Boost falloff in different gears.........

[Eastwood95]

Ok, So I have a 14b with supporting mods, FMIC etc...........
recently I've noticed that in 2nd gear, boost will hit the 17-18psi I have it set to, then fall to 15 in higher rpms..........in 3rd gear it will hold on 17psi until redline....................whats the deal with that?

 

[nazthug]

my t04b also does this, more boost in 3rd then 2nd

2nd always goes to 21psi but falls to 18, in 3rd, it holds 21psi..wtf?

 

[pickens]

Boost leak.

 

[psychlow]

Where are you tapping your boost source for the wastegate?

If it's not off of the BOV line (sourced from the intake manifold), it can cause this. Stock, it comes from the compressor housing outlet pipe, which isn't the best source IMO.

 

[Eastwood95]

I'm tapping into the BOV line. I think I have a small boost leak, I'm going to make a leak tester and check it out..........

 

[green92gsx]

Alot of it has to do with the flapper door opening to early. Try adding preload to the wastgate actuator. Also over porting and a large flapper/o2 dump will cause boost drop when trying to run higher boost levels.