bit weird this one ... my boost spools nicely to ~13psi (0.9bar) is I floor it from anything under ~2500rpm. BUT if I am around 3000rpm or higher, it will only hold ~11.5psi (0.8bar).
It does overboost to about 1bar (tiny bit more on a cold day) but never holds more than 11psi.
I've cleaned the solenoid & it's not changed anything.

any ideas ?

car is MY97 (TD04 turbo), with de-cat. no other mods engine-wise. was ok on old turbo before it blew oil everywhere! :eek: & IMHO the old turbo was a lot livelier!

Steve

BTTT for some help - anyone ?

which gear, do you have a boost gauge (just checking if your figures are estimates or read from the gauge)

cheers for the reply Steve,

yep got a Defi gauge - had it for a while & with old turbo too. (<1 yr old tho ! :rolleyes:)
doesnt really matter what gear, it always does it - but usually test it in 4th as 5th means a bit too much speed :)

just seems as if it you let it get there slowly it'll hold, if you try going on boost from lets say 3k it just wont hold near its target!

was wondering if it could be the wastegate actuator needing a tighten - maybe ??

Steve


[Edited by ScoobyDuck - 5/13/2003 10:58:00 PM]

and up again, coz it's going down quicker than ...........................................

ok - so noticed a pattern - it drops -almost like a switch just after 3000 rpm!

one of the boost duty cycle parameters in the ECU changes @ 3000rpm. wonder if its that change that causes it to not hold boost due to bleeding too much off ... but WHY ?

gona look at the map to make sure...

Steve
p.s. does it in 4th & 5th & 3rd

[Edited by ScoobyDuck - 5/14/2003 5:57:27 PM]

ok .. so here's the boost duty cycle's from the map.
all taken @ WOT

rpm / internal figure/ solenoid duty cycle

2600 = 218 = 85.2%
3000 = 186 = 72.6%

so does all this point to a wastgate that cant hold 0.9bar with a duty cycle of 72.6% ???

Steve