To make a long story short, my car was feeling quite slow in the upper RPM's, with quite a bit of movement back in forth on my boost gauge - spike to roughly 20psi, fall to 16, back up to about 19, and fall back to 16psi and settle. See my original thread to the problem here: https://www.evolutionm.net/forums/sh...ht=odd+problem

I decided to make my own boost leak tester tonight, took everything apart and strapped it on the turbo inlet - got about 20 pumps in and the rod on my $8 bicycle pump I bought from Walmart cracked on me, causing the base of the pump to smash down onto a little black piece located under the airbox that has two tiny tubes protruding from it, of which two hoses that run under the rubber intake pipe are connected to. Here's two crappy cell phone pictures of the piece I'm talking about:




There's supposed to be an equal size tube like the other one right where the hole is. And for a better idea of the location if needed:





So, basically one of those hoses isn't connected to say the least. What exactly is that sensor/piece that a tube broke off of?

Needless to say, my car now spikes to 22psi and sets at a fairly solid 20psi in each gear, all the way to redline. So did I accidentally bypass a boost sensor or something, or did I just fix my boost leak by taking everything off and tightening everything back up? I hope it's the latter! BTW, only addition to the car is a WORKS drop-in.

Thanks in advance!

 

that is the stock boost sensor... You need to either fix it or get a new one.

 

yes, stock boost solenoid. You basically have 0 boost control right now, and are running the maximum the turbo will deliver at WOT. If you follow the two vacuum lines that "used" to be connected to the solenoid, one should be coming from the discharge side of the turbo, and one will be connected to the wastegate actuator. Just make a direct path from point a to point b bypassing the solenoid totally. Then you should have a nice safe boost level until you can get it fixed. I'd say get a manual boost controller at this point, it's going to be cheaper than a new solenoid from Mitsu

 

/\ mbc is a better fix than getting a new oem boost solonoid

 

if you joined the two together, you have a boost leak.....
there are three hoses to that systerm.
one off the turbo, one off the wastegate, and one that goes to the intake......

the tubes going into the turbo and wastegate are "y"d together and go into that solenoid as one tube...... that piece bleeds compressed air back into the intake....
if its plugged together, it bleeds all the time.... the turbo is spinning harder to make that pressure..... if its not together at all.....it bleeds into the atmosphere.
you basically have a boost leak right now

get a mbc, it goes betweene the wastegate and turbo, and put a plug on the end of the other line or pull the line off and plug the intake hole

 

Good lord, you guys really need to have more than a clue when answering questions.

As the guy above said, thats the stock boost control solenoid, not a boost sensor. Additionally, you broke off the "vent" nipple that runs the air bled off by the solenoid back into the intake. Do you have full boost control? Yes. Is 22 psi the "max amount your turbo can suppot?" Haha, no way in hell. Does this air need to be recirculated? Absolutely not..its a very minute amount. One thing I would do, however, is find the hose that used to attach there that runs to the intake boot and plug it so you aren't sucking in unmetered air.

So why are you making more boost? Simple, you got rid of a lot of plumbing that the air bled off had to travel through which removed resistance and in essence made the bleeder solenoid flow more through it which will up boost pressure. Its a common practice with Xede boys who want more boost using the stock solenoid to add a bigger vent line from the solenoid back to the intake which also increases flow and ups pressure.

Edit: This isn't to say that you fixed your boost problem necessarily, you might have simply masked it.

 

Thanks for all of the replies, everyone. I pretty expected the answers that I did in fact break something that'll cause me to boost more

A418t81 - So is it relatively "safe" to keep it how it is for a while if I plug that return line? The boost settles at a solid 20psi after the intial spike, so I don't really see the harm right now. Thanks!

 

i have the same problem but i have a electronic boost controller so nothing goes to these. pulled intake off and has no caps on holes.same one is broke on mine.just wondering if i have to get a new one.does alot of air leak out from the holes under full boost.21 psi.thanks

albert

 

mbc is probably the cheapest fix... 30$ used to 100 new or ebc 200-300? dont know much about them

 

i just want to know if it matters if they are capped.

 

that is not the vent nipple. A broken vent side nipple wouldnt cause high boost. you probebly wouldnt even notice it.

you are running with out any boost control what so ever. the only thing keeping you from boosting even higher is the orifice that mitsu put in the line between the actuator and the solonoid for just such an occasion. if you plug that hose you will have very low boost because there will be no vent and all psi will be applied to the wastegate actuator. from the sound of things the ecm may have been seeing knock or other conditions that it would pull boost to keep bad things from happening. Now by breaking off this line to the boost control solonoid you have taken all control away and added alot more psi. I suggest you replace the solonoid and figure out why your boost was screwy before installing a mbc. you may be covering up a serious issue with the mbc in this case. It may turn out to be nothing major but I would rather be safe than sorry.

 

just wondering if this broken does this effect my performance even though i have a ebc.so nothing goes to these lines.does it affect anything with these holes not capped.

 

nobody knows?

 

On a flash Vishnu bypasses the stock boost solindoid all together. Maybe you could just go that route. If not just get a MBC or EBC.

 

i'm just wondering if this is broke and i have ebc bypassing it anyway.does this effect any performance with the peice broken?