Well i recently installed my boost gauge on my USED evo. This is the same one that needed a clutch a week after purchase. Well my gauge only reads 15psi, so after some talking with Warrtalon he told me i should go looking for some line restrictors near the bsc. Well i pulled out my air box, and low and behold i find a rather shatty little splice which i think indicates (as warr predicted) that there was a MBC in my car at one point and the a-hole who removed it did not put everything back the way it was. Here are some pictures to help everyone confirm or tell me wtf is going on...btw...i found no restrictor pills at all.

Next question....do i go to the place i got the car and ***** till i get new lines with pills? (free)

Or do i just buy a MBC? ($)

PICS.....

 

Ah, as I suspected. That is the proper routing of the lines, but you need the OEM boost lines or an MBC. Frankly, I think you should just get an MBC; however, you should also require the dealership to provide you with a factory set of boost lines for free if you got it from a Mitsu dealer. They should not be selling cars like that, but unfortunately, 99% don't even have a clue about this whole restrictor pill thing.

The good thing is you know why you're not boosting normal. Now, you just have to get it fixed. To reiterate, get yourself a nice Forge UNOS MBC, and demand a set of factory boost lines (only $25 anyway) from the place you bought the car.

 

Well they finally got those boost lines in....and still no change....15psi max.

I have an apointment for them to trouble shoot the car. Im thinking maybe bad boost control selinoid?

 

the restrictor pills don't effect how much boost you stock solenoid is going to push, they just stablize the pressure so there are no spikes. I've taken mine out before and replaced them with the same ID hose just no pills and the only difference was a small spike at peak TQ.

your problem is else where. I would first pressure test your intake and make sure you don't have any leaks. then look for a mechanical issue...

 

nope alwaysinboost....it was the restrictor pills....new lines solved the problem.....then i got a MBC anyway

 

Well, we had it diagnosed properly at least.

AlwaysinBoost, what you said is not correct. Using non-OEM hoses with the stock BCS does not give stock boost. The BCS has no way to regulate boost properly without both pills.

 

Yup im afriad Warr is right, the stock ebs does not like thicker or thinner hosing, its like putting PVC tubing where a straw should be. understand that ?

 

Well, I don't even know about the thicker or thinner hosing issue. All I know is you have to have the exact OEM hoses unless you know how to get the exact pills and install them in the exact place on a set of aftermarket hoses.

 

using non restricted boost lines with the stock bcs will give the wastegate a stronger signal faster causing it to open and bleed off your exhaust gas energy. this will produce lower boost levels. all you that rely on your boost gauges for information should be slapped. the only proper way to monitor boost levels is with a map sensor and i only know of one gauge that acutally uses one. (excluding the aem multigauge unit)

 

I don't know what to tell you... I'm not speaking out my butt, I'm talking about what actually happened. I removed my stock hoses with the pills and replaced them with new hoses with the same ID just w/o the pills and I saw NO difference in boost. Just a small spike at the TQ peak.

 

I can't think of an explanation for that. About once a week, we have someone come on here and complain that they're only seeing 11psi, and it's because they bought a used Evo that was previously modded with an MBC and had been put back to "stock" without re-using the OEM boost lines.

That's why they only see base wastegate pressure.

 

Its usually the way the lines were put back in that screws it up.. the hoses get installed a particular way for a reason.. removing the restrictor from the boost source just screws up the way the stock solenoid works, and therefore your boost ends up being alot lower..

Most of the time the two short lines end up being reversed so the actuator gets the restrictor and the source gets the open line.. so you end up getting wastegate pressure or a few psi over it..