Boost Question

[Michel Paiement]

Don't know if anyone can help me out with this, when I punch the gas, my boost climbs up to 20lbs and then levels out to 15lbs after. What are some possible solutions?

[Dave Kish]

your getting boost spike. You wastegate is your problem. Do you have a mbc yet. if not you should get one

[Jason Harwood]

Shitty boost controller most likely
Could be a ton of things

Eliminate your boost controller and see if it boost creeps on stock.

[Michel Paiement]

I got the boost controller from kinetic, maybe its shitty i don't know. The turbo is brand new T28 from forced performance, ill hook up the wastgate to the turbine housing and see what happens. Has anyone had problems with kinetic mbc before?

[Marke Bailey]

boost creep. you can port the wastegate opening to reduce it. Are you using a cat? I only got creep when I took mine out and ran straight thru.

[Michel Paiement]

I have a cat, I have been doing some reading, most people with boost creep, tend to have the problem after boosting for a while then have the boost creep up. Its weird with mine because it will spike then level out after.

[Mike Schmid]

My understanding is a boost spike is where the boost comes on fast, shoots high then falls back.  Like what you have. 

Boost creep is where it jumps up to the set level then slowly rises as you stay on boost instead of holding steady like it should. 

How is your MBC plumbed in?  How long are the lines?

[Michel Paiement]

My understanding is a boost spike is where the boost comes on fast, shoots high then falls back.  Like what you have. 

Boost creep is where it jumps up to the set level then slowly rises as you stay on boost instead of holding steady like it should. 

How is your MBC plumbed in?  How long are the lines?

I figured that I had the lines to long before, I was able to cut a foot out of the lines, I now have it mounted right by the rad so its short now, I have the lines going from the wastgate to the bottom of the mbc, the side port with the small hole in it on the mbc goes to the turbine housing port. After I shorten the lines it seemed to solve the problem the first time I hit the throttle, but after a couple tries it was back to the same thing.

[Mike Schmid]

What boost source are you using? 

Is the MBC clean too?  Mine wasn't working very well at all one day so I pulled it all apart and it looked pretty clean but I cleaned it anyways with some brake clean to get any oily residue off and it worked like a charm again. 

[Josh Letkeman]

If its spiking like that it my be the hole in the MBC is to big or small not sure of which one but Travis has that same problem.

Josh

[Michel Paiement]

A guy from my work let me borrow a mbc he had (turbo xs) never had a hole drilled in it. I did not like that one because if i was just cruising it would start building boost, I could not get on the throttle with out my knock sensor wanting to climb to the top. I had that one set to 15psi. What mbc have people had good luck with?

[John Hartman]

its not creep, its spike.  The small bleed hole in the mbc is probably blocked or didn't get drilled out all the way.

Or there is a crack or other source of lost pressure in one of the lines to or from the controller.