WGA or MBC

[bcjjones]

Just noticed, once I really got into tuning my car, that im not holding boost to redline. Not anywhere close. I could get to about 20-21 psi (which is my DD goal) and by redline I would be at wastegate pressure which is around 8 psi.

So I just unhooked my WGA hose, ran up to about 23-24 psi falling down a little in the higher rpms. But held pretty much 23-24 psi to redline. Running rich the whole time with no knock!

My MBC is a homemade one, made it myself. Just havent invested the money in one because I THOUGHT mine was working fine. Now my question is, is it more likely my WGA or my MBC?

Also 23-24 psi is pretty close to my goal, another two questions I have are

Is it bad to just run no WGA and just leave the wastegate closed?
Is 23-24, in yalls opinion, too much boost for a DD?

 

[92AWDHX40]

How is the car tuned, do you have a wideband?

 

[MHuddy1213]

what type of turbo do you have and dont leave a wastegate closed i believe its just the boost controller and if your running rich fix it fast or youll blow your piston rings and throw a bearing and all other things maybe not right away but itll happen and 23 psi is fine for a daily driver as long as your setup is able to handle it

 

[bcjjones]

I have an AEM Uego Digital wideband. Doesnt really log well, so usually when im doing a 3rd gear pull, ill log the pull and record the same pull with the Wideband and RPMS. Not the best way but it does okay until I get a tunable wideband. Tuning via Jackal speed Density and Ostrich 2.0

Sorry MHuddy, kinda hard to read what you typed, but your saying its a bad thing to always have the wastegate closed? As in by passing the WGA? Curious why thats a bad thing?

Wasnt running THAT rich, around 10.5 afrs

 

[MHuddy1213]

sorry should have wrote it better yes it is bad to run with i closed cause the unused air will have nowhere to dump to except back into the turbo itself which can cause you to blow seals ive heard

also what turbo are you running if your pushing that much boost on certain turbos youll blow them so thats why i was asking which one

i think its just the MBC your running due to that all it does is holds a certain amount of pressure and then allows it to release into the wastegate so you dont overboost and grenade the motor

 

[bcjjones]

Its an MHI Big 16g.

Yea what just confuses me about it being the MBC is why would I be able to generate 20 pounds of boost for a few hundred rpms and then it slowly decrease as the RPMS increase? I mean obviously initially its holding well enough to generate 20 PSI before sending the signal to the WGA, but I guess maybe the spring im using isnt stiff and or long enough to hold that pressure off until redline? Thus causing the wastegate to open more and no hold that boost?

 

[MHuddy1213]

that is what i believe is happening in your case or hmmm maybe your wastegate is getting stuck open for some reason try taking a video of whats happening by watching your boost gauge maybe itll help determine whats happening but you can get a good boost controller on stmtuned for a decent price i suggest the halman pro boost controller STM: HALLMAN PRO BOOST CONTROLLER

the psi your running should be okay for what turbo your running too where are you feeding your oil from?

 

[bcjjones]

Wastegate flapper moves freely, disconnected the actuator arm and tested that already. Im leaning toward my homemade MBC. Been wanting a genuine one anyways, so ill look into them and order one.

Oil is ran from head, which i've read is fine for smaller turbos.

I appreciate all y'alls help, and if anyone else has any input id be glad to hear it!

 

[MHuddy1213]

if your pushing your rpms that high feed from the OFH during high rpms and boost the head may not be sufficient enough for the turbo our turbo rebuilder on here told me that and then just put a oil restrictor on it .070" im pretty sure just my suggestion about that and ive heard great things about the hallman especially for the amount of boost your pushing and for the price

 

[bcjjones]

Yea I might just switch it to the OFH just to be safe. Im going to play with my homemade MBC to see what I can do to make it better, ill probably just order a Hallman tomorrow though!

 

[MHuddy1213]

good idea good luck hope everything works out keep us updated and ask if you have any questions