cant get max boost

[donce]

hi lets start:i have 92y 3b s2 and i have tried 2 different chip sets: one should go 1.4 bar max boost ( overboost ) other one should do 1.5 bar. these chips have been tested in other cars and they work ok. i have RR ecu with 250kpa sencor.. but, in 2nd 3rd gear i get only 1 bar max boost. in 4th and 5th gear it gets to 1.2 bar and starts droping down to ~0.65 bar at redline.
my wastegate spring is stock ( tested with two stock ones ) . i have tested - there is no boost leak from turbo to trottle body . wgfv is ok ( no leak ) . trottle body sends good signals . MAF is ok . car is stock,and runs well, apart from that i cant get full boost ideas please

[S2central.net]

Sigh

You cant get MAX boost in the low gears - you need the load on the engine in high gears to get there reliably. Looks like you aren't getting that though (assuming chips are good) - I would suggest your WGFV is a bit slow (its just a low-tech electromechanical solenoid so they slow down with age) - try changing it.

Have you tried a different MAF, or just assume this one is good ?

Are you definitely getting full throttle when the nail the pedal - make sure the cable is adjusted OK and that you get correct WOT values from throttle pot.

Paul

[A80Avant]

Paul i get something like that,and i tried a new WGFV.no results.sometimes i get overboost,sometimes i dont.Cable is ok in mine too.How do you clean one though??

[donce]

yes we tested with another MAF. and we had 2 more wgfvs and mine was in the best condition and my throttle cable is ok adjusted ,it gets to max. i know about load.but my friends get max boost in 2rd gear too.anyway,i tested in 5th gear too.anything more ?

[A80Avant]

ill keep track of this...cause my figures,are almost the same,only larger,but the loss is the same practically.Aroun 0.3bar of boost loss on overboost and steady boost...
i dont want to resolve to the wastegate spring solution just yet...

[donce]

ok,i disconnected wgfv and then it got to 0.4 boost, and somewhere around ~4500 rpm it dropped down to 0.3 bar. does it have to drop these 0.1 bar?

[S2central.net]

Nuh - you should see 0.4bar mech boost all the way to redline... Maybe you have serious wastegate creep. Try a different WG !

Paul

[A80Avant]

ok to make this more difficult.My WG does not drop boost when i disconnect the WGFV.).4bar all the way....

what can this mean??

[A80Avant]

more for the ECU gurus...
can a 100octane fuel which is not 100% pure but effectivelly is 96 octane fuel can retard the advance so much so as to produce 0.3bar of loss on at the redline??

[kwlw]

I would suggest your WGFV is a bit slow (its just a low-tech electromechanical solenoid so they slow down with age) - try changing it.

Do you know PWM frequency, what is used to drive WGFV? I have posibility to generate it and to see what happens at different duty cycle. If it leaks at 80%, I suggest it's no good - right?

Sau

[A80Avant]

also tried different DV setups today,no luck.Forge replied also and told me to use the blue spring with one maybe washer.Did that,no change.Still 3d gear is 1.6bar at most,only a slight peak to 1.7,then 1.5 again.and down to 1.2 for steady boost...

[donce]

when i disconect wg hose from wgfv,then it should make boost without any limiting factors,to something more than >1.5 bar. yes? but if i do that, boost rises very quick, and it just stops at 1.1bar in 2nd gear,and stops at 1.3bar in 3rd gear.as i said, it goes up very fast,and just stops at these kind of levels. what may be wrong? ignition?