Boost fluxuations in different gears?

[TSIHero]

This is a real newbie question and probably discussed before and I tried search but I just want to double check.

My boost fluxuates in each gear. I have the MBC set a little over 16 psi.

This is what I think off the top of my head looks like from a launch:

(all gears by the end of the shift)

Boost spikes to 20 psi every shift then drops.. The only gear it holds is 3rd.

1st Gear: 12.5/13 psi
2nd Gear: 12.5/13 psi
3rd gear: 16.5/17 psi constant
4th gear: 16 psi
5th Gear: 17/18 psi, alot of boost, not alot of power here.

I'm kind of confused as to where to set my boost. If I turn it up to try to compensate for the lower gears to have a higher boost while shifting, than my 3rd and 5th gear would be INSANELY high. Though I haven't really tried this out to see if it would work or not.

So is this normal for a stock turbo? And if so, should I be adjusting the MBC for 3rd gear pull? Considering this is the only gear that I hold constant boost?

Or should I be tuning it differently?

Throw me some suggestions... i'm real curious on this.

 

[Dootwah527]

Have you done a boost leak test yet? My EGR was screwed up once and I could only get 15 psi in 3rd gear with weird spikes at randon times. When I fixed the EGR, the whole problem went away.

 

[TSIHero]

Yeah I did a boost leak test and fixed the problems. It's always drove that way since I put the boost gauge in.

Anyone else have any ideas?

 

[keymaster]

Hey man, I have the same damn problem. Stock T25, MBC set to 15 psi, spikes to close to 19 each gear, holds solid in 3rd and 4th. Anyone got any advice besides boost leak?

 

[tstkl]

the turbo runs of of the exaust created by the engine, in higher gears there is more load on the engine which creates more exaust gases, as for the spikes, im assuming its cuz your running a t 25 at 18 psi where a shitload of hot air is being dumped into your engine and your getting a lot of knock unless you have upgraded your intercooler... the t25 isnt good for boosting past 14-15 psi, your just ruining your engine....

 

[TSIHero]

Bumping