* I posted this on another site, but want ya'lls feed back as well*

Since getting "tuned" at Dyno Day, I have not been able to control my boost pressure. Before DD, I was hitting 21-22psi, then afterwards, my turbo puts out max psi (25-30). I have rechecked my lines, check my wastegate flapper for being stuck, cleaned my forge mbc, changed mbc springs, replaced mbc with another forge one from my vr4, no change. my last attempt was to disconnect the output nipple from the turbo and plug it off, then connect the forge wastegate straight to the BOV boost source (thinking the boost referance was corrupted/clogged) and nothing. I need some advice before I go and blow my engine.

I have a Forge MBC and Wastegate. I will be using a different boost gauge this evening. I will also be removing some of the tightness of the actuator arm, if this doesnt help, I will be taking the top part of the wastegate apart to check for any kinda of contaminate or defect.

 

it sounds like boost creep to me.. if thats what it is, there are alot of threads on here about it..

 

If it was slow to come up to 31psi, then I would agree. But the car spools to 31 like a normal car would spool to 21. It is fast to spool, hardly any lag, once it hits 15psi it is like a rocket up to 31.

 

I tend to think that it is either a maladjusted actuator rod(most likely cause) or the dreaded boost creep. A too short actuator rod means you are seeing too much WG preload. A too long actuator rod setting, on the other hand, will cause wierd boost spikes in some cases.

Turn your MBC to full soft(all the way out counterclockwise) and do a WOT run in 4th or 5th. This will give you your WG preload level. For the peak boost level you want to run, the ideal preload is between 17-19#.

I realize that I´ll probably catch some flak for expressing this revanchist method, but that´s o.k. too.

 

Any help is help none the less. I have done the WOT on a soft spring and I get the 30psi quickly, It isnt creeping up. I just finished taking a half turn off the actuator buckle to lossen the rod, now it slides on easily but still keeps some tension on the flapper. I also connected another boost gauge (autometer) right off of the BOV line and have it sticking out from under the hood on the windshield.

 

if all else checks out then i would sugg. a electronic b/c.

 

I think I have narrowed it to the waste gate. I can not get it to actuate at all

 

Are you running a forge WG or just the forge BC? You could have a torn diaphram in the WG, or like the other guy said, to much preload. I would guess it being a torn diaphram if it just started doing it out of the blue. If you can put some pressure to the WG and see if it leaks, if it does that your problem, if not hit me back and I will see what else I can think of.

 

I have both forge wastegate and MBC. I installed the MBC 2 months ago with out issue. The wastegate I installed the 2 days before the Dyno Day, worked well until the tune time. Ever since then I can not control the boost at all.

Should I take it apart even thought I just bought it? I bought it from import image racing, but it was drop shipped straight from Forge.

 

wga,i broke mine when i installed it,i put it on to tight and riped the diphram.once i changed that the car boosted normal....

 

Call Forge, they will ship a new diaphram out to you free of charge. I have also have had this happen to me. It takes about a week for the diaphram. I hope this fixes your problem.

 

The easiest way to install a new diaphram is to note the clock position of it before you take it apart. Install the rod in a vise so that the of the main body of the WG is against the top of the vise and clamp down on the rod, continue to remove the screws that hold it together and once the all the screws are removed you shouldn't have much spring pressure because the vise is holding the spring down. Install the new diaphram being carful that its centered and you don't rip it. Tighten down you screws in a crossing manner and check it with 20psi before you install it back on to make sure it doesn't leak. The diaphram is fragile so be careful with it.

 

So I gather from what you are saying, that the rod shouldnt be able to twist 360 degrees if the rod isnt attached to the flapper, right? Because mine did right out of the box

 

I might be able to, but its not good for it. The piston is attached to the rod and the diaphram pushes against the piston. Its just like a hydraulic cylinder on a backhoe, instead of using oil this just uses air. You might have torn your diaphram when you were spinning your rod and it just took some time for it to blow out. When you get your new diaphram installed try not to turn it at all. I will look for the number for Forge for you.

 

1(407)447-5363 and call today because to takes awhile for it to show up. When they ship them out they ship them all the same day and they only ship them out 1 day a week, so the sooner you call the better of you are. I hope I helped.