hey i got an evo 8 and i have 3" from header back and also a mbc and intake. the turbo spikes really bad up to about 25 psi and sets an overboost code and hits fuel cut. if i close the bc slightly it wont hit fuel cut but i only boost at like 16psi i dunno if i should get a bigger wastegate or it needs more fuel i need a lil help. also i tried to put the stock bc solenoid back and it would boost no higher than 12-13psi whats that about? any comments would help greatly thanks guys

 

What MBC do you have? Did it come with any extra springs? Also you need a ECU flash.

 

its a turbo xs mbc no extra spring oh really? should i get an aftermarket computer or just a reflash

 

Just a re-flash...www.dynoflash.com cost $200 and you need one with your mods. How is your MBC hooked up?

 

Did you have it t'd into the vac line from the bov to the intake manifold and then hooked to the wastegate?

 

how they told me one vac line from turbo to mbc and other from wastegate to mbc

 

no it was just directly to turbo

 

Oh lordy lord lordy...*sigh*

Ok, of course you're hitting fuel cut if the boost is turned up too high. YOu have mods without a tune - bad move. Also, the boost is too high - bad move. If you turn it down some, it shouldn't drop to 16psi - it should go down slowly if you turn it down slowly. The TXS MBC is the absolute worst for the Evo, so you shouldn't have gotten it anyway, but it still doesn't cause this sort of problem. Are you unable to turn the boost down just a little to make it 21psi instead of going from 25 to 16? If you can't do that, then it's not installed properly.

Your stock boost system didn't work, because you didn't re-install the stock boost lines. You can't just use the hoses you are using for the MBC - they don't work. If you put the OEM lines back on, then the stock boost system will work properly, although you may still hit fuel cut due to having a TBE with no boost control and no tune.

You need to get tune for many reasons, but one thing a tune will do is remove fuel cut. You still need to keep the boost under control by using a good MBC (Hallman Pro or Forge UNOS). I am not sure how in the world someone at this point in time could actually ask if he should get an aftermarket computer or reflash - that just amazes me. You have no need for a $2000 standalone ECU when you have 2 basic mods - a $200-400 flash will do the trick.

 

Ok.. that is good now you are sure you have no cuts or kinks in the lines and also they are hooked to the right side of the MBC?

 

aight well i guess il get rid of that than. well i used the stock vac lines from the turbo to the stock bc but a reg. val line for the one from the intake to the stock bc

 

yea i tried them both ways just too make sure lol i was fed up so i put the stock stuff back on and then it was worse with that

 

You had the turbo xs hooked up right....read my post above again

 

yea everything was right no cuts nuttin all smooth bends nuttin kinked

 

Well if you have done all of that throw away the turbo xs mbc and get your self a hallman or forge

 

aight ill try that hopefully that works cause it sholud spike some but not that sever right. cause a couple people told me to get an electronice boost controller so it will catch the spike