I just put on the basic bolt-ons for the car o2 housing 3'inch exhaust test pipe downpipe upper lower intercooler piping drop in filter walbro 255 fuel pump and hallman mbc.. I went for a test run on the car set the boost low and i still end up overboostin????? What can i do to fix this get an electronic boost controller or get an external wastegate Im really stumped on this one..thanks for the help..

 

are you sure your boost controller is set low?

 

check all vacuum hoses are connected properly

 

are you sure you installed it correctly?
https://www.evolutionm.net/forums/ev...vetrain/113293

 

+1 for making sure its installed correctly

 

Im gonna check tomorrow all the hoses on the mbc and all the vacum lines if everything is ok then what else can be the problem be.. with these bolt ons i should get a tune maybe that can be it also right or wrong...

 

get a flash tune.

 

i would def get a tune but i cant really see not being tuned making you over boost

 

Sound's like it might be your o2 housing what name brsnd is it also if a cheap brand you might need to match port it to the turbo for better flow and will reduce boost spike.How much boost did you set your controller at and how much is spiking?

 

What kind or MBC do you have. Some come with two different springs a low and a high boost spring so if you have the high boost spring installed it can only set the boost so low

 

just keep turning it down until your where you wanna be.

 

+2 sounds like the vaccum lines are backwards, happened to me the first time i installed my mbc.

 

you better go get ECU tune. i had that happen too. after i did tune. i didnt get overboost, boost crip, back fire anymore.