you got a PM CJ

Thanks

 

make sure the line going to boost controller from the mbc fits snugly. when i get vacume line to run my forge mbc i brought it with me to the parts store and got hosr to fit it not knowing the turbo nipple was much smaller, it fit quite loosely and was boosting very odd just like
your car. not this is something you would see if you boost leak tested it

 

I've just reread the thread and it still appears normal to me..... the first two parts seem like its normal for aggressive driving.

Getting into boost at a low RPM and high gear will cause a higher boost spike. This is normal. Most people would simply downshift instead of lugging the motor.

 

Jeff -- Is it normal to not be able to decrease the boost with the MBC ???? I do agree that it is normal to see 21 psi in 1st and 2nd if your peak boost in 4th / 5th is ~26psi.

The issue the OP was having was that he could not decrease his boost via the MBC no matter how far he turned down the MBC. So I would suggest that he either has a defective MBC or his WG is not fully opening.

 

According to this post it does adjust the boost down ..... He isn't going to get rid of the spike and if he tunes for the spike then the lower gears see lower boost. Many people have this problem. I had it when I ran an EBAY O2 housing.

Very common.

 

Okay, here is a quick update....


After receiving a brand new waste gate from a buddy i decided to test my current waste gate first... I ran my boost hose to my waste gate allowing only my WG to do the work and to my shock, it was fine. it only boosted like 11 psi and held like 10 or so

So my WG is fine

Sunday i am having my car boost tested, and i will solve the issue Sunday....



I don't understand why it would be my 02 housing all of a sudden. It was tuned and didn't do it until about a month ago.. thats why i thought it was the WG but i was totally wrong.

Will let you guys who are interested in knowing sunday night after i get her checked out some more...

 

So with the MBC out of the picture does the boost still spike?

 

Sticking or damaged WGA. Find a way to hook a pressure source with gage to it and see when it opens and if it opens smoothly.

 

no spike at all... but its only boosting 11 psi and holding somewhere around that.. I would imagine with a leak it wouldnt show up until higher boost levels.

Will test everything on sunday thanks to Nate!

 

that will be done also, there was another person who suggested that earlier in the thread.. thanks!

 

Since your base pressure is 11 confirmed, without having to back off the turnbuckle, this means that you have zero preload on your gate. So you´re asking your MBC to contol boost all the way from from 11-21#. Probably you would have better control at higher boost levels if you were to set the preload to about 17-18#, then your MBC would do a better job of controlling boost just up top, only from the 18# preload point to the 21# target level. I´d suggest setting preload up in the 17# range, and try a Forge WGA with the red spring.

 

After lots of issues with this boost leak we finally got it...

Originally when I removed my stock FMIC, (only to have to put it back on 3 days later thanks to hose that didnt line up right) i had taken off the original clamp (coming off the J pipe) and replaced it with a T-Bolt clamp after the stock one broke...

Well thinking it was my original MBC i had on the car, i came to purchase 2 new ones thinking it was them... a few nights ago getting tired of my pipe blowing off of my throttle body under any boost, i decided to "crank down" every nut on all my hoses..

After realizing i can "just barely spin" that Tbolt with all my strength i realized that, this is considered loose in the boost world...! Replaced it and never thought to check the hose going into the MBC from the wastegate.. After having NATE from TPGtuning take time out of his personal Sunday he then boost tested me, to find that at or around 5psi it was spraying air right out of the boost line connecting to the MBC from wastegate...

Simple super tighten and bam, took her for a ride and 18 psi felt like 23 psi has been feeling for the past month...

Very excited about getting her back to running condition and cant wait to get back to the track Thinking i can get an 11.80 -11.99 now..


Ps I know i should have checked that, and i did.. it was just "not tight enough"..