boost spikes up to 19psi on mbc

[1SICKDSM]

hey whats up i have a 2g eclipse that has a evo III motor swap. I bought the car off of a guy that had one of those 10 dollar boost controllers on ebay...boost would go to 14 on first and second then shoot up to to over 20 psi, not wanting to push the car any further i stop. so i decided to use my friends turbo xs mbc and turn it all the way down intil its closed. well first and second go to 10 psi then on third it shoots up to 19. whats wrong with the car. i cant seem to figure out what exactly is going on. i figured id buy another mbc but is that going to help solve my problem. up to date i have upper and lower intercooler piping, air filter and 3" apex exhaust all the way through. it also has a big 16g please help its really making me crazy. im not sure if this makes any difference but there is no stock boost controller so theirs no way to connect the stock one back.

 

[ADrewzki]

Can you provide a quick description as to how your hoses are hooked up to your bov and your mbc? I've found that a single hose from the turbo to the mbc to the wastegate works the best for me. Others may have different methods. It's when I teed the hose from the turbo is when my boost would spike like you.

 

[1SICKDSM]

well i havent had time to see where my hoses are connected to. my bov isnt recirculated back into the intake. although with the mbc....i have one hose running from the wastegate to the bc, and the other end is connected to the j-pipe on the turbo. i hope you can understand what im saying. what im going to do is get my friends stock intake pipe and recirculate my bov...because my car wont stay on at idle but could that also help solve my problem with boost spikeing up. any help would be great.

 

[Omega]

I doubt the intake will fix the boost spike.

Take the MBC out and run a hose from the compressed air side of the turbo to the waste gate. Take it for a ride to see if what the WG is set to and if it still spikes.

What are the other mods of the car?

Pssst... Fill in your profile please.

 

[ADrewzki]

I doubt the intake will fix the boost spike.

Take the MBC out and run a hose from the compressed air side of the turbo to the waste gate. Take it for a ride to see if what the WG is set to and if it still spikes.

What are the other mods of the car?

Pssst... Fill in your profile please.

Technically the jpipe should be seeing the same pressure but, like Omega says, use the nipple on the turbo instead of the jpipe and see if that makes a difference.

 

[oldman]

First, please complete your profile, can't help you without any info on your car. I'm assumming you have a 1g since you said the nipple is on the jpipe. Make sure you're talking about boost spike and not a creep. In third gear, does it shoot straight up to 19 or creep up to 19. Like others mention, disable your mbc and see if it holds at stock level. If it does not, you probably have boost creep. If it holds, check you mbc setup.