Well my friend with an Evo IX had a brand new Forge mbc put in this weekend how it came and guess what? He had it turned all the way down and was hitting fuel cut in 2nd gear at 6k rpms. So its obviously the boost controller. Notice that most of the guys that replied here have a Forge mbc. What does that tell you?

 

Hey why dont you try and put the stock lines back on to see if that fixes your problem... Second I doubt it is your MBC, I bet it is that 02 housing that you have on there. SO just keep that in mind.. but try putting the stock lines and see if that cures the problem.. try to narrow things out..

 

Well if i install the stock boost lines boost is still gona go up high due to the fact that i have a catless tbe and an o2 housing and due to more air flow, the boost is gona go up regardless

 

the spring in the Manual boost controller is made of metal, when it is cold the spring will become more stiff, a stiffer spring will have the same affect as tightening the boost controller

this is a similar condition as when the temperatures rise some people notice a loss in boost pressure due to the spring "softening" with high heat

if you want to test this, disassemble your boost controller & place the spring in the freezer for a few hours to simulate the conditions you car is seeing ... then set your oven to warm & put the spring or complete boost controller in there for 20 mins or so

there is also a spring in the wastegate actuator that could be stiffening up as well as the one in the boost controller, compounding the problem

 

well, my last suggestion would be swap out the mbc with some one elses and see if that works...

 

its not the mbc i have hallman i swaped it out with a friend of mine who has the same mbc and it still does the same thing but on his car it works fine all he has it a greddy fmic hks intake i mean i dont know if tbe will give it more load or whatever i even cleaned my mbc and nothing same **** my mods tbe mbc apexi intake i still think its the wastegate i dont know how to mess with it i dont even want to touch it

 

i just bought a new boost controler today and it still dont work.i cant lower the boost?

 

your going to ivey wed right see what he says

 

Hmmmm so my fuel cut problems could be related to having the stiffer spring in my MBC???? Well I'm going to have my car tuned anyways shortly so well see what happens afterwards. Yeah I'm the guy with the 2nd gear fuel cut...it sucks.

 

All that says is that it came preinstalled with the stiff spring. Tell him to use the soft spring and it won't boost so high even when turned all the way down. I guess I'm one of the few that have had the Forge for over a year without a single problem using the soft spring. I'm still betting its your o2 housing which is the main reason why I never got one in the first place at the sacrifice of 10hp if even that.

 

Would a EBC fix this I just relised not one person did I see post up this problem with ebc I mean I think like 70 80% of evo owner run mbc but still anyone with a ebc having this problem??

 

Neither are EBC's immune from this problem, or something similar. A few days ago on this forum a guy had a similar boost creep problem after doing exhaust mods to his Evo. He uses one of those intelligent EBC's that learn the boost curve of your car and then adjust the manner in which they regulate the WG duty cycle accordingly.

Well, anyway, he did the exhaust mods and had serious boost creep. I thought that it was a wastegate problem needing porting of the turbine housing WG bypass port. But, it wasn't. It turns out that you have to reset your EBC to relearn the new boost curve after freeing up the exhaust with mods such as the O2 hsg.

 

So after he did that he had no more problems?

 

I had this same issue on my 05 and a couple of things were done and it was fixed eventually but honestly i dont remember what fixed it.. I have already cleaned it, swapped out boost lines and i dont know what else to think of.. I wish i could get this crap fixed...

About the stiff spring on the mbc, i dont think that will make a difference as ive had that stiff spring on my boost controller on my 05

 

I started with the stiff spring in my mbc (my car is an 05), and it got switched out for the softer one within a couple of minutes. It'll only take a few minutes to switch springs, what could it hurt? My car is running ~20psi now with the mbc turned ~20 clicks off of all the way soft, with the soft spring.