inconsistent boost!

[terbear4god]

my boost is really random im running a hahn super 16g with no shaft play with a ebay mbc

sometimes my boost will spike to 16psi than drop down 2-3psi or

sometimes itl only do 14psi and hold it...

is it just a crappy mbc??

i set my internal wastgate were its shut 100% and just were the rod barely slides on will opening the wastgate a lil bit fix my inconsistent boost??

im also going to harden the setting on my greddy bov..


any ideas???WTF
thanks

 

[pitt97gsx]

Most likely the mbc problem, get a hallman pro. They are very reliable

 

[sprmotohooligan]

Check the routing for you vacuum line to the MBC too. Mine had a pretty good kink in it once that caused some inconsistency issues

 

[terbear4god]

i tried extending my wastgate arm and no luck so im gonna try putting it about 2 turns tighter than just sliding on the wastgate.. so itl be a 100% closed and have more tension on it..

i also tried tightening my bov and it just surged so i backed that down ill check for kinks in the line thanks!

it still does it is it normal if it drops like 1-2 psi by redline??


how tight should my wastgate arm be??

the actuator itself is 8-10psi so too run 15psi i have to create that little extra tension on the arm??

would i be safe have the arm about 2 turns after the wastgate flapper is fully shut??

 

[highlandgst]

alot of things can be involved . I was told awhile ago when I had my stock turbo running 15 psi that in first and second gear I would spike and drop about 2-3 psi and hold firm there was because of the ECU is not tuned to gold that psi someone called it " work load " but either way check your lines and are you recirculating ?

 

[LiquidX]

The big question is at what RPM is it dropping down. Are you doing redline pulls on it or is it just a quick "get to 16 psi" and then let off?

 

[GsXdSmKingGsX]

The spring in your MBC is either bent or just effed. Go buy a Hallman MBC . Boost spikes are definetly not good

 

[mtchll]

yeah I bought an ebay MBC and same thing happened, really inconsistent boost. You get what you pay for though. go get a hallman, or I heard Joe P. makes a good MBC

 

[Elek_ron_ix]

Same thing happened to my Ebay MBC. I would say as a good rule not to use the Ebay parts, seem to be subpar. I went the more expensive route and I got the AEM Electronic Boost controller w/ the better boost solenoid. No Problems since. Definitely do a boost leak check I was surprised at how many I had. Even a weld on my J pipe wad leaking Good Luck!