New DSM owner. 1997 Eclipse GST Overboosting problems

[2wOrLd]

So I found me a 97 GST in mid October and managed to buy it for $1600. Apparently someone had ran into a curb or something and damaged the control arm, part of the subframe, shock, fender and bumper. I had most of the pieces to fix it from an old 98 GS that i used to have and got it road worthy in about a week. Did some cutting and welding to repair the subframe and began driving and liking the machine, so i did a few mods:
Dump tube Cut
K&N filter
Prothane Mounts all around
$3 catch can mod
Boost Solenoid restrictor mod
Boost gauge(fpr tapped)
Mounted FMIC but havent plumbed it yet.
Knock off BOV
10.2mm Spark plug wires
Tanabe Medallion 3" turbo back exhaust

Now when I bought the car, it had been fitted with a brand new exhaust system. Looked like 1"7/8 turbo back. I found out how restrictive this was when i bolted on my new 3" exhaust. Before installing it, i was boosting roughly 10 psi but now it peaks out at 20psi!! When I saw how high it was boosting, i stopped driving the car aggresively and bought a cheap ebay MBC to hold me off while i finish collecting my new turbo setup. After hooking up the MBC, and cranking it all the way down, i would still build 10psi in neutral. The only difference was that it boosted a lot slower. Drove it to work today and it would still hit 20psi.
I was wondering what could i do cheaply to turn my boost down so i dont lift the head, blow the block or 14b turbo?
Would it turn down if i replace the small restrictor on the boost solenoid?
Any help is appreciated, sorry for the long post.

After I fixed all the issues

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After Drop

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After Rims:

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[eagletalontsi0]

have you played with the waste gate at all?? and what boost gauge are you reading off of the one in the dash cluster or another one you have hooked up

 

[hugeT]

sick looking GST for $1600. If you bought a cheap ebay MBC can't you turn down the boost with that?

 

['97boostinGST]

Sounds like you have some serious spike issues...when did it start spiking that high?
After what mod?

 

[TSIturbo91]

Seems like you need to check for leaks. If your leaking air somewhere the MBC could be slowing it down now but it only works well when it's the only path of least resistance. So it sounds like your controlling a bit of it but not all of it.

And just a tip. Don't do to many mods at once if your learning how your car works. I'm not insulting your intelligence. Its just the easiest way to solve a problem. Less variables, less things to check and go wrong.

 

[V12 Killa]

Rule out a bad mbc by putting a vacuum line from the WG to your boost source (without the mbc installed) and see if it stops the boost spikes. If not, time to start porting.

 

[2wOrLd]

I have not messesed with the WG at all since i bought it. Im reading off my aftermarket installed gauge.
It began spiking after the 3" exhaust.

TSITurbo91 thnks for that tip, i did that when i began building my MR2 and learned my lesson the hard way. I havent done too many mods on this GST, i didnt really have any problem at all until i installed my exhaust.

V12 im not too clear on what you mean. Could you break it down for me?

Got it fixed!
I took the little metal insert off of a butt connector and flared it inside the boost solenoid. Peaking out at around 14psi, which is exactly where i wanted it.

Thanks for all your support,
I look forward to posting up my upcoming build this summer.

 

[mt209]

2world
what rims are those? and size?
car have a drop?
really clean car.

 

[austin johnson]

2world I am having the exact same problem as you after installing my exhaust. Removing the catalytic converter messes with flow and psi but I turned my MBC down all the way and im hitting 16-18 psi. I was running the MBC before my exhaust and was hitting 14psi. What would you suggest doing to make it run at 14 again?

 

[ThunderChild]

Got it fixed!
I took the little metal insert off of a butt connector and flared it inside the boost solenoid. Peaking out at around 14psi, which is exactly where i wanted it.

just so future members can clearly see what happened here, mind explaining if what you experienced was a mechanical (boost leak, WG issue, MBC issue etc) or an electrical issue (your comment about a butt connector used to modify the BCS)?

my thought is you had a poor connection at the BCS and remedied it with some clever wiring. just want to clerify