If I disconnect the wastegate, then...

[BoostedBird]

Hear me out on my theory. I have been trying to figure out why I am not boosting past 7-9PSI. If I disconnect the vacuum line from my MBC to my wastegate, the turbo should spool up to around 20 PSI or so (out of "control" anyways) So then my stock 2G BOV should dump once I hit around 12PSI then right? Since they are notorious for being weak around that point. Hence, the BOV would be acting like my wastegate, right? I tried this and no more PSI past 7! What the hell? So here is what I am looking at:

1. Is my boost gauge junk? I have the plastic line installed but I have checked it for cracks and pinches, nothing. Should I replace it with rubber hose.

2. I KNOW my stock BOV leaks when I do a leak test. Is it possible that it just is really shot and opens at 7PSI? I have a 1G BOV arriving tomorrow for all you flamers out there!

3. I heard a leak by the throttle body but couldn't find it. Didn't seem major but I read about the shaft seals and am ordering some now. Would that amount of leakage cause the low boost?

All I have for mods are filter, intake PVC mod and MBC. I have the MBC disconnected right now trying this new thinking.

Please look this over and let me know what you think. This is really getting old. Car runs fine, just no good boost. NO shaft play on the turbo and no smoke, so that shoudn't be the problem. ANY help is GREATLY appreciated.

 

[Defiant]

Don't even bother trying to blow up your engine any more until you've replaced that BOV. A 1G would be fine, but I suspect you'll be wanting to spend more money for looks and noise. A BOV that opens under boost will only over-stress the turbo. They on "dump" under vacuum. When it LEAKS under boost, it's because they're crap.... or you're striving for much more boost than Mitsubishi intended.

 

[BoostedBird]

Not looking for "looks or noise" Just looking for some proper boost levels. Not trying to get 18 PSI out of the stock turbo, just around 13-14. Anyone else WITH some help here.

 

[LandoAWD]

1g BOV, rubber line to gauge, MBC back on (be conservative with the Tiny25).

Edit: Thorough leak test.

 

[scuRRed whiTey]

pretty interesting theory but it wont work

first make sure ur boost controller is hooked up right...cause it seems like hteres a direct line goin fom the control to the wastegate and possibly back to the turbo inlet pipe to the intercooler

if u see what im sayin....it might be kind of confusing to understand

make sure uve capped off all ends on the nipples thart ur BCS came off with all those little hoses

if not ur leakin boost somewhere

uhm...make sure ur boost contrller is in good shape...the spring inside the boost controller...if it ball and spring...maybe weak there for opening ur wastegate up and only boosting 7-9 lbs

this problem is difficult.....try get rid of that ### ass BOV and replace it with a 1gen one......a little more dependable....well no alot...and if u crush the top they hold even more


if that dont work get back to me

make sure there are no vacuum leaks!

 

[BoostedBird]

Appreciate the help. I figured the 1G BOV would be a big help. I rehooked up the MBC this morning. Just verifying the hook up ~ Nipple opposite of the tuning knob goes to T in the BOV line, the other nipple to the wastegate. Right? I have a Hallman ES MBC. I have capped the turbo outlet nipple & both BCS nipples. I have leak tested a couple times now. Shitty 2G BOV was leaking. But more was by the TB. No by the elbow or manifold. Like in back. Trying to order some new TB shaft seals. Will see if that helps. Suppost to get the 1G BOV today or tomorrow. Will get it on and update.

LandoAWD ~ I thought that maybe I should replace that gauge line. Just seems like too easy of a spot to have problems.

Appreciate the help guys. Will update tomorrow on what is happening.

 

[crazyjoe]

Nobody has really mentioned this yet, so I guess I will.

A wastegate opens at the turbine side of your turbo, essentialy keeping the turbine from spinning faster and making more boost, and also keeping it from killing itself.

The BOV opens in the intake tract, or essentially on the compressor side of the airflow. So your turbo is still spinning like a banshee and flowing a ton of air, you're just not doing anything useful with it.

This is why disconnecting the wastegate is bad, and also why people get boost creep due to wastegate problems coupled with exhaust problems.

 

[stjoetalon]

I have the same problem. Nobody has been able to help as of yet.
Everything worked fine before the cars 2 year downtime. I put a head on it, now...

-boost leak from behind the TB so I bypassed coolant lines and filled with silicone
-14b has shaft play, but boosted fine before
-1g BOV leaks at ~9lbs. If I cover the return, I can still hear the TB leak.
-homemade licp leak. I fixed that and still no boost.

I dont know what to do next.

 

[Honda4Lunch]

If you've gotten to the point where you've disconnected the wastegate and you are still building little to no boost than use this as a guide:

1) Always check for leaks first(vaccum hoses, IC pipes, TB, etc.)
2) Check the Turbo (shaft play, etc.)
3) Check the wastegate flapper for proper seal and/or cracks.

With checking for leaks also check to ensure your wastegate actuator works. If you hook up an air compressor to the wastegate accuator the arm to the wastegate itself should move. While you're checking for leaks it's easy enough to look at the turbo shaft with the LICP off. If after all this and you still can't build boost, then check your wastegate flapper!! Take off your O2 housing and look at the wastegate flapper....mine was loose as hell and I could only get 6psi no matter what. The wastegate arm may still be moving which leads you to believe all is ok, but until you take off the O2 housing you don't know for sure if the flapper is moving or stuck. BoostedBird had this same problem as have others I've talked to. Hope this helps.