Boost Run Away....and Flutter

[Jmpin]

Hay guys got a problem with my BA xr6t... 4 speed auto

first a bit of back ground.

- the actuator has been replaced with a 12psi item

- the valve springs are done

- the injectors are upgraded

- has a monza style intercooler

- has UBP, hotside piping

-has been supposably custom tuned.

something else to point out is the coils have been replaced, the plugs have been replaced and re-gapped, and its been on and off the dyno all day friday and today (monday).

the tunes also dont seem to follow what hey are meant to, what I mean is my economy tune that was meant to be for towing (meant to run 5psi) runs almost the same as my high power tune (which is 12psi), having boost climb from when I first put my foot down.

all tunes boost up real hard and smooth, then from say 2-3 and 3-4 gear the boost just builds and builds and surges up and down.... this is not smooth boost! this was eliminated a great deal by doing the actuator... but has not fixed the problem.

any ideas would be great, as the tuner cant sort it out and it is one of the forum sponsors but that's all I'll say.

seems to me that the car does not know what boost its running.... maybe the boost sensor in the UB pipe or something, just an idea as nothing has worked yet!

[BFHOON]

it may have a punched cat causing overboost.

does it have an exhaust system added.

[typhoon_freak]

your economy tune was a 5psi tune? I thought by puttin a 12lb actuator u cudnt run anything less then 12 psi??

[our06t]

might be more than one problem , as above I didn't think you could run less than 12psi with the 12 actuator ?

I had some surging issues it was the torque limits in the transmission settings that where causing that ,it would cause it to surge drop boost flutter as you put it

[Jmpin]

it may have a punched cat causing overboost.

does it have an exhaust system added.

the exhaust is stock, except I had the centre muffler cut out... was going to look at doing the cat and dump pipe.... but these latest issues make me feel like its going to f*ck something else with every mod made...

[senna_T]

Be an idea to check the cat mate, if its collapsed and blocked you can have all sorts of issues. How does it make power? Are you getting good peak power or is it struggling up top?

[Jmpin]

your economy tune was a 5psi tune? I thought by puttin a 12lb actuator u cudnt run anything less then 12 psi??

not that I have been lead to believe, as the actuator is more a fail safe.... last resort to vent the excess boost, the 12psi means they guarantee it will hold that pressure.... the computer controls the boost anyway.

in the car with a stock actuator and before it was flash tuned it ran 7psi because I had a haltech intereptor... not boost issues what so ever... just didnt go real hard.

the the car got flashed to 9psi.... the actuator was as solid as a rock on the dyno and it made 260rwkw, then I drove the car home, sh*t house could not put your foot down with out it bouncing the boost from 5psi to 10psi and it was about as smooth as a cats tongue.

so I called 'em up.... actuator must be that.... ok so after another 2 hour drive to sydney and a whole day off.... the actuator was changed and re "tuned" ( I use it very lightly as I have less and less confidence now) 271rwkw, solid as, went for a test drive, sh*t... the car made you wobble back n forth with every big acceleration. then for the next 5 hours they changed almost everything to find the fault.... with no luck.

the torque management got switched on and off, the throttle position was changed, the whole dam throttle body was changed...

then cloing time came after a very stressful day, and I drove home with the sh*ts and a big bill, and no way ahead.

[Jmpin]

Be an idea to check the cat mate, if its collapsed and blocked you can have all sorts of issues. How does it make power? Are you getting good peak power or is it struggling up top?

its strong as in first gear, and on the dyno it was strong... the power is there, it just is not smooth once you shift gears.... and the boost starts is climb.

the car made 271rwkw repeatably yesterday, just is terrible on the road

[our06t]

some tuners seem to have a little trouble with 4spd tuning the way mine was in first fine 2nd crap locked in 3rd it was ok then 4th was shocking under load boost cut everywhere

and it doesn't show up on the dyno

[Jmpin]

so do you think its a gear box problem??? or the way the computer tells the gear box to deliver the power?

how did you fix it? get a better tuner?

.....and to top it all off, the gear box started, straight after the "retune" not dropping in to over drive... so now I get to sit on 3 grand on the highway..