[mzafar]

This might come across as a weird question. But sometimes when I'm getting on the highway, about 70-80kmph in 4th gear and I try to pull up quickly to highspeed or higher (upto 140kmph) on the 4th gear, if I put my pedal to the floor:

the car boosts
tries pulling
the boost builds up to around 14 psi
and all of a sudden at around 3k, the car looses boost and I'm at 6-8psi of boost with not much power

The car pulls perfectly fine from standstill upto 5th gear and 5000Rpm. It only happens when I'm in a higher gear than I should be.

The question I'm asking I guess is:
1) Is it normal for a car to do that and I should just go into a lower gear
2) Or if I wanted to stay in a lower gear, I should just slowly feed the power in and not go pedal to the floor?
3) Or is there something wrong with the car? It feels weird that the car builds boost but then loses it.

It's an '08 e92 6AT
Mods:
1) Charge pipe
2) Jb4 Map 1

[msjt]

Are you getting kicked into map 4?

[luv135i]

Originally Posted by msjt

Are you getting kicked into map 4?

It does sound like being kicked to map 4. You should make a log of it doing it so people can tell you wats causing it.

[mzafar]

I'll post a map soon. I didn't know JB4 could switch maps like that Thanks guys

[Jeff@TopGearSolutions]

3) The JB4 has several safety systems built in that will force a switch to map 4 (low boost) if the JB4 notices various conditions. Including boost over target, fuel pressure below target, and air/fuel ratio running lean. If you ever encounter an automatic switch to map 4 review the FAQ below for addl information.

Check out the JB4 Manual and FAQ Here:
http://www.n54tech.com/forums/showthread.php?t=10605