling off. Also there is a small adjustable needle valve on the hose fitting where it attaches to the regulator.  With the new set up it ran good up to a certain point and then it started popping and sputtering until you backed off a bit on the throttle.

I thought a wastegate was a purely mechanical way of regulating boost. The excess exhaust just goes out the wastegate pipe, never letting the turbo get beyond a specified pressure.

Originally when I got the car, the needle valve was completely shut, and the second time I ran it I opened the needle valve to half of it's adjustment. What is this valve for? The next time I'm out, I am going to try it again with the needle valve shut, or just take that hose off and plug the fittings. Any ideas? Should the wastegate control the fuel pressure? Is it shutting it off or adding more fuel?  In the car it feels like it is trying to shut the engine off.

[Yummi]

where do the steel braided lines go?  the top of the waste gate needs to come off of the boost side of the turbo, it is what controls the gate.  that may be a regulator, but take a pic of where the two steel braided lines go?

[robndeb]

One comes from the fuel rail, then goes to the regulator. The other goes from the regulator to a return fitting on top of the tank. There is a small vacuum hose, ziptied to one of the stainless hoses that comes from the throttle bodies.

[Yummi]

see, on my tial, the line on top goes to the boost side of the turbo anywhere before the throttle body plates - that is the signal to tell the waste gate to open.  Now, if yours is going to the fuel lines - i am perplexed but one of the smart boys will chime in.  Check the tial site for the diagram?  I know i posted it before, but i cant find it handy.

[Yummi]

diagram might be in this thread....

http://dtsfab.com/index/index.php?topic=378.0

[robndeb]

where do the steel braided lines go?  the top of the waste gate needs to come off of the boost side of the turbo, it is what controls the gate.  that may be a regulator, but take a pic of where the two steel braided lines go?

Here are some pics.......

A line comes from the fuel rail.....


Goes toward the fuel pressure regulator......


Then ends up here.......


Then comes out of the bottom of the regulator........


Then goes back into the tank......


Here is a pic of the line going from the wastegate to the regulator, and the small needle valve.


The vacuum line coming out of the bottom of the regulator goes to the intake manifold. That should be what controls the fuel pressure. I don't know why the wastegate should be connected to anything since it is a mechanical spring that regulates how much boost the turbo makes. I'm so confused.........

[fabr]

That fuel pressure regulator is a FMU or rising rate fuel pressure regulator.When you switched the spring out you screwed up the fuel mapping due to the FMU now receiving different "instructions".If I were you I'd do one of 2 things.Either return everyrthing to the settings you had when you got the car OR have it retuned on a dyno for the 6# spring.The little needle valve BTW is a pressure bleed that controls max pressure rise on the FMU. 


www.bellengineering.net

[robndeb]

I went onto their site and looked at a schematic of how everything was supposed to be plumbed. Mine was all messed up. The needle valve is supposed to be hooked to a check valve then vented to atmosphere, not hooked up to the top port of the wastegate. The check valve was inline on the vacuum hose from the manifold to the FMU. The top port on the wastegate is supposed to be left open, unless an external boost controller is used. I'm going to send Bell Engineering some pics of my set up and see what they tell me.

[robndeb]

I found this.......
http://www.bellengineering.net/templates/BEGi/images/Manuals/FMU_Instructions.pdf

[Boostinjdm]

I was gonna post something brilliant, now I got myself confused.  Better go brush up.  I agree with Master though and will add you'll prolly need a proper retune nomatter what you do from here.

[Boostinjdm]

sounds like you are on the right track.  I would also consider adding a BOV if you don't have one.  It would prolong the life of the turbo and decrease your lag time when you let off and then jump back on the gas, like when setting up for a hard corner.  Plus they turn heads.

[Boostinjdm]

If you don't understand what the purpose of the BOV is just ask, I thought of a really good example

[fabr]

post it

[Boostinjdm]

This can get messy so you might want to try it at a friends house.   Go into the bathroom, stand in front of the toilet.  You are the turbo, the toilet is the engine.  Start peein....
Now clamp down hard mid stream.  hurts don't it.  Your turbo feels the pain to.  Now release. This is what happens without a BOV. 

Second time around  same setup, start peein....
Now swerve off to the side and then back to the toilet.  Congratulations you just used your BOV.

When you suddenly let off the gas and the throttle slams shut all that pressure has to go somewhere.  The only escape is back the way it came.  This slows down or stops the turbo.  Causing a lot of stress.  Then when you get back on the gas the turbo has to spool back up and this takes time.
Enjoy

[SPEC]

Boostin,
That's a great scenario...Only one problem...Specinator caught me and doesn't beleive you told me to do it :P