Nick7

Ok, setup:
Garrett T2 - internal WG
10:1 FMU
IC, BOV, inline pump...

Now, the problem... internal WG was already set to lowest possible boost level (arm was lenghtened as much as possible, so it still holds shutter tight closed in vacuum). But, I got boost creeps of almost 9psi on WOT in 5th gear.

So, I tried to add another spring which pulls actuator arm - so I get lower boost due to using FMU... I want to have 6psi, and that's it...
Spring was ~5inches long, so it should keep about same tension when WG is open/closed.
Now the problem - I still get helluva boost creep and lost lots of boost under lower rpm's.
I get now like 3-4psi at 3000rpm, 5-6 at 4000rp, ~7 at 5000rpm, and ~7.5 over 5000rpm. Before I added spring I still got creep, but I had more boost at lower rpm's. I twice checked that wastegate shutter was tight shut by actuator arm, so this one is not issue.

Well, guess this internal WG suxx @$$... so - what now? Would MBC help me to get more boost on lower rpms?

Any other ideas? EBC are kinda on precey side... and adding external WG is also big pain, due to welding and not really too much space there...

Help!!!

RedTegLS

Honestly I only read your title, but when I put my turbo xs MBC in it went right to 8psi and stayed there! Maybe I was just lucky? It sounds dumb but I swear it spools up faster too.

red91sit

It could just be that the stock internal wastegate is too small for what you are asking it to do. A manual boost control will still only send the same amount of pressure to it just as a different pressure. So I would doubt this could help.

MBC will give you more faster spool because it doesnt' slowly open like the other one, it is less linear. You mihgt want to try working with the internal waste gate exhaust flow/ routing. Some go into a very poor flowing path which severly limits there effectiveness.

Nick7

Yeah... that's why I said this internal WG suxx :>

But what I was wondering.. lowering spring tension for internal WG (like set it at let's say 3-4psi), and use MBC - to get faster spool, and hopefully be able to keep it at steady boost level (at let's say 6psi).

Anyone who had boost creep problems managed to fix it with MBC?

Nick7

*bump*?

MaxSterling

if you want to stop creeping, try a more restrictive cat back exhaust. b/c right now your exhaust is out flowing the internal wastegate. boost controller probably will not solve your creeping issue.

FCdrifter

boost controllers CAN NOT lower boost beyond whatever boost you would run by just relying on the wastegate to regulate boost. All a boost controller does, manual or electric, is delay the opening of the wastegate door. You have two options:

1. increase the flow of the wastegate
2. decrease the airflow

1 - Port the wastegate hole larger, or until the edge of the wastegate puck. If it's small and there isn't room to port the hole larger then get a larger flap welded on...intake valves work good for this task

2 - self explanatory - put the stock airbox back on, go with a smaller sized exhuast, etc...

Nick7

fcdrifter - I know MBC cannot lower boost!

What I was asking - if I lower boost at wastegate, so even with full creep it comes to let's say 5psi (cannot go past that), and Iuse MBC at that point to set 6psi - will it work OK in that case? Will I get boost on low rpm's (I know this also depends on turbo size), but will the MB keep WG flapper closed untill 6psi, and than open to adjust pressure, without creep even at high rpms? (as said if stock actuator is set that *with* creep cannot go past 5psi)

That's what i want to know.. so I somehow try to lower boost on actuator, and than use MBC to raise boost to 6psi - but hopefully without creep.

Can 'homemadebuilt' MBC with ball&spring (such as from c-speed) achieve this?