Cant controll boost

[Rklock]

I have A 14b with a forge mbc and cant seem to keep my boost steady. It'll creep to about 18lbs or so after staying steady at 10 till about 5000rpm. My mbc is set at one click. I even tried to run wastegate boost by hooking the j pipe to the wastegate, and it does the same thing. please help. thanks.!

 

[92EagleAWD]

is it a factory turbo? Internally gated turbo's are notorious for boost creep, the stock 02 housing doesnt help, if you take it off and blow air into the wastegate outlet it will come out of the the turbo outlet isntead where the downpipe bolt on. but your wastegate might be bad also.

 

[jeremylee_7]

Try unhooking the wastegate rod and make sure the wastegatee arm moves freely and then reconnect the rod (you will have to unbolt the wastegate from the side of the turbo to get the rod back on).

As 92Eagle said, those stock turbo's are known to boost creep, espically if you have an upgraded exhaust system. The wastegate flapper on 14b's do not open a full 90 degrees and is a big cause for the boost creep (i did not measure it but I would guess my 14b opened maybee 75 degrees). The best thing you can do to help is to remove the turbo and port it, you can also get an upgraded 34mm flapper. Here is a link about porting, of course you will need an air or electric die grinder and a carbide bit or two. http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/186525-how-cure-boost-creep-porting.html

One thing else that could also help is switching to a 2g o2 housing if you dont already have one. Easiest way to tell is that the 1g housing has the o2 sensor towards the top sticking up and the 2g is at a 90 degree angle towards the bottom.

 

[mikhro]

If in need of a 2G O2 housing, I got a couple.......let me know

 

[Sicotic]

i say ## flapper bc when i couldnt controlmy boost(28psi) i had fuel cut im saying ## doesnt open at the right time.

 

[LiquidX]

Before taking it off, just disconnect the actuator rod from the flapper and see how much boost you can run that way. Doing this will keep the wastegate open constantly (check to make sure the flapper isn't stuck and that the actuator rod isn't binding on anything). See how much boost is able to be built. If it's a high amount, then you have some bad creep issues that will need the o2 side of the turbo ported out.

Opening 90* isn't possible with mitsu. turbos btw. Best thing to do is enlarge the wastegate hole a bit and hog out the o2 side to let gasses into the o2 pipe with the least amount restrictions. The inlet side you'll want to make it almost a straight shot to the flapper to bypass the turbine with ease. Those are the biggest causes of creep when people upgrade to a free flowing exhaust with low back pressure.

VFAQ Site - Visual Frequently Answered Questions has good info on porting if it comes down to that for you

Putting on a 34mm flapper would help with flow issues, but if you plan on running over 20# then it's not worth it as it'll blow open easy. If you plan on running over 18# now, just get the mods needed to run 18# and forget about the creep issues.


My evo3 16g has horrible creep. Took 2 porting sessions to clear it up. Even without the actuator hooked up I would still boost over 20#. Now it holds steady at the stock wastegate pressure of 10#.

 

[Rklock]

I also have the 2g o2 housing. And with my 14 at first the accuator rod wasn't hooked up and it didnt spool for shit. it took a while to notice the problem considering im new to the dsm thing but i put a coder pin in it, and now it creeps bad. So i should take the codder pin back out your sayin?

 

[LiquidX]

I just wanted to see how bad your creep issues were. When I had mine actuator rod disconnected I was still boosting 20+ on my gauge. You'll need to either port it or get an external wastegate setup. If you port, just follow the porting section of the site I posted earlier.