MBC Problems

[meangreengst]

I just recently installed a EVO3 Big 16G and installed a Joe P MBC when I accelerate with the boost controller set full out (least boost setting)the car wants to hit 30psi! no control at all ,yes its installed properly ive looked it over and over and am stumped.

the rest of the car is stock except for a HKS SSQV BOV ,cone filter,and hard lower IC pipe from dejon tool

is it that my MBC is defective???

 

[daddyrich1227]

i had the same probs when i installed my mbc. what i did was cut my vaccum tubing on the mbc to the shortest possible length and mounted to my fan. this really helped alot with spiking. then i used teflon tape and wraped it around the part with the hole that is supposed to vent. not sure if you have this hole. i have a ball and spring mbc. anyways, holding steady at 15 now. maybe try that.

 

[daddyrich1227]

also, i used a zip tie to hold the teflon tape on. hope this helps.

 

[meangreengst]

heh I dont see how that can help, but thanks, also I dont think its boost creep cause i hooked my wastgate to bov line and got 11psi spiking at 16

 

[GSntncT]

There is a possibility that you hooked up backwards, some guy around here did that about 3 weeks ago. You can also check your hoses on the mbc. The slightest rip, tear, or hole will cause that to happen. How old is your turbo? Your w/g actuator may be shot, but that depends on how old it is.

 

[jtmcinder]

Verify that the MBC works the way you are using it. Get a Mighty-Vac and a boost gauge. Use the pressure nipple on the Mighty-Vac (the one on the top) to feed both the boost gauge and what you think is the inlet on the MBC. (This will require a T-connector, of course.) Pump the Mighty-Vac (remembering the pull the lever back out rapidly to get it to make some pressure) and watch the boost gauge and listen to the MBC. Verify that the MBC starts to leak though what you think is the outlet at some very low pressure when the adjuster is backed out completely. My guess, given that you've verified already that the wastegate actuator is working and is effective, is that the MBC will not start leaking at some low psi. If I'm correct, then put the hose on the other nipple on the MBC and repeat. Some MBCs look like X nipple is in and Y nipple is out, but it's actually the other way around. If the MBC doesn't leak using either nipple as the inlet, play with the adjuster for a while. If that doesn't get it to work, send it back.

- Jtoby

 

[meangreengst]

Originally posted by daddyrich1227
i had the same probs when i installed my mbc. what i did was cut my vaccum tubing on the mbc to the shortest possible length and mounted to my fan. this really helped alot with spiking. then i used teflon tape and wraped it around the part with the hole that is supposed to vent. not sure if you have this hole. i have a ball and spring mbc. anyways, holding steady at 15 now. maybe try that.

that fixed it thanx