Adjusting wastegate, too much boost....

[ctnsupra1]

Alright, I need some help here. I just had my Mutt (Level 1) installed. I have my Extreme MBC screwed all the way out and the thing is still running 20psi. How do I adjust the wastegate (internal wastegate) in order to run lower boost? I really want to be able to get on it but seeing as I have no fuel yet, I only want about 12-13psi, not 20. Please help me out here, I want to go and drive my car, I haven't had it for 5 months!!

Conor Nixon
'95 GSX

 

[TurboTerror]

When you ordered the turbo did you specify a lower psi WG spring?

 

[turbotalon92]

Might be boost creep. What are your other mods? exhaust size?

 

[ctnsupra1]

I bought the turbo from a friend so I don't know what spring it has in it. It could be creep, most likely due to my stock downpipe (ouch ) Maybe it's time to get some porting done....

 

[TurboTerror]

you have a stock DP, but you have a cat-back correct? With that turbo you really need the full 3" exhaust. I will bet anything that it is creep.

 

[jdmawd]

Remove some tension from the actuator rod. You have to much preload on the spring.

 

[ctnsupra1]

jdmawd,

how do you release some of the tension, turn the actuator rod counter clockwise? thanks.

 

[jdmawd]

Originally posted by ctnsupra1
jdmawd,

how do you release some of the tension, turn the actuator rod counter clockwise? thanks.

thats it, once you look at it its pretty self explanitory. spool up will suffer just so that you know. how much boost do you plan to run?

 

[ctnsupra1]

I'm only going to run 14psi for the time being. Once I get my pump and 660's, I'll turn it up to 18-19 ish.

 

[Omega]

I had a similar problem when I screwed around with my MBC after the 16G install. Even with the screw backed all the way out, it would boost as high as it wanted. Try resetting the MBC:

If you don't already have a leak tester, make one.... but you will use it differently. What you want to be able to do is pressureize the input line to the MBC and be able to read the pressure (I hooked up an extra boost gauge). Basicly you will want to watch the gauge and the WG actuator. Close the MBC valve all the way and pressurize the line to set level. You will want to be able to add air to the system because it will leak out the MBC. Once you have the desired pressure in the line, back out the screw. You will know if too much or too little air is going through to the WG because it will not open all the way or fully open. Once you have the gauge showing your desired pressure and the WG opening fully, you are pretty much set. This isn't an exact method, but it will get you in the ballpark. Go out and drive it around. If you do need to adjust the MBC, only make SMALL adjustments... 1/8 turn at a time.. trust me.

Second thing to do is disconnect the WG and wire it fully open. That way you will know if you are actually getting boost creep.