boost creep with a tial 38mm

[My96AWD]

What would cause boost creep with a tial 38 off of no. 1 with dump, a b16g and 2.5 ex. I have the mbc set to 15 (which is the lowest i could set it) but it creeps to 20+ untill it fuel cuts. Take mbc out of loop then it sticks 8 pounds. Im thinking the mbc is bad but was wondering others opinions before i got another, because it worked fine when i had a 14b with internal.

 

[Flybiyou]

Are you turning the boost controller all the way down. If you are try tighting it again then give it a half turn out to a full turn out and try it again.

 

[DSM90AWD]

With an MBC you should be hooking into the side vacumme port of the TIAL38, not the top port (which should be left open to ATM)

 

[99gst_racer]

What spring in in your Tial? .55 bar?

 

[bluegs-t]

With an MBC you should be hooking into the side vacumme port of the TIAL38, not the top port (which should be left open to ATM)

if this doesn't work, try porting your wastegate hole.


Shawn

 

[DSM90AWD]

if this doesn't work, try porting your wastegate hole

He's running an external off the manifold, his wastegate hole should be welded shut

 

[bluegs-t]

He's running an external off the manifold, his wastegate hole should be welded shut

my bad. i was at work and i saw the topic. i read other's suggestions and posted what else i thought it could be. hmm... can you get creep off the manifold if the hole isn't large enough though? i don't have any experience with the wastegate ran off the manifold, just off the o2. you shouldn't have any problems with the tial, unless it is hooked up incorrectly...

 

[My96AWD]

With an MBC you should be hooking into the side vacumme port of the TIAL38, not the top port (which should be left open to ATM)

Thats the way i have it hooked up. The top port rattled loose and I lost it, just like everybody else doh.

 

[My96AWD]

Are you turning the boost controller all the way down. If you are try tighting it again then give it a half turn out to a full turn out and try it again.

Tried that already. It just turns the boost up.

 

[My96AWD]

What spring in in your Tial? .55 bar?

Not sure what spring is in it, but without the mbc it sticks 8 pounds.

 

[Andy5]

Not sure what spring is in it, but without the mbc it sticks 8 pounds.

try using someone elses mbc

 

[99gst_racer]

Not sure what spring is in it, but without the mbc it sticks 8 pounds.

If you stay at 8psi with no MBC, then you do have the .55 bar spring.

Judging from your initial post, I would assume that you have a defective MBC. I would first try replacing it with a different unit to see if your problem is corrected.

 

[My96AWD]

That's what i was thinking, but I don't like wasting money on stuff I don't need. My buddies car is down right now I will try and steal his for a lil while and try that and get back.

 

[tstkl]

so build an mbc, it cost me 10 bucks. seriously thats like skipping one meal out of one day of your life. go hungry so your dsm doesn't, .

 

[1fast97gsx]

or jsut decide what boost you want to run and order that spring for your wastagate and no need for a controller.

 

[92GSXBaltimore]

it is clearly a problem with your mbc

 

[AMS Eric #2]

You can run a 500mm wastegate way up in the #1 runner and it will creep. If you place the wastegate somewhere where it can only expell 25% of the air flow, you limit its effectiveness to control boost no matter how big it is, especially in cold weather and very well tuned cars.

 

[99gst_racer]

You can run a 500mm wastegate way up in the #1 runner and it will creep.

Replace "will" with "could". This would solely depend on the engine/turbo set-up.

If you place the wastegate somewhere where it can only expell 25% of the air flow, you limit its effectiveness to control boost no matter how big it is, especially in cold weather and very well tuned cars.

You are correct, however, running a B16G at 15 psi, he shouldn't need to expell 25% or more. I've ran my 50-trim as low as 12 psi and I have a 38mm gate on the #1 runner, and I've never had creeping issues.