Does YC=Yuba City? If you cant figure it out or resolve the issue, then bring it out here to Hayward and I'll help you fix it, no charge.

 

Everything worked just fine the first couple of times. Then after I adjusted the boost it just stayed at 13. Am I supposed to turn a full turn for every 1 psi?

 

Yes YC= yuba city.

 

OK. Try this: Turn the MBC's adjustment knob all the way out counterclockwise to full soft(-). That is the lowest boost setting possible at that particular spring pressure level. Do a WOT run in 3rd or 4th gear. Note the peak boost level attained.

I just want to be absolutely sure before we start fiddling around with things. We need to establish a baseline.

 

The steps outlined above in post #19 will establish a wastegate spring pressure baseline. From this we can gauge with a fair amount of certainty, how much the gate is preloaded beyond base pressure.

From that point we will want to increase WGA spring pressure up to a level about 3# below your peak boost level. I pretty much figure from the way your car is acting boostwise that it is an issue of insufficient WG preload. This is assuming you hooked the MBC up properly and that the MBC is working properly.

It is still unclear to me based solely on your somewhat vague description whether or not you have everything hooked up properly. That's why I was hoping that you would drive it over so that we could check everything out visually firsthand and adjust wastegate spring pressure accordingly.

I am gonna be here in the Bay Area over the 4th of July weekend and through most of next week.

You have the stock actuator on there right?

 

Yup stock actuator. And I did the wot 3rd gear and 4th gear pull with the MBC all the way down. I boosted about 12psi. I did a 1 and 3/4 turn and I'm getting closer to 13. My MBC is setup correct. I've verified with a couple shops. Does the MBC just require a lot of turns to adjust correct boost? 1 full turn equals 1 psi?

 

What is the max boost level that you want to run(peak boost)?

 

I want to give you the benefit of the doubt, but after rereading your original statement, and judging strictly from the way that you describe it above, to me at least, it sounds like you have the MBC hooked up incorrectly...backwards in fact. Incidentally, is your particular Turbosmart BOV a VTA affair or does it recirculate?

As, snowmastergt, points out, the stock actuator without any preload opens anywhere between 10-13#. You tested it with the MBC adjusted to full-soft and you saw 12#. So, you definitely need to increase WG spring pressure (preload). Send me a PM and I'll tell you how to adjust the actuator. Ultimately, you may want to invest in a heavy-duty, aftermarket actuator.

 

I bypassed the bov and went to my turbo nipple instead. So now its my turbo nipple to the input of my mbc and wg to the output. After 2 1/2 turns I am up to 15psi. So I think I just need to keep turning the mbc. And I would like to run 23psi ideally.

 

Naw. Take my word for it that you don't want to try to run 22-24# peak boost on just 12# of spring pressure on the wimpy stock actuator controlled via an MBC.

First, you need to adjust the WGA to increase spring pressure up near 16-18# at least. Those measly 12# on the gate is way too little spring tension, dude.

Try something for me: take a firm grip on the actuator rod and pull the rod axially away from the actuator cannister. If it moves fairly easily then that means that exhaust pressure inside the turbine housing is lifting the flapper valve up off it seat easily. This premature lifting is what is killing your turbo spool and limiting your peak boost to 12-15#.

EDIT: Dude just drive your sled over here to Hayward and I'll fix that thing in an hour. You'll have to buy me an In-n-Out cheese burger though.

 

Everything is fixed. Realized I have to turn the mbc a couple turns 4 to be exact. Now im steady at 20 psi. Its perfect. Im tuned to 20 psi. Everything worked out.

 

Wait a minute. Not everything is just fine and dandy. Sure, you figured out how to use the ajustment knob on your MBC. That, in and of itself, is great. We also know now that your MBC is controlling peak boost at 20#. But, not quite everytning is fixed yet. You don't get off that easy on here. You still have a long way to go.

Your WG spring pressure is still only 12#. So, your turbo cannot be spooling as quick as it should be. When you did the WOT run with your MBC set to its lowest setting and saw 12# on your boost gauge, do you remember at
what RPM your turbo reached 12PSI? If not, just tell us at what RPM you are seeing 20#, when you do a WOT run with boost set the way that you have it set now.

I am willing to bet that you arent seeing 20# until well above 3600 RPM. If so, then spoolup is just too slow.

 

Yes a little after I believe. But what does that have to do with my car as a DD. and how would I adjust psi on a stock evo 9wastegate?

 

to my knowledge you shouldnt have it hooked up to your BOV line..

 

You are fine the way it is. It's just that some people prefer to have the turbo spoolup sooner. It just means that the compressor's sweet spot would shift to the left if you were to overlay the boost plot relative to the engine's RPM curve. Basically, turbo shaft speeds will increase relative to engine RPM. The compressor will be moving more air sooner and at lower engine speeds, etc. Midrange torque and power will improve dramatically. Throttle response will be improved as well, etc.