the lower the gear, the slower my car builds boost. And it seems it didn't always used to be this bad.

In 1st:
Pos. Pressure @ ~2.5k
but doesn't hit max boost till about 4.75k

2nd:
Pos. Pressure @ 2.5k
max boost @ 4k

3rd:
Pos. Pressure @ 2.25k
max boost @ 3k

4th:
Pos Pressure @ 2k
max boost @ 3k

5th:
Pos Pressure @ <2k
max boost @ <3k

...is this normal. Could my stock wastegate be opening too early in 1st and just be bleeding off pressure. The boost build in 1st is really slow. Giving that yes, it does move through the rpms in 1st quite fast, but the boost doesn't really build like I remember it used to.

Wastegate, BOV, Vacuum leaks?

What should I check first?

 

BUMPITY

 

I noticed that my car does this too. I think it has to do with engine load. If boost takes X number of seconds to build at WOT, and each gear has a different rate of RPM acceleration (Which is true), then even if boost builds consistently in X number of seconds in every gear, you would be at different RPM in each gear when full boost is reached.

 

Nope, it's a perfectly normal behavior with the stock wasteate and manual controllers. BoostGuy951 hit the nail on the head, it has to do with accelerating rates of air-consumption. Say going from 50cfm to 100cfm to 250cfm to 300cfm through the revs. In the lower gears, the turbo has to provide a very quick increase in volume flowed from 50cfm all the way up to 300cfm in just a matter of a second or two. Since it has a limited flow-capacity, it can't do it quick enough. In the higher gears like 5th, the rate of increase is much , much slower, so the turbo can deliver enough volume to build up boost at each RPM. Going to a higher-flow turbo will solve this issue.

 

Thanks guys, that makes a whole lot of sense. I almost feel dumb for not knowing a "common sense" thing like that. Danno, would you have time for a phone call tomomorrow at any point to discuss some upgrade options through GURU?