I recently bought this evo and I noticed the boost is mostly steady at 19-20 psi but starts creeps to 25-27 psi at wot at certain higher rpm's. I have a new hallman MBC installed and it is in the open setting. does anyone know what my issue could be and where I should start looking ? I also have boost spike?? (chirping sound) when releasing from part throttle slowly.

Car is all stock except for a turboback HKS Exhaust.

Heres my vacuum hose routing : Line from Intake Manifold goes to the BOV. This line as been T'd to the MBC input and the output goes to WGC. ports on the turbo, intake hose, and the 2 ports for the wastegate solenoid have been capped off.

Please help !

 

What exactly do you mean when you state that your MBC is in the, "open setting"? Do you mean that the adjustment knob is backed out all the way(counterclockwise) to its lowest possible boost setting?

The chirping sound that you are hearing is probably the diverter valve "fluttering", or else it is compressor surge(aka, chatter).

 

Yup it's all the way counterclockwise. Even if I take out the mbc and connect it directly it does the same thing. What would cause the dv to flutter. Does this mean broken dv?

 

You shouldn't t into the bov line. Try a straight line to the bov and see if that stops the flutter. And run the boost controller line from the turbo port on the j pipe, up into the controller, and the other line straight to waste gate. That should do it.

 

Whether you reference the MBC by "T"-ing into the IM/DV line or source it directly from the compressor discharge won't have much impact on your boost creep issue. At least swapping from one source to the other wont make enough difference to cause or cure 8# of creep IMO.

 

What exactly do you mean when you state, "connect directly"? Describe for me how and what you connected directly please. Do you mean that you ran a hose directly from the compressor discharge nipple on the J-pipe to the port on the WGA cannister? This would be the "right" way to do it.

 

by connect directly I meant the line from the intake manifold was T'd and one goes to the DV and one goes to the WGA. I will try routing it directly from the compressor nipple to the WGA. The compressor surge nipple on the J-pipe is the one that is on the compressor housing correct ? just wanted to make sure Im not confused with the LICP which is also a " J looking" pipe....

 

Did u install the MBC yourself? By install I mean route all the hoses, secure all hose end fitments, fasten preferably with metal hose clamps not zipties. BTW, how did you go about plugging the unused ports(j-pipe & inlet hose)? Do you know which spring is installed inside the Hallman? Since you bought the car used you don' t know what WGA is fitted to the turbo do you? Finally, you don't know if the actuator rod is adjusted tighter and thus you might gave it way preloaded.

Let's say that the previous owner had installed an FP 25# actuator and preloaded it considerably. Makes you wonder.....

 

I'll explain the right way to you. You will want to run a length of 4mm new rubber hose directly from the port on the top of the WGA to the port that is located on the black stamped metal J-pipe which is bolted to the end of turbo's compressor housing discharge. Do you see which port/nipple I am refering to?

So you'll also need to now plug off any open ports which we have left uncovered in the process. The open end of the"T" in the IM/DV line and the reference port on the MBC come to mind.

So you are disconnecting the MBC and sealing off any open hose ends or vacuum ports for the time being. Then you are running a hose direct from the WGA to the nipple on the J-pipe. Got it now?

 

The prev owner was a southern belle who used it as a grocery getter. She barely knew what was on it.

I plugged the hoses with some 8 or 10mm bolts into the vacuum hose. I am guilty of zip tying everything however, didn't have metal clamps. The hallman is stock. Bought it recently brand new from an auth dealer.

 

Yup. Thanks much. I will route like you've mentioned and update.

 

Once you route your boost hoses this way then take it out for a spin to check boost level on gate alone. Do a 4th or 5th gear WOT pull for me. If highway safety constraints are an issue, then do a 4th gear pull on an uphill grade.

Basically, I wanna know what peak boost level is on the gate alone. It'll probably still creep but i need to know what it spikes to before it starts to creep up.

 

This iis khuuul. I too plug them as you did with a short length of vacuum hose stuffed with a tight fitting, fine thread, machine bolt and zip ties if i dont have 1/4" hose clamps. So, you are OK and ready to go.

I just dont trust those little rubber caps that they sell in the autoparts stores either for sealing off the nipple on the compressor discharge tube. I have seen them fail. The pieces of hose with a bolt screwed into the end will look crappy as hell.....but it does the job.

 

ok so I connected everything like sparky said. basically a hose from the J pipe nipple to the wgc and another hose from the intake manifold to the bov. Now I get a steady 12 psi boost at full throttle with no creep and a vacuum of -22 at deceleration.. is this how its supposed to be ? also the BOV flutter is gone.

 

anyone ? just wondering if the 12 psi sounds right ?